studies on white grub diversity isolation characterization and evaluation of metarhizium anisopliae metschinkoff sorokin against holotrichia serrata fabricius coleopteran scarabaeidae in northeastern karnataka

Abstract

Investigations were carried out at AICRP on Bio control, Department of Entomology, newlineUniversity of Agricultural Sciences, Raichur on white grub diversity, isolation, newlinecharacterization and evaluation of Metarhizium anisopliae (Metschinkoff) Sorokin against newlineHolotrichia serrata Fabricius (Coleoptera: Scarabaeidae) in Northeastern Karnataka during newline2018-19 and 2019-20. Totally 29 scarab beetles were collected out of which 19 were newlinephytophagous while 10 were non-phytophagous. Among the Scarabaeidae, Melolonthinae newlineand Cetoninae were species rich taxons (S=8) followed by Rutelinae (S=7) and Dynastinae newline(S=2). The newly documented adult species were Adoretus lasiopygus, A. stolickzae, A. newlinetestaceus., Apogonia sp., A. ferruginea, Maladera insanabilis, H. akolana, H. rufoflava and newlinePhyllognathus dionycius. Moreover, thirteen larval white grubs were identified based on newlinelarval taxonomic characters and H. serrata was predominant in sugarcane ecosystem. To newlineisolate the entomopathogenic fungi soil samples were collected and totally 43 isolates of newlineM. ansisopliae were isolated out of which 8 were subjected for molecular characterization. newlineThe phylogenetic tree analysis resulted into 2 major clusters of which UASRBC-Ma7, newlineUASRBC-Ma2, UASRBC-Ma1, UASRBC-Ma3 and UASRBC-Ma4 grouped as one cluster newlinewith boot strap value 100. Bio-assay studies of 11 promising isolates against third instar of H. newlineserrata showed that UASRBC-Ma2 and UASRBC-Ma3 had lowest LC50 of 5.37 x 105 and newline1.92 × 106 conidia/ml with lowest LT50 value. Liquid formulation-I of UASRBC-Ma2 newlineshowed highest CFU counts followed by Liquid formulation - II. Among the oil formulation newlinethe highest number of CFU count were noticed in sunflower oil followed by groundnut oil newlineand the mortality of first instar of H. serrata ranged from 30.00 to 93.33 per cent in Liquid newlineformulation I tested after 30 days of storage. newline