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ARS Home » Southeast Area » Byron, Georgia » Fruit and Tree Nut Research » Research » Publications at this Location » Publication #226888
Title: Laboratory mortality and mycosis of adult Curculio caryae (Coleoptera: Curculionidae) following application of Metarhizium anisopliae in the laboratory and field

Author
item Shapiro Ilan, David
item Cottrell, Ted
item GARDNER, WAYNE - UGA
item LELAND, JARROD - NOVOZYMES BIOLCL INC, VA
item Behle, Robert

Submitted to: Journal of Entomological Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/9/2009
Publication Date: 3/12/2009
Citation: Shapiro Ilan, D.I., Cottrell, T.E., Gardner, W.A., Leland, J., Behle, R.W. 2009. Mortality and mycosis of adult Curculio caryae (Coleoptera: Curculionidae) following application of Metarhizium anisopliae: laboratory and field trials. Journal of Entomological Science. 44:24-36.

Interpretive Summary: The pecan weevil is a major pest of pecans. One approach to suppressing this pest may be to apply insect-killing fungi to adult C. caryae when they are emerging from the soil. Our objective was to determine the potential of a fungus called Metarhizium anisopliae to control emerging C. caryae adults. In laboratory experiments, we found this fungus to possess high virulence (killing-power) versus pecan weevil. Subsequently, a commercially available M. anisopliae strain was tested under field conditions when applied as a narrow fiber band that was impregnated with fungus and wrapped around the tree trunk, and or when applied directly to the soil. Significant mortality of emerging pecan weevils was observed in both years of the field tests (2005 and 2006). Although results from field trials were variable, our research indicates that trunk band or ground applications of M. anisopliae have potential to cause significant infection in pecan weevil populations.

Technical Abstract: The pecan weevil, Curculio caryae, is a key pest of pecans. Our objective was to determine the potential of Metarhizium anisopliae to control emerging C. caryae adults. First, a laboratory test was conducted to compare four Beauveria bassiana strains (Bb GA2, BbLA3, BbMS1, and GHA) and three M. anisopliae strains (F52, MaLA4, and MaLA7) for virulence to C. caryae adults. Virulence of the M. anisopliae strains was equal or greater than B. bassiana strains. Subsequently, a commercially available M. anisopliae strain (F52) was tested under field conditions when applied as a fiber band that was impregnated with fungus and wrapped around the tree trunk, and or when applied directly to the soil. In 2005, weevil emergence was extremely low and statistical analysis was only feasible 3 d post-treatment (at which time no treatment differences were detected), and 15 d post-treatment, at which time higher mortality and mycosis was observed in both the trunk band application and the trunk band + ground treatment compared with a non-treated control (and no difference between the two fungal treatments was detected). In 2006 overall average C. caryae mycosis was higher in trunk band and ground treatment compared with an untreated control, whereas average total mortality (from the fungus or other causes) was not different among treatments except at 8 d post treatment (in which only the band treatment was significantly greater than the control). Although results from field trials were variable, our research indicates that trunk band or ground applications of M. anisopliae have potential to cause significant infection in C. caryae.