title: Flood Stress as a Technique to Assess Preventive Insecticide and Fungicide Treatments for Protecting Trees against Ambrosia Beetles.
abstract: Ambrosia beetles tunnel into the heartwood of trees where they cultivate and feed upon a symbiotic fungus. We assessed the effectiveness of flood stress for making Cercis canadensis L. and Cornus florida L. trees attractive to attack as part of insecticide and fungicide efficacy trials conducted in Ohio and Virginia. Since female ambrosia beetles will not begin ovipositing until their symbiotic fungus is established within the host, we also assessed pre-treatment of trees with permethrin, azoxystrobin, and potassium phosphite on fungal establishment and beetle colonization success. Permethrin reduced attacks on flooded trees, yet no attacks occurred on any of the non-flooded trees. Fewer galleries created within flooded trees pre-treated with permethrin, azoxystrobin, and potassium phosphite contained the purported symbiotic fungus; foundress' eggs were only detected in flooded but untreated trees. While pre-treatment with permethrin, azoxystrobin, and potassium phosphite can disrupt colonization success, maintaining tree health continues to be the most effective and sustainable management strategy.
authors.affiliation: Horticultural Insects Research Lab, USDA-Agricultural Research Service, 1680 Madison Ave., Wooster, OH 44691, USA. christopher.ranger@ars.usda.gov.|Department of Entomology, Ohio Agricultural Research and Development Center, The Ohio State University, 1680 Madison Ave., Wooster, OH 44691, USA. christopher.ranger@ars.usda.gov.
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Ranger
authors.affiliation: Hampton Roads Agricultural Research and Extension Center, Virginia Polytechnic Institute and State University, Virginia Beach, VA 23455, USA. schultzp@vt.edu.
authors.forename: Peter B
authors.initials: PB
authors.lastname: Schultz
authors.affiliation: Horticultural Insects Research Lab, USDA-Agricultural Research Service, 1680 Madison Ave., Wooster, OH 44691, USA. mike.reding@ars.usda.gov.|Department of Entomology, Ohio Agricultural Research and Development Center, The Ohio State University, 1680 Madison Ave., Wooster, OH 44691, USA. mike.reding@ars.usda.gov.
authors.forename: Michael E
authors.initials: ME
authors.lastname: Reding
authors.affiliation: Department of Entomology, North Carolina State University, Campus Box 7613, Raleigh, NC 27965, USA. sdfrank@ncsu.edu.
authors.forename: Steven D
authors.initials: SD
authors.lastname: Frank
authors.affiliation: USDA-Agricultural Research Service-Midwest Area, 1815 N. University St., Peoria, IL 61604, USA. deb.palmquist@ars.usda.gov.
authors.forename: Debra E
authors.initials: DE
authors.lastname: Palmquist
keywords: Scolytinae; Xylosandrus germanus; flood stress