Browsing by Author "Joseph, P J"
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ThesisItem Open Access Characterization and management of viral diseases of black pepper(Piper nigrum L.)(College of Agriculture, Vellayani, 2010) Ayisha, R; KAU; Joseph, P JA detailed survey was undertaken to study the occurrence and distribution of viral diseases in black pepper in Thiruvananthapuram and Kollam districts of Kerala. Disease incidence (DI) and per cent disease index (PDI) were determined during survey which showed that per cent DI varied between 0-57 and PDI between 0-18. The disease was prevalent in both the districts. Most of the local cultivars and improved varieties were susceptible to the disease. The characteristics symptoms of disease were chlorotic spots on emerging younger leaves, vein clearing, scattered chlorotic flecks followed by chlorotic mottling along veins leading to interveinal chlorosis and characteristic twisting and curling of leaves. The infected leaves were also observed to be small, crinkled, and brittle with reduced internodal length, leading to typical stunting of plants. Most of the diseased plants were found to be infected with both Cucumber mosaic virus (CMV) and Pepper yellow mottle virus (PYMo V). The presence of these viruses was confirmed through conducting enzyme linked immunosorbent assay (ELISA) on representative samples collected from different locations. The virus was not mechanically transmitted to healthy pepper seedlings. However the virus was found to be transmitted through grafting, insect vectors and also through seeds. The mealy bug, Ferrisia I virgata was found to be the efficient vector although aphid, Toxoptera aurantii, was also found to be transmitting the virus. Thermal inactivation point was recorded at a range of 40-450C and dilution end point between 10-3 and 10-4 for CMV. Host range studies revealed that virus could be readily transmitted to other species in Piperaceae family as well to some of the weed hosts. The virus was partially purified and antiserum was produced with a titre of 1:128. Identification and serological characterization of the virus was done using ELISA and DIBA. Molecular detection of the virus was also performed using PCR and a PCR product of amplicon size 500 bp and 300 bp were obtained for primers specific to CMV and banana streak virus (BSV) respectively. The pathophysiological studies revealed that virus infected plants showed increased phenol, carbohydrate and protein content. The chlorophyll content was found to be less in infected samples. The activity of defence related enzymes like peroxidase, polyphenol oxidase and phenylalanine ammonialyase were found to be more in infected plants. Electrophoretic analysis of virus infected samples through SOS-PAGE revealed the presence of two novel proteins in diseased samples. Analysis of isozymes through native gel revealed the production of an additional isoform of peroxidase and over expression of polyphenol oxidase in infected plants. In screening of varieties for the source of resistance Panniyur, 2, 3 and 4 were found moderately resistant and Karimunda was highly susceptible. Piper colubrinum showed resistance to the virus. Meristem culure attempted was unsuccessful and could not be used as a viable strategy for eliminating the virus infecting black pepper as the meristems were seen contaminated with the pepper badnavirus.ThesisItem Open Access Integrated management of leaf rot of coconut(Department of Plant Pathology, College of Agriculture, Vellayani, 2002) Vrinda, T S; Joseph, P JThe study entitled as "Integrated management of leaf rot of coconut" w as conducted at the Department of Plant Pathology, Co l.cge of Agr iculturc. Ve l l a van i and Iie ld trial was conducted at RARS. Kumarakorn. Extensive iso lai io n s. pathogenicity and characterization studies of the pathogens assoc i aic d with leaf rot infected spindle leaf of coconut from di ffercnt r e g ions 0 I' f ve southern districts of Kerala revealed that Collct otrichu m g/oco.,porioidcs. Fusarium so/ani, Fusarium. monil if..rniae, Fusari utn oxvsp or utn, Cephalosporium sacchari. Exserohilum rostrat um. Gl iocl adi um roselllll.<';C\!o!idillll7 sp. and Curv ular i a sp. played ct io lo gj 0" LRD. Based on frequency 01' isolarions. Fusarium spp. .ind C .g/()(;o.,porioides Viere identified as major pathogens or LRD in these areas. The present study constitutes the first report or the ct io log ica l ro l c of Scvt ul uliurn ::;0 in leaf rot incidence. Symptomatology of the disease based on natural incidence in the I'dd and upon artificial inoculation were clearly described The in vit ro interactions of different dual combinations of LRD pathogens were found to be predominantly associative rather than inhibitory in nature. The rapid lesion development of certain dual combinations of the pathogens upon artificial inoculation further signified the associative nature of these pathogens. Extensive in vi/m screening and leaf bit assay of different antagonistic microorganism identified T9 culture of Trichoderma