Entomopathogenic Nematodes (EPNs) from the genus of Steinernema and Heterorhabditis are known as potential biological control agents and have been widely used in various countries1. Many researchers in Indonesia have been succeeding in performing in vivo isolation of local EPNs with insect larvae. Many local isolates of EPNs has been explored and identified. Different methods were used to develop bio pesticides but they are not completely effective, which leads towards complicating application strategies and decreased field efficiency2.
Ecological and behavioral traits of Infective juveniles (IJs) of different EPNs differ regarding their persistence and survival in the soil; which depends upon the geographical condition and the habitat3, 4 restricts their distribution area. Consequently, feasibility and pathogenicity of EPNs are highly influenced by many factors, including their abiotic environment, storage method and formulation5. Generally, mass cultivation of EPNs under in vitro condition tends to change their reproductive and morphometric character6, 7.Thus, there is a requirement to evaluate the suitable temperature for their reproduction ability, viability and pathogenicity to produce effective biopesticides.
A research was conducted to compare the reproduction rate, viability and pathogenicity of EPNs from different origins and Completely Randomized Design one-way classification was used. Both EPNs were cultured in vivo condition with Tenebrio molitor larvae by white trap method. The reproduction rate of nematodes was calculated after 8 days of incubation and its viability test at six storage temperatures. The EPNs with the best viability was further tested for its pathogenicity on Macrotermes sp. The reproduction rate of nematodes were analyzed by using student’s t-test, while one-way ANOVA was used to analyze the viability of EPNs, and pathogenicity of lethal dose value was calculated using Probit analysis.
The findings showed that the reproduction rate on EPNs from Semarang isolate was significantly higher (p<0.05) than EPNs from commercial biopesticide. Various temperatures significantly affected the viability on both nematodes, but under LSD test (p<0.05) revealed that viability at storage of 21, 24 and 27°C were not different of each other.
It was observed that the reproduction rate of EPNs from Semarang isolate was 35% higher than those originated from commercial biopesticide. The optimal feasibility of both EPNs was obtained at temperature ranged from 21-27°C. The LD50value of EPNs from Semarang isolate was better than nematodes originated from commercial biopesticide.
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23 August, 2019