Growth and Development of Cotton as Affected by Toxaphene-DDT, Methyl Parathion, and Calcium Arsenate1

Abstract

Formulations of the insecticides toxaphene-DDT, methyl parathion, and calcium arsenate were utilized in two experiments conducted in 1960 to investigate further the influence of insecticides on growth and development of cotton. Insecticide treatments had no significant effect on internode length, number of internodes, plant height, per cent of bolls shed, germination, per cent lint, and the boll components seed index, lint index, boll weight, and seeds per boll. An increase in yield and boll production occurred when toxaphene-DDT was applied to cotton at weekly intervals for 12 and 8 weeks beginning with the appearance of first sqnares and first flowers, respectively; toxaphene-DDT had no effect on yield and boll production if treatments were initiated when the oldest bolls were about 30 days old and continued at weekly intervals for 5 weeks. Yield and boll production were not affected by treatments with methyl parathion. Calcium arsenate reduced yield and boll production when treatments were initiated at the appearance of first squares and continued weekly for 12 weeks. Calcium arsenate treatments of less duration had no significant effect on yield and boll production. Number of leaves and dry weight of plants were significantly increased by certain treatments of methyl parathion and significantly decreased by certain treatments of calcium arsenate; toxaphene-DDT had no effect on leaf number and dry weight.