Abstract
Strawberries in a hoophouse.
Photo by: Martin Guerena, NCAT |
This publication provides an overview of organic strawberry production methods. It also covers integrated
pest management and weed control techniques that can reduce pesticide use in strawberry production.
Included are discussions of weeds, pests, diseases, greenhouse production, plasticulture, fertility,
economics, and marketing. Lists are provided of further resources, both electronic and in print.
Table of Contents
Introduction
Strawberries are a viable crop in most
areas of the United States. Cultivars
have been developed to suit most
agro-climatic conditions. In many locations,
demand for locally produced berries
far exceeds available supplies; small-scale
producers can thus get higher returns from
strawberries than from most other crops.
Organically grown berries may command
a price premium. Organic production
excludes the use of synthetic fertilizers and
pesticides, and requires soil building and
biological pest control. Federal organic
standards restrict claims of “organically
grown” to those farms that are certified to
be organic by a USDA-accredited certification
agency. For more information, request
the ATTRA publications Organic Farm Certification
and the National Organic Program and Organic Orchard, Vineyard, and Berry
Crop Documentation Forms.
Excellent cultural information for
conventional strawberry production— planting systems, pest control, cultivar
recommendations, etc.—can be obtained
from the Cooperative Extension Service in
most states (also see Further Resources below). ATTRA's Tree Fruits: Organic Production Overview provides general information on
organic weed control, organic fertilization,
and some basic considerations for organic
disease and pest control. This publication
will cover problems specific to strawberries
and will offer organically acceptable
solutions. We have not attempted to
develop a one-size-fits-all prescription for
organic (or other ecologically based) strawberry
production. Rather we have introduced
the most common challenges and
offered some possible solutions and factors
for consideration.
For many years, conventional strawberry
growers have routinely used the soil fumigant
methyl bromide to control weeds, soilborne
diseases, nematodes, and soil-dwelling
insects. In October, 1998, the Congress attached an amendment to the Clean Air
Act which required EPA to make regulatory
changes to the US phase-out of methyl bromide,
resulting in a 100 percent reduction
by 2005. (Anon., 2002) Currently, a critical-use exception has been issued extending
the phase out to 2007 for those who believe
there are no technically and economically
feasible alternatives to methyl bromide.
There are feasible alternatives in strawberry
production, as many organic growers
can attest.
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Planting Systems
Plasticulture Strawberries
Photo by: Martin Guerena, NCAT |
Planting systems for strawberries vary,
depending on the environment and
production goals. The grower must decide
the relative priorities of yield, size, flavor, or
other qualities of the fruit, and seek a system
that balances these goals. Systems that
focus primarily on yield are the least sustainable
because of the enormous amount
of energy used for maintenance, plastic,
and transportation. In many of these systems,
the plants are grown on raised beds
as annuals. This results in removal of the
plants, plastic mulch, and irrigation system
at the end of every season. Regardless
of the system used, conventional yields
are usually higher than organic yields.
However, studies have shown that organic
producers can earn more profit per acre
than conventional producers. (Gliessman
et al., 1996)
Raised Bed Plasticulture. Organic and
conventional growers in California and Florida,
where most of the nation’s strawberries
are produced, tend to favor this system.
They grow plants as annuals, transplanting
strawberry crowns in the late summer or
early fall. Production starts in the late winter
and continues through the summer and
into late fall, depending on the area and
the varieties grown. Since methyl bromide
is not allowed in organic production, crop
rotation, green manure crops and compost
are critical to control soil-borne diseases
and pests.
Two types of raised beds are used in these
intensive systems. Narrow beds have two rows of plants with one drip line running
between them. The distance between beds
averages 40 inches. Drip tape is buried at
a depth of about 2.5 inches. Wide beds
usually have four rows of plants and two
drip lines, with 64 inches between beds.
Spacing between plants in both types of
bed averages 12 to 14 inches.
Plastic mulch is used in both narrow and
wide beds and can vary from a single strip
of plastic laid between the plants to full bed
coverage, where holes must be punched for
the plant to develop. Some conventional
growers in California use clear plastic, which
warms the bed faster, stimulating early-season
growth; these growers use fumigation
to control most weeds. Black plastic
is used in organic production, primarily for
weed control. Since the black plastic prevents
the sun’s rays from penetrating, the
beds remain cool, resulting in slower initial
growth of the plants and reduced irrigation
frequency compared to clear plastic mulch.
There is a plastic mulch on the market that
selectively permits soil-warming radiation
to penetrate while eliminating the light that
promotes weed growth. This type of plastic
is preferred by growers in the Southeast.
Raised beds provide good drainage. Since
they make the flowers and fruit easier to see
and reach, raised beds also help growers
to forecast yields, while making harvesting
easier and faster. Some growers dig deep
furrows between the beds so that harvesters
do not have to stoop so low to search
for fruit. In cold climates, plants in raised
beds may be prone to freeze damage. Still,
raised beds usually out-produce flat beds.
Due to increased aeration and protection from splashing soil particles, plants in plastic-mulched raised beds have less disease.
Machinery is available to shape the bed,
lay out the irrigation line, and cover the
bed with plastic mulch all in a single pass.
Sources of bed-shapers and transplanters
are listed in the ATTRA publication Season
Extension Techniques for Market Gardeners.
Or check the following web pages: www.mechanicaltransplanter.com/layer.html
www.marketfarm.com/cfms/mulch_layers.cfm
Recent research indicates that any variety
that normally does well in a specific region
will do well when grown using plasticulture
in that region. (Nourse, 1999) However,
some of the cultivars that come from
the California and Florida systems perform
best at a 12- to 14-inch spacing, while many
northern cultivars do best at an 8- to 10-inch spacing.
By now, growers and researchers in many
states have adapted and validated at least
parts of the production model described
above. Growers should check with their
state Extension Fruit Specialist to see if specific
plasticulture guidelines are available for their area. Otherwise, a complimentary
copy of Nourse Farms Success with Plasticulture can be obtained by calling Nourse
Farms at 413-665-2658.
Plasticulture, Sustainability, and Organic Farming
Plasticulture is not without its serious critics. The plastic has to come from somewhere, and it has to be discarded at the end
of the one- to three-year production cycle. Clearly, critics say, this is not an environmentally sustainable system. And, says
Cornell University fruit researcher Marvin Pritts, PhD, if you consider all the environmental costs to society, plasticulture is also
not economically sustainable in the long run. Pritts also points out that even more plastic—in the form of row covers, tunnels,
hoop houses, etc.—is needed to make the system work in cold climates.
USDA researchers have shown that fields mulched with plastic cause four times more water runoff than fields mulched with
organic materials. Due to this high rate of runoff, fields mulched with plastic suffer up to fifteen times more soil erosion than
fields mulched with organic matter. (Anon., 1999c) Planting grasses or other types of vegetation alongside drainage ditches
can reduce the rate of erosion and provide habitat for beneficial insects.
Yet, even organic growers—especially those in California, where plasticulture has reigned the longest—are buying into the
plasticulture production model. Why? The answer is weeds. Strawberries are notoriously prone to weed encroachment
with resultant loss of productivity. Plasticulture provides good to excellent weed control without herbicides. The National
Organic Program (NOP) states that plastic or other synthetic mulches are allowed in organic production, provided that they
are removed from the field at the end of the growing or harvest season.
Pritts admits that implementing some of these ideas requires well-informed and committed management. Moreover, production
in each locale may require fine-tuning to get the right mix of groundcovers and timing for planting, mowing, and other
manipulations. This is probably not going to be as easy as rolling out the plastic sheeting. Nevertheless, using small amounts
of post-emergent herbicide, though not allowed in organic production, may be more sustainable than the continued use of
tons upon tons of non-renewable, non-recyclable plastic mulch. Corn- and soybean-based biodegradable plastics are being
developed, but it will be a while before a sturdy and durable biodegradable plastic capable of withstanding solar radiation,
moisture, and equipment is available for strawberry production. Synthetic biodegradable polymers are being developed,
but since they are synthetic, it seems unlikely they will be allowed in organic production any time soon. |
Matted Row System. In this system the
crowns are planted in early spring. As the
plants produce flowers, the blossoms are
removed to encourage runner (or daughter
plant) production. The daughters root on
the bed and produce a crop the following
spring. Weeds can be a problem in this
system, and dead leaves and other debris
must be removed to reduce disease and pest
problems. However, once established, this
system can produce for three to four years,
depending on pest pressure. The distance
between plants is 18 to 24 inches, and the
distance between the rows varies from 36
to 50 inches, depending on the cultivation
equipment used. According to Marvin
Pritts of Cornell University, the matted row
system offers northern strawberry growers
a low-risk system that requires less focus
and time than annual plasticulture systems
(Pritts, 2002).
Researchers at the USDA Agricultural
Research Service (ARS) in Maryland
have developed a “modified or advanced” matted row system to address weed and
pathogenic pests. This system uses matted
row-type culture established on raised beds
with subsurface drip irrigation and organic
mulch. The mulch consists of a mixture of
hairy vetch (45 kg/hectare [40.1 lb/acre]),
rye (78 kg/hectare [69.6 lb/a]), and crimson
clover (34 kg/hectare [30.3 lb/acre])
that fixes some nitrogen and provides an
economical, biodegradable mulch for suppressing
weeds and diseases, and reducing
erosion. The organic mulch is cut or rolled
down in April and two weeks later the bare
root strawberry plants are planted through
the layer.
Since 1996, the small-fruit breeding program
has conducted replicated performance
trials on both the advanced matted row system
and a regional adaptation of annual hill
plasticulture. Both of these systems were
managed without methyl bromide fumigation
or fungicide application. Data from
these trials were used to compare advanced
matted row and plasticulture for yield, fruit
quality, and length of harvest season. Yield
for the two systems was variety-dependent,
and the advanced matted row system had
later production and slightly
lower fruit quality. (Black
et al., 2002)
Ribbon Row System. This
system can employ high-density
or low-density planting on
a single row. With low-density
planting, the spacing is 12 to
36 inches between rows and 14
to 18 inches between plants.
With high-density planting,
the distance between the rows
is the same but the distance
between plants varies between
4 and 12 inches. The crowns
are planted in the fall. Once
they start blooming, the flowers
are not removed, and fruit
is produced in the first season.
