Browsing by Author "Koshy Abraham"
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ArticleItem Open Access Bacterial wilt of pumpkin (Cucurbita Moschata Poir) and snakegourd (Trichosanthes anguina L.) incited by pseudomonas solanacearum (Smith) Smith from India(Kerala Agricultural University, 1994) Sally K Mathew; Beena, S; Baby Lissy Markose; Koshy Abraham; KAUThesisItem Open Access Characterization and management of bacterial wilt of chillies caused by Pseudomonas solanaceasum E F Smith(Department of Plant Pathology, College of Horticulture, Vellanikkara, 1992) Jyothi, A R; KAU; Koshy AbrahamBacterial wilt is one of the most serious disease of chillies in Kerala. The pathogen was isolated from infected chilli plants and its pathogenicity established. Ten isolates of the pathogen viz., five from chillies , two each from tomato and brinjal and one from ginger were used in the study and they werre characterized and identified as blovar III of Pseudomonas solanacearum (Smith) Smith based on the morphological, cultural, biochemical and physiological characters, coupled with its pathogenicity. Twentynine accessions/varieties of chillies were screened for host resistance against bacterial wilt and the study revealed that the variety 'Manjari' (KAU Cluster/CA 33) was resistant to the disease. The accessions CA 205 and CA 207 exhibited moderately resistant reaction. There was no significant correlation between environmental factors and wilt incidence of all the accessions/varieties except CA 408, for which a positive correlation was noticed between soil moisture and wilt incidence.ArticleItem Open Access Collar rot of murraya koenigii L. by corticium rolfsii curzi(Kerala Agricultural University, 1994) Anita Cherian, K; Beena, S; Koshy Abraham; KAUArticleItem Open Access Control of bacterial leaf spot of betel vine(Kerala Agricultural University, 1982) Koshy Abraham; James Mathew; KAUIn the in vitro screening of antibiotics, chloramphenicol, Terramycin, Streptomycin, Streptocycline and Agrimycin-100 have showed inhibitory effect to X. campestris pv. betf/cota. Among these, chloramphenicol at 500 ppm exerted maximum inhibitory effect. None of the antibiotics tested in in vivo gave absolute control of the disease. But minimum percentage index of disease status and maximum percentage survival of diseased leaves were observed in plants receiving Terramycin 500 ppm spray.ArticleItem Open Access Cylindrocladium leaf blight of Acacia auriculiformis A. Cunn(Kerala Agricultural University, 1996) Koshy Abraham; Beena, S; Anitha Cherian, K; Sally K Mathew; KAUThesisItem Open Access Endophytic microorganism mediated systemic resistance in Cocoa against Phytophthora palmivora (Butler) Butler(Department of Plant Pathology, College of Horticulture, Vellanikkara, 2011) Sainamole Kurian, P; KAU; Koshy AbrahamThe study on 'Endophytic microorganism mediated systemic resistance in cocoa against Phytophthora palmivora (Butler) Butler was carried out during 2005-2010. The pathogen causing pod rot of cocoa was isolated from infected pods , and its pathogenicity established. Based on cultural and morphological characters, it was identified as Phytophthora palmivora (Butler) Butler. Endophytes were isolated from samples of feeder roots, tender shoots, leaves and pods of cocoa collected from various locations of major cocoa growing area of the state. The population of endophytic microflora varied among different locations and parts of the plant, and in general, the population was more in roots. Bacteriaand fluroscent pseudomonads were more abundant than filamentous fungi and yeasts. Out of the 325 endophytic isolates comprising of 116 bacteria, 153 fluorescent pseudomonads, 34 years and 22 fungi, 82 were found exerting antogonism towards the pathogen. These antagonistic endophytes were further evaluated in In vitro by dual culture and by inoculation on detached cocoa pods, and leaves. It was found that, 25 isolates were more efficient antagonists.ThesisItem Open Access Management of Phytophthora disease in black pepper nursery(Department of Plant Pathology, College of Horticulture, Vellanikkara, 2003) Reshmy Vijayaraghavan; KAU; Koshy AbrahamPhytophthora rot is the serious disease of black pepper nursery. An investigation was carried out to isolate and select the efficient antagonists from black pepper nurseries and use them alone or in combination with fungicides in the integrated management of the disease. The experiment was laid out at CCRP farm at College of Horticulture, Vellanikkara, The pathogen causing the disease was isolated and identified as Phytophthora capslcl Leonian emend A. Alizadeh and P.H.Tsao based on the cultural and morphological characters. Quantitative estimation of rhizosphere microflora from different pepper nurseries yielded more soil bacteria followed by fungi and actinornycetes. All