Browsing by Author "Neena, Lenin"
Now showing 1 - 2 of 2
Results Per Page
Sort Options
ThesisItem Open Access Efficacy of Neoseiulus longispinosus (Evans) (Mesostigmata: Phytoseiidae) for the management of Tetranychus urticae Koch (Prostigmata: Tetranychidae) on Cucumber under protected cultivation(College of Horticulture, Vellanikkara, 2017) Neena, Lenin; KAU; Haseena, BhaskarA study was undertaken at the Acarology laboratory, Department of Agricultural Entomology, College of Horticulture, Vellanikkara during 2013-2016, to investigate the biology, incidence, crop phenology relationship and natural enemies of the two spotted spider mite, Tetranychus urticae Koch infesting cucumber in polyhouse as well as to study the biology, efficacy and prey stage preference of the predator, Neoseiulus ongispinosus (Evans) on T. urticae and standardize the optimum predator: prey ratio of N. longispinosus for biological control of T. urticae in polyhouse. Purposive surveys, conducted in fifteen polyhouses in four districts of Kerala viz., Thrissur, Palakkad, Wayanad and Thiruvananthapuram, revealed the occurrence of four species of tetranychid mites, namely, Tetranychus truncatus Ehara, T. urticae Koch, T. okinawanus Ehara, Eutetranychus orientalis (Klein) and one species of tarsonemid mite, Polyphagotarsonemus latus (Banks) on cucumber. The occurrence of T. truncatus and T. okinawanus is a new report on cucumber in polyhouse. Hence, DNA barcoding was carried out to confirm the species identity of T. truncatus (TOCRF001-15) and T. okinawanus (TOIR001-15). Studies on the relationship of crop stage and mite incidence on cucumber revealed that the population of spider mites was significantly higher during the late fruiting stage of the crop, followed by early vegetative stage. Relatively lower population was recorded at flowering stage and early fruiting stage.Four species of insect predators and six species of mite predators were recorded in association with spider mites on cucumber. The insect predators were Stethorus pauperculus (Weise), Oligota sp., Scolothrips sp. and an unidentified species of Cecidomyiidae. The predatory mite fauna included Agistemus garrulus Chaudhari, Amblyseius paraaerialis (Muma), Cunaxa sp., Cheyletus sp., Neoseiulus longispinosus (Evans) and Tydeus gossabaensis Gupta.Neoseiulus longispinosus was found to be the predominant species of predatory mite on spider mites infesting cucumber. Tetranychus urticae recorded a developmental period of 6.75 days in male and 7.15 days in female. Adult male lived for 8.95 days while mated and unmated female lived for 11.59 days and 13.04 days, respectively. Mated and unmated females recorded a fecundity of 47.91 and 36.08 eggs, respectively. The sex ratio was female biased (1:4.6) in T. urticae. Total developmental period of N. longispinosus was 3.91 and 4.27 days for male and female, respectively. Adult male lived for 19.66 days and the female, for 22.75 days. On an average, a single female laid 31.33 eggs and the progeny consisted of both males and females in the ratio 1:3.31. Parthenogenesis was not observed in N. longispinosus. The adult of N. longispinosus recorded significantly higher predation compared to the nymph. Both nymph and adult, showed preference towards egg compared to active stages of the prey. The time needed to eliminate the available prey population was found to increase with increase in prey density. Studies conducted to identify the optimum predator: prey ratio required for field release of N. longispinosus against T. urticae on cucumber in the laboratory showed that, at ratios of 1:5 and 1:10, the prey population was completely eliminated by tenth day. The prey population recorded in the ratios, 1:20, 1:25 and 1:33 were on par with this. In the polyhouse, the predator: prey ratios of 1:20 and 1:25 were found to significantly reduce the population of T. urticae on cucumber. The present study has revealed the potential of the predatory mite, N. longispinosus as a biocontrol agent of the spider mites. The short life cycle, longer life span of adults, female biased sex ratio and preference for egg stages and above all, the density dependant nature of