Abstract
Pears
Photo by Scott Bauer
©2004 ARS
|
This guide is an overview of issues relevant to commercial organic
production of temperate zone tree fruits and, to a lesser extent,
tree nuts. It includes discussions of marketing and economics,
orchard design, and cultural considerations, including crop varieties,
site selection, site preparation, soil fertility, weed control,
and pest management (insects, diseases, and vertebrates). It raises
questions for the grower to consider in making decisions about
orchard and enterprise design. Lists of electronic and print resources
offer further, more detailed information.
Table of Contents
Introduction
This publication focuses on production and marketing of organic fruits
and nuts, highlighting a systems approach to orchard production
and farm management. Not intended as a comprehensive production
guide for individual fruit crops, this publication introduces key production
issues that merit consideration in any specific crop or production region.
As noted below, ATTRA has other publications for specific fruit and nut
crops. General information on cultural practices for fruit production (choosing
varieties, spacing, pruning, training, irrigating, harvesting, postharvest
handling, etc.) is relevant to both organic and conventionally managed operations,
and it is widely available from the Cooperative Extension Service,
nurseries, and in horticulture literature.
A note about Organic Standards: Included in this publication are references to the organic standards authorized by the USDA’s National Organic Program, www.ams.usda.gov/nop. Organic producers should verify with the appropriate certification bodies that their practices and any materials they intend to use are compliant with applicable standards for their intended markets. This is especially true if those markets are international, where there may be additional production and labeling requirements. |
Organic Fruit Production
Almonds
|
Organic production is defined by USDA’s National Organic Program
(NOP) as “A production system that is managed...to respond to site-specific
conditions by integrating cultural, biological, and mechanical practices
that foster cycling of resources, promote ecological balance, and conserve
biodiversity.”
Organic fruit production involves more than simply excluding synthetic
pesticides and fertilizers. Benign neglect does not meet NOP standards
for production. Organic agriculture is an integrated approach to
active and observant management of a farming system. It begins
with good soil management for nutrient cycling, productivity, and
tilth. It involves an integrated, preventative approach to pest
management to protect the health and productivity of the orchard.
ATTRA has additional information
on organic fruit production and organic agriculture. Please
refer to the list below for guides to production of specific
fruit crops. Many of these publications discuss the transition
from conventional to organic farming, as well as how to become
certified, write an organic systems plan, and develop markets
or value-added enterprises. See the ATTRA Web site, www.attra.ncat.org,
for a complete list of publications, or call 800-346-9140
to request a current Publications List.
ATTRA Publications on Organic and Low-Spray Fruit Production
Download Acrobat Reader. |
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Marketing and Economic Considerations
To plan for economically successful enterprises, farmers must design their
fruit production systems to match their marketing strategies. Good fruit
production alone does not lead to a successful enterprise. Profitability
depends on a combination of production volume, quality, size, and a reliable
marketing strategy. Marketing channels range from direct markets to wholesale
shippers. Growers must understand what each of their customers wants and
be prepared to meet the expectations of the markets they intend to reach.
For example, at farmers’ markets, customers seek good tasting
fruit at or near the peak of ripeness for prompt consumption, but supermarket
distributors demand that fruit be uniform and shippable. It is important
to market in an appropriate niche, one where the production of your operation
can consistently meet the buyers’ expectations of volume, quality,
and timing.
Good production
and good quality do not guarantee good returns.
My late friend, farmer, and master machinist Grover Parsons
recounted how he planted 10 acres of apricots in San Juan
Bautista, California. He chose the best-tasting variety,
Royal Blenheims. He cultivated them organically, but that
was before there were organic standards for market differentiation
and premium pricing. The variety was also well-suited to
the climate and soil. They grew beautifully and began producing
good yields of excellent fruit. He harvested the apricots
at the appropriate time and sold them to a local buyer. With
each successive season he found the price more and more discouraging;
it did not adequately compensate him for his work. He got
on his tractor and took out the orchard—all but a few
trees along the fenceline. Those trees were still providing
him with good fruit for home use decades later.
- Ann Baier |
Premium pricing can be critical to the viability of organic fruit operations,
because production costs are often higher than those for conventional
orchards. Organic pest control, particularly labor costs for hand
thinning and weed control, is generally more expensive than conventional
practices. Yield and quality can vary widely, depending on the
growing season and management practices. In the past it may have
been true that organic yields and pack-out rates (the percent of marketable
fruit) were lower than in conventional production. Today, however, those
differences have narrowed, and yields in some organic production systems
can match or exceed those of conventional systems. To achieve good yields,
organic growers must be prepared to develop innovative production and marketing
strategies. Many commercial organic fruit producers, especially family-scale
farmers, minimize waste and losses of potential revenue by processing (drying,
preserving, or juicing) fruit considered unsuitable for the fresh
market. See ATTRA’s
publication Adding Value to
Farm Products: An Overview.
[PDF / 259 kb]
Download
Acrobat Reader.
There are tradeoffs in every marketing strategy. A successful grower must
develop markets in which the price for organic produce adequately compensates
for all production costs. Additionally, the marketing process must
be compatible with the grower’s personality and business skills. The
particular combination of components in any grower’s marketing strategy
will depend on local marketing opportunities as well as the grower’s
desire to be directly involved in marketing, tolerance for stress,
and ability to balance a variety of risk factors. For more information,
request the ATTRA publications Evaluating a Rural Enterprise,
Keys
to Success in Value-Added Marketing, and Direct Marketing.
Cost-Benefit Analysis of Markets
Several certified organic apple growers in the Central Coast
region of California sell their culls to Martinelli’s,
a longstanding locally-based juice company. The company has
a low-volume organic juice line that produces a limited number
of runs each year, if farmers can time their harvest to match
it. Even though the company does not give a premium for organic
fruit that goes into their regular juice line, its proximity
to the farms, fair payment practices, and good business relations
make for a satisfying and cost-effective sale for many organic
growers. Although there are organic processors in other parts
of the state, the price premium for organic fruit does not
always offset the increased transportation costs, volume
requirements, hard bargaining, or worry about late payments
from more distant organic processors. Being certified organic
increases one’s marketing flexibility. An organic certificate
provides the option but not the obligation to use the organic
claim. When it is advantageous, organic produce can be sold
as conventional, but never vice-versa. |
Cultural practices in fruit production begin with selection of an appropriate
site, fruit crop, rootstock, and fruit variety, followed by site preparation
(tillage and pre-plant soil amendments) and orchard layout (tree and row
spacing). These considerations will largely determine the productivity,
health, and efficiency of operations in your orchard over the
long term, and they cannot easily be changed once the orchard is established.
If you are managing an existing orchard, you will continually need to take
stock of its assets and limitations in relation to current markets, and
either work within those limits or make plans for some degree of orchard
renewal. If you are considering the purchase of an existing orchard,
ask the owners about their financial history (production costs and
sales records), and research the market to assess the economic feasibility
of continuing with the business as it is currently practiced. Once you have
made the most realistic cost estimates possible, you can develop a plan
to adjust the production system, revise the marketing plan, or walk away
while you still have your shirt.
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Planning and Planting an Organic Orchard
Site Selection
Fruit trees, like most crops, respond to good soil with vigor
and productivity. Trees can successfully produce economic
yields on hillsides, rocky soils, and other sites not suitable
for frequent tillage. Look carefully at your site and take
stock of its soil, slope, and aspect, water infiltration
and drainage, frost patterns, maximum and minimum temperatures,
length of growing season, distribution of annual precipitation,
availability of water for irrigation, proximity of the water table,
and wind and air circulation patterns. Most of these are beyond
your control, and your planting plan must suit the natural conditions
of the site. While farmers may be able to improve the soil over
time, they cannot change the subsoil layers, influence the
prevailing wind, or modify temperatures to any significant
extent.
All the factors regarding site suitability for conventional
fruit plantings apply—even more so—to organic operations.
While conventional growers may fall back on chemical fertilizers
and pesticides to compensate for some poor site decisions, organic
growers cannot. Good drainage and air circulation are essential
for disease control. The presence of certain weeds and forage species
is of particular concern to the organic grower. Bermuda grass,
Johnson grass, quack grass, and several other pernicious species
can be serious problems to fruit growers and are difficult to control
with organic methods once an orchard is established.
An assessment of physical and environmental factors will help
the grower determine whether a crop can be grown easily, marginally,
or not at all. While someone with a home orchard may consider it
worthwhile to cover a lemon tree before each anticipated frost,
or to nurse a few apricot trees through Midwestern winters in order
to savor the delicious fruits two seasons out of seven, these would
likely not be viable commercial enterprises. However, stretching
the limits of production within reason can be worthwhile under
certain circumstances. For example, subtropical fruits grown in
the coastal valleys of California bring a premium for their freshness
and novelty, offsetting the expense of the extra care they require.
Depending on the crop, harvesting either early or late in the season
can also provide a market advantage. While California’s San
Joaquin Valley is not known for apple production, its warmer spring
and summer temperatures can bring the crop to maturity a few weeks
ahead of coastal producers. The price premium for first-of-the-season
organic fresh-market apples may offset the overall lower crop yields.
Fruit grown in its primary growing region may be more difficult
to distinguish from the rest of the fruit in the market, and so
lose its competitive edge.
Pragmatism is critical in crop and variety selection. The fruit
grower must take into account not only factors of yield, productivity,
quality, and flavor, but also of marketability. Diversification
of varieties and marketing channels is a prudent strategy. While
one farm in California may receive a good return for the fruit
from one lone jujube tree, there is no assurance that such a profit
can be scaled up to an extensive orchard of specialty fruits. Conclusions:
while the jujube is a tasty and unusual fruit, and the value of
fruit from one tree may be substantive, the regional market for
this novelty would not accommodate production from 200 trees. Similarly,
in his book Epitaph for a Peach, Mas Masumoto describes
the wonderful flavor and quality of the Suncrest peach. Yet his
family farm substantially decreased their plantings of this variety.
It was a practical business decision to plant more of the newer
varieties that the current market demands, and keep a smaller block
of the sumptuous Suncrests that are more difficult to ship and
store. This seasoned fruit grower advises a production and marketing
plan that includes a combination of mainstream and specialty varieties.
