Control of Plant Bugs and Other Insects on Kentucky Bluegrass Grown for Seed1

Abstract

Insecticide tests were conducted in bluegrass fields to study the control of plant bugs and other insect pests; also the effect of these insects on yields of foliage and seed. Most insecticides gave excellent control of plant bugs but Leptopterna dolabratus (L.) was more difficult to kill than Amblytylus nasutus (Kirschbaum). Dieldrin was more effective as an emulsion than as the granular formulation. Control broke down when the bugs became adults. However, adult movement was for a comparatively short distance and damage to seed was not demonstrated by this stage of the insects. In dieldrin-treated plots, leafhoppers were suppressed at first but built up later to populations exceeding those of the untreated plots. Some insecticides probably had a carry-over effect against plant bugs from one year to the next. There was a residual effect against the armyworm (Pseudaletia unipuncta (Haworth)) and grasshoppers (Melanoplus spp.) hatching after the earlier spring insecticide applications. Increases in yield of viable seed in some insecticide-treated plots were significant, but a relationship to insect control was not established.