Runners are removed to stimulate flower formation and to increase
fruit size. At the end of the second season
the planting can be changed to the matted
row system by letting the runners fill in
empty spaces on the beds.
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Varieties
Selection of appropriate varieties is important.
Besides determining yields and quality,
the variety also determines production
seasons and pest-control practices. Your
county extension agent can usually recommend
varieties that have been shown to
respond well to the area’s climatic conditions.
However, variety trials are usually
conducted utilizing conventional production
systems. The variety’s performance may be
different in an organic system. Therefore,
organic growers are advised to plant more
than one of the recommended varieties and
conduct their own variety trials. Other
organic growers in your area may also be
able to advise you.
Strawberry varieties are classified as
either “June-bearing” or “Everbearing.” June-bearing or short-day varieties
start forming flower buds as the daylength
gets shorter and temperatures get
cooler. Everbearing or day-neutral varieties
are insensitive to day length and produce
fruit throughout the season as long as
night-time temperatures drop below 60° F.
(Strand, 1993)
Trials conducted in the northeast comparing
strawberry varieties under conventional and
organic management systems demonstrated
that the “Honeoye” variety was the most
productive in terms of numbers and weight
of harvested fruit and most profitable for
organic producers. (Rhainds et al., 2002)
See Appendix B for a list of recommended
strawberry varieties.
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Fertility
ATTRA's Tree Fruits: Organic Production Overview covers organic fertility management in
a general way. However, there are at least
two aspects of strawberry production that are unique and distinct from other perennial
fruits with respect to fertility.
June-bearing strawberries set buds for
the following year’s fruit in the fall. (Most
perennial fruit crops set their fruit buds in
the spring or early summer.) To get a good
bud set, the plants must have adequate
chilling and not be nutritionally stressed.
Therefore, fertilizer applications are usually
warranted in the late summer, giving
the organic fertilizer material enough time
to break down and provide nutrients for the
plants during the crucial fall bud-set.
Timing is critical in supplying nitrogen to
berry crops and the nitrogen release rates
for organic fertilizers may not match the
nitrogen needs of the crop. A study on
organic fertilizers in California found great
variability in the nitrogen availability of different
sources of fertilizers. (Gaskell, 2004)
These included guano, feather meal, liquid
fish emulsion, fish meal, pelleted chicken
manure, compost, and a green manure
crop. Initially, the soil nitrate nitrogen from
the green manure crop and compost kept
the level of nitrogen at adequate amounts
(50 to 75 ppm) for three to four weeks and
then declined to background soil levels
below 10 ppm.
Supplemental fertilizing is therefore necessary
to carry the crop through the season.
Strawberry producers using the annual
plasticulture system must rely on soluble
organic fertilizers applied through drip
irrigation lines. Farmers using these systems
must face solubility and the capacity
of these products to be filtered through
fine mesh without plugging drip emitters.
Products injected into the system may not
emerge at the same concentration. In other
systems, foliar or side-dress applications
will be warranted.
While all perennial fruit crops will benefit
from the fertility provided by pre-plant
cover-cropping and green-manuring, strawberries
are so prone to weed problems that
pre-plant preparations to reduce weed pressure
are practically mandatory in organic
production. A thick cover crop of a grass/
legume mix will help to smother out many weeds and will provide important longterm
improvements in soil fertility and soil
organic matter. In areas such as coastal
California, long growing seasons and high
land rents may make the extended use of
cover crops uneconomical. However, many
growers believe that the long-term benefits
of cover crops and rotations to soil fertility
and pest and disease suppression are worth
the cost.
Compost can be used as a supplement or
alternative. Spreading and incorporating
the compost on the beds only, avoiding
the furrows, will help concentrate fertility
and microorganisms where they are most
needed. Compost application rates vary
from 10 tons/acre to 3 tons/acre. Supplemental
fertigation is necessary to carry
the plants through the production season:
Research from Ohio has shown that vermicompost
(compost made from earthworm
waste) applications increased strawberry
growth and yields significantly. (Arancon et
al., 2004) These responses seemed not to
be dose-dependent. Strawberries at one site
grew fastest and yielded most in response
to the 10 ton/hectare (4.05 ton/acre) vermicompost
application rate, whereas strawberries
responded positively and similarly
to both the 5 ton/hectare (2.02 ton/acre)
and 10 ton/hectare rates of application at
another site. These responses could not
have been mediated by the availability of
macronutrients, since all plots were supplemented
with inorganic fertilizers to equalize
macronutrient inputs for all treatments.
Based on other research in the laboratory,
however, the responses could have been due
to production of plant growth regulators by
microorganisms during vermicomposting.
The foliar application of aerobically-prepared
compost tea increased yields in a
British Columbia study. (Welke, 2004)
Besides reducing incidences of Botrytis, the
compost tea treatment increased yields in
strawberries by 20 percent compared to the
control and water sprays.
For more information on organic fertilizers,
vermicomposting, compost and cover crops,
request these ATTRA publications: Sources of Organic Fertilizers and Amendments, Alternative Soil Amendments, Worms for
Composting (Vermicomposting), and Overview
of Cover Crops and Green Manures.
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Weed Control
Weeds are one of the biggest problems
that organic strawberry growers face. Preplant
site preparation is critical. Refer to
ATTRA’s Tree Fruits: Organic Production Overview for site preparation strategies as well as
for basic weed-control ideas.
Cultural Methods
Organic growers will find that some hand
weeding is necessary. Weeds in organic
plasticulture systems can become troublesome
even where black plastic mulch is
used. In such situations, the weeds emerge
from the planting holes made for the strawberry
plants. The rows must be straight and
the plastic laid precisely to allow mechanical
cultivation of the furrows without damaging
the beds and plastic.
A variety of colored mulches have been
studied in California to determine their contribution
to weed control and crop response.
Black mulch provides the best weed control
but does not warm the soil as well as
clear plastic. Soil warming with clear plastic
results in plants that grow and produce
earlier in the season, but weeds are not controlled.
Research determined that the effect
of mulch color on transmittance of photosynthetically-active light (400 to 700 mm)
through mulches was the key weed-control
factor. (Johnson and Fenimore, 2005)
Green and brown plastic mulches provided
the best combination of soil warming and
weed control benefits at all trial locations.
The matted row system (where plants from
runners form a 6- to 30-inch-wide solid bed)
is commonly used by strawberry growers
in many regions of the U.S. This method
precludes mechanical cultivation for weed
control within the bed, though cultivation
is commonly used to renovate or narrow a
bed. Weed problems tend to increase with
the age of the planting. Many organic growers
have therefore chosen shorter fruiting rotations. That is, a bed may be allowed
to fruit for two seasons before it is turned
under and replanted to a cover crop.
A weed competition study in a mature
matted row planting was conducted over
a three-year period by Marvin Pritts and
Mary Jo Kelly of Cornell University (2004).
The impact of weeds on subsequent productivity
was determined. Plants in the weed-free
plots had the highest yield, while season-long uncontrolled weed growth reduced
productivity by 51 percent. However,
plants in several plots with a limited amount
of weed competition had higher yields than
those in the continuously weeded controls.
This indicates that plants from a well-established
matted row planting may be tolerant
to a limited amount of weed competition for
at least two years. Growers should direct
a majority of their efforts and resources
towards controlling weeds in the planting
year. Once the planting is well established,
growers may limit the number of times they
hand weed to two or three per season.
Planters’ paper, a black paper mulch, was
used in matted rows for a biodegradable
mulch study. (Weber, 2003) It reduced
weeds but degraded quickly along the edges
where it was covered by soil, allowing the
wind to tear and blow large pieces off the
plots. The rate of degradation the first year
was quick but the paper still reduced weed
population compared to clear mulch and
the control.
Mechanical Methods
European strawberry growers and researchers
have led the way in innovations and
research involving mechanical weed control
in strawberries. Recent research in the
U.S. has confirmed the usefulness of the
flex-tine harrow, the brush hoe, and the finger
weeder for weeding strawberry plantings.
(Pritts and Kelly, 1999) For instance,
the brush hoe required only three passes
per season plus two hand weedings for complete
weed control, compared to standard
cultivation with a rototiller, which required
three passes and four hand weedings. Visit
the European Weed Research Society’s Physical Weed Control Web page for more information
on these and other mechanical cultivation
tools. In plasticulture systems, harvest
crews are sometimes used to weed when the
weed pressure is high or when the harvest
day is short.
Biological Methods
Before the widespread adoption of herbicides,
geese were commonly used for weed
control in commercial-scale strawberry production.
In areas of concentrated crop production,
farmers often had the benefit of
weeder-geese services for hire. Weeder
geese can still be used to control grasses
and a few broadleaf weeds, but close management
of the geese is essential. Not every
farmer will find the extra requirements
suitable to his or her management regimen.
The extra work may be offset to some
degree by on-farm consumption of the geese
or by sales of geese and their products. In
any case, the geese must be removed before
fruiting season, because they will eat strawberries
before going after grass.
Under the National Organic Program (NOP),
raw animal manure must be composted
unless it is incorporated into the soil not
less than 120 days prior to harvest of a crop
whose edible portion has direct contact with
the soil surface or soil particles. Therefore,
geese would need to be removed from the
field and their manure incorporated at least
four months prior to the beginning of strawberry
harvest. ATTRA has more information
on the proper management of weeder
geese available on request.
Organic Mulches
Strawberry plants, especially in the North,
are commonly mulched with straw over the
winter to minimize cold damage. In the
spring, the straw is raked into the aisles
where it provides some control of weeds and
helps to keep the berries clean. Caution
must be taken with some organic mulches
in that they may harbor pests like snails,
slugs, cutworms, earwigs, and sow bugs.
On the other hand, straw provides excellent habitat for spiders and has been known to
reduce diseases. A study in Ohio showed
that straw mulch between strawberry rows
was equally or more effective than fungicides
for controlling leather rot (Phytophthora
cactorum). (Ellis et al., 1998)
Research in West Virginia indicates that
shredded or chopped newsprint makes an
excellent and safe mulch. (Baniecki et al.,
1995) It can be applied over the top of
the plants at the onset of winter, just like
straw. It should be applied in a layer 4 to
5 inches thick (this will require about 500
to 600 pounds of chopped paper per 1,000
square feet), and will be subject to being
windblown until it is stabilized by rain or
overhead irrigation. Only newspaper or
other recycled paper, without glossy or colored
inks, may be used as mulch under the
National Organic Program standards.
