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.

No abstract

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.

No abstract

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).