Fruit & Vegetable Magazine

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Pear pest’s chemical “come hither” identified


July 7, 2010
By USDA-ARS

Topics

pearpsyllaJuly
6, 2010, Wapato, WA – Pear psylla is a cicada-like pest with a vexing tendency
to develop resistance to insecticides. But now, a new weapon could be in the
works.



July
6, 2010, Wapato, WA – Pear psylla is a cicada-like pest with a vexing tendency
to develop resistance to insecticides. But now, a new weapon could be in the
works.

Agricultural
Research Service (ARS)
and University of California-Riverside (UCR) scientists
have jointly identified a key component of the female psylla’s chemical sex
attractant, or pheromone, which could set the stage for luring amorous males to
their doom.

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Entomologists
Christelle Guédot, Dave Horton and Peter Landolt at the ARS Yakima Agricultural
Research Laboratory
in Wapato, Wash., discovered the compound, 13 methyl
heptacosane (13-MeC27), in collaboration with Jocelyn Millar, a professor of
entomology at UCR’s College of Natural and Agricultural Sciences.

Besides
luring male psylla onto sticky traps, the compound’s discovery could give rise
to lures for either monitoring the pest or disrupting its mating. Both
approaches could diminish the reliance on insecticides – saving growers money,
sparing beneficial insects, and forestalling the pest’s development of
insecticide resistance. 

Pear
psylla’s most damaging stage is the nymph. The flat, red-eyed nymphal stage
causes reductions in fruit quality as its honeydew drips onto and marks developing
fruit. Heavy infestations cause premature leaf fall and loss of yield.

Researchers
performed chemical analyses and behavioral assays to isolate and then identify
the volatile chemicals extracted from female pear psylla that were most
attractive to males. The team’s studies showed that 13-MeC27 was the most
attractive of several chemicals evaluated. Laboratory assays were then done
which confirmed that the attractiveness of the compound to males was equivalent
to male response to females. Experiments in pear orchards confirmed that the
compound is attractive to males and can be used to bait traps to capture pear
psylla.

Under
a patent application filed in September 2009 by ARS on behalf of the U.S.
Department of Agriculture (USDA)
, the scientists intend to combine 13-MeC27
with other attractants to produce blends for use in pheromone dispensers, bait
stations or traps.

The
team recently published its findings in the Journal of Chemical Ecology.