Woolen landscaping fabric was the best
alternative treatment in a study conducted
in Minnesota. (Forcella et al., 2003) A
one-ply woolen fabric centered over the crop
nearly eliminated weeds from rows, promoted
daughter plant rooting, and allowed
maximum fruit yield equivalent to that
obtained in plots that were hand weeded.
Cornell small-fruit researchers Marvin Pritts
and Mary Jo Kelly have worked extensively
with cover crops for weed suppression in
strawberries. They have tried several species—including tall fescue, marigold, buckwheat,
and ryegrass—but sudangrass has
the most desirable characteristics: rapid
establishment, low water use, low nutrient
use, and competitive displacement of
weeds. Their research suggests that interseeding
sudangrass between beds and mowing
it twice a year provides acceptable weed
control without herbicides, especially when
used in conjunction with a winter straw
mulch. However, a later study found that a
sorghum-Sudan grass hybrid “killed” cover
crop suppressed pathogens and weeds but
adversely affected strawberry growth and
yields. (LaMondia et al., 2002)
See the Matted Row System section above
for information on a USDA study using a
killed cover crop mulch (hairy vetch, rye, crimson clover) to suppress weeds and
reduce erosion.
In USDA zones 6 and colder, another option
is to plant spring oats in the fall. Freezing
weather will kill the oats, leaving a nice
mulch. Yet another option is to plant sorghum-Sudan grass in the late summer; it is
not at all cold tolerant, and will be killed
by the first frost. For information on the USDA’s hardiness zones, check the United States National Arboretum Web
site.
Thermal Controls
Thermal technology, from flamers to infrared
burners, keeps evolving with new products
emerging onto the market. At present,
thermal control methods include handheld
flamers, mounted row crop flamers, infrared
weeders, steamers, hot water, and hot foam.
Timing is critical for successful thermal
control of weeds. The younger the weed,
the easier it is to desiccate. Grasses can
be burned back but the growing point usually
sends out new growth. Some of these
devices may not fit in a particular system
but others may be successful components of
a weed control program.
For a list of thermal devices for weed control,
see Appendix A.
Vinegar and Essential Oil Herbicides
The use of vinegar for weed control has
been the least-toxic choice of many home
gardeners. Its effectiveness varies, depending
on the type of weeds sprayed and the
concentration of acetic acid. Most vinegar
available commercially is 5 percent acetic
acid. Through distillation, the concentration
can increase to 15 percent and by other
non-synthetic processes to 30 percent acetic
acid. Caution must be taken with formulations
greater than 5 percent. Though there
are more concentrated solutions of acetic
acid that are derived synthetically, these
types are not allowed in organic production
systems. Some commercial formulations
of vinegar herbicide include lemon juice
or citrus oil. The mode of action consists of the acidic solution degrading the leaf’s
waxy cuticle layer, causing desiccation.
The thicker the cuticle layer on the weeds,
the more frequent the applications or the
more concentrated the solution should be.
If preparing a homemade solution of vinegar
herbicide, include citrus oil or lemon
juice along with a small amount of liquid
soap as a surfactant. Some commercial formulations
are Alldown™ (SommerSet Products ) and Ground Force™ (Abby Laboratories).
The Organic Materials Review Institute
(OMRI) lists vinegar and clove oil herbicides
as restricted, meaning the need for and
use of these herbicides must be explained
in the Organic System Plan. Essential oil
herbicides (clove, thyme, and mint oils)
contain phytotoxic compounds that have
been reported to kill grasses and broadleaf
weeds. Commercial products include
Xpress™ (Bio HumaNetics) which is a formulation of thyme
(10.4 percent) and clove (10.1 percent) oils
and Matran 2™ which is 45.6 percent clove
oil. According to the manufacturer, the
addition of the yucca extract ThermX 70
(0.3 fl. oz. /gallon) with fulvic acid (6 fl. oz./gallon) to Matran 2™ significantly enhances
its coverage and performance. Matran 2™ is also used in combination with vinegar.
Be careful when spraying weeds and keep
the sprays off strawberry plants. Also care
needs to be taken to avoid contact or inhalation,
as the high acid content will burn skin
and lung tissue. For more information on
vinegar as an herbicide, check the USDA Agricultural Research Service
Web site.
Woven Synthetic Fabric Mulches
Synthetic fabric mulches (trade names:
Weed Lock, Weed Barrier, Weed Stopper,
etc.) offer some of the same weed suppression
as regular plastic mulches, but have
the advantage of being water- and air-permeable.
Though initially more expensive
than regular plastic, the higher-quality
grades of fabric mulch can be used year
after year. These woven mulches are used
in essentially the same way as plastics in the systems described above. However, because
they are water-permeable, it should not be
necessary to add irrigation lines under the
mulches in areas with adequate rainfall.
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Insect and Mite Control
Numerous insects feed on strawberry plants
and threaten yields. Extension Service specialists
are familiar with pests common to
specific areas and can help with proper
identification, which is the first step in pest
management. A scouting program with regular
monitoring can help growers determine
both the pest pressure and presence of beneficial
insects. Once pest pressure reaches
the economic threshold, control actions
are necessary. If biological controls are
to be used, they must be deployed before
the pests reach critical levels. That is why
monitoring is so important. In large operations,
where harvest crews are used regularly,
training the crew foreman to identify
insect pests and diseases can help in the
monitoring process.
Beneficial-insect habitats planted alongside
strawberry fields provide shelter, pollen,
and nectar sources to predators and
parasites of insect pests. Beneficial insects
are able to take refuge in the habitat when
fields are treated with a pesticide. When
purchased beneficial insects are released,
these habitats encourage the beneficials to
remain and continue their lifecycles, helping
reduce pest populations. Some pests
may also inhabit the refuge along with
beneficials, so it is important to monitor
these habitats: For additional information,
request ATTRA’s Biointensive Integrated
Pest Management and Farmscaping
to Enhance Biological Control.
Although pest problems vary with location,
common strawberry pests include white
grubs, strawberry weevils, strawberry rootworms,
caterpillar worms, lygus bugs, and
spider mites. For more detailed information
on the pests themselves, refer to the publications
listed in the Further Resources section below (see especially the publications
by Funt et al., 1997, Kovach et al.,
1990, Maas, 1987, and Strand, 1993).
White Grubs
Primarily a problem in the eastern U.S.,
white grubs can cause serious damage if
strawberries are planted immediately after
a sod crop. White grubs are the larvae of
May and June beetles and other beetles in
Scarabaeidae. Late-summer or early-fall
plowing destroys many larvae, pupae, and
adults in the soil and also exposes these
stages to predators. The milky-spore-disease
bacteria, Bacillus popillae and Bacillus
lentimorbus, are important natural enemies
of Scarab beetles. Grubs ingest spores of
these bacteria on the thatch or roots of the
grasses they eat. The spores then germinate
and the bacteria multiply inside the grubs,
which die and disintegrate, leaving many
new, viable spores to spread the disease to
succeeding generations. (Daar, 1988)
Beneficial nematodes are also effective
against soil-dwelling grubs. Steinernema
carpocapsae will infect its host near the soil
surface while Heterorhabditus bacteriophora actively searches for its host below the soil
surface. (Flint and Dreistadt, 1998) These
nematodes and milky-spore bacteria are
widely available through mail-order garden
supply companies.
Strawberry Clipper (Strawberry Bud Weevil)
The strawberry clipper or bud weevil, Anthonomus signatus, occurs only east of the
Rockies. Adult beetles emerge in the early
spring, lay eggs in the buds, and then cut
partly through the stem, causing strawberry
buds to fall over or fall to the ground.
Contrasting studies on strawberry clipper
or bud weevil have been conducted.
One study found that most of the 12 varieties
studied compensated for a significant
amount of flower bud loss, provided that
the loss occurs early in the development of
the inflorescence. (Pritts et al., 1999) A
later study showed that liberal thresholds
developed from the previous studies were
exceeded in two of the three research sites
and damage levels were severe enough to
reduce yields significantly. (Handley et al.,
2002) The clipper moves at the very slow rate of 30 feet per season. In a new planting,
it is unlikely that the damage would
extend more than 30 feet from the perimeter
into the plot. Damage may be somewhat
more extensive in older plantings, but still
limited by the rate of movement of the clippers
(they will have moved approximately
60 feet into a two-year planting and 90 feet
into a three-year planting). Organic growers
should destroy damaged buds, which contain
eggs, eliminate trash and nearby foliage
that provide hibernation sites for adult
weevils, and apply an organically approved
insecticide as a last resort.
Stawberry Rootworm
Strawberry rootworm (Paria fragariae)
adults feed mainly at night, making holes
in the leaves. The larvae feed on fine
roots and eat the crowns close to the
ground. Cultural control consists of
plowing infested fields after harvest and
setting new plantings away from woods
(favorable hibernation sites) and from older
strawberry plantings.
Apparently, IPM damage thresholds have
not been established for the rootworm. If
the grower feels that pesticide treatment
is necessary based on scouting, nocturnal
treatment should be aimed at the foliar-feeding
adults, since there are no effective
or registered insecticides available for control
of the larvae. Soil-dwelling predators
such as ground beetles or insect-attacking
nematodes like Steinernema species may
provide some control.
Strawberry Root Weevil
The adults of these species feed mostly on
leaves, causing minor damage. The larval
stage is the problem, as the larvae feed on
roots and crowns of the strawberry plants.
Root weevils have many alternate hosts
including other small fruits, cranberries,
grapes, mint, hops and many ornamental
plants. Rotation with non-host crops like
corn, wheat, clover, and alfalfa can reduce
populations. (Berry, 1998)
Like other ground-dwelling pests, Strawberry
Root Weevils are susceptible to attack from ground beetles and from parasitic
nematodes such as Steinernema or Heterorhabditus species. The root weevils
are crawling insects that also have been
excluded from fields by fences, trenches
and barriers like sticky tape. (Bomford and
Vernon, 2005; Strand, 1993)
Lygus Bugs
Lygus bug.
