1. KAUTIR (Kerala Agricultural University Theses Information and Retrieval)

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    Biorational management of major pests of Kerala, Abelmoschus esculentus(L.) moench
    (Department of Entomology, College of Agriculture, Padannakkad, 2023-11-13) Gagan, B S.; Ramesha, B
    The study entitled “Biorational management of major pests of okra, Abelmoschus esculentus (L.) Moench” was carried out in the Instructional Farm, Karuvachery during two seasons viz., summer (January to May) and kharif (June to September) in the year 2022 to study the efficacy of different microbial agents, neem based and biorational insecticides against major pests of okra viz., okra shoot and fruit borer, aphids, jassids and leaf roller. Bioassay studies were conducted in the laboratory of Department of Entomology, College of Agriculture, Padanakkad during 2022-23 to evaluate the efficacy of microbial agents, neem based and biorational insecticides against aphids, jassids and leaf roller. Treatments were applied on test insects as three replications and the percentage mortality at fixed intervals was worked out. The field experiment was laid out in randomized block design (RBD) with nine treatments and three replications. The okra variety ‘Salkeerthi’ released by KAU was selected for the study. Treatments included were; T1: Bt formulation 2× 109 cfu/ml @ 10 ml/l of water; T2: Neem based formulation (Azadirachtin 1%) @ 2 ml/l of water; T3: Raksha (Neem oil, garlic, soap based formulation- KAU product) @ 6 g/l of water; T4: Emamectin benzoate 5% SG @ 0.4 g/l of water; T5: Pyridalyl 10 EC @ 1.5 ml/l of water; T6: Flonicamid 50 WG @ 0.6 g/l of water; T7: Spinosad 45 SC @ 0.4 ml/l of water; T8: Malathion 50 EC @ 2ml/l of water- Standard check; T9: Absolute control. Treatments were imposed at 30th, 45th and 65th day after sowing and observations were recorded at weekly intervals corresponding to standard weeks. The data were subjected to square root transformation and analysed using ANOVA in GRAPES (General R-shiny based Analysis Platform Empowered by Statistics) software. Bioassay studies indicated that highest percentage mortality of aphids, jassids and leaf roller were recorded in treatment T6 (Flonicamid 50 WG), T4 (Emamectin benzoate 5% SG) and T7 (Spinosad 45 SC) respectively after 24 hours of treatment application. Analysis of field experimental results showed that there is significant difference between the treatments in reducing the pest status of the crop as well as yield parameters of the crop. After three sprays, treatment T7 (Spinosad 45 SC @ 0.4 ml/l of water) at fortnightly intervals completely reduced shoot and fruit borer larvae in both summer and kharif seasons and leaf roller larvae in kharif season. Therefore, it was found that Spinosad 45 SC was effective in reducing the population of shoot and fruit borer and leaf roller as well as the percentage of shoot and fruit infested. During summer season, treatment T6 (Flonicamid 50 WG @ 0.6 g/l of water) was found to be the most effective treatment in reducing the nymphs and adults of aphids and their percentage shoot infestation in the vegetative phase of the crop. Treatment T4 (Emamectin benzoate 5% SG @ 0.4 g/l of water) and T2 (Azhadirachtin 1% @ 2 ml/l of water) were found effective in controlling the nymphs and adults of jassids in both summer and kharif seasons. T6 (Flonicamid 50 WG @ 0.6 g/l of water) also provided effective control of jassid population in the crop. Among the different treatments, maximum fruit length was recorded in T7 followed by T4 during both summer (17.13 and 15.50 cm) and kharif season (17.32 and 16.10 cm) respectively. Total yield was highest in T7 followed by T4 showing per plant yield of 384.87 and 360.53 g respectively during summer season and 502.65 and 479.47 g respectively during kharif season. Also, the same treatments recorded highest marketable yield of 369.79 and 339.75 g/plant respectively during summer season and 482.91 and 458.83 g/plant respectively during kharif season. During both seasons viz., Summer and kharif, highest benefit-cost ratio was recorded in T4 (2.73 and 3.62) and T7 (2.70 and 3.54) respectively. The results of the investigation clearly indicated that, along with then recommended package of practice, spraying of Spinosad 45 SC @ 0.4 ml/l of water provides effective control of okra shoot and fruit borer and leaf roller without reducing the marketability of the fruits. Spraying of Flonicamid 50 WG @ 0.6 g/l of water can be used to effectively control the sucking insects like aphids and also jassids. Emamectin benzoate 5% SG @ 0.4 g/l of water and Azadirachtin 1% @ 2 ml/l of water can be used to control nymphs and adults of jassids on okra
