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20173
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Subject: Zoology × End date: 2017 × Start date: 2017 × Type: Thesis × Thesis Type: Ph.D ×
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    ThesisItemOpen Access
    Comparative impact of insecticides on bacterial and acetylcholinesterase activity of Eisenia fetida (Savigny) and Pheretima posthuma (Kinberg)
    (CCSHAU, 2017) Yadav, Jyoti; Dharambir Singh
    The present study was carried out to analyze the toxicity of chlorpyrifos and carbofuran on E. fetida and P. posthuma. Paper contact toxicity test was used to determine LC50. LC50 of chlorpyrifos against adult E. fetida and P. posthuma was 0.25% and 0.11%, respectively. While LC50 of carbofuran against adult E. fetida and P. posthuma was 5.14% and 4.11%, respectively that confirms the greater sensitivity of P. posthuma towards insecticide induced toxicity in comparison to E. fetida. Lower LC50 value of chlorpyrifos confirms its higher toxicity as compared with carbofuran. Total 52 bacterial isolates were isolated from the gut of worms, out of which six resistant gut bacterial species having agricultural importance were identified as Sphingobacterium sp., Citrobacter freundii, Citrobacter murliniae, Bacillus australimaris and Burkholderia paludis. Inhibition in AChE activity due to chlorpyrifos and carbofuran exposure was observed at 24h. While E. fetida exposed to carbofuran tried to maintain AChE level, which may be seen as strategy to cope up with toxicity after prolonged exposure.
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    ThesisItemOpen Access
    Management of Tyrophagus putrescentiae Schrank (Acari: Acaridae) in Oyster mushroom, Pluerotus sajor-caju and its molecular characterization
    (CCSHAU, 2017) Komal; Gulati, Rachna
    The studies on population buildup of Tyrophagus putrescentiae on compost and fruiting body of Pleurotus sajor-caju revealed that irrespective of initial inoculums level mite number decreased significantly at each observation period. No mites were recorded after 24, 24, 30 days and 24, 34, 38days on wheat straw and wheat straw plus calcium sulphate based compost at initial inoculums level of 10, 20 and 30 T. putrescentiae pairs, respectively. The weight loss of the compost was 0 to 10.3 percent in these levels. Percent loss in total sugar, reducing sugar, non reducing sugar, starch, protein content of compost was in the range of 13.3 to 52.1%, 11.3 to 27%, 1.2 to 4.07%, 14.2 to 35.7%, 45 to 71%, respectively. In fruiting bodies, a peak in population (41.66, 59.00, 83.00 mites/10g fruiting body) was recorded at initial inoculums level of 10, 20 and 30 T. putrescentiae pairs. Weight loss of the fruiting body was 0.00 to 20.5 percent in these levels. Significant reduction in total sugar, reducing sugar, non reducing sugar, starch, protein content of fruiting bodies was recorded. It was 0.134, 0.055, 0.070, 0.010, 0.279 mg/10g fruiting body at 30 mite pairs as compared to 0.162, 0.075, 0.099, 0.029, 0.741mg/10g fruiting body in control. Percent reduction in T. putrescentiae population with Withania somnifera, Azadirachta indica, neem oil and neem cake was 82.20 to 100, 43.64 to 100, 23.00 to 100 and 25.60 to 100 percent after 45 days post-treatment. Higher concentrations (2 and 1%) were significantly more effective as these showed no T. putrescentiae counts as compared to initial pre treatment count (50 mite pairs). Molecular characterization of four T. putrescentiae populations was done by RAPD- PCR to know the genetic similarity among them. The yield of DNA from T. putrescentiae population collected from soil samples of horticulture, forestry plantations and vegetable crops and wheat flour ranged from 876to 2000 μg/ml. A total of 208 bands were generated for T. putrescentiae where 204 bands (98.07%) were polymorphic and 4 1.92%) bands were monomorphic. Among the four populations range of polymorphism was 87.5 to 100 percent. The T. putrescentiae populations collected from soils of vegetable and forestry plantations were found to be the most diverse with a minimum similarity value of 0.475.
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    ThesisItemOpen Access
    Evaluation of damage potential of mite, tyrophagus putrescentiae schrank (Acari: Acaridae) in button mushroom, agaricus bisporus (Lange)
    (CCSHAU, 2017) Itisha; Gulati, Rachna
    The studies on population buildup of T. putrescentiae on compost and fruiting body of Agaricus bisporus revealed that irrespective of initial inoculumn level mite number decreased significantly at each observation period. No mites were recorded after 20, 38, 42 days and 20, 30, 38 days on compost and fruiting body at initial inoculmn level of 10, 20 and 30 T. putrescentiae pairs, respectively. Highest inoculums level (30 mite pairs) harboured statistically higher number of mites (37.76 mites/ 10 g compost) followed by 20 pairs (19.47 mites/ 10 g compost) and 10 mite pairs (6.33 mites/ 10 g compost). Percent loss in total sugar, reducing sugar, non reducing sugar, starch, protein content of compost was in the range of 10.47 to 24.60%, 22.89 to 68.67%, 0 to 0.92%, 16.33 to 33.33%, 0 to 10%, respectively. The weight loss of the compost and fruiting body was 1.3 to 6.1 percent in these levels. Comparative evaluation of different composts revealed that significantly higher population developed on wheat straw + poultry manure based compost (46.46 mites) followed by wheat straw + wheat bran based compost (44.20 mites), wheat straw + cotton seed meal (40.39 mites), paddy straw based compost (38.20 mites) and wheat straw + paddy straw based compost (36.93 mites).Susceptibility studies of five A. bisporus strains revealed Abl-5 as most susceptible strain as maximum population developed (102.37 mites) on this strain. The other strains Abl-2, Abl-3, Abl-4 and Abl-6 showed 95.33, 96.29, 95.20 and 94.62 mites, which were statistically comparable with each other. T. putrescentiae pairs released from M. perniciosa infected plates to A. bisporus culture plates disseminated pathogenic spores on A. bisporus culture. After 6 days, whitish mouldy growth (wet bubble disease) was started on A. bisporus culture which spread to whole culture within 18 days. The colour of culture changed from pale brown to white. The T. putrescentiae population rose to 177.25 mites within 22 days on A. bisporus culture from initial inoculums of 10 pairs.