Fruit Crop and Variety Selection
Because fruit trees are perennial and represent a considerable
investment of both time and money, it is important to start by
planting your orchard with the optimum varieties for your location
and intended markets. Research on the front end can pay the grower
back many times over. Information on species and varieties is available
from Cooperative Extension, nurseries, and other local growers.
Many land grant universities have field stations where they have
planted many varieties of fruit trees and gathered data and observations
over several years. A visit to such a site can provide you with
the invaluable opportunity to see the trees growing, talk with
the manager of the experiment station about production challenges
such as pests and diseases, and even taste the fruit.
Crop Species Selection
Clearly, the first decision is what species to plant. Is a tree
orchard the best use of your land and talents? Or is your site
and marketing plan better suited for a somewhat shorter-term investment
in smaller plants such as blueberries, caneberries (raspberries,
boysenberries, olallieberries, other blackberry varieties), grapes,
kiwi, or even strawberries? If you are sure that you are willing
to manage tree fruits and nuts, will your focus be to produce almonds,
apples, apricots, avocados, cherries, figs, grapefruit, jujubes,
lemons, oranges, pawpaws, peaches, pecans, pears, persimmons, plums,
pluots, or zapotes?
Careful consideration of environmental conditions, as well as
the locations of markets and suppliers, is of tantamount importance.
For example, organic peach production in the East is greatly complicated
by the presence of the plum curculio and by greater disease pressure
than in the drier climates of the West. In general, the West’s
arid climate is better for organic fruit production. The small
fruits (blueberries, blackberries, raspberries) are easier to produce
organically than tree fruits in almost all locations.
The availability of production supplies and markets in your region
can be a critical factor in crop selection. Being the only one
growing a certain fruit may provide you with a local marketing
niche; however, the value of readily available supplies and services
should not be underestimated. While some supplies can be easily
and cost-effectively shipped by mail, others cannot. Pest management
materials such as codling moth pheromone traps can be efficiently
shipped from a distant supply company. But how far do you have
to drive to purchase boxes and bulky packaging supplies? How far
to cold storage, a packing house, distributor, processor, or transportation
terminal? Driving several hours to purchase appropriate boxes or
to deliver fruit to a broker’s cooler can make an otherwise
viable enterprise unprofitable.
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Variety and Rootstock Selection
Once the question of crop species is settled, the next decision
is what variety (or combination of varieties) to plant. Considerations
include, but are not limited to:
- harvest season: early, mid, or late season, or a combination
of these to achieve a more continuous supply or to ensure a crop
during early or late marketing windows
- adaptability to the region: cold hardiness, temperature
ranges for optimal growth, requirements for soil fertility or pH
- chill requirements for fruit set and flavor
- water requirements: need for irrigation or protection from
waterlogging
- stature: dwarf, semi-dwarf, or standard
- resistance to diseases and pests
- marketability: color, flavor, nutritional value, storage
requirements, shipability, uniformity, shelf life—any characteristics
that define quality for your customer
- proximity to appropriate markets
You can select for desired characteristics, especially in grafted
trees, with a combination of varieties of rootstock and fruiting
wood.
Sources of Planting Stock
Apple Orchard
Photo by Scott Bauer
©2004 ARS |
It is important to get clean planting stock. Buying from
reputable nurseries that provide stock certified by state
inspectors to be free of diseases and insect pests is best. Organic
planting stock is required, if commercially available, for certified
organic fruit production. If organic planting stock is not available,
organic growers must document their search for organic stock
and its lack of commercial availability. Most certifiers
interpret the organic standards as requiring organic management
of non-organic planting stock for at least 12 months before harvesting
a crop that is to be sold as certified organic.
With newly planted tree crops, this is a non-issue, since they
generally grow for at least three years before producing a marketable
crop.
Type and Size of Planting Stock
The type of rootstock—standard, dwarf, or semi-dwarf—will
determine the size of the tree at maturity. Tree size determines
the spacing, number of trees per acre, training system, years to
bearing, and timing of economic return. Orchard design should reflect
the grower’s production and cash-flow goals. For example,
standard trees produce more fruit when mature, and initial purchase
and planting costs are lower. Smaller trees have higher initial
planting costs, since more trees are needed to achieve density.
Dwarf and semi-dwarf trees generally come into production sooner.
Smaller trees simplify many field operations, including
pruning, grafting, thinning, pest management, and harvest. Efficiency
and safety are greater when a majority of operations can be accomplished
from the ground as opposed to on ladders or by climbing. Weeds
are less of a problem in the shade of a densely planted orchard.
Depending on the species and variety, bareroot trees are often
the most practical form of planting stock to ship, and the most
economical to purchase. This is a good option for deciduous trees.
Other varieties, such as citrus, must be purchased in containers.
Given the option of different sizes of bareroot trees, some walnut
growers say that investing in a 1-inch tree over a 3/4-inch tree
is worthwhile, because larger trees grow more vigorously. An experienced
apple grower who produces without irrigation beyond the first
year, however, stated his preference for 5/8-inch bareroot trees,
which have a good balance of roots and are neither too big nor
too small.
Disease and Pest Resistance
Genetic resistance refers to inheritable traits that enable
a plant to inhibit disease and resist pest damage. A very
important control measure for organic growers is to choose cultivars
that are resistant to the pests—especially the diseases—most
prevalent in their areas. In some cases, such as that of bacterial
spot in peaches, cultivar resistance is the best or only control
for a particular disease. A cultivar may be quite resistant
to one disease but still susceptible to another. Prima apples for
instance, are very resistant to scab but very susceptible to cedar-apple
rust. A planting stock resistant to a particular pest provides
only relative resistance, not absolute immunity. A moderately resistant
or tolerant variety may show symptoms of the disease but exhibit
little to no reduction in yield.
Disease resistance must be weighed against other advantages. For
example, walnut growers in the coastal regions of California have
lost large numbers of trees in recent years to “black line,” a
fungal disease for which there is no treatment, only resistance.
Payne variety is susceptible and Chandler is highly resistant to
this disease. (Some say that Chandler also appears to suffer lower
damage levels from codling moth and walnut husk fly, the
other common walnut pests in the region.) A trade-off is that Paynes
mature sooner and can be harvested earlier in the fall, whereas
Chandlers come in at least a month later when early rains can hinder
harvest operations and make field preparations for planting a winter
cover crop difficult or impossible.
While no fruit trees are resistant to insects that damage their
fruit, it is possible to find stock that is resistant to insects
that feed on other parts of the plant—Phylloxera-resistant
grape rootstocks, woolly aphid-resistant apple rootstocks, and
nematode-resistant peach rootstocks, for example. As important
as this resistance is, there is no cultivar of any fruit species
with multiple insect pest resistance; therefore, an integrated
pest management plan is necessary to protect fruit plants
from a complex of several pest species. It will be important to
identify the most troublesome pests for your crop and region in
terms of frequency of incidence, severity of damage, cost
of control, and economic consequences of the damage. Then
seek out varieties that are resistant to those key pests and take
into account any trade-offs you may make with other desirable characteristics,
including seasonality, productivity, and flavor. Substantial
crop-and variety-specific information on pest and disease
resistance is available on the Web site of the University of California
IPM project and other university pomology departments. Be sure
to check with local suppliers of planting stock, and talk with
other growers in your area about what has worked best for them.
Site Preparation
Important considerations in site preparation include alleviating
soil compaction, enhancing fertility, adjusting soil pH, and managing
weeds, pests, and diseases. Attention to the details of site preparation
can help reduce weed and disease problems and assure a vital planting
through soil improvement. What needs to be done depends on the
previous use of the land, including crops grown, current vegetation,
and the presence of pests and diseases. Many growers rip or chisel
the soil to loosen layers of compaction before they plant a new
orchard, since deep tillage will be disruptive once the trees are
established.
Before establishing an orchard, it is important to adjust the
soil pH to best suit the crop you’ve selected. Soil tests
can assess current soil conditions, including pH, mineral levels,
and their relative proportions. Traditionally, pH has been adjusted
through applications of lime (to raise the pH) or sulfur (to lower
pH). Most fruit plants perform best around pH 6.5, although they
tolerate a pH range between 5.5 and 7.2. Blueberries are an exception.
They require an acid soil—ideally pH 4.8 to 5.2. Soil test
results help to guide applications of soil amendments such as compost,
lime, gypsum, or other rock powders, to provide good soil conditions
that meet the nutritional needs of the orchard.
In general, fruit crops do not require highly fertile soils for
good production, though this varies with the species. Highly fertile
soils, rich in nitrogen, can promote too much vegetative growth
at the expense of fruiting in trees such as apples. A nutritionally
balanced soil, proper soil pH, and plentiful organic matter are
the fundamentals of an organic fertility management plan for fruits.
Pre-plant soil improvement for organic fruit plantings usually
involves some combination of cover cropping and applications of
compost, natural minerals, or other organic fertilizers.
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Weed Management Prior to Orchard Establishment
It’s easier to manage weeds before an orchard is established.
Cover crops (see ATTRA’s Cover
Crops & Green Manures)
produce a thick stand that will shade or choke out weeds. Combined
with a well-planned sequence of tillage, cover cropping is an effective
pre-plant weed suppression strategy that also contributes to soil
fertility and stable humus. The basic strategy begins with plowing
under or disking the existing vegetation, ripping or deep chiseling
to loosen compaction, planting a cover crop to suppress weed growth,
mowing down and tilling under the cover crop(s), and finally planting
the fruit crop. Several cover crop and tillage sequences may be
necessary before planting.
Specific cover crops and management strategies vary with location
and purpose. The two cases below raise the kinds of questions you
need to ask to choose an appropriate cover cropping system. The
cover crops you choose for site preparation (before planting the
orchard) may be entirely different from those you want once the
orchard is established.
Bart Hall-Beyer, co-author of Ecological Fruit Production
in the North (1), provides one example of how cover crops
can be used to suppress weeds in the growing season prior to
fruit crop establishment. His program consists of fall plowing,
to allow the sod to rot, then disking as soon as the soil is
dry in the spring, followed by harrowing every 10 days for at
least one month to kill germinating weeds. He next incorporates
compost and mineral nutrients and seeds buckwheat as a smother
crop. He then tills the buckwheat into the soil after it has
started flowering but before seed-set. Hall recommends additional
cultivations at 10-day intervals, followed with rye as a fall
cover crop. The rye is incorporated the following spring and
the fruit crop planted.
