Matteson, Nancy A.

Stoltz, Robert L.

Undetermined

ScholarsArchive@OSU

Section VIIForage & Seed InsectsEVALUATING TRICHOGRAMMA AGAINST EGGS OF THE WESTERNBEAN CUTWORMR.-L. Stoltz and N. A. MattesonUniversity of Idaho, Twin Falls R and E CenterP.O. Box 1827, Twin Falls, ID 83303-1827208/736-3600bstoltz@uidaho.edu,nmatteson@uidaho.eduWestern bean cutworm moths were live-trapped and allowed to lay eggs on corn plants in cagesin the insectary. Approximately 250 one to three day-old eggs left on corn leaves were stapled to3x5 cards. The cards were then stapled on to the bottom of a bean leaf of an individual beanplant in a commercial bean field. Bean plants with eggs were approximately 2 m apart. Afteraffixing the eggs to the plant, 4-6,000 Trichogramma (one square of commercially producedinsects) were placed at the base of each plant in a plastic cup. Each plant was then covered witha 5 gal paint bucket that had been modified to allow air circulation and screened to keep insectsin the bucket. Five species of Trichogramma and untreated check eggs were replicated fourtimes in a RCB. After three days in the cage with Trichogramma, the eggs were removed. Theegg parasites were allowed to develop and after seven days the no. of parasitized and non-parasitized eggs were counted. Data were analysed using ANOVA and Newman- Keuls meanseparation tests.Eggs in cages without Trichogramma received 2.5% parasitism because the wasps wereemerging while being put into the field. Percent egg parasitism rates for T bactrae, T minutum,T. brassicae, T platneri, and T. pretiosum were 3.5, 57.8, 30.4, 33.6, and 38.8%, respectively.Because of variation in parasitism rates, only T. minutum was significantly different from thecheck while the others were intermediate in significance.Check squares of Trichogramma were allowed to emerge in the lab to test for percentemergence. Lab emergence was good for all species. However, emergence is not a good indexof vigor. Lack of vigor may have contributed to variation in the results. These results are thereverse of tests conducted in 1995where T bactrae was the only species to show any degree ofegg parasitism ofwestern bean cutworm eggs.C:\l 997pnw\97trich97.doc97

Evaluating Trichogramma Against Eggs of the Western Bean Cutworm

https://ir.library.oregonstate.edu/downloads/gt54kt12w

Evaluating Trichogramma Against Eggs of the Western Bean Cutworm

Abstract

Similar works

Full text

Available Versions

ScholarsArchive@OSU