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    Screening of superior genotypes of ailanthus triphysa (Dennst.) Alston. (Matti) for matchwood quality
    (Department of Forest Products and Utilization, College of Forestry, Vellanikkara, 2018) Jagaddish Kumar Das; Anoop, E V
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    Insecticide based bait formulation aganist tobacco caterpillar spodoptera litura (fabricius) (lepidoptera: noctuidae)
    (Department of Agricultural Entomology, College of Horticulture, Vellanikkara, 2018) Shahanaz, M R; Berin Pathrose
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    Cloning of genes encoding insecticidal proteins (cry/vip genes ) of Bacillus thuringiensis from Western Ghats of Kerala
    (Centre for Plant Biotechnology and Molecular Biology, College of Horticulture, Vellanikkara, 2007) Neema, P M; Girija, D
    The study entitled ‘Cloning of genes encoding insecticidal proteins (cry/vip genes) of Bacillus thuringiensis from Western Ghats of Kerala’ was carried out in the Molecular Biology Laboratory of the Centre for Plant Biotechnology and Molecular Biology, College of Horticulture, Vellanikkara during the period 2005- 2007. The crystal protein genes (cry/vip) of B. thuringiensis possess insecticidal activity against larvae of insect orders Lepidoptera, Diptera and Coleoptera. In the present study, an attempt was made to isolate and clone cry genes of B. thuringiensis from the Western Ghats of Kerala. Bacillus thuringiensis strains were isolated from soil samples collected from different locations of the Western Ghats of Kerala. The pure colonies obtained were stab inoculated and stored under refrigerated conditions. Variability among the isolates were studied by various cultural, morphological and biochemical tests. The insecticidal activity of the isolates was determined by bioassay against the major lepidopteran pest of cucurbitaceous vegetables, the pumpkin caterpillar. The information on cry1A gene sequences of different species of Bacillus thuringiensis available in the public domain NCBI was collected and subjected to multiple sequence alignment to detect conserved boxes of the gene among species. Based on the data, one pair of gene specific primer was designed for amplification of partial cry1A gene fragment of about 800bp in B. thuringiensis isolates. Total DNA was isolated from the B. thuringiensis strains of Western Ghats of Kerala. Profiling of cry1 and cry4 genes of bacterial isolates were done using universal primers for cry1 and cry4. Amplification was obtained with cry1 gene for seven isolates and with cry4 gene primer for two isolates. The amplicons obtained with universal cry1 primer from two isolates and with cry4 primer from one isolate were used for cloning. The amplicons obtained with cry1 and cry4 primers were eluted, cloned in pGEMT vector and transformed into competent cells. High level of recombination was observed on blue-white screening. Recombination of the insert was confirmed by PCR of the plasmid isolated from white colonies. The cloned fragments were sequenced. The amplicon obtained with cry4 primer in the second isolate was sequenced after purifying the PCR product. The cry1ky5 and cry1em11 sequences when subjected to Blast search revealed significant levels of homology with cry1 genes reported from other B. thuringiensis strains deposited in the public domain. The cry4em10 sequence when subjected to Blast search, showed high level of similarity with cry4 genes from B. thuringiensis. The cry4ky1 sequence showed similarity with cry genes of different species of B. thuringiensis. The sequences were also subjected to various sequence analysis using bioinformatics tools which include ORF finder, SOPMA, GENSCAN, AASTAT and TCAG tools of Biology Workbench and Interproscan. PCR of all the isolates found positive in cry1 gene profiling, was done with cry1A primer designed during this study. Amplification was obtained with cry1A primer in two isolates. The amplicon obtained in one isolate was subjected to sequencing after purifying the PCR product. The cry1Aky3 sequence showed similarity with other cry genes of Bacillus thuringiensis present in the NCBI databank. 1500 bp long variable region of cry1 was amplified in two isolates using specific primers. Future research works should be focused on the isolation of B. thuringiensis from completely undisturbed ecological niches. Novelty of cry genes can be detected by restriction digestion of the genes. Characterization of novel full-length cry genes and its expression in transgenic crops will help to develop resistant varieties thereby reducing insecticide applications and resistance development in insect pest populations.