In the Mid-South, researchers at the Kerr Center for Sustainable
Agriculture in Poteau, Oklahoma, evaluated a number of cover
crops for weed suppression on heavy soils.(2)
They converted pasture land to horticultural production, using
rotations of cover crops and tillage. By this method, they virtually
eradicated Bermuda grass from the fields in one to two years. Among
their general observations are the following.
- Dense warm-season cover crop plantings of several species
demonstrated a high degree of weed suppression, whether close-drilled
in 6-inch rows or planted on wider 32-inch rows and row-cultivated.
- The length of the warm season may allow more than one cover
crop to be grown in succession. Some cover crops may also be cut
and allowed to regrow.
- Legume cover crops of purple hull peas (cowpeas), crotolaria,
and sesbania all demonstrated good-to-excellent weed suppression,
while supplying nitrogen and biomass to the soil.
- Of these, sesbania produced the most biomass and was the
most effective weed suppressant. When cut with a sickle-bar mower
at flowering, it regrew well and continued to suppress weeds. It
is very drought-tolerant. Seed cost and delivery, however, were
quite high. If allowed to re-seed, sesbania can create a moderate
weed problem the following year.
- Crotolaria (sun hemp) was a better nitrogen producer, but
a less effective weed suppressant than sesbania. It, too, can be
cut at flowering with a sickle-bar mower and allowed to regrow.
Like sesbania, it is very drought-tolerant. The cost of seed can
be high. Crotolaria seed is toxic—especially to birds—and
the plants should not be allowed to go to seed.
- Because crotolaria and sesbania are quite fibrous, they
should be mowed with rotary or flail mowers prior to soil incorporation.
- Cowpeas produce somewhat less nitrogen than crotolaria,
and less biomass than either sesbania or crotolaria. They are,
however, less fibrous and, therefore, decompose faster.
- Allowing cowpeas to flower and produce mature, dry seed
prior to incorporation creates an inexpensive, self-seeded succession
cover crop.
- Sudan grass proved the most effective of all warm-season
weed suppressants. It can be flail or rotary mowed several times
if regrowth is desired.
- Winter cover crops can be planted in rotation with warm-season
cover crops. A combination of grain rye and hairy vetch was the
most effective in this location. Winter peas and oats, and winter
wheat—often grown in combination—also have good competitive
ability.
Soil Solarization
Soil Solarization
Photo by Randall Smith
©2004 ARS |
Soil solarization is placing transparent plastic films on moist
soil to capture solar energy. Solarization takes four to eight
weeks to heat the soil to a temperature and depth that will kill
harmful fungi, bacteria, nematodes, weeds, and certain insects
in the soil. Solarization can be a useful soil disinfestation method
in regions with full sun and high temperatures, but it is not effective
where lower temperatures, clouds, or fog limit soil heating. Other
disadvantages of solarization as a weed control method include
its expense and disposing of the plastics. Solarization is most
commonly used in smaller areas, such as greenhouses and nursery
beds, though it has been used experimentally to treat orchard soils,
either prior to planting or during establishment. Experiments are
underway to evaluate using biodegradable spray mulches for solarization.
Researchers emphasize that solarization should be seen as just
one component of an integrated pest management system, rather than
as a “stand alone” technology. A University of California
Cooperative Extension leaflet
(No. 21377), “Soil Solarization:
A Nonchemical Method for Controlling Diseases and Pests,” details
the technique.(3) The Web site www.uckac.edu/iwgss provides links
to current research and publications on solarization.
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Orchard Layout and Design
Orchard layout influences the long-term health of the trees and
the ease of field operations such as pruning, irrigation, fertilization,
and weed and pest management. Everything is related: the decisions
you make about the space between rows and between trees in the
row will have an impact on everything from disease management to
harvest operations. While the specific spacing and training of
trees will largely depend on the species, the following questions
offer general considerations that will save time, resources, and
expenses throughout the life of the orchard.
What is the lay of the land? Which way does the water run?
What is the angle of the sun during different seasons? How will
these affect the movement of both water and air, and in turn, temperature
and humidity levels, crop ripening, and incidence of diseases and
pests? Do the rows need to be planted on the contour for soil conservation
or to capture limited seasonal moisture? Or should they be sloped
to drain excess moisture? Given the degree of slope, which direction
will provide the greatest safety for operating equipment and ease
of harvesting ?
What are the diseases and pests that affect this crop in
this region? What are their life cycles? Alternate hosts? Natural
enemies? What conditions favor their growth and severity? What
design strategies might promote or reduce these conditions? Would
a certain orientation of the rows provide better exposure to the
sun or better air circulation? Will you rely on seasonal pruning
to maintain an open canopy to increase air flow through the foliage
and sun to the fruit?
What equipment will you use for field operations? Consider
all possible tasks, including planting, mowing (or incorporating
orchard floor vegetation), cultivation, pruning, irrigation, application
of materials for pest management, and fruit harvest. Be sure that
your row spacing is adequate to allow entry and maneuverability
of any tractor, trailer, spray equipment, string trimmer, wagon,
wheelbarrow, or hand cart that you plan to use.
What crop density do you seek? How soon after planting?
The decision will depend on the species and stature of your trees,
the cost of purchasing and planting them, the years to maturity,
the prevalence of weeds, and other considerations. Using close
in-row spacing or double rows of trees may complicate weeding in
the first year or two, but thereafter shading will greatly reduce
the need for weeding the inter-row. Some farmers plant slower-growing
trees (such as walnuts) using closer spacing, then remove every
other tree when they reach a certain maturity. The estimated benefits
of earlier harvests must be considered against the costs of planting,
managing, and eventually removing the trees. Alternatively, annual
crops can be grown between immature orchard trees.
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Managing an Established Organic Fruit Orchard
Orchard Floor Management/Cover Crops
The orchard floor—the tree rows and alleyways— can
be managed in a variety of ways, using tillage or mowing with cover
crops, grazing, or mulching (described in detail in the Organic
Weed Management section). A system that provides full
ground-cover provides the best protection against erosion. Some
fruit growers have practiced “clean cultivation,” eliminating
vegetation throughout the orchard, but this system has many disadvantages,
even if accomplished with allowed tillage practices instead of
organically prohibited herbicides. A bare orchard floor is
prone to erosion, gradual depletion of organic matter, increased
soil compaction, and reduced water infiltration. It’s also
difficult to move equipment through the orchard in wet weather.
However, a ground cover that is actively growing in the summer
uses up water. This is a severe disadvantage in irrigated orchards
where water is limited and expensive.
Orchard floor management can control erosion, improve the
soil, and provide beneficial insect habitat.
• Where they are adapted, orchard grass, fescue, and
other cool-season grasses are practical because they go dormant
during the heat of the summer, minimizing competition with the
fruit crop for water. With proper fertility management, these grasses
can also provide plentiful mulch. Likewise, grasses are a good
choice in apple orchards, for example, where the excess nitrogen
provided by legumes can actually reduce fruit yields.
• Many warm-season legumes are deep-rooted and compete with
the trees for water. Normally, they should not be allowed
to grow under the tree canopy. However, leguminous ground
covers can provide significant nitrogen to fruit trees or
vines.(4) Grass and legume ground covers alike promote water infiltration
and hold the soil in place during the rainy season. Ground covers
help maintain and increase soil organic matter, which increases
the soil’s ability to retain moisture. Cool season legumes,
such as fava or bell beans, vetches, and clovers, also can achieve
these goals.
• Planting subterranean clover into established orchards
can provide mulch, fertilizer, between-row ground cover, and beneficial
insect habitat. This clover reseeds itself in early summer
and dies back during the hottest part of the growing season, leaving
a relatively thick, weed-suppressive mulch. This system is
used in apple and peach orchards in Arkansas (5)
and for a variety of orchard crops in California (6, 7, 8, 9),
but not where winter temperatures regularly drop below 0°
F. Subterranean clover can provide habitat for such beneficial
insects as ladybeetles, syrphid flies, big-eyed bugs,
soft-bodied flower beetles, and other predators.
Crop Rotation
In an organic orchard,
crop rotation does not mean changing the economic crop
itself, but diversifying the vegetation that grows around
the fruit crop. California organic almond farmer Glenn
Anderson describes how important maximum plant diversity
is within the orchard and in the surrounding vegetation.
He takes advantage of every practical opportunity to
diversify vegetation: the orchard floor
grows cover crops; the landscaping around the family home situated
in the midst of the orchard provides shelter and food for a variety
of beneficial species; the roadway, farm perimeter, and
even the paths of the irrigation lines provide habitat for these
beneficials. Research studies confirm the positive effects
of organic practices on beneficial insects. Several articles
compared yields, pest and beneficial insect populations, and
water and air quality factors on Anderson’s farm to those
of his brother’s adjacent, conventional almond farm (10)
and found favorable results with organic practices. Mr. Anderson
gives credit for the health of his orchard to the host of creatures
that contribute to ecological balance on the farm. He believes that
all the trees, shrubs, and plants he encourages help sustain beneficial
insects, spiders, bats, and birds within and around the orchard.(11)
The USDA National Organic Program
Final Rule defines crop rotation in 7 CFR § 205.2 as “The
practice of alternating the annual crops grown on a specific
field in a planned pattern or sequence in successive crop
years so that crops of the same species or family are not
grown repeatedly without interruption on the same field.
Perennial cropping systems employ means such as alley cropping,
intercropping, and hedgerows to introduce biological diversity
in lieu of crop rotation.”
According to 7 CFR § 205.205 Crop Rotation Practice Standard, the benefits
of rotation are to
“(a) Maintain or improve soil organic matter content;
(b) Provide for pest management in annual and perennial crops;
(c) Manage deficient
or excess plant nutrients; and
(d) Provide erosion control.”
|
Cover Crops
Steps and considerations for selecting and managing
a ground cover:
• State your objectives in order of priority. For example: suppress weeds,
break up soil compaction, add organic matter to the soil (increase tilth, water
infiltration rates, and water-holding capacity), enhance soil fertility
(fix nitrogen), attract and sustain beneficial insects, serve as
a trap crop for pests.
