Effect of Nitrogen Fertilization on the Abundance of Cotton Insects1

Abstract

Tests were conducted from 1964-1966 to determine the effect of different rates of nitrogen side dress applications on the abundance of and damage from cotton insects in nonirrigated cotton under a seasonal insecticidal control program. Insect infestation or damage counts were made on the boll weevil, Anthonomus grandis Boheman; bollworm, Heliothis zea (Boddie); and the cotton aphid, Aphis gossypii Glover. The insecticidal spray programs resulted in effective control of boll weevil and bollworm during each of the 3 years. Significant differences in boll weevil square infestation caused by the different treatments of nitrogen were obtained only 1 year. Significant differences in bollworm damage to bolls did not occur among treatments with nitrogen during any of the 3 years. Although there was an indication that more aphids occurred on leaves as the rate of nitrogen was increased, significant differences among treatments were obtained only 1 year. The effects of nitrogen side dress applications on the yield of seed cotton per acre were inconsistent.