Field application of biopolymercoated Beauveria bassiana F418 for clover root weevil ( Sitona lepidus) control in Waikato and Manawatu

Abstract

Clover root weevil (CRW) (Sitona lepidus) continues to have a severe impact on white clover in pastures in the North Island of New Zealand Trials were established in October 2005 as part of a continuing evaluation of the insectpathogenic fungus Beauveria bassiana F418 strain for management of this pest F418 was applied as a rice biopolymer formulation targeting CRW larvae in the clover root feeding zone (35 cm below the surface) Overall there was a reduction in CRW numbers at all of the test sites The number of larvae recovered was significantly lower in F418treated than control plots after 3 weeks and the number of pupae was similarly lower in F418 than control plots after 6 weeks Higher levels of fungal propagules were recovered from 06 cm in the soil profile than 610 cm