the 22 fungi, five out of 20 bacteria and none of the actinomycetes tested were antagonistic to P. capsici. Among the fungal isolates, 13 isolates including standard culture of T. harzianum recorded cent per cent inhibition of P. capsici. Further, selection of the efficient isolates was carried out based on the antagonistic index (AI). The isolates 22 F and 34 F recorded an AI of3000 and 1500 respectively and these were identified as Trichoderma longibrachiatum and Trichoderma viride. The standard culture of T harzianum also recorded an AI of 1500. The three antagonists were found parasitic on Picapsici as evidenced by excessive coiling, penetration and disintegration of the hyphae. The fungicides viz., Bordeaux mixture, Kocide, Captaf and Kavach were incompatible with the three antagonists, while, lndofil M-45, Ridomil I\.1Z, Akomin and Anthracol were compatible. Fytolan showed partial compatibility with Tviride and 1~ harzianum but incompatible with T. longibrachiatum. Among the eight insecticides tested, Phorate and Carbofuran showed compatibility with the antagonists, whereas Monocrotophos, Quinalphos, Endosulfan, Dimethoate, Cypennethrin and higher concentration of Chlorpyrlphos were incompatible. In general, fertilizers like Urea, Rajphos, Ammonium sulphate and Muriate of potash (MoP) were compatible with antagonists, while, Factomphos and higher concentration of Urea did not support good growth. 149 Bordeaux mixture, Fytolan, Kocide, Indofil M-45, Ridomil MZ and Captafat all concentrations and higher concentration of Akomin-40 and Anthracol were inhibitory to P. capsici. The insecticides Phorate, Carbofuran and Chlorpyriphos showed comparatively good inhibitory effect against the pathogen but complete inhibition of pathogen was noticed with Monocrotophos, Endosulfan, Quinalphos, Dimethoate and Cypermethrin. The fertilizers viz., urea, MoP, Rajphos supported growth of the pathogen while, Factomphos and ammonium sulphate exerted an inhibitory effect. Solarization of potting mixture resulted in the build up of soil temperature and the build up was more in the upper layer of soil. Solarization of potting mixture and application of biocontrol agents had a positive effect in increasing the sprouting and reducing the pre-sprouting mortality of cuttings and is comparable to plants raised as per PoP. Observations on the incidence and severity of Phytophthora rot in black pepper showed that in general soil solarization, application of antagonists and spraying of Ridomil MZ had a favourable effect in checking the disease and the effect is almost similar to that of disease management as per PoP. A variation in the population of soil microfIora in different treatments was o~~rved. Thy cuttings raised in solarized potting mixture incorporated with native antagonists had a significant effect in increasing the height and number of leaves.ArticleItem Open Access New bacterial wilt of Coleus Vettiveroides Jacob(Kerala Agricultural University, 1992) Estelitta, S; Beena, S; Koshy Abraham; Ravi, S; Varadarajan Nair, P; KAUArticleItem Open Access New leaf spot disease of kodampuli (Garcinia Cambogia) desr.(Kerala Agricultural University, 1996) Anita Cherian, K; Beena, S; Koshy Abraham; KAUArticleItem Open Access On the physiological variation of xanthomonas campestris Pv.betlfcola (Patel, Kulkarni and Dhande) dye(Kerala Agricultural University, 1983) Koshy Abraham; James Mathew; KAUArticleItem Open Access Screening of betelvine cultivars for host resistance against leaf spot pathogn Xanthomonas Betlicola Patel, Kulkarni and Dhande(Kerala Agricultural University, 1981) Koshy Abraham; James MathewSeven cultivars of betelvine were screened for host resistance against the leaf spot pathogen Xanthomonas betlicola. The study revealed that none of the cultivars were absolutely resistant to the disease, but the minimum disease severity was observed in the cultivar Tulasivettila. The minimum defoliation within 20 and 30 days after inoculation were observed in the cultivars Karilanchikarpuran and Tulasivettila.ThesisItem Open Access Studies on the bacterial leaf spot of betel vine incited by Xanthomonas betlicola Patel et al.(Department of Plant Pathology, College of Agriculture, Vellayani, 1980) Koshy Abraham; KAU; James MathewThe bacterial leaf spot of betel vine incited by Xanthomonas betlicola Patel et al. is one of the most serious diseases recorded on the plant and was first reported in the year 1951. The occurrence and severity of the disease in Kerala was reported from 1978 onwards. The symptoms of the disease is characterised by water soaked lesions, bacterial exudations, dark brown patches with yellow halo, marginal infection, shot hole type symptoms, defoliation, stem and petiole infection. Minor variations in the above symptoms were observed with different isolates of the pathogen.