Scouting Notes - August 2007

California: Watch for tomato virus. In March, the virus that causes tomato yellow leaf curl was discovered on greenhouse tomatoes grown by a California high school science class. Since this disease is new to the state, University of California plant pathologist Robert Gilbertson worked with UC Statewide IPM to develop a brochure to inform growers and advisers about the disease. The virus is vectored by thrips and whiteflies.

For more: Robert Gilbertson, University of California, (530) 752-3163; www.ipm.ucdavis.edu.

Fungus may control whitefly. A new fungal species, Isaria poprawskii, has been shown to be an entomopathogenic species that can parasitize and then kill or disable silverleaf whitefly (Bemisia argentifolii). Studies by scientists at the USDA-ARS Beneficial Insects Research Unit in Weslaco, Texas, have shown the fungus is effective against both whitefly larvae and adults. The fungus has also been found to harm the larvae and adults of glassy-winged sharpshooter, Homalodisca vitripennis.

The fungus can survive in the absence of insect hosts, has high spore production in common culture media and can establish in semiarid regions where temperatures reach 107°F.

For more: H. Enrique Cabanillas, USDA, (956) 969-4861; ecabanillas@weslaco.ars.usda.gov.

Mexico prohibits shipments to avoid moth. Effective May 10, Mexico prohibited shipment of propagative plants, fruit and vegetables that are host of light brown apple moth (Epiphyas postvittana) from Hawaii and from any California counties where the moth has been detected. From all other counties, host fruits and vegetables must be accompanied by a phytosanitary certificate and must be free of leaves and residual debris. Host propagative plants must be accompanied by a phytosanitary certificate and a declaration that the shipment is coming from a Mexican-approved company or exporter.

For more: California Department of Food and Agriculture, (916) 654-0466; www.cdfa.ca.gov.

Catnip attracts predator. Compounds from catnip may have the potential to attract natural predators. Chemist Kamal Chauhan at USDA’s Agricultural Research Service discovered a method for separating compounds from catnip oil. He found that a compound derived from Z,E-nepetalactone attracts lacewings.

Chauhan’s discovery provides an economical way to make large amounts of the desired compounds. The attractant is environmentally benign and remains active for five weeks, degrading slowly. Chauhan is working with Sterling International to commercialize formulations that attract specific beneficials.

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For more: Kamal Chauhan, ARS Chemicals Affecting Insect Behavior Laboratory, (301) 504-5166; chauhank@ba.ars.usda.gov.