Submitted to: Southwestern Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/24/2022
Publication Date: N/A
Interpretive Summary: A recently new bacterial strain, identified as Bacillus velezensis LP16S, has been shown to control multiple major disease pathogens in sorghum. The southern green stink bug is a common pest of sorghum, alfalfa, cotton, soybean, fruit and nut trees, causing significant losses in yield and quality. Southern green stink bugs rely on a variety of bacterial organisms within their gut to remain healthy. This work was carried out to determine the effect of the new bacterial strain on the survival of adult southern green stink bugs. On average, the survival and lifespan of adult stink bugs fed green beans contaminated with B. velezensis LP16S was reduced by 15 and 22%, respectively, compared with adults fed sterile beans. Based on these results, the new Bacillus strain shows some activity as a biocontrol agent for the southern green stink bug.
Technical Abstract: Strains of Bacillus velezensis have been successful biological control agents for various plant diseases. A novel strain – Bacillus velezensis LP16S – was recently shown to inhibit mycelial growth and spore germination in four major pathogens of sorghum. Southern green stink bug [Nezara viridula (L.)] can infest sorghum and is known to possess beneficial endosymbiotic bacteria within the insect gut. Because B. velezensis LP16S was detrimental to the propagation of certain fungi, we hypothesized that B. velezensis LP16S may affect internal microbiota, thereby affecting survival and longevity of N. viridula. Adult male and female N. viridula were fed for 2-d on a diet of green bean sections that were either sterile or contaminated with a derivative strain of B. velezensis LP16S (i.e., B. velezensis LP16SR). Diet treatment significantly affected survival. Adults fed B. velezensis LP16SR had a significantly shorter mean survival than adults fed sterile beans. The interaction term of Diet treatment by Sex was significant, indicating that females fed B. velezensis LP16SR exhibited significantly shorter mean survival than females fed sterile beans. Also, the former group exhibited maximum longevity at 72 d while the latter group exhibited a maximum longevity of 92 d. Given the observed differences in mean survival and longevity, the implications and future research avenues to consider B. velezensis LP16S as a potential entomopathogen for control of N. viridula are discussed.