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Submitted to: Journal of Entomological Science
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 4/24/2006 Publication Date: 10/1/2006 Citation: Tillman, P.G. 2006. Tobacco as a trap crop for Heliothis virescens (F.) (Lepidoptera: Noctuidae) in cotton. Journal of Entomological Science. 41(4):305-320. Interpretive Summary: The tobacco budworm is one of the most economically important pests of cotton in the United States. Thus, a three year study was designed to evaluate tobacco as a trap crop for the tobacco budworm in cotton. Tobacco budworm females preferred tobacco over cotton, for greater numbers of tobacco budworm eggs per plant occurred on tobacco than on cotton for each year. With one exception, populations of tobacco budworms did not reach the economic threshold for this pest in cotton for all three years. On two dates, 11 June 1996 and 19 June 1996, the Boll Weevil Eradication Program applied malathion to all tobacco and cotton killing almost every natural enemy in the test. Therefore, on 21 June 1996, cotton had to be treated for control of tobacco budworms. For each year, percentage mortality of tobacco budworms on tobacco was very high, ranging from 91.4 to 99.9%, demonstrating that the tobacco trap crops were sinks for this pest in cotton. In conclusion, tobacco served as a trap crop and sink for the tobacco budworm in cotton, preventing the population of the pest from reaching damaging levels in cotton. Technical Abstract: A three year study was designed to evaluate tobacco, Nicotiana tabacum L., as a trap crop for the tobacco budworm, Heliothis virescens (F.), in cotton, Gossypium hirsutum L. Heliothis virescens females preferred tobacco over cotton as an ovipositional site, for greater numbers of H. virescens eggs per plant occurred on tobacco than on cotton for each year. With one exception, populations of H. virescens did not reach the economic threshold for this pest in cotton for all three years. On two dates, 11 June 1996 and 19 June 1996, the Boll Weevil Eradication Program applied malathion to all tobacco and cotton killing almost every natural enemy in the test. Therefore, on 21 June 1996, cotton had to be treated for control of tobacco budworms. For each year, percentage total real mortality (rx) of H. virescens on tobacco was very high, ranging from 91.4 to 99.9%, demonstrating that the tobacco trap crops were sinks for H. virescens in cotton. Larval mortality was attributed in part to parasitization by Cardiochiles nigriceps Viereck and Campoletis sonorensis Cameron and an infection by an ascovirus of H. virescens. In conclusion, tobacco served as a trap crop and sink for H. virescens in cotton, preventing the population of the pest from reaching damaging levels in cotton. |
