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ThesisItem Open Access Studies on the burrowing nematode radopholus similis (cobb,1893) thorne 1949 on pepper(Piper nigrum L.) and its role in slow wilt disease(Department of plant pathology, University of agricultural sciences, Bangalore, 1976) Venkitesan, T S; Setty, K G HThesisItem Open Access Studies on the pathogenicity and physiology of Cornespora cassiicola (Berk & Curt.) Wei.(Division of plant Pathology ,Agricultural College and Research Institute ,Vellayani, Trivandrum, 1970) George, P V; KAU; Paily, P VThesisItem Open Access Quick wilt disease of pepper (Piper nigrum Linn)-1 symptomatological studies on the quick wilt disease of pepper(Department of Plant Pathology, College of Horticulture, Vellanikkara, 1978) Mammootty, K P; KAU; Abi CheeranThe present study on the quick wilt disease of pepper caused by Phytophthora palmivora (Butler) Butler was conducted at the Pepper Research Station, Vellanikkara using Panniyoor-1 pepper variety. The objectives of the investigations were to study the symptoms of the disease and to find out suitable control measures using fungicides. The first visible symptom on leaf, stem and root was noticed 24 to 48 hours; two to five days and 24 to 48 hours respectively after inoculation, depending on the maturity of the plant part. A fully developed lesion had a dark brown hononecrotic centre and plesionecrotic boarder surrounded by yellow halo. The yellow halo was not noticed during prolonged wet and humid conditions. Under these conditions lesions was uniformly brown in colour. Zonations were noticed during the alternate wet and dry conditions. On the stem, branches and roots symptom usually developed as a uniformly brown and dark coloured lesions. Pathogen entered mainly though lower surface of the leaf. After infection, defoliation took place within five to ten days. Development of flaccidity, drooping and defoliation of the leaves were the marked symptoms during the progress of disease when the stem, branches or roots were infected. All the fungicides tested checked the growth of the fungus in vitro for a period of three days. The fungicides when sprayed or drenched two hours before inoculation completely checked the disease. However, there was mild infection on plant where Dithane M-45 was used for drenching the soil. As the interval between the fungicidal spray and inoculation prolonged there was progressive reduction in the control of the disease. None of the fungicides was able to eradicate completely the established pathogen on leaves. When fungicides were applied one day after inoculation there was complete control of the disease on stem. While the control was not complete when it was applied two days after inoculation. All the fungicides except Dithane M-45 completely checked the development of the disease when they were drenched in soil.ThesisItem Open Access Studies on the control of bacterial wilt of tomato with reference to organic soil amendments and chemicals(Department of Plant Pathology, College of Agriculture, Vellayani, 1977) Jayaprakash, M G; KAU; Rajan, K MThe pot culture and field experiments were conducted to assess the effort of organic soil amendments and chemicals on the incidence of bacterial wilt of tomato. The population dynamics in relation to the causal organism, total fungi, bacteria and actinomycetes were also studied. Theresult of the investigation revealed that organic materials did not chook the disease incidence to a satisfactory level . However , the application of organic material followed by the treatment with chlorotomycin and streptocycline gave a satisfactory control of the disease.ThesisItem Open Access Studies on the effect of fungicides and silica in the control of sheath blight of rice caused by Corticium Sasakii (Shirai) Matsumoto(Division of Plant Pathology, College of Agriculture, Vellayani, 1975) Mathai, G; KAU; Paily, P VA field experiment to determine the effect of two fungicides under three levels of silica on the incidence and intensity of sheath blight of rice was conducted at the Agricultural College Farm, Vellayani during the crop season February to May 1974. The fungicides, hinosan and dithane M-45, were effective in reducing the intensity, per cent infection and rate of spread of the disease and thereby increasing the yield. Among the fungicides tried hinosan was significantly superior. Application of silica was found to have significant effect in reducing the intensity of the disease on the 75th day. However, the per cent infection, rate of spread and the intensity on the 85th day indicated that the effect of silica in imparting resistance to infection by the pathogen was not significant.ThesisItem Open Access Studies on the bacterial blight (Wilt) of Tapioca incited by Xanthomonas manihotis (Arthaud-Berthet) Starr(Department of Plant Pathology, College of Agriculture, Vellayani, 1979) Mani, T Cherian; KAU; James MathewThe bacterial blight of tapioca, incited by Xanthomonas manihotis (Arthaud-Berthet) Starr, probably the most serious of all the diseases recorded on the plant, was reported sporadically from different parts of Kerala since 1975. The disease is characterised by loss of turgidity, shrivelling and wilting of leaves, gum extraction, die-back and death of shoots, vascular discolouration of stem and roots and damage and decay of tubers. The pathogen was confirmed to be Xanthomonas manihotis from morphological, physiological and biochemical studies coupled with symptomatology and host specificity. The pathogenicity was confirmed on tapioca using different methods of artificial inoculation, of which inoculation after nipping the bud was found to be the best.ThesisItem Open Access Studies on the grey leaf blight disease of Coconut palm caused by Pestalotia palmarum Cooke.(Department of Plant Pathology, College of Agriculture, Vellayani, 1977) Francis, A J; KAU; Paily, P VAn investigation was carried out in the palms at the Coconut Research Station, Balaramapuram during the months of May, June, July, August and September of 1976 to study the influence of different nutrients on the intensity of disease caused by Pestalotia palmarum. The experiment was conducted on the palms which were treated with different combinations of NPK in a 3 confounded factorial design . Morphological characters of different species of Pestalotia were also studied along with this investigation. Highest degree of infection was noticed in the month of June and the lowest in September. Higher disease intensity was noted in the palms which were treated with 1 level of nitrogen, 2 levels of phosphorus and 2 levels of potassium than in these that were treated with 0 level of nitrogen, 1 level of phosphorus and 0 level of potassium.ThesisItem Open Access Studies on the mosaic disease of snake gourd (Trichosanthes Anguina L.)(Department of Plant Pathology, College of Agriculture, Vellayani, 1978) Joseph, P J; KAU; Ramanatha Menon, MA mosaic disease of snake gourd (Trichosanthes anguina L.) caused by a virus, was investigated which was prevalent at Vellayani and nearby localities. The symptoms manifested as mosaic and formation of dark green blisters on the lamina was also observed. The affected leaves were severely reduced in size, variously crinkled and malformed. Growth was retarded and internods were shortened. The infected plants blossom sparingly and set only very few fruits. The affected portions of the leaf were thinner than healthy areas, palisade cells reduced in size and loossly packed. The mesophyll cells contain only few chloroplasts.ThesisItem Open Access Rhizoctonia damping off of Cardamom (Elettaria cardamomum Maton) and its control(Department of Plant Pathology, College of Agriculture, Vellayani, 1978) Sasi, P S; KAU; Wilson, K IThe role of Rhizoctonia in causing damping off of Cardamom in the primary nursery was established and the symptoms of the disease have been described . The fungus grew well on a number of solid media. The morphological characters of the fungus were studied. It was able to infect 27 plant species including Achyranthes aspera, Commelina benghalensis, Phyllanthus niruri Colonyotlon -puricatum Cyperus rotundum, Abutilon indicum, Heliotropiumindicum and Azolla pinnata on artificial innoculation . These plants have been found to be new hosts o f the fungus in our country. The pathogen was Identified as Rhizoctonia solani Kuhn.