sp. PSI culture of Pse u domonasfluorescens as two potential agents against i he major pathogens of LRD. The in vitro interactions study of the selected fungal and bacterial antagonist showed that both are incompatible and hence unsuitable for combined delivery. Bioassay results showed that fungicides hcxaconazo lc and propiconazole completely inhibited the growth of C. gloeosporioides. E. rostra/um and F. solani while mancozeb was more effective at higher concentrations. one of the fungicides was inhibitory to P. j7uorescens while Trichoderma sp. was inhibited by hex aconazo!e and hence the fungal antagonist was unsuitable for combined delivery with the fungicides. Evaluation of different components of disease management indicated that phytosanitation coupled with hexaconazole application was effective in reducing disease severity of leaf rot in the field.ThesisItem Open Access Management of rhizome rot and root-knot of ginger (Zingiber officinale R.) using V A mycorrhizal fungi and antigonists(Department of Plant Pathology, College of Agriculture, Vellayani, 1997) Joseph, P J; KAU; Sivaprasad, PManagement of rhizome rot, the most destructive disease of ginger incited by Pythium aphanidermatum (Edson)Fitz. using native arbuscular mycorrhizal fungi (AMF) and antagonists was attempted. The extensive survey in the ginger growing belts of the state revealed a definite negative relationship between AMF development and disease incidence. Based on preliminary evaluation with six AMF species, Glomus constrictum was selected as most efficient for disease suppresion, growth enhancement and yield and used as reference culture for the subsequent studies. The population of Heloidogyne incognita, a pre disposing factor for the disease, was reduced in the presence of all the six AMF species particularly with G. fasciculatum. Characterization studies of native AMF associated with ginger indicated that Glomus spp. were more frequent and G. fasciculatum was the most predominent species. Influence of soil types on the AMF occurrence in ginger was evident. Out of the fourteen native AMF developed from ginger rhizosphere, Mi-l and Mi-4, identified as Glomus species, were the most efficient isolates for rhizome rot suppression yield increase and growth enhancement in ginger. Eleven native antagonistic fungi, selected from in vitro evaluation, were screened in the green house and Ai-12, identified as Trichoderma viride, was the most effective isolate for suppression of rhizome rot, growth enhancement and yield of ginger. Ai-13 isolate, identified as Aspergillus fumigatus, was also effective for disease suppression. The isolates, Mi-l, Mi-4, Ai-12 and Ai-13 were tested for their combined effect in the green house. Dual inoculation of Ai-12 with Mi-l and Mi-4 resulted in remarkable synergistic interaction in reducing the disease and enhancing biomass and yield. Both single and dual inoculations of Ai-12, Mi-l and Mi-4 significantly reduced the disease and enhanced plant growth and yield in the field also. Isolate Ai-13 inhibited AMF development and increased disease in the green house and field. Application of AMF inoculum on ginger rhizome after starch coating was very effective for rapid and early colonization of AMF. Out of the various plant protection chemicals tested, thiram and carbofuran least affected the AMF and antagonist development. An effective management strategy of rhizome rot of ginger is evolved in the present study by combining appropriate native AMF (Mi-l and Mi-2) and antagonistic fungi (Ai-12) for inoculation of seed rhizomes at planting time. The present study forms the first report of detailed documentation of native AMF associated with ginger and extensive study on the utilisation of AMF. antagonists and their combined effect for the management of rhizome rot.ThesisItem Open Access Standardization of mass production technique for VA mycorrhiza(Department of Plant Pathology, College of Agriculture, Vellayani, 1999) Saritha V Elizabeth; KAU; Joseph, P JDifferent methods to standardize the mass inoculum production techniques of AMF was attempted in the present investigation. Effort to identify suitable substrate combination indicated that a substrate combination consisting of basal medium of vermiculite 65 per cent, perlite 20 per cent, cowdung 5 per cent and soil 10 per cent as components was ideal for maximum AMF spore production as well as for plant growth. Mycorrhizal setaria plant was found to be the ideal host for biomass production while maximum AMF spore count was obtained with stylosanthes, which possessed only less root volume. A host combination of congosignal and stylosanthes was found to be the ideal system for achieving maximum AMF colonization and spore production apart from increased plant growth and biomass. Application of different plant growth regulators stimulated plant growth, biomass production and AMF spore production. Foliar application of humic acid 2000 ~l r' resulted in maximum increase in spore production and hence can be recommended for application in routine AMF inoculum