News and Reviews

Biological Control at National Entomology and Plant Pathology Meetings

The following is a continuation of brief summaries of some presentations made at the joint Meeting of the Entomological Society of America and American Phytopathological Society in Las Vegas (see previous issues).

1. Effect of the imported fire ant pathogen, Thelohania solenopsae, on nontarget ant species - D. Williams, USDA, Gainesville, FL

T. solenopsae apparently only infects imported fire ants, and has not been recovered in colonies of other ant species in Southern states where surveys have been conducted. Infection could not be detected either in laboratory colonies of non-target ants intentionally exposed to the microsporidium.

2. Transmission of the entomopathogen, Thelohania solenopsae, within red imported fire ant colonies - D. Oi, USDA, Gainesville, FL

T. solenopsae -- a microsporidium pathogen of imported fire ants -- slowly debilitates the queen, reduing egg production and eventually killing her. Colonies can be infected by introducing infected larvae, but infected workers do not directly infect the queen; infected workers infect larvae which may lead to queen infection.

3. Effect of Naturalis-T, Beauveria bassiana, on turfgrass beneficial invertebrates - L. Allee, Cornell Univ.

Populations of ants, spiders, rove beetles, ground beetles, and earthworms were not significantly lower in turf plots after fungus applications. Percent infection was highest in spiders, lower in ants and rove beetles, and zero in ground beetles and earthworms.

4. Biological control of Fusarium wilt diseases by nonpathogenic Fusarium spp.: Formulations and field efficacy - R. Larkin, USDA, Beltsville, Maryland

Isolate CS-20 consistently reduced the incidence of Fusarium wilt of tomato 40-50% and of muskmelon 43-59%. It also increased total fruit yield of tomato. Granular formulations were effective for tomato in greenhouse tests.

5. Evaluation of repellents and microbial insecticides for grasshopper control in gardens - N. Demirel, Colorado State Univ.

In lab bioassays, Botanigard WP (B. bassiana) and Conserve SC (spinosad) showed good activity in control of migratory grasshoppers. Trilogy and BioNeem (neem oil) reduced grasshopper feeding in the lab, while Hot Pepper Wax reduced feeding in one field trial, but garlic sprays did not.

6. Selection of antagonistic Bacillus strains for biological control of Rhizoctonia solani on bedding plants - D. Norman, Univ. Florida

None of the 7 species of Bacillus tested suppressed Rhizoctonia on impatiens as well as fungicides did, but some have potential if applied at seeding and transplanting when they aid plant growth in soilless mixes.

7. Early spring grazing as a component of alfalfa integrated pest management - R. Berberet, OK State Univ.

Alfalfa weevil larvae and aphids were so effectively controlled by early spring cattle grazing that only a single insecticide application was needed in one of the four years of the study. Grazing also aided in the control of cool-season weeds, and did not reduce stand density or yield compared to prebud or early bloom harvesting.

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