Document Type

Peer-Review Article


The occulrence and abundance of 22 species of orthopteroids is compared for isolated farm yards surrounded by corn fields which were either treated or not treated with a pesticide combination consisting of the herbicides Sutan and AAtrex, and the insecticide Dyfonate. All 22 species were present in the untreated plots, whereas only 12 were recorded in the treated plots, a 45.5% reduction.

Species characteristics determining the observed differences, in the order of decreasing importance, are: general abundance in non-treated areas, seasonal periodism, and vagility. More common species and fewer uncommon species were present in the treated areas, apparently because of the more diverse feeding habits of the former. Nearly all vernal species were absent from the treated areas, possibly because of direct mortality incurred at the time of pesticide application (spring). Those species with greater flight ability were better represented in the treated areas; evidently the corn fields to which the pesticides were applied formed an effective barrier that inhibited immigration of at least the short-winged or flightless species.

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Entomology Commons