Liquid Phase Media for Mass Production of Metarhizium anisopliae against Sorghum Chafer, Pachnoda interrupta, using Rice as Solid Substrate

Microbial biological pest control agents such as entomopathogenic fungi (EPF) can be an effective alternative for the control of sorghum chafer, Pachnoda interrupta, an important pest in Ethiopia. Production of inoculums of high quality with reasonable quantity on mass production substrates is important for its use as mycoinsecticides. Three liquid phase media viz. sucrose /waste brewer’s yeast (SWBY), molasses/yeast extract (MYE) and lennoux broth base (LB) were evaluated for effects on mass production characteristics of three M. anisopliae isolates viz. PPRC51, PPRC2 and IC69 using rice as a solid substrate in the diphasic mass production technique. Effects of liquid media on shelf-life and virulence of the isolates against P interrupta was also evaluated. Weight of spores/kg of rice substrate, number of spores/g of spore powder and viability of spores varied significantly across the three isolates (P<0.0001). There was no significant difference among liquid phase media and their interactions with isolates (P > 0.05). The highest weight of spores (119.72g/kg) was obtained from IC69 mass produced by using MYE as a liquid phase medium. PPRC2 produced the highest number of spores (4.57x1010 spores/g) when using LB as liquid phase medium. Using MYE as liquid phase medium, the virulence of the three isolates of M. anisopliae did not vary significantly. Using either of the liquid media does not significantly affect all the quality variables for mass production, virulence and shelf life of the isolates selected for control of P. interrupta. Therefore any of the liquid phase media can be used for mass production of the selected isolates on rice without significantly affecting virulence and shelf life. Pest Managment Journal of Ethiopia , Vol. 19 (2016): Pest Managemernt Journal of Ethiopia