TARNISHED PLANT BUG (HEMIPTERA: MIRIDAE) AND PREDACEOUS ARTHROPOD POPULATIONS IN COMMERCIALLY PRODUCED SELECTED NECTARIED AND NECTARILESS CULTIVARS OF COTTON

Abstract

The effect of nectariless cotton cultivars on tarnished plant bug, Lygus lineolaris (Palisot de Beauvois), and beneficial arthropod populations was studied in Washington and Sunflower counties, Mississippi, in 1981 and 1982. Fifteen and 18 fields of nectaried and nectariless cotton were sampled in 1981 and 1982, respectively. Field size ranged from approximately 16 to 60 hectares, and all fields were sampled weekly with a D-Vac insect collector during June and July of both years. Adult tarnished plant bug populations were significantly (P < 0.01) lower in the nectariless cotton in overall mean numbers in both years, and overall mean numbers of nymphs were significantly (P < 0.10) lower in the nectariless cotton in 1981. The combined adult and nymph population of tarnished plant bugs was reduced in the nectariless cotton an average of 44.0 and 34.0% in 1981 and 1982, respectively .These results demonstrate that nectariless cotton can suppress plant bug populations over a large area of cotton. A corresponding reduction in total numbers of predators also occured in the nectariless cotton. The overall mean for predators was reduced significantly (P < 0.01) in the nectariless cotton in both years of the study. In 1981, percent reduction in number of tarnished plant bugs in nectariless cotton was significantly related to field size.