Lab Diets for Two Pest Insects
|| The Y2K bugs at
ARS' Insect Biocontrol Laboratory in
Beltsville, Maryland, aren't of the computer kind. Rather, they're two
crop-attacking insects: the Colorado potato beetle and the silverleaf whitefly.
Both are the focus of separate, though related, projects of entomologists Dale
B. Gelman, Robert A. Bell (now retired), Jing S. Hu, and Michael B. Blackburn.
As part of their research, these scientists are creating artificial diets to
sustain lab colonies of the insect pests so new weaponry can be more easily
tested against them.
Furthest along is work against the beetle, whose larvae cost tomato, potato,
and eggplant growers over $150 million annually in losses and insecticide
The pesticide Admire is a standard defense, but experts fear the beetle may
soon develop resistance to it. That's why the Beltsville team is looking for
ways to streamline research aimed at finding insecticide replacementsor
biological alternatives like parasitic Edovum puttleri wasps.
Until now, rearing lab colonies of beetles meant feeding them on a living host,
such as potato plants. But growing the plants is expensive and time-consuming.
So Gelman's lab developed a relatively simple artificial diet using oats,
lettuce, potato leaf powder, and other ingredients. Dried into powder, lettuce
replaces most of the potato leaf material normally required. In addition to
cutting costs, "lettuce is easier to obtain because you can buy it at the
grocery store," Gelman says.
More importantly, it stimulates most beetles to eat the diet. Gelman's lab has
reared nine beetle generations on it so far. After analyzing each generation's
average weight, growth, egg production, and other data, the scientists plan to
publish their findings.
Indications are "the diet will prove useful for growing beetles in the lab
for research purposes," says Gelman. "And you can rear them on it
year-round in a cost-effective manner."
Gelman, Hu, and Blackburn are also artificially rearing silverleaf whiteflies
to better understand the growth requirements of wasps like Encarsia
formosa that parasitize the pests.
They hope that by learning to rear the whiteflies, an artificial wasp diet can
be created. However, "this project is still in its infancy," Gelman
says. "Right now, we're just dissecting the parasites out of the
whiteflies and seeing how they develop."By
Agricultural Research Service Information Staff.
Dale B. Gelman, Michael B.
Blackburn, and Jing S. Hu are at USDA-ARS
Laboratory, Bldg. 003, 10300 Baltimore Ave., Beltsville, MD 20705-2350;
phone (301) 504-8909, fax (301) 504-8190.
"Lab Diets for Two Pest Insects" was published in the
issue of Agricultural Research magazine.