Photo courtesy of USDA/ARS. |
The tarnished plant bug or lygus bug (primarily Lygus lineolaris in the East and L.
hesperus in the West) can be troublesome,
especially in plantings of day-neutral varieties
which fruit throughout the growing
season. Adults and nymphs (the nymphs
cause the most damage) suck sap from the
plant and inject a toxic saliva. This feeding
results in a characteristic deformation of
the fruits called cat-facing, which makes the
berries unusable and unmarketable.
Keeping any groundcover well clipped for a
distance of five to ten yards around a strawberry
field, and otherwise destroying places
favorable for hibernation, may help reduce
lygus-bug populations. Adult lygus bugs
hibernate under leaves, stones, and bark.
They usually lay eggs in the stems of herbaceous
cultivated plants and broadleaf
weeds. Legumes (vetches, clovers, alfalfa,
etc.) can harbor large populations of these
pests. This must be considered if beneficial
habitats using these plants are established
near strawberry plantings.
Trap crops are also useful in lygus bug
management. In California, an annual trap crop mix of one dormant and one semi-dormant
alfalfa variety, two radish varieties
(Daikon and Cherry Belle) and sweet alyssum
has been used with success. Lygus
bugs move in from surrounding fields and
settle on the trap crops, which can then
be treated with insecticides or vacuumed.
(Dufour, 2000)
Bug vacuum.
Photo courtesy of USDA/ARS. |
Bug vacs range from tractor-mounted machines to small hand-held
devices and are actually vacuum cleaners
for pests. A trial by University of California
researchers concluded that three similar
grower-designed vacuum machines reduced
lygus bug damage compared to untreated
controls, but were not equal to chemical
control with a pyrethroid insecticide. The
damage, though reduced, was still considered
economically unacceptable. (Pickel et
al., 1995) Research done in Watsonville,
California, demonstrated that lygus bugs
were more attracted to a field-edge alfalfa
trap crop than to a radish/mustard or strawberry
row. (Swezey, 2004a) Vacuuming
the alfalfa trap crop with a tractor-mounted
bug vac reduced damage due to lygus bug
feeding in associated strawberry rows when
compared to vacuuming the whole field. This saved operating costs of the bug
vac and increased marketable fruit. For
more information on Bug Vacs, see the
ATTRA publication Bug Vacuums for
Organic Crop Protection.
Research conducted in New England found
variation in susceptibility to the lygus bug
among 20 strawberry cultivars. (Handley
et al., 1991) Honeoye, Sparkle, Veestar,
and Canoga suffered the least from feeding,
while Kent, MicMac, Scott, Blomidon, and
Redchief suffered most.
A fungus, Beauveria bassiana, has some
efficacy against lygus bugs. In New York,
three years of tests concluded that the commercial
formulation of B. bassiana, Mycotrol™, reduced lygus damage about 50 percent
compared to untreated controls, but
was still considerably less effective than
synthetic insecticides such as malathion.
(Kovach and English-Loeb, 1997) Mycotrol™ worked best when targeted at younger
nymphs and when humidity levels were
adequate. In combination with other cultural
controls (choosing the right cultivar
and close mowing near the planting), use of
Mycotrol O™ (Laverlam Intl.), Botanagard
(Laverlam Intl.) or Naturalis (Troy Biosciences)
could be of help to organic growers
in controlling lygus.
Parasitic wasp Peristenus digoneutis.
Photo courtesy of USDA/ARS. |
While the lygus bug has several natural
insect enemies, none of the native ones has
proved consistently effective in providing
a commercial level of control in strawberries.
A small (1/8th-inch) wasp, Peristenus
digoneutis, was introduced from Europe in
1984 and has exhibited excellent control
potential. However, this nymphal parasitoid
is difficult to rear, and is not commercially
available. While it is spreading naturally
in the northeastern U.S., it has not moved
south of latitude 41°N (New York City).
(Day et al., 1990) In California, Peristenus
digoneutis and P. stygicus were released
in 1998. They have become established
and annual increases in parasitism were
noted in 2000-2002. (Fuester et al., 2004)
Higher rates of parasitism by P. digoneutis were observed in New York on organic or
casually sprayed farms than on intensively
treated farms. (Tilmon and Hoffmann,
2003) Anaphes ioles is a lygus egg parasitoid
that has been used in California and in
other states with some success. Researchers
who released 15,000 A. iole weekly on
one-acre strawberry plots observed a 64
percent suppression of Lygus hesperus compared
to a 44.7 percent reduction achieved
with a pesticide application. (Udayagiri
et al., 2000)
Since lygus nymphs are most troublesome,
aim scouting efforts at this life stage. Start
checking for nymphs as soon as flowers appear. Tap 10 to 15 flower clusters over a
white plastic saucer so that the bright green
nymphs can be seen and counted. Determine
the average number of nymphs per
cluster (total number of nymphs divided
by total number of clusters). If sampling
is concentrated near weedy borders, the
action threshold is 1 nymph per cluster, but
if done randomly throughout the planting,
0.5 nymphs per cluster should be considered
adequate to prompt a pesticide treatment.
(Kovach et al., 1993) However, Cornell
researchers caution that growers who
intend to use the slow-acting biological
insecticide B. bassiana may need to use a
lower threshold. (Kovach and English-Loeb,
1997) If other natural enemies of lygus
are present—such as spiders, bigeyed bugs
(Geocoris species), assassin bugs (Zelus and Sinea species), damsel bugs (Nabis species),
and lacewing larvae (Chrysoperla species)—you might want to consider adjusting the
threshold numbers accordingly.
Mites
The web-spinning spider mites are in the
genus Tetranychus, which includes the two-spotted spider mite, Pacific spider mite,
and strawberry spider mite, among others.
These plant-feeding mites consume juices
from strawberry leaves. Large populations
can reduce photosynthetic capacity, resulting
in weakened plants and reduced fruit
yields. Some growers who do not often
use botanical pesticides may see very few
mites—if not reduced by pesticides, the natural
enemies of the mites will usually keep
them in check. These natural enemies
include other mites such as Phytoseiulus persimilis, Metaseiulus occidentalis, and Neoseiulus
californicus, and insects like bigeyed
bugs, damsel bugs, minute pirate bugs,
lacewings, spider mite destroyers, and six-spotted
thrips. Growers can buy some of
these predators from commercial insectaries
to release on the farm. The predators
can also be attracted and conserved naturally
through the use of insect habitats.
Contact Information for Beneficial Organisms
Companies that sell mites and other beneficial
organisms are listed in the California Environmental
Protection Agency’s Department of Pesticide
Regulation booklet, Suppliers of Beneficial
Organisms in North America. (Hunter, 1997) An online PDF booklet is free online and contains
contact information for 142 commercial suppliers
of the more than 130 beneficial organisms
that are currently used in biological pest control.
It not only indexes the suppliers by the natural
enemies they sell, it also matches the beneficial
organisms with their target pests. |
Insecticidal soaps, “narrow range” oils,
vegetable oils, neem-based products such
as Trilogy®, and sulfur are acceptable miticides
in organic production (check with
your certifier regarding specific products).
Application instruments must thoroughly
cover the leaves’ undersides, and products
that are diluted must be applied in high
volumes (more than 100 gallons of water
per acre) to achieve complete coverage.
Both oils and soaps can burn plants if
over-applied or if high temperatures
(greater than 80° F) occur during and
after treatments.
A scouting method for two-spotted spider
mites has been developed in British
Columbia and successfully implemented
both there and in New York. (Kovach et al.,
1993) To sample for these mites, walk diagonally
across the planting while randomly
picking one mature, fully expanded leaflet
from every other row, until 60 leaves are
collected. If 25 percent are infested with
mites (about 5 mites per leaflet), treatment
may be in order. Again, the number of
natural enemies should also be considered
when determining a threshold for chemical
treatment. While this scouting method is
probably applicable to most areas, growers
outside the New York region should check with their local Cooperative Extension Service
for scouting guidelines.
Some of the mites you see when scouting
may be predator mites. You may need a
magnifying glass to distinguish between
these beneficial mites and the pest mites.
One key to telling them apart is that the
beneficial predator mites are generally more
active than the two-spotted mites—they
typically move quickly about the leaf surface
looking for prey. Depending on your
geographical area and the species involved,
the recommended ratio of beneficial mites
to pest mites varies, but seems to average
approximately 1:10. That is, if there
appears to be at least one beneficial mite
for every 10 pest mites, control of the pest
mites will probably be achieved naturally
without the intervention of miticidal sprays.
Dust that accumulates on the spider mite’s
webbing creates an ideal shelter for the
mites and their eggs. These little dust “tents” discourage predators and prevent
the miticide from reaching the mites
and their offspring. California growers
commonly water roads, post “slow” signs,
plant windbreaks and beneficial insect
habitats, and use fencing to decrease dust in
strawberry fields.
Other Pests
Other arthropods that will occasionally
reach pest status include aphids, spittlebugs,
whiteflies, Cyclamen mite, various
caterpillars, earwigs, and leafhoppers. If they become a problem, consult your
local farm advisor, visit the numerous
websites listed below under Further
Resources, or call ATTRA’s toll-free number
for information. [800-346-9140 (English) or 800-411-3222 (Español)]
Back to top
Disease Control
Diseases in plants occur when a pathogen
is present, the host is susceptible, and the
environment is favorable for the disease to
develop. Altering any one of these three
factors may prevent the disease from occurring.
Organisms responsible for plant
diseases include fungi, bacteria, nematodes,
and viruses. If these organisms are present,
then manipulation of the environment
and the host, to make it less susceptible,
helps manage diseases on strawberries.
Soil health and management are the keys
for successful control of plant disease. A
soil with adequate organic matter can
house numerous organisms such as bacteria,
fungi, nematodes, protozoa, arthropods,
and earthworms that may suppress
soil-borne pathogens. This disease suppression
is caused by either antagonism,
competition for nutrients, or competition for
space around the root (the rhizosphere) and
induced systemic resistance (ISR) or systemic
acquired resistance (SAR) triggered
in the plant. Increasing soil organic matter
by incorporating cover crops or adding
compost and organic fertilizers will
help maintain these beneficial organisms.
For more information, see the ATTRA
publication Sustainable Management of Soil-Borne Plant Diseases.