• Take into account the climate, rainfall pattern, soil type, and potential
for soil erosion.
Orchard Cover Crops
Photo by Gary Kramer
©2004 ARS |
• Describe desired growth patterns and characteristics:
Does this cover crop have a tap root? Will it regrow if mowed? Does it fix
nitrogen? How much biomass does it produce? Is it fibrous? How long
will it take to break down? Will I need to mow or chop it to speed its decomposition?
When should I incorporate it? Will it reseed itself? What is its potential to
become weedy if it goes to seed? Does it attract insects? What kinds? Will it
serve as beneficial insect habitat? Is it a host for pests? Can it be used
as a trap crop?
• Consider planting techniques and timing: When and how
should I plant a cover crop? How can I manage its growth for production
of organic matter and nitrogen fixation? Are there seasonal weather
constraints to getting equipment into the field? What methods provide
the best germination rate for the effort—broadcast, drilled,
frost-seeded (the technique of broadcasting seed so that it is
incorporated by the motion of the soil freezing and thawing)? What
equipment do I have available—disc, broadcast seeder, seed
drill, flail mower, chisel plow, spading machine? What is the seed
cost? Do I need to inoculate it with Rhizobium bacteria
to increase nitrogen-fixing nodulation?
• Is the best cover crop for my situation a single crop,
a mixed seeding, or a series of different cover crops?
The UC SAREP cover crop resource page includes a guide for selecting
the right cover crop for your purpose: www.sarep.ucdavis.edu/ccrop/CCPubs/SelectingCoverCrop.html.
Back to top
Pest Management
Organic pest management relies on preventative cultural, biological,
and physical practices. Organisms—insects, mites, microorganisms,
or weeds— become pests when their populations grow large enough
to prevent growers from reaching production goals. Integrated Pest Management
recognizes that the mere presence of a potentially damaging species does
not automatically mean that control actions are necessary. Knowledge of
pest life cycles and monitoring techniques developed in IPM programs are
useful for organic growers as well, because they mirror some of the elements
of the organic pest management standard.
The National Organic Program Final Rule 7 CFR §205.206 Crop Pest,
Weed and Disease Management Practice Standard reads:
(a) “The producer
must use management practices to prevent crop pests, weeds and diseases
including but not limited to:
- Crop rotation and soil and crop nutrient
practices…;
- Sanitation measures to remove disease
vectors, weed seeds, and habitat for pest organisms;
and
- Cultural practices
that enhance crop health, including selection of plant
species and varieties with regard to suitability to site-specific
conditions and resistance to prevalent pests, weeds and
diseases.
(b) Pest problems may be controlled
through mechanical or physical means including but not limited
to:
- Augmentation or introduction of predators or parasites
of the pest species;
- Development of habitat for natural enemies;
- Non-synthetic controls
such as lures, traps and repellants.
(d) Disease problems may be controlled
through
- Management practices which suppress the spread of disease
organisms; or
- Application of non-synthetic biological, botanical or
mineral inputs.
(e) When the practices provided for in paragraphs (a)
through (d) of this section are insufficient to prevent or control crop
pests, weeds and diseases, a biological or botanical substance, or substance
included on the National List of synthetic substances allowed for use
in organic crop production may be applied to prevent, suppress or control
pests, weeds, or diseases: Provided, That the conditions for using the
substance are documented in the Organic System Plan.”
|
Three tiers of pest management strategies are described in the NOP
Final Rule.
1. First, the producer should use cultural management practices that
prevent pest and disease problems. These include multiple components
of a holistic, systems approach to organic farm management and crop
production.
2. In the second tier of pest management, biological and physical
methods provide additional protection and need no justification.
These practices build on and complement good cultural practices, but
cannot compensate for poor cultural practices.
3. The third and final tier—the last resort—may be
applying an allowed material if the first two tiers of response
are ineffective and if the conditions for their use are described in
the grower’s Organic System Plan (OSP). A material response may
be necessary under some circumstances, but it will be just one component
of an integrated pest management plan that is part of an overall
OSP.
Mexican Fruitfly on Grapefruit
|
Common arthropod pests of fruits include insects (aphids, caterpillars,
leafrollers, twig borers, flies, psylla, scale insects, leafhoppers,
mealybugs, earwigs, thrips, and beetles) and mites. Identification
and preventative management are essential to organic production
systems. Identification charts are available from many university
Extension
Web sites and publications. Organic Fruit Tree Management (15)
provides a useful list of important fruit pests, their hosts,
status (potential impact on various stages of fruit tree growth
as well as on crop production and quality), identification
(adult, immature/larva, pupa, and eggs), life cycle, monitoring/thresholds,
and management.
This book was written for fruit growers in the North and may
not address the key pests in all other regions. Nonetheless,
its approach and outline serve as an extremely useful models
for growers developing informed and integrated organic pest
management strategies for their orchards.
While there are many other components to insect and mite pest management,
in recent years there has been a good deal of research on vegetation
management to enhance natural biological control. Approaches to
cover crop and vegetation management described by Bugg and
Waddington (13) include:
- resident vegetation
that harbors beneficial arthropods
(insects, mites, spiders);
- strip management of cover crops
to ensure the continuous presence of habitat for both beneficials
and pests;
- insectary mixes of plants attractive to beneficial
arthropods;and
- use of mulch from mowing to harbor generalist
predators.
There is also increasing evidence that managing vegetation
adjacent to economic crops (fencelines, roadsides, etc.) as habitat
for beneficial
insects has a positive impact on pest management. These areas
often include native plants and shrubs that flower at different
times of the year, providing sources of pollen and nectar for
beneficial arthopods. See the ATTRA publication Farmscaping
to Enhance Biological Control.
The long-term nature of growing fruit using cover crops and other resident
vegetation management can sustain populations of predators, parasites,
and other beneficial organisms.(14, 15, 16) There are many possible
trade-offs that emphasize the need for careful planning and the importance
of research and monitoring.
• Apples and pecans: California apples and Georgia pecan orchards
planted in a diverse mix of cover crop species provided habitat and
food for an array of beneficial organisms, resulting in a decrease
of orchard pests.
• Peaches: Some winter annual broadleaf weeds have been implicated
in increased populations of tarnished plant bugs in peach orchards,
and dandelions and chickweed can serve as hosts for viruses that affect
peaches and apples.(15)
• Walnuts: Two species of ladybeetles were more abundant in an
orchard floor where a cover crop was maintained from February
to May, and helped keep walnut aphid populations in check.
• Apples: Codling moth infestations of apples were lower where
bell beans grew.(13) Bell beans are known for their extrafloral
nectaries that help sustain beneficial insect populations
even when the flowers are not open. Insect-eating birds can also
reduce codling moth populations, but not control them. The development
of pheromone mating disruption has been a major breakthrough in
the past several years, making organic codling moth management feasible
and organic apple production competitive.
• Cherries: In regions of California where the mountain leafhopper
transmits buckskin disease, growers should use caution in establishing
permanent covers that include cool-season alfalfa and clover species
that harbor the leafhopper. This case emphasizes the importance of understanding
and carefully considering the pest’s life cycle, with respect
to the presence of host plants where the pest can reproduce.
• Citrus
and avocado: Wind-blown pollens from grasses and trees can be alternate
food sources for the predatory mite Euseius tularensis in late winter
and early spring, and may, therefore, help build and sustain populations
of predatory mites that attack pest species that include the avocado
brown mite, citrus thrips, citrus red mite, and scale insects.(13)
• Some legumes are also known to attract hemipterous pests like
tarnished plant bugs and stink bugs.(17, 18)Where
these pests are a problem, legumes may be less desirable as
orchard cover crops, unless they can be managed as trap crops
for lygus bugs. Alternatives such as mustards, buckwheat, dwarf
sorghum, and various members of the Umbelliferae (carrot, cilantro,
dill, fennel, anise, etc.) and Compositae (sunflower and other
composites) families support substantial numbers of beneficial insects
without attracting as many pests. However, mustards flower
and seed early, providing early season food for hemipterans, including
stink bugs.
Conversations
with several organic farmers reinforce these research findings.
Many organic walnut growers plant cover crops that are mixtures
of legumes—such as bell beans, vetch, or alfalfa—to
produce nitrogen and create a beneficial insect habitat, in
combination with cereals that produce organic matter and
provide support for the legumes. Growers alternate rows when
they mow or disc, intentionally leaving strips of cover crops in the
orchard to provide areas with flowering plants that sustain populations
of beneficial insects. In any orchard setting it is important
to watch for gopher problems. In addition to their many benefits,
cover crops can also provide food and cover for gophers.
Back to top
Disease Management
Disease can be a significant limiting factor in organic
fruit production. Diseases may be caused by fungi, bacteria,
viruses, nematodes, mycoplasmas, or protozoans. Disorders caused
by the weather or by nutrient imbalances (deficiency or toxicity)
can create symptoms that look like diseases. Proper identification
and preventative management are imperative. For example,
boron toxicity or blossom-end rots cannot be cured with fungicides.
Cooperative Extension and university Web sites can help in identification.
The book Organic Tree Fruit Management (12)
includes detailed descriptions of diseases of fruit crops, including
hosts, status (potential impact), symptoms, life cycle, monitoring/thresholds
for treatment, and organic management strategies. This book’s
organic context and perspective are invaluable. Thresholds
for action may be distinct in an organic pest management system
(in which the impact of a disease organism is considered not
only on this year’s crop but also in terms of the future implications
for control, potential buildup, and impact on the health
of the trees), compared to conventional IPM programs (in which
the availability and allowability of pesticides is assumed).
As described in the NOP standard, a combination of cultural controls
forms the foundation for a good disease-management strategy. As
discussed earlier in this publication, selecting resistant varieties
or rootstock is of utmost importance, as is selecting the right
growing location. In an established orchard, one can practice good
sanitation by cleaning up debris, pruning, and removing diseased
plants and disease vectors. Some plants can serve as alternate
hosts for diseases. Eastern red cedars, for example, are alternate
hosts for cedar-apple rust. Wild blackberries can harbor blackberry
rust, and wild plums can foster peach brown rot. A good defense
against plant disease is to maintain the crop plants in excellent
health and vigor, with sufficient—but not excessive—soil
nutrients and moisture.
