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Subject: Mycology and Plant Pathology ×

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Now showing 1 - 9 of 19
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    ThesisItemOpen Access
    Studies Of Helminthosporim Diseaes Occrring On Wheat In Chotanagpur Plateau Of Bihar
    (Birsa Agricultural University, Ranchi, 1990) Roy, Shambhu; B. Misra
    During the survey and surviellance programme of the department, two species of Helminthosporium viz H. sativum P.K. & B. (Spot blotch) and H. tritici-repentis Died (Leaf spot) were collected, isolated, identified and described from Chotanagpur region of Bihar. The two species were quite different from each other affecting wheat (Triticum aestivum L.) crop of the region. These two species were quite distinct to each other. H. sativum having fusoid conidia (widest in the middle) with heavy wall and rounded ends with brown to olavaceous colouration was quite different than that of H. tritici-repentis having fusiform elliptical conidia, hyaline án colour with snaky hood at the basal cell. There were differences in symptom expression also. The farmer had brown spots and the later had straw coloured with distinct yellow halo margin. The sporulating ability of H. sativum was excellent (more than 50 conidia per 10 x 10 optic microscopic field) whereas it was completely absent in case of H. tritici-repentis. The two species differed from each other in cultural characters as well. Although optimum pH for both the species was the same (pH 5), but H. sativum had 28+1°C optimum temperature for growth and it was 25+1°C for H. tritici-repentis. However, both the species were proved to be pathogenic under artificial inoculated condition. Amongst twenty five varieties of wheat screened against the two organism, four varieties viz: BR 380, HUW 206, K 8020 and BR 1011 were found to be resistant to both the pathogens. Amongst different fungicides tested, Dithane M-45 and Blitox 0.2% were proved to be effective against the pathogens. For biological control trial, Trichoderma viride produced certain toxic metabolites in PDA in vitro which turned the medium light greenish yellow (75% of the medium) within 72 hours of inoculation and inhibited the growth and sporulation of H. sativum (100%).
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    ThesisItemOpen Access
    Studies On Wilt Of Tomato Caused By IN Chotanagpur, Bihar
    (Birsa Agricultural University, Ranchi, 1990) Patra, Mihir Kumar; B. Misra
    Wilt of tomato (tycopersicon eseilentum Ni11) caused by pasarium oxysporum f. Spe lyconersici (sacc.) snyder and Hansen is present in almost all the tomto growing areas of Chotobogpur region of Bihar which varied between 15-75 per cont. The pathogen is mainly soil borne and attacks the plants at any stage of the growth period, The disease development was faster and more on injured root than on the unjured one. Koch's postulates test wore satisfied in the present endings The fungus produces three types of Spores vis; micro-conidie, macro-conidia and chlamydospores in culture. Macro-ecp1d1a rerely occur on the upper surface of the wilted plants, In cultural studies, Sabouraud's dextrose both in solid and liquid media proved to be the best for excellent growth and sporulo- tion of the pathogen temperature of 281°c and pl 5.0 were recorded A to be the best temperature for the growth of the organis However, it 5.5 uos optimum for excellent sponu lotion. Pant T3 and NDR-120 varieties of tomato were free from the disease. However, four cultivars namely selection-s Azad Kirti, B.W. Rs and KS were found to be moderately resistant to the disease at Ranch environmental condition. Direct seeding of tomato from 16th September to 16th January was found to most suitable for cultivation at Ranchi condition, Direct sown crop was less affected with the wilt than transplanted one. Bavistin proved to be most suitable fangcide which increased the germination percentage of artificially inoculated seeds. The fungcide (Bovistin) was also most effective in suppressing the mycelial growth in the laboratory experiments. Trichodersa viride enhanced germination of Fusariom OXYSnords f. p. 1yeonepetal Inoculated seed and vos found as a strong antagonist which could effectively control the pathogen (50-100 per cent) within 79 hours in vitro, however, its application at field level is still to be tested.
