SEASONAL MIGRATION OF THE BLACK CUTWORM LEPIDOPTERA, NOCTUIDAE

Adult populations of black cutworm, Agrotis ipsilon (Hufnagel), males were monitored 1 June to 31 December 19851987. Texas 70-50-cm cone tra ps baited with sex pheromone were located north to south, 41 degrees 4 5'N to 25 degrees 45'N latitude, at Ankeny, Iowa; Columbia, Missouri; Crowley, Louisiana; and Beaumont, College Station, and Brownsville, Te xas. Forecasts of nightly near-surface (100-300 m) airflow were record ed from 18 weather stations in the midcontinental United States. Avera ge moth capture summed per 2-week interval for each Gulf Coast locatio n was regressed upon nights of near surface northerly flow (southward displacement) summed per 2-week interval and also on average moth capt ure summed per 2-week interval at Ankeny or Columbia. Near-surface nor therly flow was not a limiting factor at Crowley or Beaumont. Increase d moth capture at Crowley was associated with decreased moth capture a t Ankeny and Columbia during 1987. Although not significant, there was a consistent relationship between increased capture at Beaumont and d ecreased capture at Ankeny. Farther west, in south-central Texas, ther e was strong evidence for moths captured at College Station to be rela ted to near-surface northerly flow (one of three years) and to source moths (two of three years) from Ankeny. Farther south and west, captur e at Brownsville was also associated with near-surface northerly flow two of three years of the study. During 1987, similar to moth capture at Crowley, moth capture at Brownsville was related to source moths fr om Ankeny. These results suggest that near-surface (100-300 m) norther ly winds may be responsible for autumnal southward migration of black cutworm moths.