Rotating strawberries with other crops is
a critical factor in organic production and
many certifying agencies require it as a
component of the organic system plan.
Crop rotation reduces insect, disease and
weed pests, improves soil fertility, improves
soil tilth and structure, reduces soil erosion
and improves water management. Cover
crops, vegetable crops, legumes, and cereals
are recommended rotation choices. Avoid
Solanaceous crops like tomatoes, potatoes,
peppers, and eggplant that may harbor diseases
such as Verticillium. Research in the Salinas Valley of California found that
incorporating broccoli residues reduced Verticillium
dahliae in the soil and that rotation
with broccoli may be a feasible approach to
manage Verticillium diseases in susceptible
crops. (Subbarao et al., 1999)
Compost teas or extracts and other innovative
concoctions such as yeast-sugar solutions,
sodium bicarbonate (baking soda),
and milk have become popular as foliar
disease preventatives among many organic
growers. Compost teas and yeasts introduce
non-plant-pathogenic microorganisms
and biocontrol agents that compete with
and antagonize disease spores as they try
to establish themselves on the host. Baking
soda works at the chemical level, interfering
in spore germination. For more information,
request ATTRA’s publications Notes
on Compost Teas and Use of Baking Soda as
a Fungicide.
Elemental copper and sulfur have long been
used by conventional and organic growers
as pesticides for foliar bacterial diseases
and powdery mildew, respectively.
Soil Solarization
Imagine harnessing the sun’s energy to destroy your enemies. Like Archimedes—the ancient Greek who used mirrors to concentrate
sunlight to burn the Roman fleet—farmers can destroy or disable insects, diseases, nematodes, and weeds in the field.
The technique known as solarization consists of laying clear plastic mulch on moist soil. Heat is trapped under the plastic,
raising the soil’s temperature, killing or debilitating pests. Most of the research worldwide has concentrated on hot and arid
areas, but any place with hot summers is a potential site for this system. Usually this soil pasteurization process takes four to
six weeks, but the amount of time depends on many factors such as rain, wind, day length, soil texture, and the quality of the
polyethylene mulch. Ultraviolet-protected plastic is recommended so the mulch can be removed and re-used.
Before solarization, certain types of organic matter, such as compost and residues from Brassica crops such as broccoli and
the mustards, can be added to the soil for “bio-fumigation.” When heated in the solarization process, this organic matter
releases volatile compounds that are toxic to many pests. Before solarization takes place, the land where the crop is to be
seeded or transplanted must be prepared for planting. Beds must be shaped, drip tape installed, and fields leveled. This is
to avoid stirring up the soil after solarization, which would bring fresh pest organisms to the soil surface. Depending on outside
temperature, intensity of sunlight, and types of pests, soil solarization can provide good pest control 8 to 10 inches deep,
although the best control is generally obtained down to 6 inches.
Special caution: During solarization, drip tape must be buried at least one inch deep to avoid damage from the sun’s rays. In
experiments where the tape was placed on the surface of the bed and then covered with clear plastic, the drip tape was damaged
by sunlight that was magnified by water droplets condensing on the underside of the plastic.
Research conducted in southern California and Oregon has demonstrated that solarization has potential as a component in an
integrated pest management program for root diseases in strawberry production. (Hartz et al., 1993; Pinkerton et al., 2002)
Soil Solarization websites
Soil Solarization Home
International Workgroup on Soil Solarization and Integrated Management of Soil-borne Pests
Soil Solarization: A Nonchemical Method for Controlling Diseases and Pests (PDF / 104K)
|
Root Rot Complex
Soil borne fungi such as Phytophthora, Pythium, Rhizoctonia species, and Verticillium
dahliae are major pathogens that affect
strawberries worldwide. In organic production,
the cultural methods described above—crop rotation, compost application, and
solarization—aid in the control of these diseases.
Other cultural controls include using
resistant varieties, planting strawberries in
a pathogen-free, well-drained soil, avoiding
over-watering, and planting only certified
disease-free plants. Some growers inoculate
the soil or the plants with a variety of
commercially available biological products
such as Vesicular Arbuscular Mycorrhizae (VAM) or Arbuscular Mycorrhizae (AM), Trichoderma species (Promot, SoilGard), Streptomyces griseovirdis (Mycostop), and Streptomyces lydicus (Actinovate).
Anthracnose
Anthracnose can be very serious, causing
strawberry plants to die out in midsummer.
The disease produces a rust color throughout
the crown and eventually stops the
plants from growing. Symptoms are most
noticeable during summer dry spells.
Since high soil fertility favors anthracnose,
little or no fertilizer should be applied
when disease pressure is strong. However,
resistant cultivars can be grown successfully
at much higher fertility levels. (Maas,
1987) Anthracnose is more prevalent in
the Southeast than elsewhere. Commercial
growers in the Southeast should avoid
planting on former strawberry sites and use
locally adapted resistant cultivars.
Botrytis (gray mold)
Gray mold, caused by the fungus Botrytis
cinerea, is one of the most common and
serious fruit rot diseases. The fungus grows
best in cool damp weather, and gray mold
can be devastating if rainy weather coincides
with harvest, when strawberry fruit is
at its ripest and most susceptible. Pickers
handling infected berries can spread the
infection to healthy berries. Control of gray
mold is aided by removing infected debris
from the field and by providing good drainage.
Infected fruit can be picked off the
plants and placed in the furrow as long as
a cultivator can go through the field and
bury this fruit. Clean mulch, which keeps
fruit off the ground, is also highly recommended.
Removing leaves from the field as
soon as the harvest season ends can significantly
reduce the incidence of gray mold on
fruit in June of the following year. (Sutton
et al., 1988)
The following biorational products are
available commercially for Botrytis control:
Serenade (Agraquest), Mycostop (Verdera
Oy), and Promot (JH Biotech). Research in
Israel found that combining two biocontrol agents (a yeast and bacterium) resulted in
better suppression of Botrytis and reduced
the variability of disease control. (Guetsky
et al., 2001)
Although there is not a high level of graymold
resistance in any one strawberry cultivar,
Earliglow is relatively resistant compared
to most cultivars. (Turns, 1990)
Leaf Spot
Leaf spot diseases—identified by the presence
of spots on strawberry leaves and
stems—can be caused by the fungi Mycosphaerella
fragariae, Ramularia tulasnei,
or Phomopis obscurans, or by the bacterium Xanthomomas fragaiae. These pathogens
are spread by splashing water and are
harbored by dead leaves and other plant
debris. Sanitation, as well as the recommendations
mentioned above on foliar disease
preventatives, apply to leaf spot.
Please Note
Preventive treatments such as sulfur, copper, or
compost teas applied prior to wet weather are
advisable for many diseases like leaf spot, gray
mold, and powdery mildew. Also, studies have
shown that systems using organic mulches have
a reduced incidence of soil-borne pathogens. |
Powdery Mildew
Powdery mildew is a fungal disease that
affects strawberry foliage, f lowers, and
fruit. Caused by Sphaerotheca macularis,
its spores prefer intermittently moist conditions
and will not germinate in free-standing
water. In coastal California strawberry
fields, the practically year-round production
season, foggy cool nights, and warm days
make the disease a major and very persistent
problem. Sulfur is the most common
control agent on both conventional and
organic farms. Milk has been used successfully
against powdery mildew on cucurbit
crops. (Bettiol, 1999) Sonata™ is an OMRI-approved
commercial formulation of Bacillus
pumilis that is used on strawberries for
powdery mildew control. Seven- to fourteen-day application intervals are recommended,
depending on disease pressure.
Back to top
Greenhouse Production
Five factors—light, heat, pollination, pest
control, and economics—make winter strawberry
production in a greenhouse very different
from field production.
Lighting is critical for winter production.
The day-neutral cultivars (e.g., Tribute and
Tristar) or the short-day types (e.g., Jewel)
are much easier to grow during the short
days of winter than most of the traditional
June-bearing types. It is difficult and
expensive to get the June-bearing types to
fruit out of season. Even with the day-neutral
types, some supplementary lighting will
be necessary to get high-quality fruit.
Supplementary heat will have to be available
(in some cases the lighting will provide
enough heat). While some non-fruiting vegetables
(e.g., leafy greens, such as spinach)
can produce well in unheated greenhouses,
strawberry plants need about a 68º F day
and 54º F night to produce good yields of
high-quality berries.
The grower will have to provide pollination.
Bumblebees are probably the best pollinators
in a greenhouse environment. Two
commercial sources, GB Systems (P.O. Box
300, Locke, NY 13092; 315-497-3129)
and The Green Spot (93 Priest Rd., Nottingham,
NH 03290; 603-942-8925) sell
bumblebees and bumblebee nesting boxes.
Certain pests (usually the larger ones,
e.g., tarnished plant bugs) can be effectively
excluded from greenhouses, but others,
such as mites, aphids, whitefly, thrips,
and fungus gnats are likely to thrive and
proliferate. Due to the need for bumblebees
for pollination, controlling these pests
with conventional pesticides is not a good
idea. Fortunately, they can be effectively
managed with biological controls, such as
beneficial mites and lacewing larvae. For
the details of greenhouse pest management,
contact ATTRA for our series of publications
on greenhouse IPM (or go directly to Integrated Pest Management for Greenhouse Crops).
Finally, prospective greenhouse growers
should spend some time exploring local
markets (restaurants, groceries, etc.) Off-season
greenhouse growers will be competing
with strawberries from California, Mexico,
Chile, and Florida. Prices will have
to offset the costs of production, so growers
will have to produce an outstanding
product. Cornell researcher Marvin Pritts
found that the break-even price for greenhouse-grown strawberries was $3/pint.
He reports, however, that a small but significant
number of consumers are willing
to pay that price for high-quality berries.
For more detailed information on greenhouse
strawberry production, go to www.hort.cornell.edu/department/faculty/pritts/BerryDoc/Berrydoc.htm.
Back to top
Harvest and Postharvest
Strawberries must be picked and handled
very carefully. The fruit must be firm, well-colored,
and free from rot. When harvested
at the right time and handled properly,
strawberries will remain in good condition
for many days. Most California- or Florida-grown
strawberries found in supermarkets
are picked three-quarters ripe to withstand
shipping. The color of these strawberries
is a full red but the taste is disappointing.
