Oil Treatments for Leafminer and Associated Parasitoids on Snap Beans, 1990

Four oils and a insecticide-oil treatment were applied on 22 Oct with a prototype electrostatic sprayer (Terronics, Inc., Elwood, Ind.). Beans were planted 31 Aug in double rows on beds with 40 inch centers at the Bruce Church of Arizona, Inc. farm located near Poston, Ariz. Two rows of each variety were planted side by side in the 4 row block. Beans, especially the 04' variety, were heavily infested with leafminers and much defoliation and leaf drop had occurred with the lower leaves prior to the 16 Oct treatment. Plants were very heavily infested with sweetpotato whiteflies, Bemisia tabaci (Gennedius). Plots were 25 ft long by one bed wide and treatments were replicated 4 times in a randomzied complete block design. Plots were sampled on 19 Oct for leafminer parasitoids. Parasitoid complex was comprised of mostly Diglyphus spp., Chrysocharis spp., as well as other similar parasitoids. Other parasitoids also included about 1% Opius and 3% Chrysonotomyia. Three samples were taken per plot. Samples consisted of placing a 8.5 inch × 17 inch × 1.5 inch deep styrofoam food tray between bed rows, shaking the foliage, and counting the parasitic wasps on the trays. Leafminer samples were obtained by leaving 3 trays/plot between rows from 3-8 DAT. Leafminer pupae that had emerged from leaves and collected in trays were counted.