Entomologist studies harmful insects, natural predators
By JOHN SCHMITZ
For the Capital Press
CORVALLIS, Ore. -- USDA-ARS entomologist Jana Lee spends a lot of time working with good guys and bad guys. But she's no cop.
The bad guys in her world are insects that can do harm to plants and crops. The guys in the white hats are beneficial predators and naturally occurring compounds she hopes will disable the bad guys in one way or another.
Lee, who works out of the USDA-ARS Horticultural Crops Research Lab on the Oregon State University Campus in Corvallis, spoke to nurserymen in Portland earlier this year about the experimental work she's doing with beneficial organisms and materials.
One compound that shows promise in attracting friendly predator insects to the defense of spruce and red maple production fields is methyl salicylate, or oil of wintergreen.
"It's commercially available, and a natural odor produced by many plants when they're being fed upon by herbivores," Lee said.
Methyl salicylate has been shown to attract ladybugs, green lacewings and minute pirate bugs, which, among other beneficial insects, destroy destructive pests.
"Luckily, it's fairly cheap to produce, a little over $1.20 a packet," Lee said.
While methyl salicylate has proven itself under commercial field conditions in three different studies, it may also have applications in greenhouses, Lee said.
In one study, where methyl salicylate was used on 5-gallon, Alberta spruce container trees up to 4 feet tall, tiny parasitic wasps the compound attracted left in their wake numerous parasitized aphids.
Aphids cause wax buildup on plant needles and also deform the needles.
The wasps lay their eggs inside the aphid.
In red maple nursery fields, Lee has been successful in using methyl salicylate to draw parasitic wasps and green lacewings.
Green lacewings "attack anything from aphids to mites -- anything soft-bodied," Lee said.
While destructive spider mites were not affected, both aphid and thrips counts were lower near methyl salicylate traps.
Methyl salicylate, which is manufactured by AgBio and sold under the tradename PredaLure, is distributed in fields in little packets. Methyl salicylate is also sold by other companies in liquid form to mask unpleasant odors of pesticides.
Lee, who has a doctorate in entomology from the University of Minnesota, has also been working on finding a predator for black vine weevil with Oregon State University Extension pest expert Robin Rosetta.
"We are looking into whether a predator mite (will) eat new larvae."
Black wine weevil larvae, which emerge from eggs laid on the soil surface and then work their way downward, feed on the roots of many different ornamental plants.
So far in the preliminary study, the mites have performed well in a laboratory setting, Lee said.
Other pests Lee and her associates are targeting for natural control include the drosophila vinegar fly, white flies, scales and mealybugs, which are preyed on by parasitic wasps, and fungus gnats and shore flies, which are controlled by predatory mites and rove beetles.
In addition to experimenting with odors that attract beneficial insects, Lee is also looking at odors that will repel pests.
Lee said that interest in biological controls is growing among nurserymen.