Virulence of Metarhizium isolated from infected Oryctes rhinoceros L. (Coleoptera: Scarabaeidae) larvae around coconut plantations in East Java, Indonesia

Abstract Background Metarhizium is one of the entomopathogenic fungi (EPF) that has been widely reported as a useful agent for controlling coconut rhinoceros beetle (CRB), Oryctes L. (Coleoptera: Scarabaeidae). Application this fungus biopesticide influenced by regional environmental conditions affect pathogenic activity against targeted pest. Several studies have proven native fungal isolates strong than EPF introduced from other regions. The identification local species strategic approach to develop potential biopesticides with standard properties including host specificity, climate suitability, and significantly suppressing target pest population. This study aimed identify isolated infected CRB larvae high pathogenicity pests in East Java, Indonesia. Results Thirteen were obtained which divided into 4 clades based on phylogenetic analysis ITS rDNA region, namely M. anisopliae var. lepidiotae , brunneum majus . Identified exhibited varied sizes conidia, but fell within size ranges previous studies. Interestingly, isolate MaSi produced conidial lengths well above range recorded placed these ( ) MGT clade, known MALC s.l. large conidia). present investigation MaLe, MaMa, MaWa, higher mortality values isolates, supporting had O. species. Neighbor-joining showed close resemblance between MaMa strain ARSEF 1946, was CRB. In addition, highest virulence larval cadaver faster lethal time (for 50% mortality). result indicated possible relationship status or DNA sequence polymorphisms specificity. Conclusions larvae, larvae. similarity CRB-isolated strains suggests specificity polymorphisms.