Small-scale growers who pick ripe fruit
can easily compete with supermarket
berries by offering a tastier, fresher berry
to local consumers.
Proper postharvest handling of strawberries
is essential. Cooling the berries will remove
field heat and increase shelf life. Harvesting
early in the day while temperatures
are cool and then pre-cooling the fruit
before shipping will extend the shelf
life significantly.
Forced-air cooling is the most common
method used on strawberries. The flats
are stacked parallel to each other in a
cold room with an open space between the
flats. A tarp is then placed over the top
and ends of the stacked cartons, with a fan
located between stacks. The fan pulls cold
air between the gaps of the stacked flats,
removing the field heat from the berries. It is vital that the fruit be cooled as soon as
possible. The more the delay between harvesting
and cooling exceeds one hour, the
greater the losses to deterioration. (Kader,
1992) Water loss from strawberries can
be a problem, so it is critical to maintain
high humidity in the cooling facility.
Avoid wetting the fruit, which can cause
decay problems.
Fresh-market strawberries are usually sold
in pint or quart baskets covered with plastic
wrap. However, one-piece molded-plastic
containers called “clamshells” are rapidly
replacing this packaging. The time
and labor involved in packing the fruit in
the traditional pint-size plastic baskets is
considerable, because shippers and buyers
grade fruit packed in this manner by the
arrangement of the fruit in the flat. This
puts additional burden on the farm worker
to pack the fruit correctly. The use of clamshells
makes the strawberry pickers’ job a
little easier; the wholesalers are not as concerned
with the appearance of the fruit
pack since it looks uniform with the clear
lid. Many of these clamshells are recyclable.
A drawback to the clamshells is the
greater difficulty of cooling the fruit. The
holes in the containers are not big enough to
allow for rapid cooling, so extra time in the
forced-air cooler is necessary. The clamshell
containers also hold less fruit than the
pint baskets and are sometimes sold at a
lower price. If you sell wholesale or directly
to stores, the buyers may require this type
of packaging.
Wholesale strawberries that are shipped
long distances are placed on pallets and
are covered by bags that are injected with
carbon dioxide after the fruit is thoroughly
cooled. This modified-atmosphere process
is patented by the Transfresh Corporation
of Salinas, California and is known as the
Tectrol® Atmosphere Pallet System. The
process extends the shelf life of the fruit,
allowing for transport and marketing. It
is also accepted in organic production. It
should be noted that large volumes need to
be shipped to make this process economically
feasible. For more information on the Tectrol® system go to the Transfresh
Web site.
Back to top
Economics
Strawberries are one of the most popular
fruits in the U.S. The majority of commercial
production is in California, Florida,
Oregon, and Washington. Growers in these
states produce 95 percent of reported U.S.
output. Growers in the South, East, and
Midwest generally have small strawberry
acreages located near population centers,
and rely on direct-market sales.
Strawberries are a high-value crop, but they
also have special production requirements,
a short shelf life, and a brief marketing season.
Initial investment in land preparation,
irrigation and other equipment can cost
about $2,000 per acre for a matted row
system (Ernst, 2003) to $10,000 per acre
for a plasticulture system. (Karcher, 2002).
However, plasticulture systems produce earlier
and have higher yields—up to double
the yield of matted row systems. Earlier
harvest may allow producers to receive the
higher prices available at the beginning of
the season.
Organic strawberries are in high demand
and this segment of the organic industry
continues to grow at a rapid pace. Organic
strawberries now rank sixth among all
California organic fresh commodities,
with over 160 organic strawberry growers
registered with the California Organic Program.
(Swezey, 2004b).
Continuous cropping of strawberries is not
possible in an organic system that relies
on crop rotations. The production cycle is
shorter (one to two fruiting years) and yields
are both lower and more variable than in
conventional systems. Labor requirements
may be as much as twice those of a conventional
system. (Pritts and Handley, 1999)
Since they face higher costs of production
(Table 1), organic growers must secure a
premium price in order to make a profit.
Table 1. Sample Organic Strawberry Production Costs
and Returns ($ per acre), Central California Coast, 2003
(Bolda et al., 2003) |
GROSS RETURNS |
|
3,750 12-pound trays @ $8.50 |
$31,875 |
|
|
OPERATING COSTS |
|
Transplants |
$1,323 |
Fertilizers |
$1,114 |
Irrigation |
$704 |
Insect & Disease Control |
$778 |
Materials |
$163 |
Assessment Fees |
$237 |
Harvest Materials |
$6,938 |
Harvest Labor |
$1,500 |
Machine Labor |
$639 |
Non-machine Labor |
$12,399 |
Fuel, lube, repairs |
$273 |
Interest on operating capital |
$881 |
|
|
CASH OVERHEAD COSTS |
|
Insurance, taxes, land rent, etc. |
$2,544 |
NON-CASH OVERHEAD |
|
Buildings, machinery, equipment |
$513 |
|
|
TOTAL COSTS |
$30,006 |
|
|
NET RETURNS |
$1,869 |
California research shows that at median organic production levels, profitable organic production can begin at an average price of $8.00 to $8.50 per 12-pound tray. (Swezey, 2004b) Since a 12-pint flat weighs about 10.25 pounds, profitable organic production at median organic production levels would begin at an average price of about $6.80 to $7.25 per flat. Prices for a 12-pint flat were reported in the Organic Business News Fax Service reports as averaging about $14 farmgate in June and July of 2005, indicating that profi table production is quite possible. In areas where local market demand is strong and a high proportion of the crop is sold directly to the consumer, prices tend to be higher.
As is clear from the chart below, organic strawberry prices generally drop during the April to August period. Use of season extension techniques to bring strawberries to market during other periods of the year can allow producers to capture some of the higher out-of-season prices.
Prices for fresh-market strawberries have been relatively stable in recent years because of increasing demand. However, organic price premiums are declining as larger growers get into organic production, marketing and distribution systems improve, and a larger supply of organic berries reaches the market. For instance, in Monterey County, California, a top strawberry-producing area, price premiums for organic strawberries went from $0.75 per pound in 2001 to $0.11 per pound in 2002. (Monterey County Agricultural Commission, 2003)
Back to top
Marketing
Four basic marketing alternatives are available to the
strawberry grower: wholesale markets, cooperatives,
processing firms, and direct sales to retail outlets
or consumers.
In wholesale marketing, either you or a shipper can
take your crop to the market. Shippers generally sell
and transport strawberries for a predetermined price.
Wholesale marketing is subject to price fluctuations and
is not usually very profitable, compared to direct marketing.
Jim Cochran of Swanton Berry Farm in California,
says, “I consider myself lucky to get five percent of
gross. So, on a twenty-dollar flat of strawberries, (there
is) a dollar for the company to keep.” (Inouye and Warner,
2001). Marketing cooperatives generally use a
daily pooled cost and price, which spreads price fluctuations
among all participating producers. Depending
on your location and size, processors may or may
not be a marketing option. Processors are less likely to
contract with small-acreage growers.
If you are interested in exploring wholesale or processing
markets, a good place to start is the Organic
Trade Association’s Organic Pages Online directory. Using this directory, you can locate organic
strawberry buyers and contact them to learn more about
potential opportunities.
Strawberries are successfully direct-marketed in a
variety of ways, including farmers’ markets, roadside
stands, and pick-your-own (PYO) operations. With pick-your-own operations, you save on harvest costs, but you
must also be willing to accept some waste. The trend
in recent years has been toward an increase in prepicked
strawberry sales at the farm, and a reduced reliance
on pick-your-own marketing. (Poling and Monks,
1994) When Pritts et al. compared the profitability
of retailed berries picked by hired hands to marketing
with a pick-your-own (PYO) strategy, profits were
far lower in the PYO system. (Pritts et al., 1999). Poor
picking by inexperienced customers was assumed to
reduce yield in the PYO by 10 percent. The PYO’s
savings in harvest labor were not outweighed by the
lower price charged to the consumer. For more information
on PYOs, including the results of a survey of
PYO strawberry customers, go to Factors Affecting Consumer Purchases of Direct Market Strawberries (PDF / 1.6M). Local restaurants and retailers such as grocery or
health-food stores are another possible market, but
you must take the time to contact produce managers
and provide good-quality strawberries when stores
require them.
For more information on direct-marketing options, see
the ATTRA publications Direct Marketing, Farmers’ Markets, Community Supported Agriculture, Selling to
Restaurants and Entertainment Farming and Agri-Tourism. For information on organic markets, see ATTRA’s Organic Marketing Resources.
Other ATTRA Publications of Interest
Back to top
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Handley, D.T., A. Wheeler, and J.F. Dill. 2002.
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Hartz, T.K., J.E. DeVay and C.I. Elmore. 1993.
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1020 N. Street, Room 161
Sacramento, CA 95814-5624
916-324-4100
www.cdpr.ca.gov/docs/ipminov/bensuppl.htm
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crops. Second edition. Publication
3311. University of California. p 227.
Karcher, M. 2002. Strawberry plasticulture offers
sweet rewards. June 28. Ohio State University
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A guide to sampling for common pests in New
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Kovach, Joe, and Greg English-Loeb. 1997. Testing
the efficacy of Mycotrol ES, Beauveria bassiana,
on tarnished plant bugs, Lygus lineolaris,
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LaMondia, J.A., W.H. Elmer, T.L. Mervosh, and R.S.
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and G.E Windom. 2002. The use of soil
solarization for the management of soilborne
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plasticulture guide for North Carolina. North
Carolina Cooperative Extension Bulletin AG-515. 16 p.
Pritts, M.P., and M.J. Kelly. 2004. Weed competition
in a mature matted row strawberry planting.
HortScience 39 (5): 1050–1052.
Pritts, M.P., M.J. Kelly and G. English-Loeb. 1999.
Strawberry cultivars compensate for simulated
bud weevil damage in matted row plantings.
HortScience 34 (1): 109-111.
Pritts, M. and D. Handley (eds.). 1999. The strawberry
production guide for the Northeast,
Midwest, and Eastern Canada, NRAES-88. NRAES, Ithaca, New York.
Pritts, Marvin and Mary Jo Kelly. 1999. Trials and
tribulations of weed management in strawberries.
New York Fruit Quarterly. Vol. 7, No. 3.
