Alfalfa Weevil and PEA Aphid Control, 1990

Abstract

Abstract Nonirrigated alfalfa, 10 cm tall, was sprayed 13 Apr. Insecticides were applied in water (20 gal/acre) with a C02-powered backpack sprayer. The ‘ c . c ’ that appears after 2 of the Lorsban treatments denotes the Hi-Yield Spreader/Sticker surfactant, produced by Hi-Yield Chemical Company, Bonham, Tex. that was mixed with these treatments. The sprayer boom was equipped with Delevan HC-12, 70 degree nozzles positioned to deliver a broadcast spray pattern. Winds were largely calm. A randomized plot design with 4 replicates was used. Plots measured 20 × 20 ft with unsprayed alleys separating adjacent plots. Eight stems were collected from undisturbed areas within each plot on each sample date. Samples from each plot were individually bagged, returned to the laboratory, and frozen. Samples were later thawed and examined under magnification for AW larvae and aphids (primarily pea aphids). Eight stem counts were converted to 10-stem count equivalencies before analysis. Pretreatment counts were taken. Postapplication sampling occurred at 3, 5, 7, 10, 17, and 21 DAT. Stem height increased from 8 cm at spraying to 18.4 cm at 21 DAT.