Seed Treatment of Cotton with Systemic Insecticides Alone and in Combination with a Fungicidal Treatment1

Abstract

Small plot experiments were conducted with Thimet and Bayer 19639 seed treatments used alone and in combination with an in-the-furrow fungicidal treatment with nabam. The systemic insecticide seed treatments were also compared with a standard toxaphene spray program. The seed treatments resulted in effective thrips control until midJune and some aphid control until midAugust. Bayer 19639 appeared to give slightly better aphid control than Thimet. In the April plantings, when the soil was cool and damp, there were serious reductions in stand in the systemic seed treatments. The addition of nabam to the systemic insecticide seed treatments resulted in much better stands, and also lessened the severity of the phytotoxic effects of both Thimet and Bayer 19639. Results indicated there should be no reduction in stand, provided the same number of seed are planted, from the use of the systemics under conditions conducive to good germination. Yields were not increased by the use of the systemic insecticides or toxaphene spray treatments. The maturity of the plants was delayed considerably in the plots having the seed treated with systemic insecticides.