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20173
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Subject: Nematology × End date: 2017 × Start date: 2017 × Type: Thesis ×
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    ThesisItemOpen Access
    Studies on physiological changes induced by cereal cyst nematode (Heterodera avenae) in wheat (Triticum aestivum)
    (CCSHAU, 2017) Sindhu, Ajay Singh; Kanwar, R.S.
    Present study was conducted to investigate the the sequential effect of Heterodera avenae on physiology of wheat, the effect of sowing time on physiology of H.avenae infected wheat and the effect of different inoculum levels of H.avenae on physiology of wheat. The experiments were conducted in screenhouse of Department of Nematology, CCSHAU, Hisar during Rabi-2016. For evaluating the sequential effect of H.avenae on wheat cultivar WH 1105 was sown on 7th Nov. and observations on physiological parameters were recorded 30, 60 and 90 days after sowing (DAS). Total chlorophyll, carotenoid and chlorophyll fluorescence were significantly lower in inoculated plants as compared to uninoculated plants at 90 DAS. They were reduced to the tune of 37.78%, 36.73% and 10.46%, respectively. Total chlorophyll, carotenoid and chlorophyll fluorescence increased till 60 DAS and decreased at 90 DAS. Photosynthetic rate, transpiration rate and stomatal conductance decreased with the increase in age of plant. Inoculated plants when compared with uninoculated plants showed significant decrease at 60 DAS by 38.17, 47.39 and 42.85%, respectively. For comparing the physiology of H.avenae infected wheat sown on 1st, 15th and 30th Nov., observation were taken 30 DAS. Total chlorophyll (25.00%), carotenoid (28.94%), chlorophyll fluorescence (6.27%), photosynthetic rate (57.33%) and stomatal conductance (62.50%) showed maximum reduction in inoculated plants of 15th Nov. sowing when compared with uninoculated plants while transpiration rate decreased significantly (56.19%) in inoculated plants of 30th Nov. sowing. Inoculated plants showed significant reduction in these parameters when compared with uninoculated plants at all the three sowing dates. Biomass of 15th Nov. sown plants was greatly hampered by nematode parasitism as compared to plants sown on 1st and 30th Nov. Maximum nematode population was obtained in 15th Nov. sown plants. Effect of different inoculum levels viz. 5, 10 and 15 eggs and juveniles/g soil of H.avenae on physiology of wheat was studied by recording observations 30 DAS. With the increase in inoculum level of H.avenae, there was significant decrease in total chlorophyll, carotenoid, chlorophyll fluorescence, photosynthetic rate, transpiration rate and stomatal conductance at each level. Maximum reduction in these parameters was observed at 15 eggs and juveniles/g soil that was 39.71, 30.55, 7.90, 39.75, 51.58 and 64.86% respectively. Maximum nematode population build up and least biomass were obtained at highest inoculum level.
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    ThesisItemOpen Access
    Studies on the incidence, interaction and management of root- knot nematode, Meloidogyne incognita and soil borne fungus infesting cucumber in polyhouse
    (CCSHAU, 2017) Jaydeep Ashok, Patil; Sewak Ram
    Survey of polyhouse crops revealed 68.4 %, and 45.8 % frequency of occurrence of root-knot nematode, Meloidogyne incognita, respectively, in Rewari and Jhajjar districts. The fungus, Fusarium oxysporum f. sp. cucumerinum which was found most prevalent during survey of the polyhouse crops proved pathogenic on cucumber. Concomitant and sequential nematode and fungus inoculation resulted in a significant reduction in number of galls per plant. Maximum galling was observed when the nematodes were inoculated 7 days prior to the fungus. Soil treatment with formalin @ 30 %, followed by NSKP as soil amendment @ 30 g per kg soil proved significantly effective in pots against M. incognita and F. oxysporum f. sp. cucumerinum in improving plant growth parameters and reduced nematode reproduction and wilt severity. Seed treatment with liquid formulation of bio-agents @ 15 ml per kg seed followed by seed treatment with neem oil @ 20% v/w in pots proved most effective against M. incognita and F. oxysporum f. sp. cucumerinum. Combinations of soil fumigation with formalin @ 30 % + seed treatment with Paecilomyces lilacinus @ 20 g per kg seed was found highly effective against M. incognita and F. oxysporum f. sp. cucumerinum. Integration of most effective management practices of soil and seed treatment in cucumber against M. incognita and F. oxysporum f. sp. cucumerinum under polyhouse conditions revealed that soil amendment with neem cake @ 200 g per sq meter + seed treatment with P. lilacinus @ 20 g per kg seed in cucumber proved most effective in significantly improving plant growth parameters while soil fumigation with formalin @ 30 250 ml per sq meter + seed treatment with P. lilacinus @ 20 gm per kg seed was significantly better in suppressing nematode reproduction and fungal wilt incidence.
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    ThesisItemOpen Access
    Efficacy of entomopathogenic nematodes (EPNs), Steinernema spp. and Heterorhabditis spp. on tobacco caterpillar, Spodoptera litura F.
    (CCSHAU, 2017) Babita kumari; Sewak Ram
    Out of 120 soil samples collected from different habitats, 9 samples (7.5%) were found to be positive for EPN. The highest frequency of occurrence of EPNs (58.3%) was recorded in Ber orchard with 7 samples infected for EPNs followed by citrus and cactus (8.3%). Amongst them, the frequency of occurrence of Steinernematid and Heterorhabditid nematodes were 41.7 and 16.7 per cent, respectively. As the inoculum level increased, there was a gradual increase in progeny production of both S. abaasi and H. indica. The present study revealed that both the species strain of EPNs were found to be virulent and could cause 50 per cent mortality at 10 infective juveniles/larva under in vitro conditions. Among all the isolates of EPNs, S. abaasi isolate HAR-EPN-Sa-3 was highly virulent against S. litura. It was followed by other isolates in the order of HAR-EPN-Sa-2, HAR-EPN-Sa-5 and HAR-EPN-Sa-4. The strain HAR-EPN-Sa-1 recorded the least virulence of all the isolates. However, nearly 50 per cent mortality of the larvae was observed at an inoculum level of 10IJs per larva after 24h. In case of H. indica, isolate HAR-EPN-Hi-2 was highly virulent and HAR-EPN-Hi-1 recorded the least virulence against S. litura. Mass multiplication of EPNs, highest yield of S. abaasi isolate HAR-EPN-Sa-3 followed by HAR-EPN-Sa- 2, HAR-EPN-Sa-5 and HAR-EPN-Sa-4. The strain HAR-EPN-Sa-1 recorded the least multiplication of all the isolates. In case of H. indica, highest yield of HAR-EPN-Hi-2 followed by HAR-EPN-Hi-1. Laboratory studies revealed that S. abaasi in combination with H. indica had been more virulence than S. abaasi and H. indica when applied alone. S. abaasi in combination with H. indica caused 72.5, 87.4, 97.3 and 99.7 per cent mortality, respectively against S. litura as compared to virulent strain of Steinernema spp alone. Mass production of IJs of tested EPNs from S. litura larva showed highest yield of EPNs (H. indica+S. abaasi) followed by S. abaasi alone and H. indica.