title: Evaluation of the effectiveness of entomopathogens for the management of wireworms (Coleoptera: Elateridae) on spring wheat.
abstract: Wireworms, the larval stage of click beetles (Coleoptera: Elateridae), are serious soil dwelling pests of small grains, corn, sugar beets, and potatoes. Limonius californicus and Hypnoidus bicolor are the predominant wireworm species infesting wheat in Montana, particularly in the 'Golden Triangle' area of north-central Montana. Wireworm populations in field crops are increasing, but currently available insecticides provide only partial control, and no alternative management tools exist. In our study, three entomopathogenic fungi were tested for their efficacy against wireworms in spring wheat at two field locations (Ledger and Conrad, Montana, USA) in 2013. The three fungi (Metarhizium brunneum F52, Beauveria bassiana GHA, and Metarhizium robertsii DWR 346) were evaluated as seed-coat, in-furrow granular, and soil band-over-row drench applications in addition to imidacloprid (Gaucho® 600) seed treatment (as a chemical check), the approach currently being used by growers. Wireworm damage in these treatments was evaluated as standing plant counts, wireworm population surveys, and yield. The three fungi, applied as formulated granules or soil drenches, and the imidacloprid seed treatment all resulted in significantly higher plant stand counts and yields at both locations than the fungus-coated seed treatments or the untreated control. Significant differences were detected among the application methods but not among the species of fungi within each application method. All three fungi, when applied as granules in furrow or as soil drenches, were more effective than when used as seed-coating treatments for wireworm control, and provided an efficacy comparable or superior to imidacloprid. The fungi used in this study provided significant plant and yield protection under moderate wireworm pressure, supporting their value in the management of this pest.
authors.affiliation: Western Triangle Agricultural Research Center, Montana State University, 9546 Old Shelby Rd., P.O. Box 656, Conrad, MT 59425, USA. Electronic address: reddy@montana.edu.
authors.forename: Gadi V P
authors.initials: GV
authors.lastname: Reddy
authors.affiliation: Western Triangle Agricultural Research Center, Montana State University, 9546 Old Shelby Rd., P.O. Box 656, Conrad, MT 59425, USA.
authors.forename: Khanobporn
authors.initials: K
authors.lastname: Tangtrakulwanich
authors.affiliation: Western Triangle Agricultural Research Center, Montana State University, 9546 Old Shelby Rd., P.O. Box 656, Conrad, MT 59425, USA.
authors.forename: Shaohui
authors.initials: S
authors.lastname: Wu
authors.affiliation: Western Triangle Agricultural Research Center, Montana State University, 9546 Old Shelby Rd., P.O. Box 656, Conrad, MT 59425, USA.
authors.forename: John H
authors.initials: JH
authors.lastname: Miller
authors.affiliation: Western Triangle Agricultural Research Center, Montana State University, 9546 Old Shelby Rd., P.O. Box 656, Conrad, MT 59425, USA.
authors.forename: Victoria L
authors.initials: VL
authors.lastname: Ophus
authors.affiliation: Western Triangle Agricultural Research Center, Montana State University, 9546 Old Shelby Rd., P.O. Box 656, Conrad, MT 59425, USA.
authors.forename: Julie
authors.initials: J
authors.lastname: Prewett
authors.affiliation: United States Department of Agriculture, Agricultural Research Service, Northern Plains Agricultural Research Laboratory, 1500 N. Central Ave., Sidney, MT 59270, USA.
authors.forename: Stefan T
authors.initials: ST
authors.lastname: Jaronski
mesh_terms: D000818:Animals; D052982:Beauveria; D001517:Coleoptera; D018556:Crops, Agricultural / Q000382:microbiology; D007814:Larva / Q000382:microbiology; D052981:Metarhizium; D010572:Pest Control, Biological / Q000379:methods*; D010935:Plant Diseases / Q000382:microbiology; D014908:Triticum / Q000382:microbiology*
keywords: Beauveria bassiana; Metarhizium brunneum; Metarhizium robertsii; Spring wheat; Wireworms