Effect of Pre-seeding Insecticide Treatments of the Seed Bed on Red Clover Stands and Forage Yields1

Abstract

Massive dosages of five insecticides, DDT, BHC, chlordane, toxaphene, and parathion, and a fungicide, Arasan, were applied to soil and disked in with a rotary hoe. Kenland, Midland, Wisconsin Mildew Resistant, and Michigan Common varieties of medium red clover were planted in the insecticide-treated soils. The best agronomic, cultural, and insect- and disease-control practices were followed. Insect populations of the crop year on July 11, 1951, showed marked differences among the treatments, particularly for grasshoppers, aphids, Diptera, and Hymenoptera. Differences that were highly correlated with data taken the following year occurred in stand among the various treatments in the seeding year. The effect of BHC in reducing the stand of grasses and the companion oat crop was marked. Highly significant differences in stand were present in the spring of the crop year. Yields when corrected for stand differences were significantly affected. Second-crop forage yields showed notable differences among the varieties, with Kenland outstandingly good. The BHC plots produced the highest yields. The final stands on October 17, 1951, showed that plots treated with BHC or with a mixture of insecticides maintained the stand best for all varieties, but were particularly effective for Wisconsin Mildew Resistant and Midland. Kenland went into the second winter with an 84% stand.