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Kerala Agricultural University, Thrissur
The history of agricultural education in Kerala can be traced back to the year 1896 when a scheme was evolved in the erstwhile Travancore State to train a few young men in scientific agriculture at the Demonstration Farm, Karamana, Thiruvananthapuram, presently, the Cropping Systems Research Centre under Kerala Agricultural University. Agriculture was introduced as an optional subject in the middle school classes in the State in 1922 when an Agricultural Middle School was started at Aluva, Ernakulam District. The popularity and usefulness of this school led to the starting of similar institutions at Kottarakkara and Konni in 1928 and 1931 respectively.
Agriculture was later introduced as an optional subject for Intermediate Course in 1953. In 1955, the erstwhile Government of Travancore-Cochin started the Agricultural College and Research Institute at Vellayani, Thiruvananthapuram and the College of Veterinary and Animal Sciences at Mannuthy, Thrissur for imparting higher education in agricultural and veterinary sciences, respectively. These institutions were brought under the direct administrative control of the Department of Agriculture and the Department of Animal Husbandry, respectively. With the formation of Kerala State in 1956, these two colleges were affiliated to the University of Kerala. The post-graduate programmes leading to M.Sc. (Ag), M.V.Sc. and Ph.D. degrees were started in 1961, 1962 and 1965 respectively.
On the recommendation of the Second National Education Commission (1964-66) headed by Dr. D.S. Kothari, the then Chairman of the University Grants Commission, one Agricultural University in each State was established. The State Agricultural Universities (SAUs) were established in India as an integral part of the National Agricultural Research System to give the much needed impetus to Agriculture Education and Research in the Country. As a result the Kerala Agricultural University (KAU) was established on 24th February 1971 by virtue of the Act 33 of 1971 and started functioning on 1st February 1972. The Kerala Agricultural University is the 15th in the series of the SAUs.
In accordance with the provisions of KAU Act of 1971, the Agricultural College and Research Institute at Vellayani, and the College of Veterinary and Animal Sciences, Mannuthy, were brought under the Kerala Agricultural University. In addition, twenty one agricultural and animal husbandry research stations were also transferred to the KAU for taking up research and extension programmes on various crops, animals, birds, etc.
During 2011, Kerala Agricultural University was trifurcated into Kerala Veterinary and Animal Sciences University (KVASU), Kerala University of Fisheries and Ocean Studies (KUFOS) and Kerala Agricultural University (KAU).
Now the University has seven colleges (four Agriculture, one Agricultural Engineering, one Forestry, one Co-operation Banking & Management), six RARSs, seven KVKs, 15 Research Stations and 16 Research and Extension Units under the faculties of Agriculture, Agricultural Engineering and Forestry. In addition, one Academy on Climate Change Adaptation and one Institute of Agricultural Technology offering M.Sc. (Integrated) Climate Change Adaptation and Diploma in Agricultural Sciences respectively are also functioning in Kerala Agricultural University.
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ThesisItem Open Access Management of bitter gourd mosaic by enhancing host resistance(Department of Plant Pathology, College of Horticulture, Vellanikkara, 2015) Ashwini, K N; KAU; Vimi, LouisBitter gourd (Momordica charantia L.) is one of the important vegetable crops that occupy a pivotal position among fruit vegetables, particularly in south India. The fruits of this crop which have high commercial value and are being used for culinary preparations and various medicinal preparations. In spite of the economic importance of this vegetable, the research work carried out on protection of crop from viral disease is quite scanty. In many case, cent per cent mosaic incidence was recorded in the crop resulting in substantial economic loss. So the present study was focused on screening of bitter gourd accessions and management of bitter gourd mosaic by enhancing host resistance using defense inducers. The three different viruses causing mosaic in bitter gourd are cucumber mosaic virus (CMV), potyvirus and bitter gourd distortion mosaic virus (BDMV). As these viruses causes mixed infection in field, the separation of individual viruses was carried out using systemic indicator host plants. For separation of CMV and potyvirus, systemic indicator host plants used were cosmos and papaya respectively. BDMV was separated by white fly transmission. The pure cultures of viruses were maintained on the susceptible bitter gourd variety Preethi. The symptoms developed by different viruses were recorded under natural and artificial conditions were recorded CMV produced mosaic specks, yellow-green mosaic patches, leathery leaves and downward rolling of leaf margin. Symptoms of potyvirus infection were vein