Compatibility of the Predatory Beetle, Delphastus catalinae, with an Entomopathogenic Fungus, Cordyceps fumosorosea, for Biocontrol of Invasive Pepper Whitefly, Aleurothrixus trachoides, in Florida

SIMPLE SUMMARY: The solanum whitefly, Aleurothrixus trachoides, is a polyphagous pest known to attack > 70 crops worldwide. Endemic to the Neotropical region, in the past few years, it has emerged as a significant pest of several horticultural crops including pepper in the United States. To develop an eco-friendly sustainable management strategy for this pest, in this study, we evaluated the efficacy and compatibility of two commercially available biological control agents, predatory beetle Delphastus catalinae (Dc) and entomopathogenic fungi Cordyceps fumosorosea (Cfr) under laboratory conditions. Results showed both Cfr, treatments (alone or in combination with Dc) were efficacious, and Cfr did not negatively impact the beetle longevity. This study’s outcome is important not only for organic horticultural growers, but also for conventional growers as it offers a low-risk alternative tool for solanum whitefly integrated pest management in Florida and other affected regions. ABSTRACT: Aleurothrixus (formerly known as Aleurotrachelus) trachoides Back (Hemiptera: Aleyrodidae), commonly known as pepper or solanum whitefly, is a new emerging whitefly pest of several horticultural crops in the United States. During the preliminary survey for pepper whitefly infestation in Florida, a whitefly-specific predatory beetle Delphastus catalinae Horn (Coleoptera: Coccinellidae) was observed associated with this pest in the natural ecosystem. The current study was undertaken to determine the efficacy of this naturally occurring predator, D. catalinae, and an entomopathogenic fungus, Cordyceps (formerly known as Isaria) fumosorosea (Cfr) (Wize) (Hypocreales: Cordycipitaceae), alone or in combination, under controlled laboratory conditions. Whitefly mortality for Cfr (88%), beetle (100%) and Cfr + beetle (100%) treatments were similar and significantly higher compared to control. In the combination treatment, Cfr did not impact D. catalinae longevity and daily food intake, indicating a neutral interaction between the two treatments. Results showed that both of these natural biological control agents could potentially offer an effective alternative in the battle against invasive whiteflies such as pepper whitefly in U.S. horticulture production, either as a stand-alone strategy or in an integrated approach. Although these findings are promising, compatibility of the two treatments needs to be evaluated further under greenhouse and semi-field conditions before recommending to commercial growers.