No abstract

The present study, deal about the antibiosis activity of soil bacteria, isolated from 10 different locations of rhizosphere and diverse cultivation at Kochi, Kerala, India. The bacteria were isolated by standard serial dilution plate techniques. Morphological characterization of the isolate was done by Gram’s staining and found that all of them gram positive. Isolated bacteria were tested against 6 human pathogens viz., Escherichia coli , Enterococcus sp., Pseudomonas aeruginosa , Klebsiella pneumoniae , Staphylococcus aureus and Acinetobacter sp. Primary screening was carried out by perpendicular streaking and seed overlay method. Based on the result of primary screening most potential isolates of S1A1 and S7A3 were selected for secondary screening. Both the isolates showed positive results against Enterococcus sp. and S.aureus . The maximum antagonistic activity of 20.98 and 27.08 mm zone of inhibition was recorded at S1A1 against Enterococcus sp. and S. aureus respectively, at 180 µl concentration. Molecular identification was carried out by 16S rRNA sequence. The 16S rRNA was amplified from the DNA samples by using PCR. The amplified 16S rRNA PCR products were purified and sequenced. The sequences were subjected to NCBI BLAST. The isolates S1A1 and S7A3 BLAST results showed 99% and 95% respectively, similarity with the available database sequence of Bacillus amyloliquefaciens . The sequences were deposited in GenBank and the accession numbers KY864390 (S1A1) and KY880975 (S7A3) were obtained.

As per our knowledge, this is the first report for ovicidal activity of A. monophylla against S. litura, A. monophylla could be used for the management of S. litura and other insect pests.

No abstract

Indiscriminate use of synthetic pesticides to control the pests causes negative effects on non-target organisms. Some of the chemicals under B and C categories are carcinogenic to humans. The present study was aimed to assess the antifeedant, larvicidal and pupicidal activities of Hygrophila schulii (syn. H. auriculata) and Blumea mollis against Helicoverpa armigera. Maximum antifeedant activity of 70.01% was observed in ethyl acetate extract of H. schulii at 5.0% concentration with LC 50 value of 2.0%. B. mollis ethyl acetate extract at 5.0% concentration showed antifeedant activity of 35.40% with LC 50 value of 8.38%. The data for antifeedant activity showed homogeneity of variances in Levene Statistics and normality in ShapiroWilk test. Ethyl acetate extract of H. schulii at 5.0% concentration showed 68.66% larvicidal activity with LC 50 value of 2.97%. It also showed 73.33% pupicidal activity and was statistically significant from other treatments. No pupicidal activity was observed in ethyl acetate extract of B. mollis. All concentrations of ethyl acetate extract of H. schulii showed promising biological activities which differed statistically from other treatments. Ethyl acetate extract of H. schulii could be used to develop new botanical formulations to manage agricultural pests.