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.
Capsule is a stable formulation wherein the bioagent is encapsulated in coatings and thus protected from extreme environmental conditions. In this study, various coating materials were tested for their stability based on the time taken for disintegration when kept under ambient conditions both in vitro and in vivo. The in vivo performance was assessed for placement in soil as well as in banana pseudostem. The coating materials tested was Hard Gelatin Transparent (HGT), Hard Gelatin Coloured (HGC) and Hydroxy Propyl Methyl Cellulose (HPMC), while the carrier materials used were talc, chitin, chitosan, sodium alginate and calcium alginate. The entomopathogen encapsulated was Beauveria bassiana (Balsamo) Vuillemin and the efficacy of product was assessed against pseudostem weevil, Odoiporus longicollis (Olivier). HGT was the best coating material as it was stable under room temperature and normal atmospheric humidity. For soil placement, chitosan based capsules in transparent gelatin coating took only 24 to 48 hr to disintegrate completely under varying soil moisture. Talc based capsules in transparent gelatin coating got disintegrated completely at the end of 24 hr when placed in banana pseudostem, owing to the receipt of sufficient humidity. Placement of capsules in leaf axils or pseudostem sheath can be adopted for prophylactic control of pseudostem weevil and placement in bore holes can be considered for curative application. The ideal moisture content of filler material for fungal encapsulation was determined as 10%. Through this research paper, we would like to disclose about the ideal coating material, carrier material and moisture content for the encapsulation of entomopathogenic fungi.
Carrier material plays a pivotal role in maintaining the viability and virulence of an entomopathogenic fungus (EPF). Evaluation studies using sunflower oil, groundnut oil and talc as the basic carrier materials and their enrichment with chitin and chitosan, was conducted. The ideal proportion of carrier material and technical ingredient and viability were assessed based on number of colony forming units (cfu) over a period of storage of 3 months. Chitin enriched ground nut oil (GNO + Chitin) and chitin enriched sunflower (SFO + chitin) were observed as the best carriers for formulating the fungus. Ideal proportion of carrier and technical ingredient in oil formulations was found to be 65:35 per cent. The number of cfu observed with chitin enriched GNO and SFO by the end of three months of storage was 2.27 x 10 6 ml -1 and 2.20 x 10 6 ml -1 under room temperature respectively. Enrichment of oil formulations (GNO and SFO) with chitin could thus sustain viability as well as spore count of L. lecanii till the end of experimental period (three months).
Lecanicillium saksenae (Kushwaha) Kurihara and Sukarno is a versatile indigenous entomopathogenic fungus with high speed of kill on hemipteran insects. Investigations were carried out to explore the volatile metabolites of L. saksenae and bioefficacy of its crude toxin to different life stages of brinjal mealybug, Coccidohystrix insolita. GCMS spectrum of crude toxin extracted from cultures grown in potato dextrose broth and Czapak Dox medium revealed the presence of 25 compounds each. The major secondary metabolites identified were 2,6 pyridine dicarboxylic acid (dipicolinic acid), n-hexadecanoic acid, octadecanoic acid, harmine, dl- mevalonic acid lactone, 2-piperidinone, 4H-pyran-4-one 2,3-dihydro-3,5dihydroxy-6methyl, acetamide,N-(2-phenylethyl), pyrrolo [1,2-a] pyrazine-1,4-dione, hexahydro. The biological properties of these compounds include insecticidal to nematicidal and antimicrobial activities. Bioefficacy studies with crude toxins revealed the toxicity of secondary metabolities to C. insolita. The dose dependent bioassay revealed 100 per cent moratality at a higher concentration of 1000 ppm at 72 and 96 h after treatment on nymphs and adults respectively. Results highlighted the role of secondary metabolites in the pathogenicity of saksenae and pave way to the utilization of its biocide molecules in safer pest management.
This study aimed at finding out the efficacy of electrostatic sprayer on pest control in comparison with mist blower and air compression sprayer. Six pests were selected based on specific characteristics viz. integumental, movement and ecological niche. Energy use efficiency in production and application of pesticides used by different sprayers for the control of selected pests were quantified based on application efficiency, pre and post pest count and reoccurrence of pest infestation after spray. The greenhouse gas emission for the total energy usage for the corresponding quantity of pesticide were computed for all the selected sprayers. The energy use efficiency of electrostatic sprayer was found to be 1.5 times more than that of mist blower and 2 times more than that of air compression sprayers. The chemical usage by electrostatic sprayer was reduced by 65%, and that of knapsack mist blower was 35% with air compression sprayers. The corresponding greenhouse gas emission was only 20% for electrostatic sprayer and 65% for powered mist blower than that of air compression sprayers. The post pest count was almost nil in all the categories of pest while applying with electrostatic sprayer and the reoccurrence of the pest to the threshold level was minimum. This contributes a significant reduction in emission of CO2 when considered globally, and ultimately contribute to mitigation of global warming.
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.