A novel strain of Bacillus velezensis as a potential biological control agent for Nezara viridula (L.)

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. We hypothesized that B. velezensis LP16S could 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 will be discussed.