ARS | Publication request: Potential of topic applications, leaf residues and soil drenches of the fungus Paecilomyces fumosoroseus (Deuteromycotina: Hyphomycetes) for management of the Diaprepes root weevil: laboratory and greenhouse investigations

Submitted to: Society for Invertebrate Pathology Annual Meeting
Publication Type: Abstract
Publication Acceptance Date: August 1, 2008
Publication Date: August 3, 2008
Citation: Avery, P., Hunter, W.B., Hall, D.G., Jackson, M.A., Powell, C., Rogers, M. 2008. Potential of topic applications, leaf residues and soil drenches of the fungus Paecilomyces fumosoroseus (Deuteromycotina: Hyphomycetes) for management of the Diaprepes root weevil: laboratory and greenhouse investigations [abstract]. The 41st Annual Society Meeting for Invertebrate Pathology. August 3-7, 2008, Coventry, United Kingdom. p. 65.

Technical Abstract: Diaprepes root weevil, (DRW) Diaprepes abbreviatus is a key pest of citrus and ornamental plants in Florida and Texas. DRW larvae burrow through the soil feeding on roots which when girdled causes secondary infection of the structural roots or root crown by Phytopthora spp. wherein mature citrus trees may die. Few effective and environmentally appropriate control measures are currently available to control DRW. To meet the industry needs, we evaluated application of a blastospore formulation of the entomopathogenic fungi, Isaria fumosorosea = Paecilomyces fumosoroseus, ARSEF strain 3581 (Pfr), as a management tool against DRW. Topical spray applications caused 13 percent and 19 percent mortality in DRW larvae and adults after 7 days, respectively. When DRW were fed only one Pfr treated leaf, 100 percent mortality occurred 35 days post-treatment. Pfr soil drench application with 1400 mL of water showed 2 percent larval mortality. Biological control measures using Pfr and other fungi may provide an additional treatment against DRW adults, while benefits from soil drenching may not significantly increase larval mortality. However, a better means of Pfr soil application, or using a higher concentration of inoculum with improved timing of drench treatments during the early springtime conditions when adults oviposit and are susceptible to infection, may improve the efficacy of this fungus for controlling DRW larvae in the soil.