production systems. Induction of stress to the host plants using different stress inducing substances stimulated AMF sporulation. Water stress induced on 75 DAP resulted in maximum spore production. The stress inducers which increased spore production also include ethrel 25 ul r', NaCI 0.5, 1.0, 1.5 per cent and ABA 2.0 mg r ' treatments. Although the plant protection chemicals viz., metalaxyl (1000 mg rl) and streptomycin (1000 and 2000 mg rl) promoted plant growth, there was significant reduction in the AMF spore production and hence are unsuitable for application on hosts intended for AMF inoculum production. The present study revealed that infective propagules of AMF in the inoculum could be increased by selecting substrates and host combinations suitable for inoculum production which could further be boosted up by applying selective growth promoting substances such as humic acid 2000 III r' and inducing water stress during the later stages of plant growth.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.ArticleItem Open Access Studies on the mosaic disease of snake gourd (Trichosanthes Anguina L.)(Kerala Agricultural University, 1978) Joseph, P J; Ramanatha Menon, M; KAUThe symptom of snake gourd mosaic disease manifested as mosaic pattern with dark green raised blisters on the leaf lamina. The size of leaves severely reduced ; internodes shortened and the growth of the plant is retarded. The infected plants blossom sparingly and set few fruits. The virus is sap and insect transmissible; both Aphis gossypii and A cracdvora transmitted the virus. Studies on the vector-virus relationships with A. cracdvora showed that the vector could acquire the virus with 5 minutes acquisiton feeding and transmit it with 5 minutes feeding on a healthy test plant. A minimum of 5 aphids are required for transmission and pre-acquisition starvation increased the efficiency whereas pre-infection starvation beyond 30 minutes ^uucod it. The vector could met retain the virus for long periods and the relationship was of non-persistent nature. The physical properties of the virus are: T.!. P. of 70 -75°C, D.E.P. ,of 1 '.5000-1 :1 0000, longevity in vitro of 72-96 hours at room temperature and 144—168 hours at "lOt). Eight species of plants in 3 families ^c susceptible to infection by the virus. Based on the above characteristics, the virus causing mosaic disease of snake gourd in Kerala is identified as a strain of ucumis virus 1 .ThesisItem Open Access Viral diseases of Vanilla(Vanilla planifolia Andrews) in Kerala(Department of Plant Pathology, College of Agriculture, Vellayani, 2006) Abhilash Dinkar; KAU; Joseph, P JPreliminary survey conducted in Kottayam and Idukki districts of Kerala indicated the incidence of three virus diseases in vanilla and were categorized as those producing a) Symptom Type No.1 b) Symptom Type No.2 and c) Symptom Type No.3. The most widely occurring virus disease was the one which produced Symptom Type No.1, the characteristic symptoms of which were mosaic pattern on leaves up on which necrotic spots developed later with leaf crinkling, distortion, and leaf size reduction. The virus is named as Vanilla mosaic virus disease (VMVD). The disease was prevalent in the two districts surveyed. The mean per cent disease incidence varied from 6.683 to 8.205 during summer season. The mean disease index varied from 2.553 to 2.976 during summer season .The virus was not sap transmissible to vanilla test plants but was easily transmissible to Chenopodium amaranticolor, exhibiting chlorotic local lesions in which highest per cent transmission was obtained using 0.1M sodium phosphate buffer (pH7.2). The disease was not transmitted by insects such as Aphis gossypii, A. craccivora and Bemisia tabaci. Hundred per cent transmission was obtained when infected cuttings were used as planting material. The virus was found to be transmitted to vanilla test plants by wedge and approach grafting and budding even though perfect graft and bud union did not establish. The virus has a dilution end point between10-4 and10-5, thermal inactivation point between 60and 65oC and longevity in vitro at room temperature between 24 and 48 hours and under refrigerated conditions between 48 and 72 hours. The virus could be transmitted only to Nicotiana glutinosa systemically and to C.amaranticolor with local lesions. Drastic reduction in total chlorophyll, chlorophyll a, chlorophyll b and total carbohydrate were observed in virus infected plant samples while total soluble protein and phenol content were greatly enhanced. Peroxidase, polyphenol oxidase and phenylalanine ammonia lyase activities were found to be increased in response to virus infection. SDS PAGE analysis revealed the presence of an additional major polypeptide band of 37 KDa in infected samples in addition to the identical bands. The virus was partially purified and antiserum was successfully produced with a titre between 1:500 and 1:1000. A rapid method of diagnosis of vanilla mosaic virus disease was developed employing microprecipitin and DAC- ELISA tests.