[NAFEX] FW: Virus Can Attack Apple Worm

Lon J. Rombough lonrom at hevanet.com
Mon Aug 16 11:03:08 EDT 2004

From: ARS News Service <NewsService at ars.usda.gov>
Reply-To: ARS News Service <NewsService at ars.usda.gov>
Date: Mon, 16 Aug 2004 08:03:52 -0400
To: ARS News subscriber <lonrom at hevanet.com>
Subject: Virus Can Attack Apple Worm

Insect Virus Targets the Proverbial Worm in the Apple

ARS News Service
Agricultural Research Service, USDA
Jan Suszkiw, (301) 504-1630, jsuszkiw at ars.usda.gov
August 16, 2004

A virus that infects and kills codling moth larvae can offer fruit growers
an insecticide alternative for fighting the pest, Agricultural Research
Service studies suggest.
ARS entomologists Lawrence Lacey and Steven Arthurs conducted tests in 2003
at four Washington State apple orchards, where they sprayed trees with the
Cydia pomonella L. granulovirus. The treatment killed moth larvae for up to
14 days, with 94 percent becoming infected within the first few days of
application. All infected larvae died shortly thereafter. Lacey and Arthurs,
with the agency's Fruit and Vegetable Insect Research Unit at Wapato, Wash.,
reported their findings in the journal Biological Control.

Besides apples, codling moths attack walnuts, pears and other fruit. The
larvae damage the fruit by boring deep inside it, ruining marketability.

Until integrated approaches to controlling codling moths were adopted in the
Pacific Northwest--including use of sex pheromones to disrupt the moths'
mating--the standard defense was to spray orchards with insecticide. But
such spraying is costly, ecologically worrisome and dangerous to beneficial
insects. Although heavy infestations of codling moths may still necessitate
insecticide use, moderate infestations can be subdued by combining
biocontrol agents with mating disruption or other measures.

Researchers have studied the granulovirus for 30 years, thoroughly
documenting its safety, host specificity and biocontrol potential. Even so,
fruit growers have been slow to use it. Lacey attributes this to
formulation, quality and other problems tied to early granulovirus products,
including their rapid degradation by sunlight.

The recent study compares the persistence and effectiveness of three new or
improved formulations, which the manufacturers registered for use on apples,
pears, walnuts and plums. The key is timing the applications of granulovirus
so they prevent larvae from penetrating the fruit too deeply. Infected
larvae die in five to 10 days, but the granulovirus poses no threat to
humans, other mammals or non-host insects.

ARS is the U.S. Department of Agriculture's chief scientific research

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