![Photo: Two apples. Link to photo information](https://webarchive.library.unt.edu/eot2008/20081106055143im_/http://www.ars.usda.gov/is/pr/2008/apples081023.jpg) ARS scientists are working on
a new way to rid stored apples of codling moth larvae. Click the image for
more information about it. |
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Scientists Pit Fungus against Apple Pest
By Jan
Suszkiw October 23, 2008
A cocktail of gaseous compounds emitted by a beneficial fungus
may offer a way to biologically fumigate stored apples, ridding them of codling
moth larvae.
That's the implication of studies conducted by entomologist
Lerry
Lacey and others at the Agricultural
Research Service's (ARS)
Yakima
Agricultural Research Laboratory in Wapato, Wash. In earlier studies, they
showed that a blend of alcohols, esters and other gases released by the fungus
Muscodor albus killed adult potato tuber moths and larvae, costly pests
of stored tubers. The ARS researchers' work is part of a cooperative agreement
with AgraQuest, Inc., of Davis,
California.
In the Pacific Northwest, codling moths (Cydia pomonella) are
problematic for both growers and distributors. Stored apples are often
fumigated with broad-spectrum chemicals when the fruit is destined for foreign
markets. However, biobased treatments may provide options for codling-moth
control with economic and environmental advantages over standard chemical
fumigation.
The Wapato team's investigation of M. albus falls under a
larger program to diminish reliance on synthetic chemical controls by using
biocontrol agents in an integrated pest management approach.
In laboratory trials, Lacey placed adult codling moths inside special
fumigation chambers and exposed them for three days to fungal fumes that killed
83 percent of the insects. Similarly exposing the larvae killed up to 87
percent, depending on their developmental stage. The fungal gases even reached
larvae that burrowed inside apples, killing 73 percent of the pests.
Although the initial short-exposure tests didn't yield results
comparable to broad-spectrum chemicals, biofumigation's full potential has yet
to be evaluated within apple cartons, where the pests will be exposed to fungal
fumes for prolonged periods of time. For example, 14-day exposures of the
moth's overwintering stage--cocooned larvae, which are the hardest to
control--resulted in 100% mortality.
Research by AgraQuest and others has also shown Muscodor's potential
to kill other fungi and bacteria harmful to stored fruit and vegetables and to
humans.
ARS is a scientific research agency of the
U.S. Department of Agriculture.