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United States Department of Agriculture

Agricultural Research Service

Research Project: CONTROL OF ARTHROPOD PESTS OF PECAN AND PEACH

Location: Fruit and Nut Research

Title: Microbial control of the pecan weevil

Authors
item Shapiro Ilan, David
item Cottrell, Ted
item Gardner, Wayne -

Submitted to: Pecan National Workshop Proceedings
Publication Type: Proceedings
Publication Acceptance Date: November 10, 2009
Publication Date: November 1, 2010
Citation: Shapiro Ilan, D.I., Cottrell, T.E., Gardner, W. 2010. Microbial control of the pecan weevil. In: Proceedings of the 6th National Meetings of Pecan Scientists, May 26-29, 2010, Ardmore, Oklahoma. p. 26-35.

Interpretive Summary: Alternatives to chemical insecticides for suppression of the pecan weevil, are needed. Microbial control agents such as entomopathogenic nematodes and fungi are potential alternatives. In this paper we review several studies on fungi and nematodes as microbial control agents of pecan weevil. In the fungus experiments, we discovered numerous new entomopathogenic strains of Beauveria bassiana and Metarhizium anisopliae that showed superior laboratory virulence to the commercial strain (labeled for pecan weevil). Additionally, in field studies targeting pecan weevil, our results indicated that trunk applications of B. bassiana are superior to ground applications, though ground applications with cover crops also showed promise. In nematode experiments, which were conducted in pots buried under the orchard canopy, relative to non-treated pots we observed 81.1% control of pecan weevil using the nematode Steinernema carpocapsae; the overall survival of pecan weevil in nematode treated pots was < 1%. Finally, in laboratory experiments, we discovered that carbaryl and cypermethrin can cause synergistic levels of pecan weevil mortality when combined with microbial agents. Based on these results, additional research to determine the efficacy of microbial agents for pecan weevil suppression is warranted.

Technical Abstract: Microbial control agents such as entomopathogenic nematodes and fungi are potential alternative control agents for the pecan weevil, Curculio caryae. In this paper we review several studies on fungi and nematodes as microbial control agents of C. caryae. In the fungus experiments, we discovered numerous new entomopathogenic strains of Beauveria bassiana and Metarhizium anisopliae that showed superior laboratory virulence to the commercial strain (labeled for C. caryae). Additionally, in field studies targeting C. caryae, our results indicated that trunk applications of B. bassiana are superior to ground applications, though ground applications with cover crops also showed promise. In nematode experiments, which were conducted in pots buried under the orchard canopy, relative to non-treated pots we observed 81.1% control of C. caryae using the nematode Steinernema carpocapsae; the overall survival of C. caryae in nematode treated pots was < 1%. Finally, in laboratory experiments, we discovered that carbaryl and cypermethrin can cause synergistic levels of C. caryae mortality when combined with microbial agents. Based on these results, additional research to determine the efficacy of microbial agents for C. caryae suppression is warranted.

Last Modified: 9/1/2014
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