Production of Conidia by Entomopathogenic Fungi and Their Pathogenicity Against Coptotermes sp.

Entomopathogenic fungi have the potential to infect most arthropods including termites which are economically important major insect pests of wood, wood products and building structures. However, the application of this fungus in the field has not shown satisfactory results yet, one of which is constrained in mass production of conidia. The purpose of this study was to evaluate 16 types of biodegradable products and waste as substrates for mass production of conidia using solid state fermentation method and two types of inoculum (solid and liquid inoculum). Toxicity tests were carried out on subterranean termites (Coptotermes sp.) based on JIS K 1571, 2010. The parameters observed were the number and dry weight of the conidia produced, conidial viability, nutrient content of the substrate, and percentage of termite mortality. The results showed that rice, sorghum and corn were the best media for the growth of entomopathogenic fungi based on the number of conidia and dry weight of the conidia produced. Metarhizium sp. T4.B23 produced the highest number of conidia, 1.12 x 1011 conidia/100 g substrate and yielded 180.9 ± 0.623 g dry conidia/kg of rice; followed by Metarhizium sp. B2.2 grown on sorghum that resulted in 1.11 x 1010 conidia/100 g substrates and 127.8 ± 0.570 g/kg sorghum; and B. bassiana produced 8.3 x 109 conidia/100 g substrate and 31.24 ± 0.407 g/kg sorghum. Metarhizium sp. B2.2 showed the highest toxicity to termites with 100% mortality that was observed within the second day of testing. The novelty of this research is we found two strains of Metarhizium indigenous Indonesia (T4.B23 and B2.2) that isolated from soil in Wangameti, Sumba, East Nusa Tenggara and Mount Gandang Dewata, West Sulawesi, respectively. In this study we not only can produce the high number of conidia from these fungi using cheap media but also it has high toxicity to termites. Furthermore, the conidia of these fungi are very potential to be developed as a biopesticide for termite control, so the use of chemical pesticides can be reduced. [ABSTRACT FROM AUTHOR]