Gut bacterial influence on susceptibility of lepidopteran pests to Bacillus thuringiensis subsp. kurstaki

DOI: 10.22161/ijeab/1.3.41

Abstract:
Influence of gut bacteria on susceptibility of lepidopteran pests viz., Spodoptera litura, Helicovepa armigera, Plutella xylostella and Crocidolomia binotalis to Bacillus thuringiensis subsp. kurstaki was studied by antibiotic mediated elimination of gut bacteria. Bioassay was performed against laboratory reared and field collected larvae of test insects to study the influence of gut bacteria on susceptibility of lepidopteran pests to B. thuringiensis subsp. kurstaki. Results indicated that both lab and field population of test insects were more susceptible in the presence of gut bacteria by recording lower LC50 values against B. thuringiensis subsp. kurstaki. Field population of test insects viz., S. litura, H. armigera, P. xylostella and C. binotalis recorded LC50 values of 0.62, 0.48, 0.77 and 0.44 g/l, whereas laboratory population recorded LC50 values of 0.37, 0.32, 0.48 and 0.29 g/l respectively. In the absence of gut bacteria both laboratory reared and field collected larvae found less susceptible by recording higher LC50 values. Antibiotic treated field collected larval population of test insects viz., S. litura, H. armigera, P. xylostella and C. binotalis recorded LC50 values of 0.74, 0.54, 1.07 and 0.56 g/l respectively. Similarly antibiotic treated laboratory reared larval population of test insects recorded LC50 values of 0.49, 0.38, 0.57 and 0.43 g/l respectively.

Keywords:
Gut bacteria, Bacillus thuringiensis subsp. Kurstaki, Antibiotics and LC50 .

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