Dr. George Heimpel is the latest addition to the Department of Entomology at the University of Minnesota. George completed his doctorate at University of California-Davis and spent a few years in Madison, Wisconsin as a post-doctoral associate. He has worked on biological control of armored scales by Aphytis parasitoids, cover-cropping in orchards, biological control and genetic diversity of natural enemies, and parasitoid sex ratios and biological control. At Minnesota his research will focus on interactions between biological control and transgenic crops, habitat management for natural enemies, and quality control of commercially-reared biological control agents.
At the annual meeting of the North Central Regional Committee on Biological Control of Pest Arthropods in October (NCR-125), state representatives reported on biological control activities in their states. Some of the many projects are summarized here. For further information contact the state representatives that are listed.
Two databases concering insect pathogens can be accessed at http://insectweb.inhs.uiuc.edu. The Ecological Database of the World's Insect Pathogens contains over 8,000 records for parsitism by viruses, bacteria, nematodes, protozoa and fungi. The Viral Diseases of Insects in the Literature database can be searched by keywords to find literature published up to 1980.
Scotch pine trees infested with pine needle scale were placed in different habitats and monitored to identify pine needle scale natural enemies and evaluate the prevalence and efficacy of scale parasitoids in East Central Illinois.
A new wasp parasite from China is being tested for its effectiveness against European corn borer in the laboratory.
Foreign exploration for natural enemies of Colorado potato beetles continues. The egg parasitioid Edovum puttleri was collected from three high altitude sites; preliminary investigations suggest a new biotype that has higher parasitism rates.
Research on the parasitoid Leptomastix dactylopii shows that plant architecture influences its attack rate on mealybugs.
Field trials showed that strip tilling killed rye decreases defoliation in potato by Colorado potato beetle.
Companion plantings in vegetables increased natural enemy activity, but did not reduce insect damage on most crops.
Iowa - John Obrycki and Les Lewis (USDA)
Colonization of corn by Beauveria bassiana was studied to ascertain how the fungus gets into the plant.
In an assessment of both biotic and abiotic factors affecting European corn borer populations, mortality averaged 95%.
Augmentative releases of Trichogramma brassicae produced a maximum of 54% parasitism of European corn borer egg masses in field corn compared to 93% in European trials.
Attempts to reduce dispersal of convergent lady beetles by releasing preconditioned beetles and using sugar and protein sprays were only moderately successful.
Studies of carabid beetles in corn fields indicate that the most abundant beetles are arthropod predators (few are seed predators) and these beetles had a significant impact on the experimental prey used in the studies.
Epizootics of the gypsy moth fungus Entomophaga maimaiga were observed at four sites in Michigan, even where gypsy moth populations were low. Infection varied weekly, from 30-99%, with high cumulative mortality over the season.
The USDA's cereal leaf beetle project focused on collecting parasitized larvae for redistribution and on education programs.
A survey of Midwestern greenhouse operators indicated only 10% of growers are using biological control in commercial greenhouse production, and success rates of 50% or less for most biological control agents must be improved if greenhouse operators are to continue using biological control as part of their pest management programs.
A series of on-farm studies is planned to evaluate different cultural practices for controlling house flies by conservation of manure-inhabiting predators and parasites in closed, high-rise poultry production
In late fall, only 31% of the pea aphid mummies collected from alfalfa fields contained the primary parasite Aphidius ervi; the remaining 69% had the hyperparasite Asaphes lucens. Despite the high percentage of fall hyperparasitism, up to 56% of pea aphids were parasitized by A. ervi the following spring.
Ants, spiders, ground beetles, rove beetles, bigeyed bugs and parasites were some of the beneficial insects associated with buffalograss plots. A parasitoid wasp, Rhopas nigroclavatus, was reared from buffalograss mealybug.
North Dakota - Denise Olson and Larry Charlet (USDA)
Sunflower beetle larvae were collected from five species of native sunflowers at 25 sites in North Dakota and Minnesota and dissected to determine the presence of larval parasitoids. About half of the sites had larvae that were parasitized by Myiopharus macellus (a tachinid fly). Larvae were also collected from commercial fields at 13 locations in North Dakota and Minnesota ; 62% of these locations had larvae parasitized by M. macellus.
Replacement of broad spectrum insecticides with pest specific biorational insecticides increased the diversity of the natural enemy complex in potatoes and cabbage, leading to enhanced biological control of pests such as aphids.
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