Location: Southern Insect Management ResearchTitle: Lethal and sub-lethal effect of Beauveria bassiana strain NI8 on Chrysoperla rufilabris (Neuroptera:Chrysopidae)
Submitted to: Florida Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/15/2017
Publication Date: 9/30/2017
Publication URL: http://handle.nal.usda.gov/10113/5852191
Citation: Portilla, M., Snodgrass, G.L., Luttrell, R.G. 2017. Lethal and sub-lethal effect of Beauveria bassiana strain NI8 on Chrysoperla rufilabris (Neuroptera:Chrysopidae). Florida Entomologist. 100(3):627-633. https://doi.org/10.1653/024.100.0321.
Interpretive Summary: The entomopathogenic fungus Beauveria bassiana strain NI8 is a potential candidate for biological control of tarnished plant bugs, TPB Lygus lineolaris Palisot de Beauvois in the Mississippi Delta. The impact of this entomopathogenic fungus on non-target organisms is critical information for its expected use, especially cultivated areas with wild host of TPB. Decisions to deploy NI8 as a biological control for TPB in different host environment should be based on an overall assessment of ecological and economic benefits and costs. In this study we explored the potential impact of NI8 on green lacewings, Chrysoperla rufilabris Burmeister, a common predator of many pests. Results indicated that NI8 has comparable activity against C. rufilabris and L. lineolaris. This suggests that non-target impacts of the entomopathogenic fungus against TPB should be measured in field experiments and that deployment strategies should strategically consider these ecological costs.
Technical Abstract: A Mississippi Delta native strain (NI8 ARSEF8889) of Beauveria bassiana (Balsamo) Vuillemin (Sordariomycetes: Hypocrales), isolated from Lygus lineolaris (Palisot de Beauvois), was bioassayed on green lacewings, Chrysoperla rufilabris Burmeister (Neuroptera: Chrysopidae) at four spray concentrations (7.02 x 104, 105, 106 and 107 spores/ mL) to evaluate effects on the insect predator’s reproductive rates and adult life expectancy. The application method simulated atomized spray and concentrations tested were similar to those used to measure impacts of the fungus on L. lineolaris. Significant effects of B. bassiana on adults of C. rufilabris were found and the severity of impact depended on the concentrations tested. Beauveria bassiana impacted all demographic measurements of C. rufilabris reproduction and survival. Intrinsic and finite rate of increase and gross and net reproductive rates of adults treated with the highest concentrations tested were significantly decreased while doubling time increased for adults treated with the lowest test concentrations. Based on these observations, C. rufilabris will be affected by sprays of B. bassiana targeted at L. lineolaris if they are present at the time and location of treatment. The measured LD50 of 2.11 viable spores per mm2, compares to a LD50 of 2.71 spores per mm2 for L. lineolaris (Portilla, 2014). Higher concentrations were needed for sporulation (LS50 of 13.60 viable spores per mm2) of the entomopathogenic fungus on C. rufilabris.