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Reevaluation of Trichogramma Releases for Suppression of Heliothine Pests in Cotton

Charles P.-C. Suh, David B. Orr and John W. Van Duyn


Field studies were conducted at 3 sites over 2 years to reevaluate the feasibility of releasing Trichogramma wasps for suppression of heliothine pests (Helicoverpa zea + Heliothis virescens) in cotton. Overall, releases of T. exiguum significantly increased egg parasitism and reduced bollworm egg hatch in release plots. However, there was not a proportional reduction in number of instar 5 larvae or boll damage, and upon final assessment, there was no significant difference in yield between release and control plots. Analysis of 1996 bollworm data revealed that this lack of suppression may have been in part due to the interaction of density-dependent egg and larval mortality factors (compensatory mortality).

Reprinted from Proceedings of the 1998 Beltwide Cotton Conferences pp. 1098 - 1101
©National Cotton Council, Memphis TN

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Document last modified Sunday, Dec 6 1998