INFLUENCE OF PLANTING DATE AND INSECTICIDE TREATMENT ON INSECT PEST ABUNDANCE AND DAMAGE IN DRYLAND COTTON

Objectives of this study were to measure the influence of planting dat e and insecticidal control on pest abundance and damage in dryland cot ton. 'Paymaster 145' cotton was planted in late April, late May (which is the recommended delayed uniform planting date for management of th e boll weevil, Anthonomus grandis grandis Boheman), and late June for 4 yr from 1986 to 1989 in the northern Texas Rolling Plains. Subplots within each planting date were no insecticide treatment, and treatment with aldicarb at planting and application of an appropriate insectici de when a pest attained it damage threshold. Insects sampled were thri ps (including the western flower thrips, Frankliniella occidentalis [P ergande]); cotton fleahopper, Pseudatomoscelis seriatus (Reuter); boll worm, Helicoverpa zea (Boddie); cotton aphid, aphis gossypii Glover; a nd boll weevil. Thrips densities were highest in cotton planted in lat e April; densities were reduced by aldicarb treatments in late April a nd late May cotton but not in late June cotton. Highest densities of c otton fleahoppers occurred in cotton planted in late May; densities we re reduced by aldicarb treatments in late May and late June cotton but not in late April cotton. Densities of overwintered boll weevils were highest in April-planted cotton and lowest in June-planted cotton. Bo ll weevil damage during the growing season was lowest in cotton plante d in late May, and insecticides applied for boll weevil control during the growing season suppressed damage for all planting dates. Bollworm densities were not influenced by planting date or by insecticide trea tment. Cotton aphid densities were highest in cotton planted in late J une. Delayed uniform planting for boll weevil management does not adve rsely affect damage by the other important cotton pests in dryland cot ton in the northern Texas Rolling Plains. Planting in late May reduces damage caused by thrips, cotton aphids, and boll weevils.