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Rhainds, M., J. Kovach, G. English-Loeb. 2002.
Impact of strawberry cultivar and incidence of pests on yield and profitability of strawberries under conventional and organic management
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19 (4): 333-353.
Strand, Larry L. 1993. Integrated Pest Management for Strawberries. Pub. 3351. University of
California. p. 15.
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into field soil for Verticillium wilt control in
cauliflower. Plant Disease 83: 124-129.
Sutton, J.C., T.D.W. James, and A. Dale. 1988. Harvesting
and bedding practices in relation to
grey mould of strawberries. Annals of Applied
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Swezey, S. 2004a. Trap cropping the western tarnished
plant bug, Lygus Hesperus Knight, in
California organic strawberries. Proceedings,
California Organic Production and Farming
in the Millennium: A Research Symposium.
July 15, 2004. International House, Berkeley,
California.
Swezey, Sean L. 2004b. Organic Strawberries Continuing
To Grow. American Fruit Grower.
June.
Tilmon, K.J., and M.P. Hoffmann. 2003. Biological
control of Lygus lineolaris by Peristenus spp. in
strawberry. Biological Control, 26 (3): 287-292.
Turns, E. E. 1990. Strawberry breeding has many “ifs.” American Fruit Grower. February
1990. p. 48, 50, 52, 54.
Udayagiri, S., S. C. Welter, and A. P. Norton. 2000.
Biological control of Lygus hesperus with inundative
releases of Anaphes iole in a high cash
value crop. Southwestern Entomologist Supplement
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Weber, C.A. 2003. Biodegradable mulch films for
weed suppression in the establishment year of
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25 (1): 57-68.
Back to top
Further Resources
Print Resources
Cooperative Extension.
Almost every state’s Cooperative
Extension Service has one or more publications on strawberries,
most of them free. Contact your county office. Find your county office online, or if you do not
have access to the Internet, look in your phone book or
call ATTRA.
Funt, R., M. Ellis, and C. Welty (eds.). 1997. Midwest
small fruit pest management handbook, Bulletin
861. Ohio State University, Wooster. 181 p.
$5.50 softbound, $11.00 hardbound plus $3.85 postage
from:
Extension Publications
385 Kottman Hall
2021 Coffey Rd.
Columbus, OH 43210-1044
614-292-1607
Kovach, J., W. Wilcox, A. Agnello, and M. Pritts.
1990. Strawberry scouting procedures. Cornell
Cooperative Extension, Ithaca, New York. 53 p.
Contact:
NRAES, Cooperative Extension
152 Riley-Robb Hall
Ithaca, NY 14853-5701
Maas, J.L. (ed.). 1987. Compendium of strawberry diseases. American Phytopathological Society,
St. Paul, Minnesota. 138 p.
$37 plus $5 shipping and handling from:
APS Press
St. Paul, MN 55121-2097
800-328-7560
Organic Business News
Offers current prices for organic crops (fresh fruits, vegetable and herbs, dairy, grains,
beans, and oilseeds) on a weekly basis through its
Organic Commodity Price Fax Bulletin. Annual subscriptions
(50 issues) are $205 by fax, $110 by U.S.
mail. Visit the Web site for information on subscription
discounts.
Contact:
Organic Business News
Hotline Printing and Publishing
P.O. Box 161132
Altamonte Springs, FL 32716
407-628-1377
407-628-9935 FAX
DnnsClnk@cs.com
Pritts, M., and D. Handley (eds.). 1998. The strawberry
production guide for the Northeast, Midwest,
and Eastern Canada, NRAES-88. NRAES, Ithaca,
New York. 162 p.
$45.00 per copy (plus shipping and handling) from
NRAES, Cooperative Extension
152 Riley-Robb Hall
Ithaca, NY 14853-5701
Proceedings of the North American Strawberry
Growers Association
(Proceedings of the annual meetings).
Contact:
Erin Bruzewski, Executive Secretary
2400 Beck Rd.
Howell, MI 48843
Strand, L. L. 1993. Integrated pest management for
strawberries. University of California Pub.
3351. University of California, Oakland,
California. 142 p.
Electronic Resources
California Strawberry Commission
Midwest Small Fruit Specialists
North American Strawberry Growers
North Carolina Cooperative Extension
Small Fruit
Northwest Berry & Grape Info Net
Oregon Strawberry Commission
Organic Strawberry Production Systems
2005 Southeast Regional Strawberry Plasticulture Production Guide (PDF / 311K)
Strawberry Information Link
Strawberry Production in Florida
Strawberry WebRing
Plant Sources
AG Ammon Nursery Inc.
P.O. Box 488
Chatsworth, NJ 08019
609-726-1370
609-726-1270 FAX
Allen Plant Company
P.O. Box 310
Fruitland, MD 21826-0310
410-742-7123
410-742-7122
410-742-7120 FAX
Boston Mountain Nurseries
20189 N Hwy 71
Mountainburg, AR 72946
501-369-2007
501-369-2007 FAX
pense@valuelinx.ne
Burnt Ridge Nursery
432 Burnt Ridge Rd
Onalaska, WA 98570
360-985-2873
360-985-0882 FAX
burntridge@myhome.net
Cooley’s Strawberry Nursery
P.O. Box 472
Augusta, AR 72006
501-724-5630
Coulter Farms
3871 N Ridge Rd
Lockport, NY 14094
716-433-5335
716-434-5700 FAX
coultfarms@aol.com
Daisy Farms
28355 M-152
Dowagiac, MI 49047
616-782-6321
616-782-7131 FAX
daisyfarms@beanstalk.net
DeGrandchamp’s Nursery
15575 77th St
South Haven, MI 49090
616-637-3915
616-637-2513
info@degrandchamps.com
Edible Forest Nursery
Box 260195
Madison, WI 53726
edforest55@hotmail.com
Edible Landscaping
P.O. Box 77
Afton, VA 22920
434-361-9134
434-361-1916 FAX
Fall Creek Farm & Nursery Inc.
39318 Jasper-Lowell Rd
Lowell, OR 97452
541-937-2973
541-937-3373 FAX
berries@fallcreeknursery.com
Hartmann’s Plant Company
P.O. Box 100
Locata, MI 49063
616-253-4281
616-253-4457 FAX
info@hartmannsplantcompany.com
Indiana Berry & Plant Co, LLC
5218 W 500
South Huntingburg, IN 47542
812-683-3055
812-683-2004 FAX
berryinfo@inberry.com
Jersey Asparagus Farms Inc.
105 Porchtown Rd
Pittsgrove, NJ 08318
800-499-0013
856-358-6127 FAX
jaf@jafinc.com
KM Spooner Farms Inc.
9710 SR 162 E
Puyallup, WA 98374
253-845-5519
253-845-5717 FAX
spoonerkm@aol.com
Krohne Plant Farms Inc.
65295 CR342
Hartford, MI 49057
616-424-5423
616-424-3126 FAX
Lassen Canyon Nursery Inc.
1300 Salmon Creek Rd
Redding, CA 96003
530-223-1075
530-223-6754 FAX
info@lassencanyonnursery.com
Lewis Nursery and Farms Inc.
3500 NC Hwy 133
West Rocky Point, NC 28457
910-675-2394
910-602-3106 FAX
Norcal Nursery Inc.
P.O. Box 1012
Red Bluff, CA 96080
530-527-6200
530-527-2921 FAX
Northwind Nursery & Orchards
7910-335th Ave NW
Princeton, MN 55371
612-389-4920
northwind9@juno.com
Nourse Farms Inc.
41 River Rd
South Deerfield, MA 01373
413-665-2658
413-665-7888 FAX
info@noursefarms.com
One Green World
28696 S Cramer Rd
Molalla, OR 97038
503-651-3005
800-418-9983 FAX
Oregon Exotics Nursery
1065 Messinger Rd
Grants Pass, OR 97527
541- 846-7578
541-846-9488 FAX
Raintree Nursery
391 Butts Rd
Morton, WA 98356
360-496-6400
888-770-8358 FAX
Saint Lawrence Nurseries
325 State Hwy 345
Potsdam, NY 13676
315-265-6739
trees@sln.potsdam.ny.us
Sakuma Bros Farms Inc.
P.O. Box 427
Burlington, WA 98233
360-757-6611
360-757-3936 FAX
craigf@sakumabros.com
Southmeadow Fruit Gardens
P.O. Box 211
Baroda, MI 49101
616-422-2411
616-422-1464 FAX
smfruit@aol.com
Tower View Nursery Inc.
70912 CR 388
South Haven, MI 49090
616-637-1279
616-637-6257 FAX
mnnelson@btc-bci.com
Tripple Brook Farm, Inc.
37 Middle Rd
Southampton, MA 01073
413-527-4626
413-527-9853 FAX
info@tripplebrookfarm.com
Virginia Berry Farm
Box 4
Ruther Glen, VA 22546
800-448-2312
804-448-4430 FAX
berryman@bealenet.com
Weeks Berry Nursery
6494 Windsor Island Rd N
Keizer, OR 97303
503-393-8112
503-393-2241 FAX
plants@weeksberry.com
Whitman Farms
3995 Gibson Rd NW
Salem, OR 97304
503-585-8728
503-363-5020 FAX
lucile@whitmanfarms.com
Back to top
Appendix A: Sources of Thermal
Weeders
Handheld Flamers
BernzOmatic 800-654-9011
Flame Engineering, Inc.
P.O. Box 577
LaCrosse, KS 67548
888-388-6724
785-222-3619 FAX.
flame@awav.net
Red Dragon
Peaceful Valley Farm Supply
P.O. Box 2209
Grass Valley, CA 94945
888-784-1722 (toll-free)
contact@groworganic.com
Flamers and supplies
Rittenhouse & Sons
RR#3, 1402 Fourth Ave.
St. Catharines, ON
Canada L2R 6P9
800-461-1041 (toll-free)
prosales@rittenhouse.ca
Weed Torch
Row Crop Flamers
Flame Engineering, Inc.
Two- to eight-row flamers for tractor operation (see
above).
Thermal Weed Control Systems, Inc.
