A new indigenous isolate of Lecanicillium namely L. saksenae was tested for its efficacy against rice bug. Lecanicillium. lecanii was non pathogenic to rice bug. Peculiar pre mortality symptoms like ataxis, aggregation, convulsions were exhibited by test insects upon infection. L. saksenae was characterized by it's quick kill effect, causing 100 per cent mortality of adults and nymphs within 72h after treatment with high spore doses of 10 8 and 10 7 spores mL-1. Furthermore, probit analysis done at 6 days of treatment, revealed the LC 50 as 2.99 x 10 4 and 1.72 x 10 4 spores mL-1 for nymphs and adults respectively. LT 50 (10 8 spores mL-1) was 17.58 and 18.58 hours for nymphs and adults respectively. Although the quick kill effect was not exhibited in field, the count of rice bugs in plots treated with oil formulated L. saksenae were significantly lower (1.33 bugs per plot). Moreover, all the bioformulations applied as treatments were evidently safe to natural enemies present in rice ecosystem. The yield recorded from plots treated with oil formulated L. saksenae was also higher (3.48 kg per plot of 2 x 2 m). This study projects the prospect of utilizing L. saksenae, and its oil formulations as an effective biocontrol agent against rice bug which is a major sucking pest of rice.
The study was conducted in the Department of Agricultural Entomology, College of Agriculture, Vellayani in 2022 with an objective to test the bio efficacy of liquid and bait formulations of Beauveria bassiana Bb 6063 and SlNPV against two most damaging pests of vegetable cowpea Spodoptera litura F. and Aphis craccivora Koch. Emulsifiable suspension (ES) formulation (comprising of Bb 6063 conidia and SlNPV @1.78 x 1010 Conidia mL-1 and 5.24 x 108 POB mL-1 respectively, in 95% sesamum oil and 5% Span- 20 + Triton-X-100 (29:71)) and bait formulation (consisting of SlNPV @4.13 x 107 POB mL-1 in, 75% wheat flour + 25% chickpea flour base matrix) developed in the current study, was evaluated under field conditions. NPV bait when applied alone and in combination with ES formulation, recorded low population of S. litura (1.33, 1.00 larvae plot-1 respectively, after two rounds of application), though inferior to chemical check Flubendiamide 39.35 SC (0 larvae plot-1). However, the leaf damage intensity score in treatments with Flubendiamide (1.53), ES formulation applied along with NPV bait (1.73) and NPV bait alone (1.57) at 10 days after two rounds of treatments were statistically on par with each other and significantly lower than rest of the treatments. Treatments with ES formulation alone and in combination with NPV bait application recorded lowest Aphis craccivora population also (0.67, 0.33 aphids plot-1) as against 9.33 aphids plot-1 in untreated control. Thus, ES formulation of Bb 6063 and SlNPV as well as SlNPV bait can be employed in the management of S. litura, wherein the former treatment is effective in controlling A. craccivora as well.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.