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Subject: Zoology × Author: Manoj Kumar × End date: 2018 × Start date: 2016 × Type: Thesis × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    Quantitative and qualitative losses due to Tyrophagus putrescentiae Schrank (Acari: Acaridae) in pearl millet and its management
    (CCSHAU, 2017) Manoj Kumar; Gulati, Rachna
    Monthly observations on the average population of T. putrescentiae in pearl millet grains revealed that mite number increased significantly at each observation period. The population was 73.33, 313.33, 680.67, 1065.67, 1316.00 and 1720.33 mites/5g grain after 30, 60, 90, 120, 150 and 180 days with the initial infestation density of 10 pairs of mites. On pearl millet flour, the population of T. putrescentiae was 439.00, 968.33, 1707.33, 2121.00 2366.00 and 3487.33 mites/ 5g flour after 30, 60, 90, 120, 150 and 180 days, respectively which differed significantly with each other from pre count of 10 mite pairs. Pearl millet flour was found significantly better in harbouring T. putrescentiae population as more number of mites (1587.00 mites/ 5g flour) was recorded than on pearl millet grains (741.33 mites/ 5g grain). Irrespective of the form of pearl millet, maximum number of mites (2603.83 mites/ 5 g pearl millet) was witnessed at 180 days which showed significant difference with mite numbers at other observation periods. Between the two forms of pearl millet, per cent weight loss was significantly more (10.50%) on pearl millet flour, as compared to pearl millet grain (6.00%). A significant negative correlation between the mite population and grain weight (r = - 0.99), flour weight (r = - 0.98) was obtained. Qualitative estimation of infested grains and flour revealed the decrease in total soluble sugars (19.72, 18.99mg/g), non reducing sugars (12.14, 10.01mg/g) starch (554, 454.13 mg/g) and protein (119.10, 114.77 mg/g) after 180 days of infestation, respectively as compared to 20.91, 13.90, 602.23 and 128.63mg/g at 0 day; depicting significant negative correlation. However, the reducing sugars exhibited a significant increase from 7.01 to 7.58, 7.65mg/g at 180 days of mite exposure in pearl millet grains and flour, respectively when subjected to initial count of 10 mite pairs, showing significant positive correlation. Percent loss in pearl millet germination due to T. putrescentiae population at different durations was recorded as 4.00, 20, 69.22, 98.67 and 99.33 per cent after 0, 30, 60, 90 and 180 days. All concentrations (0.2, 0.4, 0.6 and 0.8%) of aqueous extracts of lemon and orange peels in pearl millet grains caused 100 percent mortality in T. putrescentiae 20 and 28 days post treatment, respectively. In Aonla fruits extract treated grain, 13.20 mites were recorded from 8 percent concentration as compared to 20.11 mites in 0.8 percent.