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    ThesisItemOpen Access
    Studies On Leaf Blight Disease Of Wheat Caused By Alternaria Triticina In Chotanagpur Plateau Of Bihar
    (Birsa Agricultural University, Ranchi, 1990) Roy, Rajendra Prasad; K.K. Rai
    Leaf blight of wheat caused by Alternaria tritieina has been observed to be present in almost all wheat growing areas of Chotanagpur. So for no systematic research work has been carried out on this disease, it was considered worthwhile to conduct researches on this disease. The disease symptoms appeared on leaves, awns and glumes of the plants as small, oval, discoloured lesions. Conidia collected from affected parts were larger than from the culture. Susceptibility of the plants increased with the increase in the age of the plants. Pathogenicity was proved with the help of Koch's postulate tests. In cultural studies Standard nutrient both in solid and liquid media proved to be the best for excellent growth and sporulation of the pathogen. The optimum temperature and pH were recorded to be 25 + 1°C and pH 6, respectively both for the growth and sporulation. Among the thirty six varieties tested under field conditions, six varieties viz; KS 26, BAU 2375, BAU 2395, BAU 2378, BAU 2398 and BAU 33 were found to be resistant to the disease. Dithane M-45 at 250 ppm and 500 ppm inhibited the highest spore germination percentage in vitro condition. It also gave the lowest disease intensity at 0.2 per cent in vivo condition.
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    ThesisItemOpen Access
    STUDIES ON DIE-BACK OF CHILLIES AND ITS CONTROL
    (Birsa Agricultural University, 1988) SUMAN, SUSHIL JHA; Sinha, S.K.
    Die-back and fruit-rot of chilli caused by Colletotri chum capsici (Syd.) Butler and Bisbywas collected during September and October 1985 from Horticultural Farm, Kanke, Ranchi. The causal organism was isolated, identified and described from Chotanagpur region of Bihar. The pathogen could infect fruits of tomato, brinjal, pea, gram, guava and papaya. Amongst these, guava and papaya may serve as hosts during the off-season. Seeds were determined to be infected both externally and internally. Richards' medium proved to be the best for growth of the fungus whereas host extract medium gave abundant sporulation both in solid and liquid condition. Temperature and pH for optimum growth were found to be 28°C and pH 6.0, respectively. Sucrose and asparagine as carbon and nitrogen sources respectively, supported the best mycelial growth whereas lactose and asparagine gave best sporulation of the pathogen. A-126 and Jwala varieties of chillies showed resistant reaction against the pathogen. Thiram (0.25 per cent) was proved to be the best seed treatment fungicide for suppressing the infection and increasing the germination of seeds. Bavistin (0.10 per cent) was found to be the best fungicide in controlling the disease both in vitro as well as in vivo and increasing the yield.
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    ThesisItemOpen Access
    STUDY OF SEED BORNE PATHOGENS OF SOME COMMON PULSES AND THEIR CONTROL IN RANCHI, BIHAR
    (Birsa Agricultural University, 1987) ORAON, LAXSMON; JHA, D.K.
    Seeds of different pulses were tested for seed borne fungi by four methods viz., Blotter method, Agar plate, 2-4-D and Deep freezing method. Altogether fourteen fungi were found to be associated with seeds of Green gram, Black gram, Cowpea, Pigeonpea and Chickpea. Amongst the methods, Blotter method proved to be the best for detecting fungal flora. Infection of seed of Chickpea was found to be occur in three ways 1.e. Superficial contamination of spores, Myce lium in seed coat and mycelium in cotyledons. However, all the three forms were equally responsible for causing the disease symptoms. Amongst the fungicidal tests, Bavistin + DID (e 0.2%) as seed treatment proved to be superior in respect to germination count and controlling the pre and post-emergence mortality.
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    ThesisItemOpen Access
    STUDIES ON WILT OF BRINJAL CAUSED BY E.F.SMITH IN RANCHI , BIHAR
    (Birsa Agricultural University, 1987) Pandit, RAJENDRA PRASAD; SINHA, S.K.
    A regular survey and surveillance technique was followed in and around Ranchi during 1984 to study the wilt problem of brinjal which yielded a bacterium on isolation. Morphological, physiological and pathological investigations confirmed that the causal agent of the wilt was Pseudomonas solanacearum. It grew optimum on TZC medium at 30 °c and had a thermal death point at 52+1 °c. The bacterium can survive 6 months in sterile soil alone and 8 month in combination with brinjal tissues. It can be preserved 10 months in sterile distilled water for laboratory studies. The pathogen caused 10-62.2 loss of brinjal plants in the field during rainy season (At 25 to 35 °c and 90% RH). The bacterium has a wide range of hosts which harbour the causal agent and as act reservoir in off season but Brinjal seedlings are the main source of primary inoculums for the spread from one locality to the other through local markets. However, Pusa Purple Cluster is the one variety which can be cultivated economically in endemic areas of Chhotanagpur and it can be utilized as resistant gene donor into susceptible commercial varieties against the wilt.
