Damage and Costs Associated with Insect Management Options in Irrigated Cotton

Abstract

This study measured the influence of planting date, cotton cultivar, and insecticidal control on pest abundance, damage, yield, and net returns in irrigated cotton. Cotton was planted in late April, late May, and late June from 1986 to 1989 at the Texas Agricultural Experiment Station at Monday. Densities of drips, Franklin fella occidentals (Pervade), were highest in cotton planted in late April and lowest in cotton planted in late June. Densities were not affected by the cultivates TOMCAT CANDIE or Lankart Sel 611. Lowest densities of cotton fleahoppers, Pseudatomoscelis seriatus (Reuter), were recorded in cotton planted in late April and highest in cotton planted in late June. Cotton fleahopper densities were significantly higher in ‘CAMD-E’, as compared with ‘Lankart Sel. 611’, in the late June planting; but differences were not observed between cultivars in the other two planting dates. Densities of overwintered boll weevils, Anthonomus grandis grandis Boheman, were highest in cotton planted in late April. When averaged over the four years, densities of bollworm, Helicoverpa zea (Boddis), larvae were not influenced significantly by planting date or by cultivar. Boll weevil damage during the growing season was almost twice as high in the late-June planting compared with damage in the late-April and late-May plantings. Percentage square damage was reduced in both cultivars treated with insecticides compared with damage in untreated plots when cotton was planted in late April; there were no differences between treated and untreated plots in either cultivar when cotton was planted in late May. When cotton was planted in late June, percentage square damage was reduced in ‘CAMD-E’ plots treated with insecticides compared with damage in untreated plots, but differences were not observed between treated and untreated plots in ‘Lankart Sel. 611’. Ninety-four percent of the insecticide applications were for management of boll weevils. Lint yields were similar in the late-April and late-May planting dates; both dates produced higher yields than those in the late June planting. Yields were higher in ‘CAMD-E’ than in ‘Lankart Sel. 611’, and yields in treated plots were higher than those in untreated plots. Net returns were lowest in late June cotton, but they were similar in the late-April and late-May plantings. Net returns for ‘CAMD-E’ were higher than those for ‘Lankart Sel. 611’. Returns were higher in untreated cotton compared with treated cotton in the late-April and late-June planting dates. Differences were not observed between returns in treated and untreated plots in the late-May planting date.