News and Reviews

Biological Control at National Entomology Society Meetings

Biological control of insects was the topic of numerous oral and poster presentations at the National Meeting of the Entomological Society of America in Las Vegas, December 17-21. Many of these will be the basis of future articles in MBCN. The following are very brief summaries of a few presentations. (Only the presenting author is mentioned).

1. Integrated biological control of leafminers, Liriomyza trifolii, on chrysanthemum - R. Sher, Univ. Calif. - Davis

Nematodes alone are not sufficient for control of leafminers, but nematode infection reduces emergence of the parasitic wasp Diglyphus begini. However, wasps preferentially choose uninfected leafminers to lay eggs in, and nematodes infected more healthy than wasp-paralyzed leafminers.

2. Inundative releases of aphelinid parasitoids to control Bemisia argentifolii - M. Hoddle, Univ. Mass.

The silverleaf whitefly parasitoid Eretmocerus californicus is a much more efficient host-searcher than is Encarsia formosa. Because it's so efficient, at high release rates it usually kills most of the whiteflies by hosts-feeding so that few are left for reproduction.

3. Egg parasitoid of Empoasca fabae: Density and distribution in alfalfa monoculture and alfalfa-orchardgrass diculture - D. Liewehr, Univ. Maryland

Anagrus nigriventris, an egg parasitoid of potato leafhopper, averaged 69% parasitism in the third cutting, but was substantially less in the second and fourth cuttings.

4. Establishment, distribution, and impact of Lathrolestes nigricollis on the birch leafminer in New England -R. Van Driesche, Univ. Mass.

This wasp parasitizes mature leafminer larvae before pupation. Originally released at 3 sites in New England, it is now widespread throughout the Northeast. Although it can have a substantial impact on leafminer populations, control and damage reduction is not rapid.

5. Control of strawberry root weevil and Colorado potato beetle with indigenous entomopathogenic nematodes - R. Berry, Oregon State Univ.

Heterorhabditis marelatus, a new species of nematode discovered in Oregon, is a cool-temperature adapted species that may provide better control of soil pests in northern temperate areas. At cool temperatures it outperformed other species of nematodes for controlling strawberry root weevil, and provided complete control of last instar Colorado potato beetle (as they moved down into the soil).

6. Preliminary evaluation of Trichogramma platneri for control of obliquebanded leafroller in apples - R. Pfannenstiel, Tree Fruit Res. Cent., Wenatchee, WA

They had relatively high levels of parasitism, indicating this species of Trichogramma is a promising parasitoid of leafrollers.

7. Attraction of natural enemies to sugar applications in Honduran maize - L. Canas, Purdue Univ.

Sugar applications seem to increase the activity of natural ememies in tropical corn: higher numbers of natural enemies were associated with fewer fall armyworms.

8. Evaluation of a resistant parasitoid for biological control of weevils in insecticide-treated wheat - J. Baker, U.S. Grain Marketing Res. Lab, Manhattan, KS

Anisopteromalus calandrae parasitizes insects feeding internally in grain kernels. A malathion-resistant strain can parasitize weevil larvae even when sprayed, so the parasite and insecticide can be integrated in a control program.

9. Behavior and efficacy of filth fly hymenopterous parasitoids on Nebraska feedlots - J. Peterson, USDA, Lincoln, NB

In the Midwest, early spring temperatures are cool, so there is a delayed response from wasp parasite releases made then. Hot temperatures also suppress parasite activity. Releases from sheltered locations within the feedlot are best - just sprinkling them over the ground results in pupae cooked in the sun or trampled by cows before the wasps emerge. Release techniques are very important to successful biological control!

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