clearing, puckering, malformed leaf with reduced leaf size and rugosity. BDMV infection produced mosaic, puckering, leaf distortion, hairy growth on leaves and vines with reduction in leaf size and internodal length. For the screening of bitter gourd accessions against CMV and potyvirus, potassium phosphate buffer pH 7.0 was found to be the most suitable buffer. Among 22 accessions screened, three accessions viz., TCR 285, TCR 39 and TCR 53 were highly resistant to CMV; one accession Biliagala was highly resistant to potyvirus and 11 accessions viz.,TCR 285, TCR 39, TCR 493 ,TCR 416, TCR 492, TCR 494,TCR 380, TCR 202 and TCR 149, Green long and Biliagala were highly resistant to BDMV. The field experiment was undertaken with the objective of management of bitter gourd mosaic by using defense inducers. The three different defense inducers viz., salicylic acid 25 ppm, barium chloride 0.1% and Pseudomonas fluorescens 2 % were evaluated on the moderately resistant cultivar white long and susceptible variety Preethi. The mosaic symptom was recorded after 51 days of sowing in salicylic acid treated plants and after 40 days of sowing in control. A time gap of 5-10 days after spray of defense inducer was required for development of resistance in plants. The lowest disease severity was observed in cultivar White long treated with salicylic acid. The highest yield was recorded in Preethi treated with Pseudomonas fluorescens.ThesisItem Open Access Physiological and cultural studies on blue oyster mushroom (Hypsizygus ulmarius (Bull.:Fr.) Readhead)(Department of Plant Pathology, College of Agriculture, Vellayani, 2016) Sumi, I; KAU; Geetha, DThe present study entitled “Physiological and cultural studies on blue oyster mushroom (Hypsizygus ulmarius (Bull.:Fr.) Redhead)” was carried out in the mushroom unit, Instructional Farm, College of Agriculture, Vellayani during 2014-2016, with the objective to standardize the technology for cultivation of Hypsizygus ulmarius and to study its morphological and physiological aspects. The initial culture of H. ulmarius was isolated from the mushroom beds maintained in the mushroom unit of instructional farm through tissue culture method and purified by hyphal tip method. Morphological studies of H. ulmarius showed that the sporocarps were medium to large in size having a dark blue colour in the pinhead stage which became creamy white on maturity with an irregularly shaped, convex pileus with gills attached to the stem, but not decurrent and cylindrical, smooth and eccentric stipe. Microscopic studies revealed septate hypahe with clamp connection, oval shaped, hyaline basidiospores and the spore print was white. Studies on developmental morphology showed that H. ulmarius took an average of five days from the day of pinhead formation to complete maturity. The maximum mycelial growth was recorded on potato dextrose agar. A temperature of 25 0C, pH of 8 and dark conditions are found favourable for maximum mycelial growth. Evaluation of different substrates for spawn production revealed that paddy grains was the best medium in which spawn run was completed in fifteen days with thick fluffy growth and recorded less contaminants followed by wheat and sorghum. Evaluation of different substrates for mushroom production revealed that paddy straw was the best material for the cultivation of blue oyster with a total yield of 985 g kg-1 from three harvests followed by rubber sawdust (905 g kg-1). The minimum time for mushroom production was recorded for sugarcane bagasse and the maximum time for rubber sawdust. The average weight of sporocarp was maximum in mushrooms harvested from rubber sawdust and the maximum number of sporocarps was recorded in paddystraw. Beds prepared from sugarcane bagasse were heavily contaminated with Trichoderma sp. When compared with Pleurotus florida, H. ulmarius took more time (18 days) for complete spawn run in paddy grains and the yield was higher on paddy straw (1.096 kg kg-1) than P. florida (976 g kg-1). Infestation of pests viz., phorid flies (Megaselia sp.) and staphylinid beetles were prevalent during spawn run as well as sporocarp formation. The competitor moulds recorded were Trichoderma sp., Aspergillus sp. and Coprinus sp. Analysis for the proximate constituents in H. ulmarius revealed that it contains appreciable amount of carbohydrate (29 %), protein (32 %) and fibre (17.69 %). Sensory evaluation was done on steam cooked mushrooms for attributes like appearance, colour, texture, flavor and taste using five point score card and an overall acceptability score of 3.6 was obtained for H. ulmarius compared to P. florida (3.0). In the preference study conducted for both the mushrooms using Hedonic rating scale, 30 per cent of evaluators extremely liked H. ulmarius than P. florida (10 %). The study on the keeping quality of mushrooms in normal atmospheric condition indicated a shelf life of eight hours for H. ulmarius compared to six hours for P. florida. The study also showed that blue oyster mushrooms stored under refrigeration (4 0C) in perforated polythene covers had better shelf life (5 days) compared to P. florida (3 days). The present study indicated that blue oyster mushroom can be cultivated successfully in tropical areas on locally available materials like paddy straw and rubber saw dust under favourable climatic conditions viz., 26-28 0C temperature, more than 90 per cent relative humidity and good aeration. The variety is superior to the presently growing oyster mushroom (P. florida) in terms of yield, presence of appreciable amount of proximate constituents and keeping quality.ThesisItem Open Access Integrated management of rhizoctonia leaf blight of amaranthus (Amaranthus tricolor L.)