OCCURRENCE OF BEET ARMYWORM (LEPIDOPTERA, NOCTUIDAE, SPODOPTERA EXIGUA (HUBNER)) MOTHS IN THE LOWER MISSISSIPPI RIVER DELTA AS INDICATED BYNUMBERS CAUGHT IN TRAPS IN 1994

A survey to determine the abundance of beet armyworm Spodoptera exigua (Hubner), adults was conducted in the west central delta region of Mi ssissippi from April to December, 1994. Fifty-four traps were installe d 2.1 km apart in a line 122 km long from near Skene, MS, in Bolivar C o., southward to Onward in Sharkey Co. Traps were baited with sex pher omone to lure male moths to the traps. Moth captures were recorded twi ce weekly. Wings on a majority of moths caught from 7 April to 30 June were covered with nearly a full complement of scales indicating that they did not fly great distances before they were captured. These moth s could have emerged from pupae that overwintered in soil of fields or ditches near the traps. Catches of moths in April ranged from 0.13 to 1.6 per trap per night. These relatively low capture levels also indi cated that the beet armyworm moths were from a local source. There wer e four distinct peaks in numbers of moths caught between 1 July and 1 November, separated by 21 to 31 days. Highest numbers of moths (400/tr ap/night) were caught on 3 October. The shape of a peak in moth captur es graphed for 29 July to 10 August, compared with sequences and amoun ts of rainfall prior to that period, indicated that many moths may hav e been carried to the region by storm fronts from the south and deposi ted in cotton fields during rain storms. Captures were sharply reduced on nights in April, September, October, and November when air tempera tures dropped below 48 degrees F. In 1994, cotton developed about two weeks earlier than in 1993. Bells matured and hardened before great nu mbers of beet armyworms appeared in the fields, and the 1994 cotton cr op escaped serious economic damage by this insect.