Many diseases of fruit crops only affect a particular species
and variety of fruit. There are, however, some diseases that are
common to almost all temperate-zone perennial fruit crops. For
instance, because of the relatively soft nature and high sugar
content of most mature or nearly mature fruits, fruit rots are
common afflictions. Sunlight and circulating air help to dry leaf
and fruit surfaces, thereby limiting fungal and bacterial infections.
The organic grower can help to minimize fruit rots by allowing
good air circulation and sunlight penetration into the interior
plant canopy. In tree crops, this would mean proper pruning and
training. In brambles and strawberries, reducing plant density
helps. In grapes, adequate pruning and removing leaves that shade
fruit clusters is beneficial. All fruit crops need a site that
allows good air circulation. Well-timed applications of allowed
fungicides can be effective in an integrated disease-control program
for mildew and fruit rots in certain fruit crops. See Applying
Materials below.
Another problem common to many fruit crops is root rot and intolerance
to poorly drained soils. Blackberries, most pear rootstocks, and
some apple rootstocks are relatively tolerant of heavy or poorly-drained
soils, but even these crops will succumb to persistently water-logged
conditions. Blueberries, raspberries, and Prunus species
(peaches, plums, cherries, etc.) are very intolerant of poorly
drained soils and are generally susceptible to root-rotting organisms
common in such soils. Even in well-drained soils, blueberries and
raspberries are often planted in hills or raised beds. Again, site
selection is very important.
Soils can be made disease-suppressive through the addition of
significant amounts of organic matter to the soil. This has been
most vividly demonstrated in Australia, where liming and cover
crops—combined with applications of chicken manure, cereal
straw, weed residues, and other materials—are used in avocado
groves to control Phytopthora root rot. This strategy, known as
the “Ashburner system,” is now common practice in many
areas where avocados are grown.(19) In contrast, mulching apple
trees in humid areas, such as New York, may increase Phytopthora root rot.(27)
To identify fruit diseases and their life cycles, please see fruit
production resources compiled by the Cooperative Extension Service.
Some of the publications in the Resources section of this publication
provide an excellent summary of fruit diseases.
Back to top
Plant Health and Vigor
Maintaining plants in good health and vigor is important in insect
pest management. For fruit plants, this adage is more applicable
to indirect pests (those that feed on foliage, stems, etc.)
than to pests that feed on the fruit. For instance, an apparently
healthy plum tree may set a good crop of fruit, yet lose
it all to the plum curculio. That same tree might suffer
significant defoliation by caterpillars early in the season;
yet, if it is in good vigor, it can compensate and bounce
back quickly—still
producing a marketable crop that year. There are some cases
where general plant health and freedom from stress do impart
a form of "resistance”—not
technically genetic resistance—to certain pests. Two examples
are apple trees in good vigor that actually cast out invading
flathead apple tree borers by smothering them with sap, and
plants not suffering drought stress being much less attractive
to grasshoppers. For more in-depth information on designing
an integrated pest management program for your farming system,
please refer to the ATTRA publication
Biointensive IPM.
Biological Control
Biological control uses living organisms to manage pest populations.
When a pest is endemic (not exotic), natural enemies are present,
and biological control occurs naturally. The fact that it is occurring
may not be noticed by growers. Researchers monitoring certain pests,
such as leafminers, have found that pest populations actually increase
after pesticide applications kill their natural enemies.
Plums
Photo by Peggy Greb
©2004 ARS |
As described above, biological control can be enhanced by
cover crops and habitat management. However, where a known
pest appears predictably and can be controlled by a specific
biological agent, timed releases of beneficial insects may
be in order. Many beneficial insects can be purchased
from commercial insectaries for release in fruit plantings.
Examples of beneficial arthropods that have been used to control
pests in fruit crops include the predatory mites Phytoseiulus
persimilis and Metaseiulus
occidentalis, which attack spider mites; lady beetles and
green lacewings, which feed on aphids; and Trichogramma wasps,
which parasitize the eggs of several pests, including codling
moth.
As a rule, beneficial arthropods are not a complete
control for direct fruit pests, at least not for commercial growers
who have a low damage threshold for fresh fruit. Usually,
additional control measures are necessary. There are four essential
components for successful use of beneficial organisms
for pest control.
1. Selection of the proper natural enemy for a target pest. For
example, Trichogramma wasps parasitize eggs and, therefore, do
not directly control adult pests already active in the field.
2. Proper timing of releases. Release of natural enemies
must coincide with a susceptible stage of the host and should be
made early enough in the cropping season to assure success.
3. Correct rate of release for natural enemies. This
is usually based on the planting density.
4. Environmental provisioning. Make sure environmental
needs—such as nectar sources, alternate prey, and water—are
available for adult beneficial insects. If the necessary environment
is not available, beneficials may leave the release area, die,
or spend so much time searching for nectar or pollen that they
do not efficiently attack pests.
Back to top
Applying Materials: Pesticides Allowed in Organic Production
Allowed materials include only natural (non-synthetic) materials
that are not specifically prohibited, and specifically
allowed synthetic materials, as described in 7 CFR §205.600-602
of the NOP. Most, if not all, allowed synthetic materials have
annotations that closely restrict how (in purpose, application
method, and quantity) they can be used. Before you apply any product,
make sure it’s
allowed for use in organic agriculture. Read the label carefully.
Are all the active ingredients allowed? What about the inert ingredients?
If it contains any undisclosed inert ingredients, you must have
documentation from the manufacturer to confirm that all inerts
are allowed by the National Organic Program (on EPA List 4). If
in doubt, ask your certifier before you use it.
Information to guide
your selection and use of materials
•NOP Standards: The National List 205.600-602. This
is USDA’s ultimate authority. This list, however, can
be difficult to use because it is not a positive statement
of materials that can and cannot be used. Instead, it states
that all natural (non-synthetic) materials are allowed, unless
they are prohibited (those materials on list 206.602), and
that all synthetic materials are prohibited unless they are
allowed, many with restrictions, as named and described on
list 205.601. In some instances, it is not clear whether
a material is natural or synthetic. For that reason, many
organic producers and certifiers also use related resources
to help interpret the National Lists and determine the allowability
of substances in organic production.
•The Organic Materials Review Institute (OMRI) reviews
and evaluates materials for consistency with the National
List and, publishes and maintains two other lists. The Brand
Name List is available in hard copy and on the Web at www.omri.org.
The Generic Materials List is available in hard copy to members
for a small fee. These generic and brand-name lists provide
an extremely useful resource to help growers identify allowable
materials and products. While many organic producers, handlers,
and certification agencies rely on and frequently refer to
the OMRI lists, users should be aware that OMRI is an independent
nonprofit organization, and USDA has not formally recognized
or authorized OMRI to interpret the National Organic Standards.
|
Several new disease-control materials on the market are allowed
for use in organic agriculture, including biofungicides,
mineral-based essential oil extracts, and botanical fungicides.
Growers in some regions are also using compost teas and plant
extracts. The OMRI list provides information about the allowability
of brand name products, but not their efficacy. You can
ask your local Extension agent about any research or use in your
region. Copper and sulfur compounds are fungicides that are allowed
(with restrictions on their use) and have been used historically
by organic growers, but they have several drawbacks. These
materials can damage plants if applied incorrectly. Sulfur dust
can cause acute eye and respiratory irritation in humans. It
is also lethal to some beneficial insects, spiders, and
mites, and can set the stage for further pest problems. Long-term
frequent use of copper fungicides can also lead to toxic levels
of copper in the soil.(20)
Fertilization
Lemon Trees
©2004 www.clipart.com |
Fruits, being largely water and sugars, remove relatively few
nutrients from the soil, compared to other crops. Therefore,
much of a fruit crop’s fertility needs can be met through
cover crop management and organic mulches (in systems that use
them) and by the application of lime and other slow-release rock
powders at the pre-plant stage. Supplementary fertilization may
still be required for optimal growth and production.
There are many commercial organic fertilizers available. As
noted above, however, organic growers should be familiar with
organic standards, and especially the National List of Allowed
Materials in the NOP’s 7 CFR §205.600-602.
The NOP Rule requires that applied raw manure be incorporated
at least 90 to 120 days before harvest of crops for human consumption
(90 days if the edible portion does not have contact with soil
or soil particles; 120 if it does). Compliance is easy: move
grazing animals to another pen or paddock at the appropriate
time.
General fertilizer guidelines
•Organic fertilizers—especially uncomposted animal
manures—should be incorporated into the soil to avoid nitrogen
volatilization and to comply with organic standards. Use shallow
tillage to prevent damage to plant roots and to minimize the
potential for soil erosion. Manures should be incorporated into
the soil at least three or four months before harvest (depending
on the crop type) to comply with National Organic Program standards
(7 CFR §205.203 (c) (1)).
•Soluble organic fertilizers such as fish emulsion, kelp,
and soybean derivatives are suitable for use in drip irrigation
and can provide quick supplemental fertility. Compost teas may
be allowed and may contribute to disease control (see ATTRA’s Notes
on Compost Teas ). Be sure to check with your certifying
agency regarding current interpretations of the organic standards
for compost production and any restrictions on the preparation
or use of compost teas.
•Most organic fertilization programs focus on supplementing
nitrogen as the key element, since it is needed in the greatest
amount for the crop. You can calculate rates of organic amendments
based on standard recommended rates for the crop, but be aware
that many fertilizer recommendations still assume the use of
synthetic materials. Organic systems behave differently. They
generally use slower-release fertilizers and rely on biological
activity to break them down into forms that can be absorbed by
the plants. For example, only a portion (perhaps half) of the
nitrogen applied as stable compost may be available to plants
in the first year. The rest is stored and released gradually.
To compensate for this, the producer may apply twice as much
nitrogen as is needed in the first year of organic management.
In subsequent years, however, more of the nitrogen is released
from the soil organic matter and becomes available. In a mature
organic farming system, nutrients and organic matter are added
to maintain, replenish, and build the bank of nutrients in the
soil.
