Combination effect of Bacillus thuringiensis Ber. with certain botanicals against major insect pests of sunflower
KrishiKosh
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Title |
Combination effect of Bacillus thuringiensis Ber. with certain botanicals against major insect pests of sunflower
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Creator |
RAJASEKHAR, Y
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Contributor |
KRISHNAYYA, P.V
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Subject |
Combination, effect, Bacillus, thuringiensis, Ber, certain, botanicals, against, major, insect, pests, sunflower
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Description |
The present investigation ‘Combination effect of Bacillus thuringiensis Ber. with certain botanicals against major insect pests of sunflower’ was taken up under field and laboratory conditions at Agricultural College, Bapatla, during rabi 2003- 04. The field investigation was carried out using Bacillus thuringiensis var. kurstaki (B.t.k.; Dipel 8 L) and botanicals [neem seed kernel extract (NSKE), Azadirachta indica A. Juss; sweet-flag rhizome extract(SFRE), Acorus calamus L.; pungam seed extract (PSE), Pongamia glabra Vent. and annona seed extract (ASE), Annona squamosa L.] alone and in combination against major lepidopteran pests of sunflower viz., Spilosoma obliqua (Walker), Spodoptera litura (Fab.) and Helicoverpa armigera (Hub.). Larval incidence of the pests was regularly monitored on alternate days and the insecticidal treatments were given as sprays twice at 55 and 66 days after sowing. The results indicated that among the eleven treatments tested endosulfan 0.07%, the standard check recorded the highest per cent reduction of larval population (S. obliqua, 66.34; S. litura, 58.87 and H. armigera 56.08) and the highest seed yield of 1420.00 kg ha-1. Combination treatments viz., B.t.k. 0.1% + NSKE 2.5%, B.t.k. 0.1% + SFRE 2.5%, B.t.k. 0.1% + ASE 2.5% and B.t.k. 0.1% + PSE 2.5% recorded significantly higher per cent reduction of the larval population (S. obliqua: 58.01, 52.18, 46.76 and 44.58, respectively; S. litura: 55.53, 50.04, 44.80 and 43.44, respectively and H. armigera: 53.18, 47.11, 43.43 and 41.07, respectively) with significantly superior seed yield (1593.34, 1520.00, 1366.67 and 1326.67 kg ha-1, respectively). The corresponding per cent larval population reduction in the individual treatments B.t.k. 0.2% and 5.0% of NSKE, SFRE, ASE and PSE was moderate ( S. obliqua: 43.15, 41.24, 36.69, 31.01 and 28.60, respectively; S. litura: 39.09, 38.90, 33.57, 28.29 and 25.83, respectively and H. armigera: 37.24, 36.62, 31.52, 26.83 and 24.51, respectively) with seed yield of 1456.67, 1200.00, 1153.33, 1120.00 and 1033.33 kg ha-1, respectively. From the point of cost benefit ratio, the most economical treatments were endosulfan 0.07%, the standard check (1: 3.85), NSKE 5.0% (1: 2.86), ASE 5.0% (1: 2.52) and B.t.k. 0.1% + NSKE 2.5% (1: 2.17). The treatments that proved efficacious in the field were consistently effective in the laboratory against S. litura, resulting in higher larval mortality ( 93.33 to 56.67%), feeding inhibition ( 90.53 to 41.84%), weight gain (135.11 to 235.88 mg), pupation (6.67 to 43.33%), pupal weight reduction (36.36 to 09.09%), normal pupae (3.33 to 34.66%) and normal adult emergence (00.00 to 24.07%) and longer larval period (10.3 to 8.3 d) and pupal period (12.0 to 10.0). The botanicals tested individually at 0.63, 1.25, 2.5 and 5.0% concentrations against S. litura were found moderately effective and their efficacy was concentration dependent. The treatment B.t.k. when it was alone recorded significantly the highest harvest of spores and cells ml-1 (253 x 1010 to 173 x1010) from 0 to 30 days after incubation and inoculation on nutrient agar medium. But harvest of spores and cells of B.t.k. was relatively poor when B.t.k. was mixed and inoculated with the botanicals for varying intervals of time. However, among the combinations, B.t.k. with NSKE at all the concentrations recorded higher harvest of spores and cells ml-1 (241.7 x 10 10 - 215 x 1010 to 156 x 1010 - 22 x1010 ) at 0.0 to 30.0 days after preparation and incubation. It was followed by B.t.k.+ SFRE (237 x 1010 - 208 x 1010 to 147 x 1010 - 17 x 1010), B.t.k. + ASE (247.6 x 1010 - 213 x 1010 to 142 x 1010 - 12 x1010) and B.t.k. + PSE (249 x 1010 - 217 x 1010 to 137 x 1010 - 10.6 x 1010). These results indicated PSE has higher antibacterial effect compared to the other botanicals viz., ASE, SFRE and NSKE. |
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Date |
2016-08-20T14:36:51Z
2016-08-20T14:36:51Z 2004 |
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Type |
Thesis
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Identifier |
http://krishikosh.egranth.ac.in/handle/1/73200
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Language |
en
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Relation |
D7934;
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Format |
application/pdf
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Publisher |
ACHARYA N.G.RANGA AGRICULTURAL UNIVERSITY, RAJENDRANAGAR, HYDERABAD
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