(Department of Plant Pathology, College of Agriculture, Vellayani, 2016) Gireesh; KAU; Radhakrishnan, N VThe study entitled “Integrated management of Rhizoctonia leaf blight of Amaranthus (Amaranthus tricolor L.)” was conducted at the College of Agriculture, Vellayani and Coconut Research Station, Balaramapuram during 2014-2016 with the objective to investigate the effect of soil solarization, biocontrol agents, chemical activator, indigenous formulations and new generation fungicides on growth, yield and severity of foliar blight of amaranthus. Samples of the infected leaves showing Rhizoctonia leaf blight in amaranthus were collected from Vellayani, Kalliyoor, Venganoor and Kakkamoola locations. Among the four isolates of the pathogen, the Vellayani isolate gave significantly superior growth rate with minimum of six days for sclerotial formation. Koch‟s postulates were proved for the pathogenicity of different isolates of Rhizoctonia solani. All the four isolates have taken three days for the first symptom development but the progression of lesion size of Vellayani isolate was maximum compared to all other isolates, hence the Vellayani isolate was selected as the most virulent isolate for use in further in vitro studies. Evaluation of biocontrol agents for in vitro suppression of R. solani showed that Trichoderma harzianum completely overgrown the pathogen with maximum inhibition of 49.56 % compared to Pseudomonas fluorescens (28.30 %). Under in vitro evaluation of chemical activator, different concentrations of Acibenzolar-S- Methyl (ASM) against pathogen, 100 ppm concentration recorded the maximum mycelial inhibition of 75.67 % and 5 ppm concentration recorded the minimum mycelial inhibition of 27.70 %. Among indigenous organic formulations, turmeric powder and baking soda combination inhibited the maximum growth of the pathogen by 64.40 %. In the in vitro studies with new generation fungicides,mancozeb in cow dung supernatant (0.4 %) and tebuconazole (0.1 %) recorded the 100 % mycelial inhibition of the pathogen. Field studies on disease suppression and plant growth promotion was carried out as two experiments, one in soil solarized plots and the other in non solarized plots. Soil solarization along with soil application of ASM (75 ppm) and foliar application of ASM (100 ppm) recorded the lowest disease incidence of 30.41 % and 30.42 % respectively, which was superior when compared with foliar application of ASM (100 ppm) and soil application of ASM (75 ppm) with the disease incidence of 37.06 % and 38.84 %. Soil solarization + foliar spray of tebuconazole (0.1 %) recorded the minimum disease index of 37.85 % which was superior compared to foliar spray of tebuconazole (0.1 %) with the disease index of 39.28 %. Among the biocontrol agents soil solarization + foliar spray of Pseudomonas fluorescens (2 %) gave minimum disease index of 45.22 % which was greater compared to foliar spray of P. fluorescens (2 %) with the disease index of 51.66 %. In case of indigenous organic formulations, soil solarization + foliar spray of fish amino acid (5 %) given the maximum control of the disease with the disease index of 49.51 % which was superior to foliar spray of fish amino acid (5 %) with disease index of 63.59 %. The number of days taken for flowering in soil solarized plots ranged from 28.67 to 35 days where as the number of days taken for the flowering of amaranthus in non solarized plots was ranged from 27.27 to 31.67 days. At the time of harvest, soil solarization + mancozeb in cow dung supernatant (0.4 %) recorded maximum plant height of 127.07 cm which was higher compared to foliar spray of azoxystrobin (0.15 %) with plant height of 117.60 cm. Maximum of 78.00 number of leaves were recorded by soil solarization + foliar spray of azoxystrobin (0.15 %) which was greater compared to foliar spray of azoxystrobin (0.15 %) with 67.67 number of leaves.Soil solarization + foliar spray of azoxystrobin (0.15 %) gave the highest yield in terms of fresh weight by 26975.00 kg/ha and dry weight of 4233.33 kg/ha which was superior when compared with foliar spray of tebuconazole (0.1 %) with the fresh weight of 23375.00 kg/ha and dry weight of 3362.50 kg/ha. It is concluded that soil solarization for 31 days with the foliar application of tebuconazole (0.1%) can effectively control the Rhizoctonia leaf blight disease severity with plant growth and yield promotion under field conditions.ThesisItem Open Access Molecular detection and characterization of phytoplasma infecting brinjal (solanum melongena L.)