N1940 State Hwy 95
Neillsville, WI 54456
715-743-4163
jonesconsulting@juno.com
Four- to eight-row flamers for tractor operation,
hooded models
Flame Weeders
Rt. 76, Box 28
Glenville, WV 26351
304-462-5589
flame-weeders@juno.com
Push along
Infrared Weeders
Forevergreen
19974 12 Avenue,
Langley,
BC,
Canada V2Z1W3
604-534-9326
info@chemfree-weedcontrol.com
Ecoweeder, push along and handheld
Rittenhouse & Sons
Infra-Weeder, push along and handheld (see above)
Steamers
Sioux Steamer
One Sioux Plaza
Beresford, SD 57004
605-763-3333
888-763-8833 (toll-free)
605-763-3334 FAX
Hot Foam
Waipuna U.S.A
715 N Independence
Romeoville, IL 60466
630-514-0364
jeffw@waipuna.com
OESCO, Inc.
P.O. Box 540, Route 116
Conway, MA 01341
413-369-4335
800-634-5557 (toll-free)
413-369-4431 FAX
info@oescoinc.com
Aquacide
Infrared and Hot Water
Sunburst
P.O. Box 21108
Eugene, OR 97402
541-345-2272
info@thermalweedcontrol.com
(adapted from Quarles, W. 2004. The IPM Practitioner.
May/June. p. 8.)
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Appendix B: Recommended
Strawberry Varieties
There are many short-day and day-neutral varieties from
which to choose. The day-neutral varieties are: Aromas,
Diamante, Fern, Hecker, Irvine, Muir, Ogallala, Ozark
Beauty, Pacific, Seascape, Selva, Tillicum, Tribute and
Tristar. Choose those that are adapted to your area and
desired production systems. Remember always to check
with the local extension agent when choosing varieties
for your area and plant more than one variety if
you can.
Alaska: Brighton, Fern, Hecker, Irvine, Mrak, Muir,
Ozark Beauty, Ogallala, Quinault, Selva, Streamliner,
Superfection, Tillicum, Tribute, Tristar, Yolo.
www.uaf.edu/coop-ext/publications/freepubs/HGA-00235.pdf (PDF / 798K)
Arkansas: Cardinal, Carmarosa, Chandler, Delmarvel,
Earliglow, Lateglow, Noreaster, Sweet Charlie,
Tribute, Tristar.
www.uaex.edu/Other_Areas/publications/PDF/FSA-6103.pdf (PDF / 74K)
California: Albion, Aromas, Camarosa, Camino
Real, Chandler, Diamante, Gaviota, Oso Grande,
Pacific, Seascape, Selva, Ventana.
www.calstrawberry.com/commission/varieties.asp
Colorado: Catskill, Empire, Fairfax, Fort Laramie,
Geneva, Guardian, Marlate, Ogallala, Ozark Beauty,
Quinault, Redchief, Red Rich, Redstar, Robinson,
Superfection, Tribute.
www.colostate.edu/Depts/CoopExt/4DMG/VegFruit/Fruits/smlfruit.htm
Florida: Calibrate, Camarosa, Florida Belle, Florida
90, Rosa Linda, Sequoia, Sweet Charlie, Strawberry
Festival, Tioga.
www.napa.ufl.edu/2000news/newberri.htm
Georgia: Apollo, Delite, Cardinal, Earliglow, Sunrise,
Surecrop.
www.caes.uga.edu/news/kits/gaagres/commodities/strawberries.html
Idaho: Allstar, Benton, Blomidon, Catskill, Cavendish,
Earliglow, Fort Quinault, Glooscap, Guardian,
Honeoye, Jewel, Laramie, Lateglow, Lester, Micmac,
Redchief, Scott, Shuksan, Surecrop, Totem, Tribute,
Tristar.
www.extension.uidaho.edu/idahogardens/fvh/straw.htm
Illinois: Allstar, Annapolis, Delmarvel, Earliglow,
Honeoye, Jewel, Kent, Seneca, Tribute, Tristar.
www.urbanext.uiuc.edu/strawberries/growing.html
Indiana: Delite, Earliglow, Fort Laramie, Guardian,
Sunrise, Ozark Beauty, Redchief, Sparkle, Surecrop.
www.hort.purdue.edu/hort/courses/HORT414/Strawberrylecture.html
Iowa: Annapolis, Cavendish, Delmarvel, Honeoye,
Jewel, Kent, Mohawk, Primetime, Winona.
www.ag.iastate.edu/farms/2001reports/se/StrawberryVarietyTrial.pdf (PDF / 11K)
Kansas: Allstar, Earliglow, Guardian, Northeaster,
Ogallala, Ozark Beauty, Primetime, Redchief, Tribute,
Tristar.
www.oznet.ksu.edu/library/hort2/mf598.pdf (PDF / 216K)
Kentucky: Camarosa, Chandler, Jewel, Northeaster,
Sweet Charlie.
www.ca.uky.edu/agc/pubs/pr/pr410/small.htm
Maine: Allstar, Bounty, Catskill, Earliglow, Guardian,
Lateglow, Midway, Mira, Mohawk, Northeaster,
Surecrop.
www.umext.maine.edu/onlinepubs/htmpubs/2184.htm
Massachusetts: Catskill, Earlidawn, Fletcher,
Guardian, Midway, Raritan, Redchief, Sparkle, Surecrop.
Michigan: Annapolis, Earliglow, Honeoye, Redchief,
Glooscap, Allstar, Jewel, Bounty, Tribute, Tristar.
http://web1.msue.msu.edu/vanburen/strawvar.htm
Minnesota: Cavendish, Kent, Mesabi, Winona.
www.extension.umn.edu/extensionnews/2002/NewStrawberryVarieties.html
Missouri: Allstar, Cardinal, Earliglow, Guardian,
Honeoye, Jewel, Lateglow, Ogallala, Ozark Beauty,
Redchief, Sparkle, Surecrop, Tribute, Tristar.
http://muextension.missouri.edu/xplor/agguides/hort/g06135.htm
New Hampshire: Allstar, Cavendish, Cornwallis,
Earliglow, Redchief, Sparkle.
http://extension.unh.edu/Pubs/HGPubs/growstra.pdf (PDF / 53K)
New Jersey: Delmarvel, Earliglow, Guardian, Latestar,
Lester, Northeaster, Raritan, Redchief, Sparkle,
Tribute, Tristar.
New Mexico: Everbearing (‘Superfection’), Fern,
Fort Laramie, Gem, Guardian, Ogallala, Ozark
Beauty, Quinault, Robinson, Selva, Sequoia, Streamliner,
Surecrop, Tribute, Tristar, Tufts.
www.cahe.nmsu.edu/pubs/_h/h-324.pdf (PDF / 53K)
New York: Allstar, Bounty, Cavendish, Delite, Earliglow,
Fletcher, Guardian, Honeoye, Jewel, Kent, Raritan,
Redchief, Scott.
www.cce.cornell.edu/counties/Suffolk/grownet/SMFRUIT/strawberry.htm
North Carolina: Camarosa, Chandler, Gaviota, Gem
Star, Oso Grande, Sweet Charlie, Treasure.
www.ncstrawberry.org/docs/ProductionMethods.htm
North Dakota: Dunlap, Ft. Laramie, Gem, Honeoye,
Redcoat, Stoplight, Trumpeter.
www.ext.nodak.edu/extpubs/plantsci/hortcrop/h16w.htm
Ohio: Delite, Earliglow, Guardian, Kent, Lateglow,
Lester, Midway, Redchief, Surecrop, Tribute.
http://ohioline.osu.edu/hyg-fact/1000/1424.html
Oklahoma: Albritton , Allstar, Arking, Blakemore,
Canoga, Cardinal, Chandler, Delite, Earliglow,
Fletcher, Guardian, Holiday, Hood, Lateglow, Luscious
Lady, Ozark Beauty, Scott, Spring, Sunrise,
Surecrop, Tennessee Beauty, Trumpeter.
Oregon: Benton, Fern, Ft. Laramie, Hecker, Hood,
Olympus, Ozark Beauty, Puget Reliance, Quinault,
Rainier, Redcrest, Selva, Sumas, Tillikum, Tristar,
Totem.
http://extension.oregonstate.edu/catalog/html/ec/ec1307/
Pennsylvania: Allstar, Annapolis, Cavendish, Delite,
DelMarvel, Earliglow, Guardian, Honeoye, Idea,
Jewel, Kent, Lateglow, Latestar, Lester, Mohawk,
Northeaster, Primetime, Raritan, Redchief, Seneca,
Settler, Sparkle, Tribute, Tristar, Veestar.
South Carolina: Albritton, Apollo, Cardinal, Chandler,
Delite, Douglas, Earliglow, Florida 90, Sunrise,
Surecrop, Tioga.
Texas: Allstar, Cardinal, Chandler, Douglas, Pajaro,
Sequoia.
http://aggie-horticulture.tamu.edu/hillcountry/Strawberries/intro.html
Utah: Fort Laramie, Guardian, Hood, Ozark Beauty,
Robinson, Selva, Sequoia, Surecrop, Tristar.
Virginia: Allstar, Delite, Delmarvel, Earliglow, Honeoye,
Lateglow, Ozark Beauty, Redchief, Sunrise,
Surecrop, Tribute, Tristar.
www.ext.vt.edu/pubs/envirohort/426-840/426-840.html
Washington: Hood, Nanaimo, Puget Reliance,
Quinault, Rainier, Selva, Shuksan, Tillicum, Totem,
Tribute, Tristar.
http://gardening.wsu.edu/library/smfr009/smfr009.htm
Wisconsin: Annapolis, Cavendish, Crimson Fern,
Fort Laramie, King, Earliglow, Glooscap, Honeoye,
Jewel, Kent, Lategrow, Lester, Mesabi, Mira, Ogallala,
Ozark Beauty, Raritan, Redchief, Seascape, Selva,
Seneca, Sparkle, Tribute, Tristar, Winona.
http://learningstore.uwex.edu/pdf/A1597.pdf (PDF / 962K)
Acknowledgment
The authors would like to thank Wyatt Brown, PhD, of
the Horticulture and Crop Science Department at Cal
Poly San Luis Obispo for his insightful review. |
Strawberries: Organic Production
By Martin Guerena and Holly Born
NCAT Agriculture Specialists
Paul Driscoll, Editor
Tracy Mumma, HTML Production
IP046
Slot 39
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