SEASONAL RESPONSES OF BOLL-WEEVILS TO PHEROMONE TRAPS IN CROPPED AND ADJACENT UNCROPPED AREAS OF EAST-CENTRAL TEXAS

Boil weevil, Anthonomus grandis grandis Boheman, pheromone trapping st udies were conducted in a large, relatively isolated area of contiguou s row-crop farms (cropped area) and the surrounding uncropped area in the Brazos River Valley of Burleson and Brazos counties near College S tation, TY during 1990 and 1991. Results indicated that variations in the timing and magnitudes of the mean weekly trap captures in the crop ped and uncropped areas were similar during the early and midseason pe riods until September when harvest of cotton began. Trap response patt erns were characterized by an early-season period of peak weekly mean weevil captures of 20 or less during late April through May, followed by a midseason period of near-zero captures from early June through mi d-July, and then a late-summer period of increasing captures that bega n in late July and peaked in early September at levels more than five times those obtained in the early season. During the late-summer perio d, weevil captures were uniform at relatively high levels, within-year s, over the cropped area and the uncropped area out to distances of 20 km in 1990 and 13 km in 1991. After the beginning of harvest with the associated habitat destruction, the timing of variations in catch pat terns for the traps in the cropped and uncropped areas remained simila r; however, the magnitudes of mean weekly captures in the cropped area increased to levels of more than five times those obtained in the unc ropped area. The magnitudes of mean weekly captures throughout the yea r in 1990 were less than half those obtained in traps at the same loca tions in 1991, probably because of the detrimental effects of abnormal ly cold temperatures in the area during December 1989.