Laboratory evaluation of CX-10282 containing Beauveria bassiana (Hypocreales: Cordycipitaceae) strain GHA against adult Rhagoletis indifferens (Diptera: Tephritidae)

Abstract

Western cherry fruit fly, Rhagoletis indifferens Curran (Diptera: Tephritidae), is a pest of cherries (Prunus spp.) in western North America that potentially could be managed using the fungus Beauveria bassiana (Balsamo-Crivelli) Vuillemin (Hypocreales: Cordycipitaceae). Here, the product CX-10282 containing 11.3% B. bassiana strain GHA was evaluated as a potential control agent for adult R. indifferens by determining whether it can cause 100% fly mortality in the laboratory. Low or high label rates of 5.4 × 107 or 1.7 × 108 conidia/ml in five different modes of application and application volumes were tested. When one 1-μl drop of CX-10282 containing 1.6 × 105 conidia was applied onto a single female fly, 100% mortality was reached by 4 or 7 d. When CX-10282 was sprayed into a container with flies to produce 2.2 × 105 to 6.9 × 105 conidia/cm2 and flies left in containers, 76.2–99.5% mortality was reached by 15–21 d. When sprayed flies were moved into clean containers, 74.8% mortality was reached by 25 d. When a 9-cm diam filter paper with 2.8 × 107 conidia/cm2 was exposed to flies inside a container, 100% mortality was reached by 9 d. When flies were exposed to CX-10282 mixed with or without sucrose on filter paper, mortality was 98.2 or 99.7% by 20 d. Dead treatment flies had mycoses rates of 68.8–93.0%. Findings suggest that field studies to evaluate CX-10282 as an organic control product for adult R. indifferens are worth pursuing.