Establishment of <i>Serratia entomophila</i> after application of a new formulation for grass grub control

Abstract

The bacterium Serratia entomophila is a naturally occurring pathogen causing amber disease of the New Zealand grass grub (Costelytra zealandica) A novel granular formulation of S entomophila Bioshieldtrade; was applied to 18 pasture sites in a largescale programme to demonstrate efficacy against grass grub No significant difficulties were encountered in application of the granules through conventional machinery There were high populations of the applied bacteria in soil within the first week of application and within 6 weeks of application there was an average of 3 x 10⁴ viable S entomophila of the applied strain per gram of soil This resulted in a significant (Plt;005) 20 increase in the incidence of amber disease in the treated grass grub populations compared to untreated populations Successful establishment of the bacteria in the soil and target population following Bioshieldtrade; granule application was demonstrated on a wide range of sites under various farming conditions