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M. Sc. Dissertations

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2010 - 20112
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Subject: Zoology × End date: 2011 × Start date: 2010 × Type: Thesis ×
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    ThesisItemOpen Access
    Feeding potential of Tyrophagus putrescentiae Schrank (Acari: Acaridae) and its management
    (CCSHAU, 2010) Anita; Gulati, Rachna
    The studies on mean population of T. putrescentiae, percent weight loss and damage caused to grains qualitatively revealed that none of the grains was completely immune to pest infestation, however their susceptibility varied significantly (p=0.05).Susceptibility of grains/ flakes increased significantly with increase in initial infestation level and duration of infestation. Among the four foods, oat flakes was found significantly more susceptible (CD = 7.87; p = 0.05) as more number of mites (240.73 mites/5g grain) was recorded than on green gram flakes (207.26 mites/5g grain) and whole grains of oats (186 mites/5g grain). Least number of mites (173.26 mites/5g grain) was recorded from whole grains of green gram. The weight loss in oat flakes was 148.49mg/ 5g followed by loss in green gram flakes (121.40 mg/ 5g), oat grains (99.65mg/ 5g) and green gram grains (92.02 mg/ 5g) at pre count of 60 mites. Highly significant positive correlation (r= 0.93 to 0.99) was recorded at 15, 30 and 45 days between T. putrescentiae population and weight loss in oat grains. Qualitative estimation of oat flakes revealed the losses in protein contents (0.4 to 1.22%), total soluble sugars (0.5 to 1.35%), starch (0.24 to 1.38%) and non reducing sugars (3.49 to 9.97%) after 45 days of infestation. However, the reducing sugars exhibited a marked increase from 1.9 g/100 g (control) to 2.72 g/100 g flakes at 45 days of mite exposure when subjected to initial count of 20 mites/ 5g flakes. Aqueous extracts of Ocimum sanctum leaves and Glycyrrhiza glabra stems showed concentration dependent activity against T. putrescentiae in oat flakes. Among the extracts, G. glabra was effective as it provided 71.53 to 94.75 percent relative protection against T. putrescentiae whereas, O. sanctum extract caused 66 to 92 percent reductions in number at different durations.
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    ThesisItemOpen Access
    Studies on insect pollinators on onion (Allium cepa L.)
    (CCSHAU, 2011) Sunita Devi; Gulati, Rachna
    The studies on insect pollinators of onion (Allium cepa L.) revealed that a total of 25 insect species belonging to fourteen families of four orders were recorded from the umbels of onion at Hisar during March – April, 2010. Hymenopterans were the major floral visitors of onion umbels and were most abundant (60%) followed by Lepidoptera (20%) and Diptera (12%). Coleoptera were recorded as least abundant (8%) amongst the four families. All the four Apis species viz. A. dorsata, A. cerana, A. mellifera, A. florea were recorded as top workers on onion umbels as pollen and nectar gatherers. Data on abundance of bee pollinators revealed that irrespective of different day hours, significantly maximum numbers of Apis dorsata was recorded from onion umbels (5.24 bees/m2/5 min.) followed by A. mellifera (4.05 bees/m2/5 min.) and A. cerana (2.93 bees/m2/5 min.) and A. florea (1.79 bees/m2/5 min.). Irrespective different species, the mean population of bees was significantly more during 0800-1000 hours of the day (bees/m2/5 min.) followed by 1600-1800 h., 1400-1600 h and 0600-800 h (2.97 bees/m2/5 min.). Apis dorsata recorded maximum frequency of occurrence (39%) during blooming period followed by A. mellifera (31%), A. cerana (16%) and A. florea (14%). Among different bee species, A. dorsata initiated foraging on onion umbels little earlier (0630 h) than other bees in morning. Total foraging (activity) time was longest for A. dorsata (1170 h) with maximum abundance (5.24 bees/m2/5 min) suggested it to be an efficient pollinator of A. cepa umbels in the present investigation. Maximum and minimum temperature showed significantly positive correlation (r = 0.609 to 0.739) with bee species whereas evening relative humidity showed significant negative correlation (r = -0.644 to -0.736). The data on foraging speed i.e. time spent by different bee species on A. cepa umbels showed A. dorsata (3.33 seconds/ umbel) differed significantly from A. mellifera (2.96 seconds/ umbel), A. cerana (2.90 seconds/ umbel) and A. florea (2.65 seconds/ umbel).On the basis of abundance, time spent on umbels, umbels visited, loose pollen grains sticking to bee body and pollination index, A. dorsata was considered as the most efficient pollinator of onion seed crops followed by A. mellifera, A. cerana and A. florea under agro-ecological conditions of Hisar. The effect of different modes of pollination showed that seed set per umbel, seed weight, germination and seedling length were statistically comparable with each other in Open-pollination and Beepollination. The trend shows that bee strength of two and three frames was equally effective (statistically comparable) in seed setting and subsequent germination, seedling length, therefore, for 10 m × 10 m area, nucleus hive of two frame strength of A. mellifera population is sufficient for seed setting in onion seed crop.