Efficacy of new formulations of Bacillus thuringiensis var. kurstaki against Helicoverpa armigera (Hubner)
KrishiKosh
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Title |
Efficacy of new formulations of Bacillus thuringiensis var. kurstaki against Helicoverpa armigera (Hubner)
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Creator |
DINESH SWAMI
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Contributor |
Bishwajeet Paul
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Subject |
biological phenomena, economic systems, marketing, sets, selection, sampling, sexual reproduction, stimulants, manpower, social sciences
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Description |
t-8047
Bioassays were conducted under laboratory conditions to assess the efficacy of new wettable powder (WP) formulations of Bacillus thuringiensis var. kurstaki (HD- 1) against IIIrd instar larvae of Helicoverpa armigera (Hubner). Sixteen new WP formulations of B. thuringiensis var. kurstaki (HD-1) were developed and relative efficacy was calculated on the basis of LC50 values. The results indicated that LC50 values of recipe-2 (0.032%), recipe-7 (0.018%), recipe-9 (0.030%) and recipe-15 (0.015%) were highly effective against IIIrd instar larvae of H. armigera in comparison to Dipel® 8L (0.037%) and Biolep® (0.046%) (Commercial formulation of B. thuringiensis var. kurstaki). On the basis of laboratory performance, recipe-7 and recipe-15 were selected for field efficacy against H. armigera in pigeonpea crop. Recipe-15 was found significantly more effective than the Dipel® 8L under field conditions. Physico-chemical properties of the test carriers were evaluated for the preparation of WP formulation of B. thuringiensis var. kurstaki (HD-1). The results revealed that barium sulphate registered highest bulk density, whereas, precipitate of silica had least bulk density. Dolomite was found to be highly alkaline and fuller’s earth was highly acidic in reaction, whereas, precipitate of silica was nearly neutral. Moisture content was highest in dolomite and lowest in precipitate of silica. Sorptivity was found to be highest for precipitate of silica and lowest for dolomite. Specific surface area for precipitate of silica was highest and for barium sulphate was lowest. Among the carrier tested precipitate of silica was found to be the most suitable for preparation of WP formulation of B. thuringiensis var. kurstaki (HD-1). |
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Date |
2017-01-03T09:48:58Z
2017-01-03T09:48:58Z 2008 |
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Type |
Thesis
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Identifier |
http://krishikosh.egranth.ac.in/handle/1/94039
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Format |
application/pdf
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