BEAUVERIA BRONGNIARTII FUNGUS INFECTING WHITE GRUBS ATTACKING SUGARCANE IN THE KWAZULU-NATAL MIDLANDS NORTH REGION

Beauveria brongniartii (Saccardo) Petch epizootics were recorded at two sites in the Dalton area of the Midlands in South Africa on the melolonthid species, Hypopholis sommeri Burmeister (Coleoptera: Scarabaeidae). To identify the disease-causing fungus, 17 different fluorescently-labelled microsatellite PCR primers were used to target 78 isolates of Beauveria spp. DNA. Microsatellite data resolved two distinct clusters of Beauveria isolates which represented the B. bassiana s.s. (Balsamo) Vuillemin and B. brongniartii species groups. Groupings were supported by two gene regions, the nuclear ribosomal ITS and Bloc, of which 38 exemplar Beauveria isolates were represented and sequenced. Microsatellite analyses also showed that B. brongniartii conidia were being cycled from epigeal to subterranean habitats and vice versa in the environment by H. sommeri beetles. This is the first record of this species of fungus causing epizootics on melolonthid larvae and adults of H. sommeri in South Africa. (Resume d'auteur)