Environmental Entomology (2003) 32, 187-195

David I. Shapiro-Ilan, Wayne A. Gardner, James R. Fuxa, Bruce W. Wood, Khuong B. Nguyen, Byron J. Adams, Richard A. Humber and Michael J. Hall (2003)
Survey of entomopathogenic nematodes and fungi endemic to pecan orchards of the southeastern United States and their virulence to the pecan weevil (Coleoptera: Curculionidae)
Environmental Entomology 32 (1), 187-195
Abstract: The pecan weevil, Curculio caryae (Horn), is a major pest of pecans in the Southeastern United States. Entomopathogenic nematodes and fungi are potential alternatives to chemical insecticides for C. caryae control. Our objective was to survey pecan orchards in the southeastern United States for entomopathogenic nematodes and fungi and determine the virulence of the new isolates to C. caryae larvae. Soil was collected from 105 sites in 21 orchards in Arkansas, Georgia, Louisiana, and Mississippi. Entomopathogens were isolated by exposing soil to C. caryae and greater wax moth larvae, Galleria mellonella, (L.). We isolated entomopathogenic fungi and nematodes from 16 and 6 of the 21 orchards surveyed, respectively. The entomopathogenic fungi included Beauveria bassiana (Balsamo) Vuillemin and Metarhizium anisopliae (Metschnikoff) Sorokin, and nematodes included Heterorhabditis bacteriophora Poinar, Steinernema carpocapsae (Weiser), Steinernema glaseri (Steiner), and Steinernema rarum (Doucet). This is the first report of Steinernema rarum in the United States. Soil characteristics in orchards were analyzed for pH, organic matter, and nutrients; we detected a negative relationship between fungal occurrence and manganese levels in soil and a positive relationship between M. anisopliae occurrence and calcium or magnesium levels. In laboratory assays, virulence of 15 nematode and 22 fungal isolates to C. caryae larvae was tested in small plastic cups containing soil. Results indicated poor susceptibility of the C. caryae larvae to entomopathogenic nematodes. Several fungal isolates that caused significantly higher mortality in C. caryae larvae than other strains (including a commercial strain of B. bassiana) should be investigated further as potential control agents of C. caryae.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): David I. Shapiro-Ilan, Byron J. Adams, Richard A. Humber

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
surveys/distribution/isolation

---

Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Curculio caryae	Pecan/hickory (Carya)	U.S.A. (SE)
Beauveria bassiana (entomopathogen)	Curculio caryae	Pecan/hickory (Carya)	U.S.A. (SE)
Metarhizium anisopliae (entomopathogen)			U.S.A. (SE)