•When making fertilizer calculations based on nitrogen,
growers need to credit the estimated contributions made by legume
cover crops and/or mulches. A cover crop of subterranean clover,
properly fertilized and inoculated, can fix from 100 to 200 pounds
of nitrogen per acre annually in a “living mulch” system.(8)
Other legume cover crops may produce as much or even more, depending
on things such as planting date, weather, and mowing.
•Consider the overall fertilizer analysis; basing application
rates solely on nitrogen content can cause problems when the
fertilizers are not balanced to meet the needs of the crop. For
example, repeated use of poultry manure, which is very high in
phosphate, can lead both to pollution problems and to zinc deficiency
in the crop. These problems can be avoided by regularly monitoring
and adjusting fertilizer selection and rates.
•The most reliable means for determining whether fertilization
is adequate is to combine field observations with soil or tissue
testing. Poor yields, unusual coloration of leaves, and poor
plant growth are all clues to a possible nutritional imbalance
or deficiency. On most fruit trees, slow elongation of branches
often indicates a nitrogen deficiency. Yellowing between the
veins of new blueberry leaves usually means the plant is suffering
an iron deficiency. Corky bark on certain apple varieties can
indicate an over-availability of manganese in the soil.
•Foliar analysis measures the nutrient content of the
leaves and can identify a nutrient deficiency or excess well
in advance of visible symptoms. It is more helpful than a soil
test because the foliar analysis is a measure of what the plant
is actually taking up, while a soil analysis only measures what
is in the soil—which may or may not be available to the
plant. Annual foliar analysis generally provides the best guide
for adjusting supplementary nitrogen fertilization.
Organic apple growers on California’s
Central Coast say that most years they plant only rye or
other grass cover crops, because leguminous cover crops would
contribute too much nitrogen, inducing excess growth, creating
more pruning work, and decreasing fruit production. Growers
monitor their nitrogen levels through leaf-tissue and soil
analysis, and manage their soil covers accordingly.
|
For more detailed information regarding sustainable soil fertility
management, including the use of organic fertilizers and nutrient
testing methods, request these ATTRA publications: Sustainable
Soil Management, Alternative Soil Testing Laboratories,
Alternative
Soil Amendments, Foliar Fertilization, and
Sources
of Organic Fertilizers and Soil Amendments.
Back to top
Organic Weed Management
Some weed control methods, such as smother crops, are discussed
in the Site Preparation section above. This
type of cover cropping is an important tool for weed management
that also contributes to good soil management, fertility, and
pest management.
Mulches
Organic Mulch
Mulching is a powerful weed management strategy that can also
contribute to good soil management, if appropriate natural materials
are used. After a planting is established, weeds can be suppressed
by applying thick layers of mulch. This can also create habitats
for beneficial arthopods, including generalist predators such
as big-eyed bugs, soft-bodied flower beetles, and spiders. Organic
mulches are usually applied in a circle around tree trunks or
vines, and down the whole row in blueberries.
Commonly, tree
fruit growers keep mulches away from the tree trunks, particularly
in winter, to prevent voles or mice from gnawing on the bark
and damaging young trees. Keeping mulches 8 to 12 inches away
from the trunk also reduces the likelihood of crown rot and other
diseases in susceptible species—most
notably apples on certain rootstocks.(23)
Mulch materials may include straw, spoiled hay, leaves, yard
trimmings, woodchips, and sawdust. Many of these materials are
inexpensive. Still, it’s wise to weigh the benefits and
risks of each, including hauling costs and the risks of their
containing impurities and prohibited materials.
Cherries
Photo by Peggy Greb
©2004 ARS |
Municipal greenwaste may be available, either raw or from municipal
or commercial composting operations. Growers must monitor the
incoming product and remove any trash to keep undesirable material
out of their fields. Growers should ask compost producers about
the sources of their materials and any pesticides that may persist
in them. Of particular concern are clopyralid and picloram, herbicides
that are extremely resistant to breakdown, even after composting.
The sale and use of these materials is restricted in some areas.
A Washington State University study showed treated grass clippings
to be the primary source of clopyralid entering the organic waste
stream. Experience from California , Oregon , and Washington
shows that at levels of 1 to 10 parts per billion, clopyralid
adversely affects sensitive vegetable crops.(21, 22)
Because organic mulches decompose over time, they require periodic
re-applications in order to continue suppressing weeds. However,
their decomposition provides other benefits. Mulching with organic
matter enhances soil aggregation and water-holding capacity.(4)
Researchers from 1937 to the present have consistently found
that mulching is the best orchard-floor management system for
retaining moisture.(15) In Michigan research, mulching was as
effective as irrigation in encouraging tree growth.(24) Organic
mulches can have positive effects on tree growth, with improvements
in soil quality and shifts toward beneficial nematodes.(27) Mulch
can also benefit the crop by moderating soil temperatures, thus
reducing plant stress.
Organic mulches provide slow-release nutrients for the long-term
health and fertility of the soil. Research indicates that potassium,
phosphorus, and nitrogen (primarily from the slow breakdown of
the mulch) are more available in mulched systems than in non-mulched
systems.(4) Some growers express concern that sawdust may acidify
their soil or bind nitrogen in the soil. However, these effects
are minimal if the sawdust is not tilled into the soil.
Raising organic matter on the farm is one way to ensure sufficient,
clean mulching material. Farm-raised hay grown outside the orchard
can provide weed-free mulch. Cover crops may be grown between
tree rows, mowed, and gathered around the trees. Some small-scale
growers use the biomass from orchard alleyways, cutting cover
crops with a sickle-bar mower and hand-raking the material under
the trees. Larger-scale operations often use forage wagons, straw-bale
spreaders, or specialized equipment to mechanize mulching
jobs. King Machine Co. (25) offers a small, trailer-or truck-mounted
square-bale chopper and blower suitable for most fruit crops.
Millcreek Manufacturing Co. (26) has developed a row mulcher
especially suitable to blueberry, bramble, and grape culture,
but also useful in tree fruit orchards. The Millcreek machines
are designed to handle bulk organic materials such as sawdust,
wood chips, bark, peat, and compost.
Geotextiles
Geotextile mulches are paper or woven plastic
fabrics that suppress weed growth. While they allow some air
and water penetration, they may reduce water infiltration,
whereas organic mulches increase infiltration.(27)
Geotextile mulches do not provide the advantages of adding matter
and nutrients to the soil, and if synthetic, they must eventually
be removed. Geotextiles have a high intial cost, though this
may be partially recouped in lower weed control costs over the
materials expected field-life—5 to 10 years for polyester
fabric; 2 to 3 years for paper weed barriers. Still, some growers
find them useful for weed suppression in orchard, tree plantations,
and cane fruit culture. The ATTRA publication Sustainable
Pecan Production provides more detail on the use of
geotextiles and outlines additional methods of weed control,
including mechanical cultivation, mulches, wood chips and living
mulches.
Sheet Mulch
You can also create weed barriers by sheet mulching: laying
down layers of cardboard or newspaper and covering them with
organic material. Sheet mulching increases the efficacy of organic
mulch as a barrier against emerging weeds. Organic growers should
avoid cardboard that is waxed or impregnated with fungicide,
as well as color print and glossy paper, in order to be compliant
with the National Organic Program standards (7 CFR
§205.601(b)(2)(i) and 205.601 (c)).
Back to top
Cultivation
Cultivation—using mechanical tillage and weed harrowing
implements—is the most widely used weed-management practice
in fruit production. In systems that maintain permanent vegetation
between rows, cultivation may be limited to the tree row under
the dripline in an orchard, or extended 1 to 3 feet from the
edge of the hedgerow in bramble plantings. The reverse is true
where mulches are used in the tree row, and cultivation is used
to control weeds and incorporate cover crops in the alleyways.
In any case, cultivation must be kept shallow to minimize damage
to crop roots and to avoid bringing weed seeds to the surface.
Hand cultivation—enhanced with the use of a wheel hoe—can
be effective in small-scale plantings. In large-scale plantings
of trees or vines, where in-row tillage is desired, “mechanical
hoes” such as the Weed Badger (28) or Green Hoe (29) are
very useful. These tractor-mounted, PTO-driven cultivators can
till right up to the tree or vine without damaging the plant.
Attachment options include powered rotary tillage tools and scraper
blades that can move soil either away from or toward the base
of the crop plants. Scraper-blade attachments, commonly known
as “grape hoes,” have been used in vineyards for
decades.
Herbicides Allowed for Use in Organic
Production
A few herbicides currently emerging on the market are
allowable for organic production, with restrictions on the location
of their use. There is ongoing research on using materials such
as vinegar, corn gluten, and citric acid as herbicides, although
they are not yet widely used by certified organic
growers. Such materials may have applications in organic systems,
such as for spot treatment of noxious weeds.
Weeder Geese, Chickens, and Ducks
For many
years, farmers have used geese to control weeds in perennial
and annual crops, including strawberries, blueberries, bramble
fruits, and tree orchards. In Oklahoma, researchers at the Kerr
Center for Sustainable Agriculture used weeder geese in commercial-scale
blueberry and strawberry production, with portable electric fencing
to keep the birds in a specific zone in the plant row.(30)
Investigators at Michigan State University studied the impacts
of populations of domestic geese and chickens in a nonchemical
orchard system. They found that the geese fed heavily on weeds—especially
grasses—and also on windfall fruit.(31) In general, geese
are more effective against emerging or small grass weeds, and
they have a particular preference for Bermuda grass and Johnson
grass—weeds that can be especially troublesome in orchards.(32)
ATTRA has additional information on weeder geese available on
request.
Those who have raised chickens know how enthusiastically
they devour fresh vegetation. If the area they inhabit is small,
they will strip it to the dirt. Properly managed, however, their
foraging characteristics can be used to the grower’s
advantage.
Fred Reid is an innovative producer of raspberries and vegetables
in Canada who has successfully employed his flocks of chickens
in weed management. He uses a system of fencing to keep chickens
in certain areas to accomplish a thorough job of weeding and
insect control. He notes that if the vegetation has grown too
high and the plants become too fibrous, the chickens will not
eat them. However, if you mow tall vegetation in advance, the
chickens will process it readily. He excludes the chickens from
raspberry plots when the new, tender leaves are emerging and,
of course, near harvest time.(33)
|
Flame Weeding
Flame cultivation uses directed
heat to kill weeds. It works not by burning the weeds but by
searing them and causing the plant cells to rupture. Farmers
began using tractor-mounted flamers in orchard and row
crops in the 1940s.(34) Technology and technique have both
been refined considerably in recent years. Several tools
now commercially available, including flame, infrared,
and steam weeders, make heat a viable option for some weed
management applications. See the ATTRA publication Flame
Weeding for more information.
