Choice behavior of the generalist pentatomid predator Podisus maculiventris when offered lepidopteran larvae infected with an entomopathogenic fungus

Authors: AVERY, PASCO - University Of Florida; GEORGE, JUSTIN - University Of Florida; Markle, Larry; MARTINI, X - University Of Florida; Rowley, Amy; Meagher, Robert - Rob; BARGER, RACHEL - Non ARS Employee; DUREN, EMILY - University Of Florida; DAWSON, JANET - University Of Florida; CAVE, RONALD - University Of Florida

Submitted to: BioControl
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/23/2021
Publication Date: 1/16/2022
Citation: Avery, P.B., George, J., Markle, L.T., Martini, X., Rowley, A.L., Meagher Jr, R.L., Barger, R.E., Duren, E., Dawson, J.S., Cave, R.D. 2022. Choice behavior of the generalist pentatomid predator Podisus maculiventris when offered lepidopteran larvae infected with an entomopathogenic fungus. Biocontrol. 67:201-211. https://doi.org/10.1007/s10526-021-10124-4.
DOI: https://doi.org/10.1007/s10526-021-10124-4

Interpretive Summary: Integrated Pest Management programs of insect pests many times involves the use of two or more natural enemies at the same time to achieve biological control. It is important to know if these species can be effective in the same environment. Researchers from University of Florida Research and Education Centers in collaboration with scientists from USDA-ARS, Center for Medical, Agricultural and Veterinary Entomology, Gainesville, Florida, and U.S. Horticulture Research Laboratory in Ft. Pierce, Florida, collaborated to assess the combined control effectiveness of a predatory bug (spined soldier bug, SSB) in combination with an insect-killing fungus (Beauveria bassiana) infection on the fall armyworm. When fed on fungus-infected fall armyworm, the spined soldier bugs developed normally. However, when presented in a choice test, spined soldier bug nymphs fed more frequently on uninfected rather than fungus-infected fall armyworm. This suggests that the kill effectiveness of utilizing two biological control methods is additive and shows that applications of fungus combined with releases of spined soldier bugs may be a more efficient and viable option for pest management in the field.

Technical Abstract: To understand the practical application of entomopathogenic fungi and predatory insects in an IPM program, it is necessary to know if these biocontrol agents are compatible in the same space. The objectives of our research were to understand the response behavior of the predatory spined soldier bug (SSB), Podisus maculiventris, exposed to volatiles from the entomopathogenic fungus Beauveria bassiana, assess the predator’s survivorship when presented with B. bassiana-infected prey, and determine the volatile profile of B. bassiana conidia. Choice behavior of SSB nymphs towards B. bassiana-infected (non-sporulating and sporulating) versus uninfected larval fall armyworm, Spodoptera frugiperda, was determined in choice arenas. The predator nymphs more frequently chose the uninfected prey and avoided fungus-infected prey. Of five SSB nymphs that fed on fungus-infected, 80% molted to adulthood, and the time required to molt to adult was similar to those that fed on uninfected prey. Y-tube olfactometer choice assays also indicated that the nymphs avoided potato dextrose agar plugs containing B. bassiana and preferred clean PDA plugs. Based on a GC-MS analysis, the primary volatile olfactory chemicals emitted from B. bassiana spores were 2-ethylhexanol and sec-butyl carbinol. Applications of B. bassiana combined with releases of P. maculiventris may be a viable option for pest management in the field.