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United States Department of Agriculture

Agricultural Research Service

Research Project: INTEGRATED PEST MANAGEMENT FOR KEY PESTS OF PECAN AND PEACH

Location: Fruit and Nut Research

Title: Controlling pecan weevil with beneficial fungi: the impact of fungal species and fertilizer regimes

Authors
item Shapiro Ilan, David
item Gardner, Wayne -
item Wells, Lenny -
item Cottrell, Ted
item Behle, Robert
item Wood, Bruce

Submitted to: Pecan Grower
Publication Type: Trade Journal
Publication Acceptance Date: May 10, 2013
Publication Date: May 15, 2013
Citation: Shapiro Ilan, D.I., Gardner, W.A., Wells, L., Cottrell, T.E., Behle, R.W., Wood, B.W. 2013. Controlling pecan weevil with beneficial fungi: the impact of fungal species and fertilizer regimes. Pecan Grower. 24(4):54-64.

Interpretive Summary: The pecan weevil is a key pest of pecan. Prior research indicated the potential for using beneficial fungi to suppress pecan weevil in the soil. These fungi are natural bio-insecticides that are safe to humans and the environment. We compared the efficacy of two fungal species, Beauveria bassiana (GHA strain) and Metarhizium brunneum (F52), in their ability to cause pecan weevil mortality. Results indicated that B. bassiana is superior to M. brunneum regardless of application method; consequently, the potential for applying B. bassiana to control pecan weevil was further explored. Specifically, the impact of different fertilizer regimes on the persistence of B. bassiana (GHA) in soil was determined. B. bassiana was applied to soil in a pecan orchard following one of several nitrogen-enhancement treatments—i.e., ammonium nitrate, crimson clover, poultry litter, clover plus poultry litter, and a no-fertilizer control. Fertilizer treatments did not impact B. bassiana persistence. We conclude that standard fertilizers for nitrogen management, when applied according to recommended practices, are unlikely to negatively impact survival of B. bassiana when the fungus is applied for suppression of emerging pecan weevil. Additional research on interactions between beneficial fungi and fertilizer amendments (or other tree nutrition or soil management practices) is merited.

Technical Abstract: The pecan weevil, Curculio caryae (Horn), is a key pest of pecan. Prior research indicated the potential for using entomopathogenic fungi to suppress pecan weevil in the soil. We compared the efficacy of two fungal species, Beauveria bassiana (GHA strain) and Metarhizium brunneum (F52), in their ability to cause pecan weevil mortality. Results indicated that B. bassiana is superior to M. brunneum regardless of application method; consequently, the potential for applying B. bassiana to control pecan weevil was further explored. Specifically, the impact of different fertilizer regimes on the persistence of B. bassiana (GHA) in soil was determined. B. bassiana was applied to soil in a pecan orchard following one of several nitrogen-enhancement treatments—i.e., ammonium nitrate, crimson clover, poultry litter, clover plus poultry litter, and a no-fertilizer control. Fertilizer treatments did not impact B. bassiana persistence. We conclude that standard fertilizers for nitrogen management, when applied according to recommended practices, are unlikely to negatively impact survival of B. bassiana when the fungus is applied for suppression of emerging pecan weevil (Shapiro-Ilan et al., 2013). Additional research on interactions between beneficial fungi and fertilizer amendments (or other tree nutrition or soil management practices) is merited.

Last Modified: 4/16/2014
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