Management of Vertebrate Pests: Mammals and Birds
Several bird species, deer, rabbits, ground squirrels,
gophers, mice, voles, raccoons, and other animals can be serious
pests of fruit plantings. Organic certification calls
for an integrated approach to vertebrate management, including
exclusion, trapping, repellents, scare devices, and protection
or development of predator habitat.
Gophers and ground squirrels can be managed on organic farms
through integrated strategies. Thomas Wittman of Gophers Limited
emphasizes that growers should not expect to eliminate these
pests, but will do well to keep populations in check. He stresses
the importance of keen observation and has tips for effective
trapping routines using commercially available traps. Persistent
year-round trapping is the primary strategy for most farmers,
complemented by enhancing the habitat of key predators such as
owls and hawks with nestboxes, perches, and appropriate vegetation.(35)
Explosive propane devices are effective against
gophers and ground squirrels. Propane gas ignited in rodent
burrows creates an explosion that kills the animals and disrupts
their tunnels. Several organic orchardists say that this works,
but most promptly abandoned its use because neighbors complained
about the noise of the explosion, similar to the sound of a gun
shot. Only two materials (sulfur dioxide for underground smoke
bombs and Vitamin D3, or Cholecalciferol) are on the National
List as rodenticides. These may be used only if they are documented
in the Organic System Plan, used with care to avoid harming non-target
animals, and only when other management practices are ineffective.
Birds can be especially troublesome in cherry, berry, and grape
plantings. Exclusion with bird netting is probably the surest
control, but the initial cost can be high for both the material
and its placement. Noise devices, “scare-eye” balloons,
Mylar tape, artificial hawk kites, and many other home
remedies have been tried, with varied success. Successful
scare tactics depend on the bird species, bird population pressure,
and the grower’s management of the devices. It is important
to remember that birds and other vertebrate pests are quick to
learn, and they often overcome their initial aversion to scare
devices or repellents. The grower will achieve the most effective
control by moving devices frequently, and by changing or mixing
the devices. For example, organic growers describe how they effectively
scare certain bird species away from newly emerging crops by
placing red- and silver-colored Mylar tape in the field for just
a few weeks, then removing it so that the birds do not get used
to seeing it. Fruit growers use sonic and visual scare devices
only at critical times in the growing season, such as fruit ripening,
and remove them promptly as soon as that period is over.
Deer can be devastating to fruit plants, especially young orchards.
Methods for preventing or controlling deer damage to crops range
from exclusion and cultural methods to scare devices, repellents,
and culling or harvest. For more information, see the ATTRA publication
Deer
Control Options. Scent and taste repellents may be effective
under light deer pressure, especially if the grower switches
periodically from one repellent or deterrent to another. Research
at the University of Wisconsin (36) indicates that none of these
repellents is very useful under heavy deer pressure. Exclusion
fencing may be the only way to manage heavy deer populations.
In most states, the Cooperative Extension Service provides suitable
plans for deer fencing. Electric fencing appears most effective.
Research indicates that even a single strand of electrified wire
can work. Where deer problems are severe, however, a seven-strand,
sloped, electrified fence may be necessary.(37)
Tree guards made of plastic, hardware cloth, or similar materials
can keep rabbits from gnawing on fruit tree trunks.(38) However,
northern growers should remember that snow can effectively raise
the gnawing height of rabbits.
Mice and voles may be attracted to mulch around fruit plants.
Such rodents take up residence in mulch during the winter, feeding
and gnawing on roots, stems, and trunks. To reduce the chance
of vole damage, mulch should be raked away from the plants in
the fall (usually 18 to 24 inches is adequate). Mulch removal
may not be practical, however, for blueberry plantings. Keeping
the planting site mowed also helps reduce rodents by exposing
them to natural predators such as hawks and owls. For pests such
as raccoons, opossums, skunks, etc., tight web-type fencing or
non-lethal traps are the best control options.
Back to top
Postharvest
Handling
Many fruits require some type of postharvest handling. Whether
done on-farm or off, these processes must be documented in the
Organic System Plan. Any off-farm postharvest handling must be
done by certified organic facilities, and appropriate measures
must be taken to prevent commingling or contamination of organic
products with non-organic products during washing, sizing, packing,
and storage. A complete audit trail must track produce from its
field of origin to the point of final sale. Growers should read
the National Organic Program Final Rule, review the National
List, OMRI lists, and consult with their certifiers about any
materials to be used postharvest, such as cleansers, shellacs,
or waxes.
Conclusion
Organic fruit production is a practical option for some growers,
but the viability of the enterprise will likely hinge on site,
scale, type of fruit, markets, and managerial skills. In general,
crops grown in the drier climates of the West have fewer disease
and pest problems. This region may, therefore, be better suited
to organic fruit production. Strawberries, bush fruits, and brambles
are probably easier to grow organically in most sections of the
country than grapes and tree fruits. Management requirements
for organic production are likely to be higher in any region,
and the producer must be closely attuned to local site conditions.
References
1) Hall-Beyer, Bart, and Jean Richard. 1983. Ecological Fruit
Production in the North. Hall-Beyer and Richard, publishers.
Scotstown, Quebec. 270 p.
2) Billy, Simon. Horticultural Farm Manager. The Kerr Center
for Sustainable Agriculture, Poteau, OK. Personal communication.
May 1997.
3) ANR Publications, University of California
6701 San Pablo
Ave.
Oakland, CA 94608-1239
510-642-2431
800-994-8849
www.anrcatalog.ucdavis.edu
4) Haynes, R.J. 1980. Influence of soil management
practice on the orchard agro-ecosystem. Agro-Ecosystems. Vol.
6. p. 3.
5) Stasiak, M.J. 1990. The influence of subterranean
clover (Trifolium subterraneum L.) on the growth and foliar nutrient
status of young peach (Prunus persicae [L.] Batsch) trees. Master
of Science Thesis, University of Arkansas , Fayetteville.
6) Finch, Clarence, and Curtis Sharp. 1983. Cover Crops in
California Orchards and Vineyards. Soil Conservation Service,
Davis, CA. 26 p.
7) Subterranean Clovers. UC SAREP Online Cover Crop Database www.sarep.ucdavis.edu/cgi-bin/CCrop.exe/
show_crop_39
Summary of crop growth, planting
recommendations and
varieties, with a link to photos of subterranean clover growing
in orchards.
8) Subterranean Clovers. 2001. Managing Cover Crops Profitably,
2nd Edition. USDA SARE Handbook. www.sare.org/publications/covercrops.htm
Detailed description of characteristics and uses of subclovers,
including Diversity of Types, Cultivars, Benefits, Management, Management
Challenges, and Crop Systems.
9) Munoz, Faustino, and Walter Graves. 1989. Legumes for use
as cover crops in orchards and vineyards. Small Farm News. July-August.
p. 5.
10) Bentley, Walt et al. 2001. BIOS and conventional almond
orchard management compared. California Agriculture Vol.
55, No. 5 p. 12-19.
11) Glenn Anderson. Personal communication. January 2004.
12) Edwards, Linda. 1998. Organic Fruit Tree Management. Certified
Organic Associations of British Columbia.
13) Bugg, Robert L., and Carol Waddington. 1993. Managing cover
crops to manage arthropod pests of orchards. UC SAREP Newsletter.
Summer.
www.sarep.ucdavis.edu/newsltr/v5n4/sa-2.htm
14) William, R.D. 1981. Complementary interactions between
weeds, weed control practices, and pests in horticultural
cropping systems. HortScience. Vol. 16, No. 4 p. 508-513.
15) Skroch, Walter A., and J.M. Shribbs. 1986. Orchard floor
management: An overview. HortScience. Vol. 21, No. 3. p. 390-394.
16) LaRue, James H., and R. Scott Johnson. 1989. Peaches, Plums,
and Nectarines: Growing and Handling for Fresh Market. Publication
3331. Cooperative Extension, University of California. p. 105.
17) McCraw, Dean, M.W. Smith, R. Eikenbary and D. Arnold. 1995.
Use of Legumes in Pecan Orchards. Current Report No. 6250. Oklahoma
State Cooperative Extension Service, Stillwater, OK. 4 p.
18) Ayers, Lesa J. 1987. Bug-killing cover crops. The New Farm.
May-June. p. 33-35.
19) Cook, R.J. 1982. Use of pathogen-suppressive soils for
disease control. p. 51-88. In: R.W. Schneider (ed.).
Suppressive Soils and Plant Disease.
APS Press, St. Paul, MN.
p. 56-57.
20) Dinauer, R.C. (ed.). 1972. Micronutrients in Agriculture.
Soil Science Society of America, Madison, WI . p. 410.
21) Clopyralid in Compost; Questions and Answers for Gardeners
and Farmers in Western Washington. Revised February 16, 2005.
Washington State University. www.puyallup.wsu.edu/soilmgmt/Abstracts&Pubs/Paper_ClopyralidQandAv10.pdf [PDF
100 kb] Download
Acrobat Reader
22) Robert Rynk. 2002. Prevalence And Fate Of Clopyralid In
Compost. BioCycle Journal Of Composting & Organics Recycling.
February. p. 57.
23) Wilcox, W.F. 1989. Influence of ground cover management
on the incidence of phytopthora crown rot. Biological and Cultural
Tests. American Phytopathological Society.
Vol. 4. p. 5.
24) Kesner, Charles. 1989. Mulching fruit trees in northwestern
Michigan. Great Lakes Fruit Growers News. May. p. 34.
25) King Machine Co.
P.O. Box 586 Scottsburg, IN 47170
812-752-6000
800-365-2467 (toll-free)
www.kingmachine.com
26) Millcreek Manufacturing Co.
