Ajay Kumar Pandey ¹

Affiliations
1 College of Forestry & Hill Agriculture, G. B. Pant University of Agriculture & Technology Hill Campus, Ranichauri, Tehri Garhwal 249 199, Uttarakhand, IN

Abstract

Field experiments were conducted at crop research center (Gaja) of College of Forestry and Hill Agriculture, GBPUA&T, Ranichauri during the year 2006-2009 to test the effectiveness of entomopathogenic fungi, Beauveria bassiana and Metarhizium anisopliae in comparison with an chlorpyriphos against cutworm, Agrotis ipsilon on potato. Lowest tuber damage (15.6%) was recorded in treatment of M. anisopliae (5.0x1011 spores/g) followed by B. bassiana (5.0x109 spores/g) with tuber damage of 17.82% as compared to control (31.82%). Highest yield of 126.97 q ha-1 was recorded in M. anisopliae treatment. However, among all the treatments, chlorpyriphos was found to be the most effective at lowest tuber damage (8.80%) with 142.01 q ha-1 yield while in control it was 65.78 q ha-1. Cost benefit ratio also revealed that application of higher dosage of M. anisopliae proved most effective followed by B. bassiana.

Keywords

Beauveria bassiana, Metarhizium anisopliae, Chlorpyriphos, Bio-efficacy, Agrotis ipsilon, Potato.

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Ajay Kumar Pandey ¹

Affiliations
1 College of Forestry & Hill Agriculture, G. B. Pant University of Agriculture and Technology, Hill Campus, Ranichauri, Tehri Garhwal 249 001, IN

Abstract

Survey was conducted to observe the natural infection of entomopathogenic microorganisms of whitegrub in the pre-selected whitegrub endemic pockets of Haridwar, Tehri and Pauri district of Uttarakhand during 2009 to 2011. The microorganisms I>Bacillus cereus, Beauveria bassiana, Metarhizium anisopliae, Steinernema sp. and Heterorhabditis sp. were the major disease causing agents in whitegrub under rainfed condition of Uttarakhand which caused 15.55 to 21.63 percent natural mortality of grubs with an average of 18.91 percent during the study period. Among the microorganisms, B. cereus was found to be more efficient (7.03 percent mortality) followed by the entomopathogenic fungi (3.80 percent mortality) and nematodes (3.20 percent mortality).

Keywords

Beauveria bassiana, Metarhizium anisopliae>, Natural Parasitization, Whitegrub.

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Ajay Kumar Pandey ¹

Affiliations
1 Department of Entomology, G. B. Pant University of Agriculture & Technology, Pantnagar- 263145, Uttaranchal, IN

Abstract

Pathogenicity of Beauveria bassiana to Spilosoma obliqua larvae was higher at low temperature (20°C) compared to higher temperature (30°C). The LC₅₀ values of B. bassiana at 20 and 30°C were 8.63 and 17.8× 10⁶ conidia ml⁻¹ against second instar larvae, 16.4 and 62.3×10⁶ against third instar, and 33.7 and 70.2×10⁶ conidia ml⁻¹ against fourth instar, respectively. The LT₅₀ values at 20°C temperature were 155.4, 159.0 and 162.9 hours to second, third and fourth instar larvae, respectively, compared to 167.6, 168.9 and 169.8 hours, respectively, at 30°C temperature. The LC₅₀ values of Metarhizium anisopliae against S. obliqua at 20°C temperature was 54.1, 66.2 and 73.8×10⁶ conidia ml⁻¹ against second, third and fourth instar larvae, respectively, which was 1.58, 1.14 and 1.08 fold lower than values obtained at 30°C temperature, i.e., 58.7, 75.1 and 80.1×10⁶ conidia ml⁻¹, respectively. Similarly, the LT₅₀ values at 20°C were 161.3, 162.9 and 169.5 hours against second, third and fourth instar larvae, respectively, which were 1.08, 1.08 and 1.05 fold lower than LT₅₀ obtained at 30°C temperature, respectively.

Keywords

Beauveria bassiana, Metarhizium anisopliae, Pathogenicity, Spilosoma obliqua, Temperature.

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Ajay Kumar Pandey ¹, K. R. Kanaujia ²

Affiliations
1 RARS, SKUAST-K, P. B. No. 146, Leh (Ladakh), 194 101 (J&K), IN
2 Department of Entomology, G B. Pant University of Agriculture and Technology, Pantnagar, 263 145, Uttaranchal, IN

Abstract

A laboratory experiment was carried out to study the influence of different grain based media on sporulation, germination and virulence of Beauveria bassiana (Balsamo) Vuillemin against third instar larvae of Spodoptera litura Fabricius. Among the six grain based media, viz. barley, finger millets, maize, sorghum, soybean and wheat, highest spore production (5.39 x 10⁷ conidia ml⁻¹) and spore viability (86.6 %) was observed in conidia produced from finger millet. The production and viability of conidia increased which ranged from 5.0 to 11.5 per cent and 1.70 to 4.65 per cent, respectively, when the media was supplemented with sucrose. The conidia produced from finger millet showed highest virulence against third instar larvae of S. litura with LC₅₀ value of 1.56 x 10⁶ conidia ml⁻¹ while soybean was lowest with LC₅₀ value of 4.98 x 10⁶ conidia ml⁻¹. However, conidia produced from SDA medium showed highest spore production (6.36 x 10⁷ conidia ml⁻¹), viability (93.75 %) and virulence (0.95 x 10⁶ conidia ml⁻¹) against third instar larvae of S. litura.

Keywords

Beauveria bassiana, Grain Media, Spodoptera litura, Sporulation, Virulence.

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Ajay Kumar Pandey ¹, K. R. Kanaujia ²

Affiliations
1 RARS. SKUAST(K), Post Box No. 146, Leh-Ladakh, IN
2 Department of Entomology, G. B. Pant University of Agriculture and Technology, Pantnagar 263145, Uttranchal, IN

Abstract

Bioassays were conducted with two isolates of Beauveria bassiana (Balsamo) Vuillimen, cultured on Sabouraud's dextrose agar (SDA) medium supplemented with host insect larval extract against Spilosoma obliqua (Walker) larvae. The LC₅₀ values of isolate MTCC 984 and MUCL 32508, grown on SDA medium, were 1.43 and 7.69×10⁶ conidia ml^-1, 2.34 and 11.6×10⁶ conidia ml^-1, and 3.53 and 19.5×10⁶ conidia ml^-1 against second, third and fourth instar larvae, respectively. However, the virulence of both isolates increased when grown on SDA medium supplemented with larval extract. The LC₅₀ values of isolates MTCC 984 and MUCL 32508 grown on SDA medium supplemented with larval extract were 0.86 and 3.31×10⁶ conidia ml^-1, 1.95 and 6.28×10⁶ conidia ml^-1, and 2.38 and 14.6×10⁶ conidia ml^-1 against second, third and fourth instar larvae, respectively, showing thereby higher virulence of the former in terms of LC₅₀ and LT₅₀ value against S. obliqua larvae.

Keywords

Beauveria bassiana, Bioassay, Larval Extract, Spilosoma obliqua.

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