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2019 - 201912020 - 20221
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    ThesisItemOpen Access
    Characterization of bacterial pathogens of Litopenaeus vannamei (Boone) and their management through herbal extracts
    (Chaudhary Charan Singh Haryana Agricultural University, 2022-07) Bamel, Karuna; Gulati, Rachna
    The enterprise and personal profile of shrimp farmers of Punjab and Rajasthan showed that 50-60% operated their farms on lease basis, 60% were registered with Costal Aquaculture Authority, 90 % used their own money,70-80 percent used solar power in addition to generators. Forty percent of shrimp farmers in Punjab and 60 percent in Rajasthan were having farm area of 6 to 10 acres (2-4 ha). 40-60 % maintained high stocking density (> 1.5 lacks/acre), took two crops per year and received 300-350 Rs/Kg for shrimps with an income of 2-4 lacks/acre/season. In Rajasthan, 40 percent of shrimp farmers were educated to the graduate level, followed by higher secondary education (30%), while in Punjab, 40 percent were educated to the secondary level. Males dominated (90%) the shrimp farming sector, majority of shrimp farmers were between the ages of 30 and 40, closely followed by 20-40 years and had less than 5 years of experience. The yield was positively correlated with the stocking density (r=0.46) and negatively correlated with shrimp sampling (r= -0.48). White muscle, vibriosis, loose shell, black gill, white faecal matter, AHPND, EHP and IHHN were the most common diseases reported in surveyed farms. Significant positive correlation coefficient of percentage infection in shrimp pond water with salinity, TDS, Na, Cl, K, Mg, TSS, total hardness, EC, turbidity, Calcium hardness was recorded. Thirty two bacterial isolates were isolated from diseased shrimps having symptoms like white gut, transparent or pale body, red telson with lesions. The isolates were found to be from Vibrio, Shewanella, Staphylococcus, Pasturella, Escherichia and Klebsiella genus. The present study reported the first report of Shewanella khirikhana, a shrimp pathogen in India. Fourteen isolates (Vibrio sp.) of the present study are potential new species of Vibrio whose only taxon (LCUE_s) is identified. Vibrio spp., S. alage, S. khirikhana and combination of Vibrio and Shewanella isolates, at 104, 105, 106 CFU/ml caused mortality and decreased the growth parameters of Litopenaeus vannamei. The MIC of Curcuma longa, Tinospora cordifolia, Coriander sativumwas10, 15, 25 mg/ml against S. algae and 15, 20, 25 mg/ml against Vibrio sp. C. longa was most effective against the bacterial challenged shrimps followed by T. cordifolia and C. sativum. The mean length, weight, SGR, biomass, total protein, carbohydrate, lipids, total haemocyte count were significantly higher in shrimps treated with different herbal extracts than bacterial challenged shrimps. The concentration of antioxidative enzymes, catalase, superoxide dismutase and glutathione peroxidase were higher in Vibrio sp. and S. algae challenged shrimps. The enzymes were high in haepatopancreas followed by muscle, haemolymph. The potential probiotic strains, Bacillus subtilis BAA3 and B. subtilis BAA96 showed antimicrobial properties against Vibrio sp. and S. algae. B. subtilis BAA3 was more effective as probiotics than B. subtilis BAA96. The shrimps treated with B. subtilis strains exhibited higher survival, better growth parameters than bacterial challenged shrimps. Histopathological studies showed necrotic hepatic tubules, ruptured basement membrane, loss of normal B, R and F cells in bacterial challenged shrimps. BOD and pH of probiotics treated shrimp water was lower on termination of experiment than on 0 day.
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    ThesisItemOpen Access
    Screening of germplasm and damage potential of Tetranychus urticae Koch (Acari: Tetranychidae) in marigold
    (CCSHAU, 2019) Bamel, Karuna; Gulati, Rachna
    The three germplasms each of African marigold, tall golden, tall orange, lemon red and French marigold, black Jafari, Hisar Jafari-2, Hisar beauty supported T. urticae population but showed significant variation in mite numbers during screening in accordance with susceptibility index. The germplasm tall orange African sheltering lowest mite populations (9.82 mites/leaf) was marked as the least susceptible; black Jafari French (19.43 mites per leaf) as slightly susceptible; tall golden African (26.17 mites/leaf), lemon red African (24.13 mites/leaf) and Hisar beauty French (27.18 mites/leaf) were marked moderately susceptible; Hisar Jafari-2 French with 32.21 mites/leaf was categorized as highly susceptible. In general, French germplasm was comparatively more susceptible (57%) to T. urticae infestation as compared to African germplasm (43%). Irrespective of germplasm, significantly higher number of mites was recorded on grown up leaves followed by tender and older leaves of marigold.The mite number was found to significantly increase with each observation period till the attainment of peak in population in the month of January (35.51 mites/ leaf) while least number of mites were recorded in the month of October (6.65 mites/leaf). During severe infestation, leaves were completely damaged and turned white, the mites spread to buds, flowers. The plants were seen completely covered with profuse webbing by T. urticae and dried up.Under screen house conditions, the studies on population dynamics of T. urticae showed the first peak in the third (144.95 mites/leaf) and fifth (96.24 mites/leaf) week of April in French and African marigold. The second peak was recorded on fourth week of November (130.59, 87.00 mites/leaf) in both the germplasms. Under field conditions, the first and second peak in T. urticae population on African marigold was recorded during third week of May, 2018 (67.09 mites/leaf) and first week of March, 2019 (37.13 mites/leaf). Statistically, ventral surface (lower side) of leaf harboured higher number of mites (72 and 74%) as compared to the dorsal (upper surface) (28 and 26 %) in both French and African marigold, respectively under screen house conditions. Season wise, statistically higher population was recorded in summer season followed by winter and rainy season, respectively. Among abiotic factors, a significant positive correlation of mite population was recorded with maximum temperature(r=0.469), sunshine hours(r=0.490) and evaporation (r=0.567). A highly negative significant correlation was recorded for morning relative humidity (r= -0.824), evening relative humidity(r= -0.798) and minimum temperature(r= -0.674). Under field conditions, highly significant positive correlation with minimum temperature (r=0.90) and average wind speed (r=0.76) was found. Sunshine hours showed non significant correlation with mite population. Significantly lower amount of total chlorophyll, chlorophyll ‘a’, chlorophyll ‘b’, carotenoids, total sugar, non reducing sugar, nitrogen, phosphorus and potassium in infested leaves was observed as compared to the uninfested leaves of marigold; depicting significant negative correlation with T. urticae population. A significant increase in reducing sugars, total phenol and proline was reported as compared to the uninfested leaves.The decrease/ increase in the phytochemicals was more pronounced in summer as compared to winter season in T. urticae infested marigold leaves. Highly significant negative correlation was found between number of mites and fruit parameters like no. of flower (r= -0.953), flower diameter (r=-0.933), flower weight (r=-0.81), and yield per plant (r= -0.923). Statistically, higher yield was observed in uninfested plants (224.05 g/plant) as compared to infested plants (124.98 g/plant).