Effect of different storage condition and duration on oil-based formulations of entomopathogenic fungi Metarhizium rileyi (Farlow) Samson against Spodoptera litura (Fabricius)

Abstract

Metarhizium rileyi (Farlow) Samson is one of the important entomopathogenic fungi under biological management of insect pests. The present article describes the study on storability and duration of spore viability of M. rileyi to utilize for the management of insect pest under field condition. So, initially 26 different formulations of M. rileyi were developed and evaluated against S. litura. Among the 26 formulation, four best formulations (groundnut oil formulation, combination of groundnut oil + rice grain, mustard oil + rice grain and mustard oil + wheat grain) of M. rileyi were tested for their virulence under different storage period (3 months) at different temperature. The storage of selected formulations in refrigerator (4 °C) and mud pot filled with wet sand recorded the highest mortality of S. litura compared to storage under room temperature (27.0 ± 1.0 °C) and incubator conditions (35 °C) after three months of storage period. Further, selected formulations of M. rileyi were evaluated against S. litura on cabbage under semi-field condition. Among the different formulations of N. rileyi, the maximum mean percent mortality was recorded in the groundnut oil (31.73%) followed by combination of groundnut oil + rice grain (29.07%), mustard oil + rice grain (27.20%) and mustard oil + wheat grain (27.47%) formulations. However, it is inferior to the NSKE (39.20%) and indoxacarb 14.5% SC (69.07%).