(Department of Plant Pathology, College of Agriculture, Vellayani, 2015) Saranya, S S; KAU; Umamaheswaran, KThe study entitled “Molecular detection and characterization of phytoplasma infecting Brinjal (Solanum melongena L.) was conducted at the Department of Plant Pathology, College of Agriculture, Vellayani, with the objectives to study the symptom development, transmission, molecular detection and characterization of phytoplasma infecting brinjal and its relationship with phytoplasma diseases of other crop plants. Brinjal little leaf (BLL), collected from the Crop museum, College of Agriculture, Vellayani and catharanthus little leaf (CLL) obtained from Coimbatore were maintained for further studies. Symptomatology revealed the characteristic little, narrow, soft, glabrous and smooth leaves produced as clusters along with yellowing, proliferation of axillary shoots, shortened internodes, stunted bushy or rosette appearance and phyllody, the conversion of floral parts into leaf like structures. The graft transmission was found to be 100% successful while the percentage transmission by dodder was only 10% in brinjal and 20% in catharanthus. Phytoplasma was maintained in vivo in plants by grafting and in vitro by culturing the infected explants on MS media supplemented with 0.2 mg l-1 BAP, 0.6 mg l-1 NAA and 0.4 mg l-1 IAA. Biochemical analysis of healthy and diseased plants revealed that the contents of protein, phenol and chlorophyll were reduced in the inoculated plants as a result of phytoplasma infection. Carbohydrate content in brinjal increased immediately after inoculation and then decreased. The activity of peroxidase (PO) was enhanced in the inoculated plants while that of polyphenol oxidase (PPO) was reduced. The activity of phenyl alanineammonialyase (PAL) was reduced immediately after the inoculation, but enhanced at 30 and 60 days after inoculation (DAI). 91 92 The electrophoretic analysis of proteins using SDS-PAGE revealed the presence of two extra protein bands in the infected samples with molecular weights of 29 kDa (Kilo Dalton) and 43 kDa. The isozyme pattern analysis of peroxidase using native PAGE revealed two isoperoxidase bands in the inoculated plants with Relative mobility (Rm) values, 0.17 and 0.47, but a single band in healthy plants with Rm value of 0.17. Molecular detection was done using nested PCR. PCR products of ~1.8 kb (Kilo base) were obtained in direct PCR with phytoplasma universal primer pair P1/P7 and the nested PCR with P1/P7 followed by R16F2n/R16R2 amplified the fragment of size 1.2 kb. The presence of phytoplasma in tissue culture plants was also confirmed using nested PCR. Comparative nucleotide sequence analysis of brinjal and catharanthus isolates with the existing data base from NCBI revealed a 100% homology with brinjal little leaf phytoplasma isolates from Haryana and IARI and 99% homology with potato witches’ broom, potato purple top, tomato big bud phytoplasma etc. The 16S rDNA sequences of BLL and CLL phytoplasma shared 99.7% similarity with that of ‘Candidatus Phytoplasma trifolii (Ca. Phytoplasma trifolii)’. Thus the two phytoplasma isolates were identified as the related strains of ‘Ca. Phytoplasma trifolii’.ThesisItem Open Access Characterization and management of ganoderma lucidum inciting basal stem rot of coconut(Department of Plant Pathology, College of Horticulture, Vellanikkara, 2012) Yunus, C; KAU; Beena, SThe present study on “ Characterization and management of Ganoderma lucidum inciting basal stem rot of coconut ” was undertaken in the Department of Plant Pathology, College of Horticulture, Vellanikkara during 2010-2012 with an aim to isolate the pathogen associated with the disease and to study the cultural, morphological and pathogenic characters of different isolates of the pathogen, symptomatology of the disease, host range and effective management of the pathogen using bio-control agents, phytoextracts and selected fungicides. Purposive sampling surveys were conducted and the occurrence of basal stem rot disease of coconut was observed through out Kerala. The isolation of pathogen from basidiocarps yielded eight isolates of Ganoderma sp. which produced fruiting body in saw dust- rice bran substrate. The pathogenicity of these isolates was tested and observed yellowing, drying and drooping of leaves of coconut seedlings inoculated with all isolates except the isolate GT- from Trivandrum. Basidiocarp formation was noticed only in one seedling inoculated with the isolate GV from Vellayani and reisolation of pathogen was done from this basidiocarp. Symptomatology of the disease under natural and artificial conditions was studied. Under field condition the typical symptom of BSR disease viz., yellowing and drooping of leaves, stem bleeding and basidiocarp formaton were observed in all surveyed areas but all the typical symptoms of disease were not observed under artificial condition. The cultural characters of all the isolates of pathogen were studied on four media viz., Potato dextrose agar, Czapek’s (DOX) agar, Richard’s agar and Soil extract agar media. All isolates produced white mycelial growth on all media but variations in texture, mycelial type, and colour change of mycelium, exudates production and formation