STORY LEAD:
Microbes Help Scientists Sucker Sap Beetles
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ARS News Service
Agricultural Research Service, USDA
Ben Hardin, (309) 681-6597, bhardin@asrr.arsusda.gov
April 19, 1999
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For the first time, scientists have identified chemical signals that
pineapple beetles heed to find food. The pests swarm to unusual airborne
compounds made by microbes in addition to more common aromas emitted by
decaying fruit.
The discovery by Agricultural Research Service scientists gives researchers
a broader view for finding ways to synthesize "calling cards" to most
effectively trap various species of nitidulids, also known as sap beetles.
Someday, traps that monitor nitidulids may be used by growers and shippers
to decide whether to apply pesticides.
Nitidulid control may become increasingly important with the advent of
"green" methods to control other insects. For example, some sweet corn is
genetically engineered with a protein to fight off caterpillars, reducing
the need for insecticide applications. Nitidulids are undeterred by the
protein. As use of insecticides that normally control both types of insects
is discontinued, nitidulids may thrive and inflict widespread kernel damage.
In addition to munching on pineapple, the pineapple beetle—Carpophilus
humeralis—feeds on dates, citrus and sugarcane.
In tests at the National Center for Agricultural Utilization Research at
Peoria, Ill., three newly isolated microbial compounds attracted the
pineapple beetles in a wind tunnel. The compounds were
4-ethyl-2-methoxyphenol, 2,5-diisopropylpyrazine and 2-phenylethanol. The
pyrazine had never before been found in nature.
Generally, Robert J. Bartelt, an entomologist with USDA's Agricultural
Research Service, and Bruce Zilkowski, a technician turned support
scientist, have found that when males of other nitidulid species get a whiff
of a favorite fermenting food, they make their own additional chemical
attractants called pheromones to call males and females alike to dinner. An
d it seems, the more complex the mix, the merrier.
The researchers have synthesized pheromones produced by nine other nitidulid
species.
An article about the sap beetle research appears in the April issue of
Agricultural Research magazine, available online at:
http://www.ars.usda.gov/is/AR/archive/apr99/micr0499.htm
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Scientific contact: Robert J. Bartelt, ARS National Center for Agricultural
Utilization Research, Peoria, Ill., phone (309)681-6237,
bartelrj@mail.ncaur.usda.gov.
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