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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: Efficacy of entomopathogenic fungi in suppressing pecan weevil, Curculio caryae (Coleoptera: Curculionidae) in commercial pecan orchards

Authors
item Shapiro Ilan, David
item Cottrell, Ted
item Gardner, Wayne -
item Behle, Robert
item Ree, Bill -
item Harris, Marvin -

Submitted to: Southwestern Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 8, 2009
Publication Date: July 1, 2009
Citation: Shapiro Ilan, D.I., Cottrell, T.E., Gardner, W.A., Behle, R.W., Ree, B., Harris, M. 2009. Efficacy of entomopathogenic fungi in suppressing pecan weevil, Curculio caryae (Coleoptera: Curculionidae) in commercial pecan orchards. Southwestern Entomologist. 34:111-120.

Interpretive Summary: The pecan weevil is a key pest of pecans. Research toward finding effective and ecologically sound pest control solutions for the pecan weevil is desirable. One environmentally friendly approach to suppressing the pest populations may be to apply entomopathogenic (insect-killing) fungi to adult weevils when they are emerging from the soil. Here we report the efficacy of two species (kinds) of entomopathogenic fungi, Beauveria bassiana and Metarhizium anisopliae, applied to trees in commercial pecan orchards at three locations: Fort Valley, Georgia, Byron, Georgia, and Comanche, Texas. At both Georgia locations, B. bassiana caused 80% mortality, which was significantly greater than mortality observed in the non-treated control (33%); mortality in the M. anisopliae treatment did not differ from control mortality. In Texas, mean pecan weevil mortality after 7 and 14 days was 38 and 55% in the control, 75 and 88% in the B. bassiana treated plots, and 57 and 75% in the M. anisopliae treated plots. These results indicate potential for B. bassiana trunk sprays to cause high levels of mortality in adult pecan weevils. Future research is needed determine if the approach contributes to economic levels of crop protection.

Technical Abstract: The pecan weevil, Curculio caryae (Horn), is a key pest of pecans. Here we report the efficacy of entomopathogenic fungi Beauveria bassiana and Metarhizium anisopliae applied to trees in grower orchards at three locations. In Fort Valley, Georgia, treatments included B. bassiana applied to the trunk with a UV-protective screen, M. anisopliae applied as a fiber band stapled on the trunk, and a non-treated control. In Byron, Georgia, we compared the B. bassiana trunk treatment to a non-treated control. Near Comanche, Texas, treatments included the B. bassiana trunk application, M. anisopliae applied as a trunk band and as a soil drench, and a non-treated control. At both Georgia locations, B. bassiana caused 80% mortality and mycosis, which was significantly greater than mortality observed in the control (33%); mortality and mycosis in the M. anisopliae treatment at the Fort Valley site did not differ from that observed in the control. In Texas, due to insufficient replication in plots, statistical comparison among treatments was not possible. However, mean C. caryae mortality after 7 and 14 d was 38 and 55% in the control, 75 and 88% in the B. bassiana treated plots, and 57 and 75% in the M. anisopliae treated plots. These results indicate potential for B. bassiana trunk sprays to cause high levels of mortality in adult C. caryae. Future research is needed to determine if the approach contributes to economic levels of crop protection.

Last Modified: 9/2/2014