of aberrant fruiting body were observed. PDA was found to be the best medium for the growth of pathogen in which all isolates recorded highest growth rate. The pathogen preferred a temperature range of 30-350C and neutral to acid pH of 5-7 for the growth. Slight variation in growth rate was observed under light and darkness. Basidiocarps showed variations in the morphological characters and were stipitate in all isolates except GC from Chirakkacode and GVe from Vettikkal, semicircular to conical shaped, yellowish red to reddish brown with smooth to waved margin, creamy white to brown pore surface, 4.4 – 12.0 x 2.6- 17.0 cm size, 1-10 mm pore length, 139- 254 x 122 – 190 μm pore diameter and 2-10 mm flesh thickness. Basidiospores were brown, ovate to ellipsoidal, truncated apex, double walled with inter wall pillars separating two walls. The size of these basidiospores showed variation in the range of 4.8-13 x 4.5-7.0μm with a spore index of 1.15-1.7. It was trimitic, with generative hyphae hyaline, thin walled, branched, septate and clamped. Reddish brown pigmented skeletal hyphae and colourless binding hyphae were noticed. Based on these observations the eight isolates of the pathogen were identified as Ganoderma lucidum (Leys) Karst. Regarding the in vitro management of the pathogen, two isolates of T. virens and one isolate of T. viride were isolated from rhizophere soil and were proved equally effective with the reference culture, T. viride and T. harzianum in inhibiting the growth of pathogen. Mycoparasitism and production of non volatile metabolites were found to be the mechanisms exhibited by the selected Trichoderma spp. The bacterial antagonists obtained from rhizosphere soil and the reference culture P. fluorescens recorded less than 50 percent inhibition on the growth except in cases of few isolates of the pathogen. It was observed that the selected bacterial antagonists were not much effective in inhibiting the pathogen compared to fungal antagonists. Among the phytoextracts, Azadirachta indica at 20 per cent concentration was found the most effective and recorded more than 50 percent inhibition on the growth of pathogen over control. It was followed by Musa sp. at 10 per cent concentration. The in vitro evaluation of fungicides showed that flusilazole, hexaconazole and iprobenphos at 0.2 per cent concentration were the most effective and recorded cent per cent inhibition on the growth of all isolates of pathogen. The study on the host range of G. lucidium revealed that the seedlings of arecanut, breadfruit, acacia and jack fruit showed yellowing and drooping of leaves and finally wilting of all the seedlings were observedThesisItem Open Access Immunological and molecular detection of banana viruses and production of disease free planting materials(Department of Plant Pathology, College of Agriculture, Vellayani, 2014) Aliya, Ferzana; KAU; Umamahesaran, KThe study entitled "Immunological and molecular detection of banana viruses and production of disease free planting materials" was conducted in College of . Agriculture, Vellayani, and Thiruvananthapuram during !he period of2011-2014. Symptomatological studies showed that the characteristics symptoms caused by BBTV were small, brittle leaves with thickened veins which remained bunched at the top of the pseudostem. Plants with early infection did not produce fruits, where plants with later infection produce bunch with reduced size, weight and mishapen fingers. The characteristic symptoms caused by BBrMV were reddish spindle shaped lesion in the pseudostem, flag leaf sheath, leaf petiole, and bract. Leaves of infected plants showed characteristic chlorotic spindle shaped lesion on the leaf lamina. The characteristic symptoms of BSV were chlorotic streaks in the leaf lamina. Later the chlorotic streaks became necrotic. The characteristic symptom of CMV was mosaic pattern in the leaf lamina. The pathophysiological studies conducted in cultivar Nendran revealed that there was significant difference in carbohydrate, chlorophyll, protein and phenol content in infected plant when compared to healthy ones .. The activity of defence related enzymes like peroxidase, polyphenol oxidase and phenylalanine ammonialyase were found to be more in infected plants. Electrophoretic analysis of protein in virus infected samples through SDS-PAGE revealed the presence of an additional protein in the protein profile. The protein profile of BBTV infected sample showed one extra band with molecular weight of 20 kDa, BBrMV infected sample showed three additional protein band with molecular weight of 38 kDa, 29 kDa and 22 kDa, BSV infected sample showed three additional proteins with molecular weight of 25 kDa, 19 kDa, and 12 kDa, CMV infected sample showed one extra band with molecular weight of 25 kDa. Electrophoretic analysis of isozyme though native gel revealed the increased action of peroxidase enzyme in infected sample. Detection of VIruS infecting banana was carried out using varIOUS immunological techniques such as DAC-ELISA and DIBA using polyclonal antiserum (Agdia) and monoclonal antiserum. Both the techniques were found to be efficient in detecting virus