A. R. Prasanna ¹, V. B. Nargund ², M. Bheemanna ², B. V. Patil ²

Affiliations
1 Department of Entomology, G K V K, UAS, Bangalore, 650 065, IN
2 Department of Agricultural Entomology and Department of Pathology, College of Agriculture, University of Agricultural Sciences, Raichur 584 101, Karnataka, IN

Abstract

Laboratory experiment was conductcd to study the compatibility of 1 hiamethoxam 70WS with growth and sporulation of Trichoderma harzianum. There wn no inhibition of mycelial growth of T. harzianum in all the concentrations except at 1.25 percent. The spore count was 1xl0⁴ spores/ ml at seven days after inoculation of Trichoderma. The reduction in the radial growth of Rhizactonia solani was 40.2 percent in presence of T. harzianum whereas no inhibition was observed In thiamethoxam at 10g/kg seed. In combination with thiamethoxam at 2,85g/kg seed+Trichoderma, 4.28g/kg seed+Trichoderma and l0g/kg seed+Trichoderma, the reduction in radial growth of R. solani was 37,3, 35,95 and 32.4 percent, respectively. The study indicated that it is possible to use Trichoderma @ 4g/kg seed and thiamethoxam l0g/kg seed as seed treatment, which find a place in the integrated insect pest and disease management.

Keywords

Bioefficacy, Compatibility, Rhizoctonia solani, Seed Treatment, Thiamethoxam, Trichoderma.

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Saroja ¹, Basavaraj Kalmath ¹, M. Bheemanna ², A. Prabhuraj ²

Affiliations
1 College of Agriculture, Bheemarayanagudi, Shahapur, Yadgiri - 585287, Karnataka, IN
2 College of Agriculture, UAS Raichur - 584104, Karnataka, IN

Abstract

Radiation severely inactivates the potency of Bacillus thuringiensis spores and crystals present in sprayed formulations leading to decreased efficacy in field. Incorporation of UV protectants to biopesticides is one of the methods to protect against radiation damage. Keeping this as objective, a native isolate BGC-1 was selected for preparation and evaluation of wettable powder formulation against second instar larvae of Helicoverpa armigera. Median lethal concentration of the BGC-1 was 1.05 g/l and assigned biopotency value was 15428.57 ITU/g. UV protectants viz., melanin, para-amino benzoic acid, polyvinyl alcohol and Congo red were evaluated by exposing formulated solution to sunlight at different intervals of time. Among four UV protectants, melanin showed an excellent UV protecting ability with the mortality of 86.67 per cent and, 116.49 μg/ml of crude protein at 5 h sunlight exposure with temperature of 43.6°C and light intensity of 4.93×10⁵ lux followed by 80.00 per cent mortality, 1.74×10⁸ CFU/ml and 109.40 μg/ml of crude protein in para-amino benzoic acid UV protectant. Next best UV protectant was congo red with the mortality of 73.33 per cent and, 90.76 μg/ml of crude protein and 1.26×10⁸ CFU/ml. It is concluded that melanin was found to be an effective UV protectant for B. thuringiensis WP formulations against H. armigera.

Keywords

Bacillus thuringiensis, Helicoverpa armigera, Lyophilized Powder, WP Formulation, UV Protectants.

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