Cricket powder in the growth medium provides nutrition for the insect-pathogenic fungus Metarhizium majus UICC 295

The genus Metarhizium consists of a diverse group of species, which have a global distribution and a wide range of insect hosts. This study investigated the effects of cricket powder as a substrate for the fungus Metarhizium majus UICC 295 and the fungal virulence on Oryctes rhinoceros larvae. The growth of M. majus UICC 295 was observed on Saboraud Dextrose Yeast Extract Agar (SDAY) with 10% (w/v) cricket powder and without addition as control. Inoculum was prepared from 15 day-old fungal culture, and the cell number was (1.75—4.3)x107 CFU/mL. Virulence of M. majus was assayed by dripping the larvae with inoculum suspension. Untreated larvae were dripped with sterile water and served as control. Mortality was recorded daily for 15 days. The results showed that there was an increase of the fungal colony’s diameter, conidia’s size, and hyphae’s width from SDAY with cricket powder compared to fungus from SDAY and control. However, there was no difference of inoculum treatment to larval mortality since all treated larvae reached 100% mortality within 11 days compared to control. Further study is required to determine the influence of cricket’s protein on the M. majus virulence by comparing the inocula from artificial and cricket powder media.