infecting banana. Molecular diagnosis of the BBTV was carried out using CP gene and replicase gene specific primers. PCR product with amplicon size of about 530 bp was observed for coat protein gene specific primer where 237 bp was observed for replicase gene specific primer. Molecular diagnosis of BSV was carried out using two CP gene specific primers resulted in PCR product with amplicon size of 664 bp and 730 bp. Molecular diagnosis of CMV was canied out using CP gene specific primer resulted in PCR product with an amplicon size of 687 bp. CP gene specific primer for BBrMV did not give positive result. Cluster dendrogram analysis revealed that the BBTV isolate was mostly related to BBTV coat protein gene of Burundi isolate, BSV isolate was mostly related to banana streak virus isolate Trichi, CMV isolate was mostly related to cucumber mosaic virus isolate Trichi coat protein gene. The meristematic region of the virus infected banana suckers were excised and inoculated to MS media with BAP and NAA. The regeneration of plants from meristematic region was difficult because of high phenol production and contamination by endogenous bacteria. Meristem culture eliminated BBTV, CMV and BBrMV but not the BSV. Based on the research result, the banana VIruses can be detected usmg immunological and molecular technique and the meristem culture can eliminate all the banana viruses except BSV.ThesisItem Open Access Potential of fortified spent mushroom substrate for the management of soil borne diseases of tomato(Department of plant pathology, College of horticulture,Vellanikkara, 2015) Arathikrishna, V K; KAU; Sheela Paul, TMushrooms are produced on natural materials taken from agricultural waste. SMS is the substrate left after harvesting of mushroom fruit bodies. SMS contains a diverse range of soil microorganisms. This is proven by its disease suppressing properties and its effectiveness in bioremediation. Additions of microorganisms to soil ultimately enhance and accelerate regular soil process such as nutrient mobilization. Among the beneficial uses of SMS the disease controlling property is quite interesting. Tomato is one of the most widely used vegetable. The bacterial wilt and damping off are the two serious soil borne diseases of this crop. The management of diseases using chemicals is not safer to environment due to residual problem. Increasing concern regarding food safety and environmental pollution has generated an interest in eco friendly practices like soil amendment and application of biocontrol agents to manage the plant diseases. Under these circumstances this study was taken up to assess nutritional and disease management aspects of fortified SMS in tomato The antagonists used for this study like Trichoderma hamatum, T. viride and Bacillus subtilis are the isolates from SMS obtained from the previous studies conducted in the Department of Plant Pathology along with reference cultures of Kerala Agricultural University viz. T. viride and Pseudomonas fluorescens. They were evaluated against major soil borne fungal pathogens like Pythium aphanidermatum, Phytophthora palmivora, Fusarium oxysporum, Rhizoctonia solani and Sclerotium rolfsii and bacterial pathogen Ralstonia solanacearum of tomato. The in vitro evaluation showed that T. hamatum was the best among three fungal antagonists. While in case of bacteria P. fluorescens was the best. A microbial consortium of these two organisms was also prepared. The selected best antagonists and consortium were applied to SMS @ 300 ml per kg and kept for biosoftening for 60 days. The fortified SMS with P. fluorescens softened the SMS to a certain level. The primary nutrients like N, P, K, secondary nutrient Ca and micro nutrient Cu were found to be decreased as the time increases. In the pot culture experiment for the management of damping off, the treatment SMS fortified with consortium gave maximum per cent inhibition against the disease. In the management of bacterial wilt also SMS fortified with consortium found to be best in disease suppression as well as plant growth promotion. All the treatments with SMS were found to posses disease management property and enhance the plant growth. From this study it is clear that fortified SMS paves a new way in disease management. For confirmative result, elaborative field study has to be conducted and the quality of SMS has to be worked out.ThesisItem Open Access Integrated management of foliar fungal disease of culinary melon (Cucumis meloL. var. acidulus Naudin)(Department of Plant Pathology, College of Agriculture, Vellayani, 2016) Narmadhavathy, S; KAU; Kamala NayarThe project entitled “Integrated management of foliar fungal disease of culinary melon (Cucumis melo L. var. acidulus Naudin)” was undertaken with the objective of making a comparative evaluation of the efficacy of foliar application of fertilizers, micronutrients, bio-control agents and newer fungicide for the management of Colletotrichum leaf spot (Colletotrichum sp.) disease of culinary melon. Surveys conducted during September 2013 to December 2013, in ten culinary melon fields located at Instructional Farm (IF), College of Agriculture (CoA), Vellayani