the prey predator relationship, brought out in the present study could provide a platform for viable biocontrol strategy based on N. longispinosus for management of spider mites under protected cultivation in Kerala.ThesisItem Open Access Infestation of the pumpkin caterpillar, diaphania indica saunders in cucurbits and its management(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2011) Neena, Lenin; KAU; Hebsy, BaiSurvey conducted in the Kalliyoor panchayath of Thiruvananthapuram district during 2009-2010 revealed the incidence of the pumpkin caterpillar, Diaphania indica Saunders in bitter gourd, snake gourd, cucumber and coccinia. The extent of infestation was high in bitter gourd, snake gourd and cucumber and low in coccinia. The infestation was significantly higher during the fruiting followed by the flowering and vegetative stages. Leaves and fruits of bitter gourd, snake gourd and coccinia were damaged by the pest. Only the leaves of cucumber were damaged. No significant differences were noted in the extent of infestation when more organic manures or more fertilizers were applied by the farmers. Similarly, the high and low doses of fertilizers applied also did not influence the extent of damage. The plant protection measures adopted by the farmers too had no significant effect on the extent of damage. The red amaranth (Amaranthus tricolor Linn.) and green amaranth (Amaranthus dubius L.) and the weed plants, the slender amaranthus (Amaranthus viridis L.) and bristly starbur (Acanthospermum hispidum DC.) were recorded as host plants of D. indica. The parasitoid Apanteles sp. was the only natural enemy recorded during the survey. Among the botanicals screened, annona seed extract 5%, neem oil garlic emulsion 2%, neem seed kernel extract 5%, Anosom 2ml l-1, Derisom 2ml l-1 and NeemAzal T/S 2ml l-1 resulted in high mortality of the caterpillars upto three days after treatment both when applied topically and released on treated leaves. The efficacy of Anosom 2ml l-1 extended to the seventh day when released on treated leaves. Topical application of spinosad 0.015%, flubendiamide 0.004%, profenophos 0.05%, diafenthiuron 0.02%, triazophos 0.05% and chlorpyriphos 50%+ cypermethrin 5% 0.05% resulted in 100 per cent mortality of the caterpillars one day after treatment. When released on treated leaves, flubendiamide 0.004% and spinosad 0.015% proved to be the better treatments, registering mortality of the pest upto 15 days after treatment. 80 Field evaluation with annona seed extract 5%, Anosom 2ml l-1, B. bassiana 2g l-1, B. thuringiensis 2g l-1, flubendiamide 0.004% spinosad 0.015% and carbaryl 0.15% indicated that flubendiamide 0.004% was the most effective, the reduction in the pest population being 60 per cent. Spinosad 0.015% and Anosom 2ml l-1 also resulted in significant reduction in the pest population, the extent of reduction being 46 and 43 per cent, respectively. Annona seed extract 5% too was equally effective as Anosom 2ml l-1 in its efficacy, the population of the pest being reduced by 40 per cent. The extent of reduction in the pest population in carbaryl 0.15%, B. bassiana 2g l-1 and B. thuringiensis 2g l-1 treatments was 35, 35 and 33 per cent, respectively. More than 50 per cent reduction in the number of fruits damaged was recorded B. bassiana 2g l-1, flubendiamide 0.004%, B. thuringiensis 2g l-1 and spinosad 0.015% treatments. Anosom 2ml l-1 and annona seed extract 5% resulted in more than 40 per cent reduction in the fruit damage. Carbaryl 0.15% registered 39 per cent reduction in the fruit damage. All the treatments increased the yield of the crop significantly, the extent of yield increase ranging from 36 to 44 per cent in the insecticide, 39 to 41 per cent in the botanical and 26 to 39 per cent in the microbial treatments. Based on the results of the study, destruction of the weed and other volunteer host plants and early detection of the pest and its management with either the botanicals or microbials would be a viable option for controlling the pest. The safer insecticides flubendiamide 0.004% or spinosad 0.015% could be used when there is a substantial increase in the pest population.