2617 Stumptown Road
Leola,
PA 17540
800-311-1323 (toll-free)
www.millcreekspreaders.com
27) Granatstein, David. Biointensive Management of the
Orchard Understory. http://organic.tfrec.wsu.edu/OrganicIFP/OrchardFloorManagement/BCOrchardFloor99.pdf
[PDF 24 kb]
Download
Acrobat Reader
See also:
Washington State University Tree
Fruit Research and Extension Center . Organic and Integrated
Fruit Production. Sponsored by the WSU Center for Sustaining
Agriculture and Natural Resources; David Granatstein, Sustainable
Agriculture Specialist, Wenatchee, WA. http://organic.tfrec.wsu.edu/OrganicIFP/Home/Index.html
and
Current Trends in Organic Tree Fruit Production.
David Granatstein and Elizabeth Kirby. Center for Sustaining
Agriculture and Natural Resources http://organic.tfrec.wsu.edu/OrganicIFP/OrganicFruitProduction/current_trends.PDF
[PDF 540 kb]
Download
Acrobat Reader
28) Weed Badger
5673 SE 95 Avenue
Marion, ND 58466-9718
800-437-3392 (toll-free)
www.weedbadger.com
29) The Green Hoe Company, Inc.
6645 West Main Road
Portland, NY 14769
716-792-9433
716-792-9434 FAX
www.greenhoecompany.com
30) Ware, Alan. Horticultural Specialist. The Kerr Center for
Sustainable Agriculture,
P.O. Box 588
Poteau, OK 74953
Personal
communication. February 1997.
31) Clark, M. Sean, Stuart H. Gage, Laura B. DeLind, and Marian
Lennington. 1995. The compatibility of domestic birds with a
non-chemical agroecosystem. American Journal of Alternative Agriculture.
Summer. p. 114120.
32) Johnson, Clarence. 1960. Management of Weeder Geese in
Commercial Fields. California Agriculture. August. p. 5.
33) Reid, Fred. 2002. Integrating Layer Chickens into
a Certified Organic Raspberry and Vegetable Farm. 14 th
IFOAM Organic World Congress Proceedings. Cultivating Communities.
p. 80.
34) Daar, Sheila. 1987. Update: Flame weeding on European farms.
The IPM Practitioner. March. p. 1.
35) Thomas Wittman. Gophers Limited. Personal communication.
January 2004. twittman@cruzio.com
36) Cooney, B. 1990. Single-strand electric fences persuade
deer to dine elsewhere. University of Wisconsin-Madison, College
of Agricultural and Life Sciences Quarterly.
Vol. 8, No. 4. p.
6.
37) Nordell, Anne, and Eric Nordell. 1997. Cultivating
questions. Small Farmer’s Journal. Spring. p. 21-24.
38) Williams, Greg, and Pat Williams. 1997. Homemade fruit
tree guards. HortIdeas.
April. p. 41-42.
Back to top
Resources
Sources of Supplies
[This list is not comprehensive and does not imply endorsement of these companies.]
Harmony Farm Supply
P.O. Box 460
Graton, CA 95444
707-823-9125
707-823-1734 FAX
www.harmonyfarm.com
Flame Engineering, Inc.
P.O. Box 577
LaCrosse, KS 67548-0577
913-222-2873
800-255-2469 (toll-free)
www.flameengineering.com/
Thermal Weed Control Systems, Inc.
N1940 Hwy. 95
Neillsville, WI 54456
715-743-4163
Periodicals
American Fruit Grower
Meister Publishing Company
37733 Euclid
Ave.
Willoughby, OH 44094
440-942-2000
www.meisternet.com
Monthly.
$19.95/yr.
Good Fruit Grower
105 S. 18 th Street, Suite 217
Yakima, WA
98902
509-575-2315
509-454-4186 FAX
www.goodfruit.com
growing@goodfruit.com
$30/yr.
Fruit Growers News (formerly Great Lakes Fruit Growers News)
P.O.Box 128
Sparta, MI 49345
616-887-9008
616-887-2666 FAX
gap@i2k.net
Monthly.
$11/yr.
Pomona North American Fruit Explorers
1716 Apples Rd.
Chapin, IL 62628
Quarterly. $10/yr.
Further Reading
Bilderback, D.E., and D.H. Patent. 1984. Backyard Fruits
and Berries. Rodale Press, Emmaus, PA. p. 162.
Lanphere, Paul G. 1989. Growing Organically: A Practical Guide
for Commercial and Home Organic Fruit Growers. Directed Media,
Wenatchee, WA. p. 24.
Edwards, Linda. 1998. Organic Tree Fruit Management. Certified
Organic Associations of British Columbia , Keremeos, B.C. Canada.
240 p. For further information about this book write to:
Certified Organic Associations of British Columbia
Keremeos,
B.C. Canada VOH 1TO
Davidson, Ralph, and William F. Lyon. 1987. Insect Pests of
Farm, Garden, and Orchard. 7th Ed. John Wiley & Sons, New
York, NY. 640 p.
Flint , Mary Louise. 1990. Pests of the Garden and Small Farm.
Division of Agriculture and Natural Resources Publication 3332.
University of California, Oakland, CA. 276 p. Primarily
for California , but lots of good information
for any fruit grower.
From: ANR Publications University
of California
6701 San Pablo Ave.
Oakland, CA 94608-1239
510-642-2431
800-994-8849 (toll-free)
www.anrcatalog.ucdavis.edu
Galletta, Gene, and David Himelrick, (eds.). 1990. Small Fruit
Crop Management. Prentice Hall, Englewood Cliffs, NJ. 602
p. Out of print. Check with any library’s interlibrary
loan program to borrow a copy. Includes chapters on minor fruits
such as elderberries, juneberries, kiwifruit, etc.
Pfeiffer, Ehrenfried. No date. The Biodynamic Treatment of
Fruit Trees, Berries, and Shrubs. The Biodynamic Farming and
Gardening Assoc., Inc., Kimberton , PA. 30 p.
Available
from:
Biodynamic Farming and Gardening Association Inc.
25844 Butler Rd.
Junction City, Oregon 97448
Phone: 541-998-0105
Fax: 541-998-0106
biodynamic@aol.com
www.biodynamics.com
Reich, Lee. 1991. Uncommon Fruits Worthy of Attention. Addison-Wesley,
Reading , MA. 273 p. Though not expressly for commercial growers,
it provides otherwise hard-to-find information on minor fruit
crops like pawpaws, jujubes, mulberries, etc.
Ryugo, Kay. 1988. Fruit Culture: Its Science and Art.
John
Wiley & Sons, New York , NY. 344 p.
Whealy, Kent. Fruit, Berry and Nut Inventory. Seed Saver Pubs.,
Decorah, IA. 366 p. Descriptions of various fruit cultivars
extant in U.S. nursery trade.
Seed Savers Exchange
3076 N. Winn Road
Decorah, IA 52101
319-382-5990
sse@salamander.com
Web Resources
Listings of Educational Institution and Government Sponsored
Sites www.crfg.org/related.edu.gov.html
U.C. Fruit and Nut Research and Information Center:
http://fruitsandnuts.ucdavis.edu/
This
site has links to specific crops, lists of farm advisors,
current research and many other useful resources.
UC Davis Postharvest Technology Research and Information Center
http://postharvest.ucdavis.edu/
This site provides practical information on postharvest handling
of many products.
University of Missouri Extension Publications
http://muextension.missouri.edu/xplor/agguides/hort/#Fruit
While this site includes information for home orchards, there is
a piece entitled “Information
Sources for Planning a Commercial Fruit Operation” that
includes contact information for local Extension horticulture
specialists:
http://muextension.missouri.edu/xplor/agguides/hort/g06011.htm (Link no longer active.)
California Rare Fruit Growers
www.crfg.org/
This
organization covers a fascinating plethora of tropical fruits,
but does not have a commercial emphasis. Contains abundant
information on deciduous fruits as well.
Cornell Cooperative Extension Fruit Production Resources www.hort.cornell.edu/extension/commercial/fruit/index.html
Much of the pest management information on this site appears to
be pesticide-focused at first glance. However, one article discusses
Organic Treefruit and IPM: http://ipmguidelines.org/TreeFruit/CH01/default.asp#_Toc160419381
There are links on this site to “Other State Resources,” such
as the following two examples. University of Connecticut IPM
for Tree Fruit Crops
www.canr.uconn.edu/ces/ipm/ipmtrfr.htm
Western Maryland Research & Education Center
www.westernmaryland.umd.edu/home.htm
There are many other state programs that have information on
fruit growing, which may or may not have significant resources
for organic orchard production.
Kearneysville Tree Fruit Research and Education Center, West
Virginia University www.caf.wvu.edu/kearneysville
This
site features keys to pest identification, with great
photos of insects and disease symptoms. Lots of useful information
for fruit growers in the Mid-Atlantic region. On-line newsletters
and publications are archived. Links to other sites.
The Mid-Atlantic Regional Fruit Loop
www.caf.wvu.edu/kearneysville/fruitloop.html
A cooperative effort bringing
together information on deciduous fruit tree production in
the Mid-Atlantic region. Cooperating state universities include
Virginia Tech, West
Virginia University, the University of Maryland, Penn State
University, and Rutgers University.
North American Fruit Explorers
www.nafex.org/
Members
of this network are professional and amateur fruit growers
who share information here and in their quarterly journal,
Pomona (see Periodicals section).
UC Davis Pomology Dept:
http://fruitsandnuts.ucdavis.edu
Links
to all sorts of fruit information from University of California.
University of Massachusetts Tree Fruit Advisor:
www.umass.edu/fruitadvisor/
Fact Sheet series addresses specific issues and crops. Information
focuses on apples, but
includes peaches, pears, plums, and cherries.
Yard & Garden Solutions Series. Illinois Cooperative Extension: www.solutions.uiuc.edu/index2.cfm?series=4
USDA articles and updates on organic farming.
www.ers.usda.gov/briefing/Organic/readings.htm
This site features tidbits of information on specific issues: Economic Research
Service briefing room, organic farming and marketing, recommended readings.
By Guy K. Ames and George Kuepper
Revised January 2004
By Ann Baier
Reviewed by Martin Guerena
NCAT Agriculture Specialists ©NCAT
2004
Edited by Paul Williams
HTML
Formatting
by J. English
IP28
Slot 33
Version 092104
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