SOME STUDIES ON PREDATORY SPIDERS IN HYBRID COTTON-6 AT ANAND

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dc.contributor.advisorYADAV, D. N.
dc.contributor.authorDHULIA, F. K.
dc.date.accessioned2018-06-04T10:25:43Z
dc.date.available2018-06-04T10:25:43Z
dc.date.issued1988
dc.description.abstractStudies were made on various predatory spiders associated with insect pests of hybrid cotton-6 at Anand Campus of the Gujarat Agricultural University during 1986-87. In all thirteen species of predatory spiders belonging to nine different families were recorded. These included five species of hunting spiders viz., Oxyopes ratnae, Glubiona sp., Castianeira sp., Plexippus sp. and Hippasa sp., four species of web-building spiders viz., Neoscona theisl, Neoscona sp.,. Uloborus khasiensis and Argiope pulchella, three species of ambushing spiders viz., Thomisus sp., T. cherapunjeus and T. projectus and one species of Olios sp. Hunting spiders dominated over other species and accounted for 63.15 per cent of the total population. Amongst these O. ratnae was found to be most important and predominant. Seasonal activity of O.ratnae, Glubiona sp., A. pulchella, Castianeira sp.. Olios sp., N, theisi, Thomisus sp. and U. khasiensis was also studied and were found predatory on insect pests such as Heliothis armigera Hxibner,, Spodoptera litura Fab., Anomis flava F., Earias vittella F., Dysdercus cinqulatus Fb., Aphis qos sypii Glover,, Ainrasca biguttula biguttula Ishida, and Bemisia tabaci Gennadius, Observations on biology of O. ratnae show that, the spider laid on an average 2.8 egg-raasses during her life span. The incubation period was 9-11 days (the average being 10.1 days) and numbers of spiderlings emerged per egg-mass varied from 30-42, with an average of 35.6. Male and female pass through 10 and 11 instars respectively to reach maturity. Male spiderlings took 157-215 days (the average being 187.20 days) whereas the female took 221-295 days (the average being 259.50 days) to complete the development. Total life span from the emergence of the spiderlings to the death of the adult varied from 260-349 days in case of male (The average being 305.8 days) whereas it varied from 323-418 days in case of female (The average being 358.80 days). The male and female mated readily under laboratory conditions, the mating lasted for few seconds. Mortality during different instars varied from 4,00 to 17.64 per cent, it was more in the 12 instar spiderlings (17.64%), The female spins silken cocoon before laying eggs and then covers them with silken threads. It was also found to take care of the eggs by sitting over them. Just hatched spiderlings were able to survive for 9.6 days when starved. The residual toxicity of fenvalerate (0.015%), endosulfan (0.07%), phosphamidon (0.03%) and monocrotophos (0.04%) was found to be high to the second instar spiderlings of 0. ratnae. Amongst them endosulfan was found having greater residual toxicity. Thus, fairly rich fauna of predatory spiders occurred in hybrid cotton-6. In view of their abundance, longer activity, long longevity and predation on variety of insects, it is suggested that as far as possible the spiders should be conserved by minimizing the apolication of pesticides such as fenvalerate, endosulfan, phosphamidon and monocrotophos. It would also be worthwhile attempting mass rearing of species like Oxyopec ratnae and Clubiona and utilizing them against insect pests of cotton. It would be interesting to study their occurrence on other crops, to know wheather these species show some affinity for particular habitat.en_US
dc.identifier.urihttp://krishikosh.egranth.ac.in/handle/1/5810048983
dc.keywordsSOME STUDIES ON PREDATORY SPIDERS, HYBRID COTTON-6 AT ANANDen_US
dc.language.isoenen_US
dc.publisherAAU, Ananden_US
dc.research.problemSOME STUDIES ON PREDATORY SPIDERS IN HYBRID COTTON-6 AT ANANDen_US
dc.subAgricultural Entomologyen_US
dc.subjectAGRICULTURAL ENTOMOLOGY, AGRICULTUREen_US
dc.subjectA STUDYen_US
dc.themeSOME STUDIES ON PREDATORY SPIDERS IN HYBRID COTTON-6 AT ANANDen_US
dc.these.typeM.Scen_US
dc.titleSOME STUDIES ON PREDATORY SPIDERS IN HYBRID COTTON-6 AT ANANDen_US
dc.typeThesisen_US
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