as well as in farmers’ fields near, CoA, Vellayani, in order to assess the prevalence of major diseases such as Colletotrichum leaf spot and downy mildew disease affecting the crop. Highest disease incidence (DI) and percentage disease index (PDI) of Colletotrichum leaf spot were observed, 75 days after sowing, at Chavadinada (70.00 per cent and 64.44 per cent respectively). Incidence and index of downy mildew disease were recorded in four out of the ten locations surveyed (Palapoor, Papanchani, Kalliyoor and Punjakari). Maximum disease incidence and percentage disease index of downy mildew disease (36 per cent and 33.33 per cent respectively) were observed at Papanchani. The most virulent isolate of anthracnose leaf spot pathogen (IF, Vellayani isolate), obtained during the survey was identified as Colletotrichum fructicola by molecular characterization. The treatment NPK 19:19:19 (0.5 per cent) combined with the fungicide mancozeb (0.4 per cent) and adjuvant was most effective in inhibiting the mycelia growth of the pathogen C. fructicola, in vitro, (100 per cent) over control as well as in suppressing artificially induced anthracnose disease and improving the growth parameters of the plants, in the two greenhouse experiments conducted at the CoA, Vellayani during March to June 2014 and August to October, 2014. Results of two field trials conducted at CoA, Vellayani, during January to March, 2015 and April to June, 2015 for testing four most effective treatments screened from the greenhouse experiments, indicated that NPK 19:19:19 (0.5 per cent) + azoxystrobin (0.15 ml/l) + adjuvant (DI 40.00 and PDI 13.05 respectively) and NPK 19:19:19 (0.5 per cent) + mancozeb (0.4 per cent) + adjuvant (DI 40.00 and PDI 13.47 respectively) were most effective in managing the disease and also increasing total yield of plants, when compared to the remaining treatments. Trials were conducted in farmers’ fields at three locations (Venganoor, Vavamoola and Venjaramoodu) for confirming the efficacy of the two most effective treatments screened from the field trials conducted at CoA, Vellayani and pooled analysis of the results indicated that the lowest PDI (12.22) and DI (28.50) were obtained in plants treated with NPK 19:19:19 (0.5 per cent) + azoxystrobin (0.15ml/l) + adjuvant, which was significantly superior to the other treatments. Results of the microbial studies indicated that there was decline in fungal flora of the plants treated with foliar fertilizer NPK 19:19:19 (0.5 per cent) + azoxystrobin (0.15 ml/l) + adjuvant, days after application of treatments whereas bacterial population was higher in plants applied with the same treatment when compared to the application of combination of foliar fertilizer NPK 19:19:19 (0.5 per cent) + mancozeb (0.4 per cent) + adjuvant. There was indication of higher induction of systemic resistance in plants treated with NPK 19:19:19 (0.5 per cent) + azoxystrobin (0.15 ml/l) + adjuvant due to the higher activity of defense related enzymes, such as phenylalanine ammonia lyase (PAL), peroxidase (PO), polyphenol oxidase (PPO), β-1,3glucanase, super oxide dismutase (SOD) and the compound phenol, all of which, reached maximum level on the 15th day after treatment. Leaf samples obtained from plants treated with foliar fertilizer NPK 19:19:19 (0.5 per cent) + azoxystrobin (0.15 ml/l) + adjuvant indicated highest nutrient use efficiency in all three locations of the confirmation trials while highest pigment status due to this treatment was observed in the trial conducted at Venganoor. Relative water content was generally high in leaf samples collected from all plants irrespective of the treatments, although it was comparatively low, in leaf samples obtained from plants of absolute control plot. Epicuticular wax content was slightly lower in the plants treated with combination of the foliar fertilizer NPK 19:19:19 (0.5 per cent) and fungicides, either azoxystrobin (0.15 ml/l) or mancozeb (0.4 per cent) + adjuvant. Stomatal frequency on the upper and lower surfaces of leaves was not much affected by application of foliar fertilizer NPK 19:19:19 (0.5 per cent) combined with the fungicides. B:C estimated ratio revealed that the highest returns were obtained from the plants treated with foliar spray of NPK 19:19:19 (0.5 per cent) + azoxystrobin (0.15 ml/l) + adjuvant, in all three locations of the farmers’ field trials. This study presents the first report of the pathogen Colletotrichum fructicola causing anthracnose leaf spot disease of culinary melon in India. In field conditions, combination of the foliar fertilizer NPK 19:19:19 (0.5%) and azoxystrobin (0.15 ml/l) along with adjuvant applied twice at 15 days’ interval was most effective in controlling anthracnose leaf spot disease of culinary melon and also increasing the yield of the crop.ThesisItem Open Access Integrated management of anthracnose of snake gourd (Trichosanthes cucumerina L.)