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20183
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Subject: Plant Pathology × End date: 2018 × Start date: 2018 × Type: Thesis × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    Epidemiology and management of early blight of tomato incited by Alternaria solani
    (CCSHAU, 2018) Ravinder; Narender Singh
    Early blight disease caused by Alternaria solani is one of the most important fungal diseases of tomato (Lycopersicum esculentum). Keeping in view the enormous loss caused by the pathogen, the present investigation was carried out to study the early blight disease progression in relation to weather parameters and its management by using the plant extracts, bio-agents and fungicides under both in vitro and field conditions during Rabi season, 2017-18 at CCS HAU, Hisar. Survey was conducted in eight villages of two districts (Bhiwani and Hisar) in Haryana and minimum per cent disease intensity was recorded in village Saral of Bhiwani district. The epidemiological study revealed that early sown crop was least affected by the early blight disease compared to the timely and late sown crop. The per cent disease intensity increased with the increased age of the plant. . Mancozeb (75% WP) and hexaconazole and zineb (72% WP) were found to be most effective among the fungicides under in vitro condition. Two plants extract (neem leaf extract and combination of garlic clove and green chili extract) and a bio-agent (Trichoderma viride) was also found effective in inhibiting the mycelial growth of A. solani among the plant extracts and bioagents, respectively. In field conditions, mancozeb 75% WP was found to be most effective in reducing the early blight disease intensity and increasing the fruits yield of tomato crop.
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    ThesisItemOpen Access
    Studies on some epidemiological and biochemical resistance parameters for powdery mildew disease in Indian mustard caused by Erysiphe cruciferarum Opiz. ex. Junell
    (CCSHAU, 2018) Sunil H. S.; Rathi, A.S.
    Powdery mildew disease caused by Erysiphe cruciferarum is an important disease of Indian mustard (Brassica juncea) particularly in northern and north eastern states of India. Keeping in view the importance of disease present study has been carried out on epidemiology in relation to weather, sources of resistance and biochemical changes due to powdery mildew infection under in field conditions during rabi 2017-18 at CCS HAU, Hisar. Powdery mildew disease first appeared in third week of February on all the three varieties (RH 0749, RH 0406 and RH 9801) sown on 16th October and delayed by a week i.e. in the 1st week of March in all the varieties sown on 26th October and 8th November, when the temperature ranged between 27.3-29.4°C (maximum) and 9.4-13.5°C (minimum), while relative humidity (RH) range was 91.7-94.0 (morning) and 37-49% (evening). Wind speed during this period ranged from 1.1-2.7 km/ha, while sunshine range was 5.4-7.7 hours. Maximum disease progression in last two dates of sowing was observed from March 4th to March 13th, when the temperature ranged between 28.2-28.7°C (maximum) and 10.7-12.3°C (minimum), while RH ranged between 81.0-91.3% (morning) and 35.7-48.3% (evening). Wind speed and sunshine hour during this period was 2.2-2.5 km/hour and 4.9-7.7 hours, respectively. Temperature (maximum and minimum), wind speed and sunshine were positively correlated with per cent disease intensity, while relative humidity (morning and evening) and average vapour pressure (morning and evening) were negatively correlated with the per cent disease intensity and AUDPC increased with delay in time of sowing. The apparent rate of infection was high during initial stages of disease development, while it was negligible from 2nd week of March in all the varieties. Varieties RH 0749 showed less disease intensity followed by RH 0401 and RH 9801. Out of 148 genotypes screened under the artificial inoculation conditions, 5 genotypes (HNS 0901, Bio 902, BioYSR, DRMRIJ 12-48 and JM-6011) were resistant and 21 genotypes were moderately resistant, 55 genotypes were moderately susceptible and 31 genotypes were susceptible, while rest of the genotypes were highly susceptible. Slightly higher amount of chlorophyll ‘a’, chlorophyll ‘b’ and total chlorophyll and total sugars was found in healthy leaves of resistant (DRMRIJ 12-48) as compared to susceptible (RH 30) genotype. After infection amount of chlorophyll (a, b and total) and total sugars reduced gradually in both genotypes, but reduction was more in susceptible genotype particularly under inoculated conditions. The amount of phenols (total and OD) and the activities of POX and PPO were increased at higher rate in resistant as compared to susceptible one at the time of disease initiation. At the time of maximum disease intensity i.e. at 120 DAS, the activities of enzymes were more in resistant genotype under inoculated condition in comparison to un-inoculated condition.
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    ThesisItemOpen Access
    Investigations on fruit and seed mycoflora of Bottle gourd and its management
    (CCSHAU, 2018) Soni, Namita; Kushal Raj
    The prevalence of wide variety of mycoflora is a major limiting factor in deteriorating bottle gourd (Lagenaria siceraria) crop qualitatively as well as quantitatively. In the present study, mycoflora associated with seeds and fruits of bottle gourd was isolated, evaluated and further investigated for impact of each isolate individually on bottle gourd seed germination, seedling vigour indices and germination speed under in vitro conditions. A total of eight genera and fourteen fungal species were isolated with prevalence of Fusarium proliferatum as external as well as internal seed borne mycoflora and Talaromyces pinophilus as external seed borne mycoflora. Amongst different isolates of bottle gourd, Fusarium proliferatum was found to be highly pathogenic due to maximum seed germination inhibition and the lowest seedling vigour index of seeds inoculated with this isolate. Pathogenicity tests conducted under in vivo conditions also confirmed the pathogenic nature of species of Fusarium. The isolates Rhizopus oryzae, Penicillium polonicum and Talaromyces pinophilus resulted in increased germination and vigour of bottle gourd. Amongst seven plant protectants evaluated against Fusarium proliferatum, Propioconazole 25% EC, Mancozeb 75% WP and Pseudomonas fluorescens 1 % WP performed better in inhibiting the spore germination. Investigations on efficacy of plant protectants in improving seedling health and minimizing seedling infection due to Fusarium proliferatum revealed that Propioconazole 25% EC, Copper oxychloride 50% WP and Mancozeb 75% WP were effective in reducing per cent frequency of infection while the highest germination percentage of bottle gourd seeds was observed in Trichoderma harzianum 1% WP treatment. The highest germination speed was observed in Carbendazim 50% WP followed by Trichoderma harzianum 1% WP treated seeds. Out of eight germplasm lines screened against anthracnose caused by Colletotrichum lagenarium, GH 34 had the maximum disease intensity of 64.81% while GH 35 was observed to have a minimum disease intensity of 23.33%.