The potential of bacteria for the microbial control of grasshoppers and locusts

Bacteria have been implicated in disease epizootics observed in field populations and laboratory-reared locusts and grasshoppers. Two species [Serratia marcescens Bizio and Pseudomonas aeruginosa (Schroeter) Migula] consistently infect locusts when ingested with food and can spread in laboratory populations. However, research on developing these organisms for microbial control of locusts and grasshoppers begun in the 1950s has not been continued. In recent years strains of Bacillus thuringiensis Berliner have been studied for activity against locusts and grasshoppers. Results of additional trials by the authors are reported. Among 393 B. thuringiensis isolates and 93 preparations of other sporeforming bacteria fed to nymphs of Locusta migratoria (L.) and/or Schistocerca gregaria Forsk., none has shown any pathogenicity to the insects. The recent discovery of novel B. thuringiensis strains active against Various diverse pests and the many properties of a sporeforming bacterium that satisfy the requirements for a microbial control agent, and the development of Serratia entomophila as a promising agent for control of grass grubs, provide incentive to continue the search for an orthopteran-active sporeforming bacterium and to re-investigate the potential of non-sporeforming bacterial pathogens as microbial control agents of grasshoppers and locusts.