(Department of Plant Pathology,College of Agriculture, Vellayani, 2016) Aswani Devi; KAU; Kamala NayarThe objective of present study entitled “Integrated management of anthracnose of snake gourd (Trichosanthes cucumerina L.)” was to make a comparative evaluation of foliar application of newer fungicides and biocontrol agents for the management of anthracnose disease of snake gourd. Surveys were conducted during October 2015 in snakegourd fields of five different locationsof Thiruvananthapuram district , viz., Instructional Farm, College of Agriculture,Vellayani, Department of Olericulture, College of Agriculture, Vellayani, Kalliyoor, Kakkamoola and Palapoor. Maximum disease incidence (90.00 per cent) and disease severity/ percentage disease index (44.22) were recorded in the snake gourd fields of Instructional Farm, Vellayani whereas disease parameters were minimum (21.89 per cent and 70.00 per cent) in the fields of Palapoor Pathogenicity tests revealed that the isolate C1 obtained from Instructional Farm, Vellayani produced maximum lesion size both on detatched leaf (2.53 cm2) as well as and on intact leaves of 30-days old potted plant (10.06 cm2). The smallest lesion size of 1.33 cm2 on detatched leaf and 1.53 cm2 on 30 days old potted plant was produced by the isolate C4 from Kakkamoola. Based on lesion size and virulence rating, C1 was screened as the most virulent isolate. Results of the cultural studies among the five isolates, showed that potato dextrose medium, oat meal medium and Richard’s medium were screened as the best media both in solid and liquid states for the growth of the tested isolates. Effect of different light sources (Fluorescent light: 253.7 - 185 nm, L.E.D light: 365 nm and UV light: 10 - 380 nm) on growth and sporulation of anthracnose pathogen indicated that the cultures exposed to fluorescent light and darkness for alternate cycles of 12 h of each day resulted in maximum mycelial growth and minimum days for sporulation for all the isolates. Growth was less when the cultures of the isolates were exposed to UV light for a period of 45 min. The morphological characters studied indicated that average conidial size of isolate C1, C2, C3 and C5 ranged from 11.40μm- 13.14μm x 4.48μm-4.82 µm and that they were cylindrical in shape with obtuse ends. The isolate C4 was ellipsoidal in shape and had a conidial size of 10.52μm x 4.40 µm. The isolates C1, C2, C3 and C5 were further identified at National Fungal Collection Culture India (NFCCI) - Pune, as C. coffeanum F.Noack and the isolate C4 was identified as C. musae (Berk. & M.A. Curtis) Arx. Isolate C1 of C. coffeanum which was earlier screened as the most virulent isolate was used for the subsequent studies conducted for the management of anthracnose disease in snake gourd. In the invitro assayconducted for screening of newer fungicides and bio control agents, effective for the inhibition of the isolate C1 of C. coffeanum, the nutrient potassium silicate (0.5 per cent) and fungicide mancozeb (0.4 per cent) resulted in hundred per cent mycelial inhibition while, KAU talc based formulations of the bio control agents viz., P. fluorescens (2 per cent) and T. viride (2 per cent) resulted in inhibition of 88.33 per cent and 87.33 per cent respectively and were selected for further evaluation in green house study. Minimum spore germination was recorded due to amendment of medium with T. viride (1.33 per cent). Conidia were also reduced in size when growth medium (PDA) were amended with tested chemicals and bio-control agents. In the green house studies using the snake gourd variety Kaumudi, maximum disease suppression was observed when plants were sprayed with 0.5 per cent potassium silicate (89.12 per cent) and 0.4 per cent of fungicide mancozeb (84.99 per cent) at fifteen days interval. Biometric parameters observed were also maximum for plants sprayed with 0.5 per cent potassium silicate followed by mancozeb and KAU talc based formulation of bio-control agents P. fluorescens and T. viride. Anthracnose affecting the foliage of snake gourd is a serious disease in snakegourd fields of Thiruvanathapuram district. The nutrient potassium silicate which was tested for the first time in Kerala against a plant pathogen, Colletotrichum sp. is found to be a promising chemical for management of the disease. The present study has also revealed the prospects of utilizing the mineral nutrient, potassium silicate for control of anthracnose disease as well as attainment growth promotion, flowering behavior, yield components and increases in yield of snake gourd which is an important vegetable crop of Kerala. Besides, this study also has highlighted the scope for integrating the fungicide mancozeb with bio-control agents like P. fluorescens and T. viride which were was also highly beneficial for the disease management as well as in improving the growth parameters of the crop under green house conditions. Such integration of fungicide mancozeb with bio-control agents will also be useful in minimizing the detrimental effects of continous and intensive use of this fungicide which is otherwise very effective in disease management. In the background of the promising results obtained from this thesis project especially from the use of potassium silicate, trials for confirming the beneficial effects of the treatments in field grown snake gourd plants would be useful for the vegetable growers in Kerala.