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    ThesisItemOpen Access
    STUDIES ON EPIDEMIOLOGY AND RELATED ASPECTS OF PAPAYA MOSAIC VIRUS FROM RANCHI
    (Birsa Agricultural University, 1986) SARKAR, DEBA PRASAD; PRASAD, S.M.
    Papaya mosaic virus from Ranchi produced mosaic mottling, blisters and leaf diatorsion including shoe strings on leaves. The stem exhibited dark green oily spots and streaks. The fruits formed were small, deeply lobed and lopsided. Within-field spread maps showed that the spread was erratic, at random and without any particular pattern. Of the 52 plant species belonging to 10 families tested, only 8 species viz, chemopodian amacanti.color, c. quinea, citrullusvulgaris,Cucumis sativus, Cucurbits neno, Lagonaria siceraries, cyphemandra betacea and solanum nigrum were recorded as hosts. Thirty three aphid specimen comprising 11 different species colonizing on different plant species were collected from Kanke, Ranchi. of the 11 different species of aphids tested 6 were able to transmit the virus. In virus-vector relationship studies with Aphis citricols, the reacquisition fasting effect was recorded and an acquisition feeding period of 2-5 minutes and inoculation feeding period of 30 minutes was found to be optimum. Soil transmission tests through nematodas were unsuccessful and the virus vas not seed transmitted. Of the 8 varieties of cultivated papaya tested, none was found to be resistant, however, the wild species , carics cauliflora was immune to Ranchi isolate also. Dry matter, orthodihydrie phenol and total phenol contents were reduced in papaya following infection with papaya mosaic virus. Electron microscopy of dip preparations from papaya mosaic infected leaves revealed flexuous particle measuring e. 730 nm x 11-14 nm.
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    ThesisItemOpen Access
    STUDIES ON RUST OF BEANS WITH SPECIAL REFERENCE TO FRENCH BEAN RUST IN CHOTANAGPUR, BIHAR
    (Birsa Agricultural University, 1986) MAHANTA, PRAFULLA; GUPTA, U.
    Rust caused by Uromyces appendiculatus is one of the common and most severe diseases of bean in Chotanagpur, Bihar. In view of the increasing importance of beans, mainly french bean and cowpea as vegetable and fodder crop, an investigation on some aspects of rust disease of beans, with special reference to french bean rust in Chotanagpur, was undertaken during 1984-85. Out of five commonly cultivated beans in this locality, rust was observed on three beans, namely, french bean, cowpea and velvet bean. The rust on french bean was found in moderate to severe form in both Kharif and Rabi seasons, the severity being more during later part of Rabi season. The disease appeared mostly on the undersurface of the leaves as reddish brown rust pustules which were powdery, circular in shape and surrounded by a yellow halo. In field trials conducted during Rabi season of 1984-85, the loss in yield of french bean caused by U. appendiculatus was found to be as high as 28.06 per cent.
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    ThesisItemOpen Access
    EFFECT OF SOME FOREST TREE PRODUCTS AND MUSHROOMS ON THE INFECTIVITY OF COWPEA MOSAIC AND PAPAYA MOSAIC VIRUSES
    (Birsa Agricultural University, 1985) KUDADA, NARENDRA; Singh, G.P.
    An attempt was made to study the effect of olls and extracts of cakes, barks and leaves of four forest trees name ly, karanj (Pongāmia glabra, mahua (Madhuca longifolia), kuau ( schleichera trijuga), and mom (Azadirachta indica) on the infectivity of cowpea mosaic virus (CpMV) in cowpea (Vigna sinensis) and of papaya mosaic virus in papaya (Carica papāya • The fruit extracts of parhasi (cleistānthus collinus and mush room (Pleurotus sp.) were also tested for their inhibition properties against these viruses. The oils and the extracts from all the trees and mushroom inhibited infection of the viruses in varying degrees. The inhibitory properties of oils as well as test extracts were wholly or partially destroyed by heating at 700 or 80°C for 10 minutes, and by dilution to 1:20 or 1: 30 with distilled water. The test oils and extracts prevented transmission of these two viruses when applied on the leaves of host plants before or after inoculation of the viruses and had no phytotoxic effect on the host plants