Assessment of losses due to Amrasca biguttula biguttula (Ishida) and management of Earias vittella (Fabricius) on okra
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Title |
Assessment of losses due to Amrasca biguttula biguttula (Ishida) and management of Earias vittella (Fabricius) on okra
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Creator |
Chauhan, Vikas
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Contributor |
Sharma, S.S.
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Subject |
Amrasca biguttula biguttula; Earias vittella; losses; okra; population dynamics; red spider mite;.
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Description |
The present studies on the assessment of losses due to Amrasca biguttula biguttula (Ishida) and management of Earias vittella (Fabricius) on okra were carried out during kharif season at Research Farm of the Department of Entomology, CCS Haryana Agricultural University during 2013. The losses due to leafhopper were measured by comparing the average plant height, number of fruits per plant and average fruit weight per plant in sprayed and unsprayed plots. The insecticide sprayed plots recorded significantly higher average plant height (66.5 cm), higher average number of fruits (15.6) and higher average fruit weight per plant (164.5 gm) as compare to unsprayed plots. The losses in plant height, number of fruits, and fruit weight per plant due to leafhopper were 47.6, 50.0 and 57.2 per cent, respectively. The management of E. vittella was carried out according the pre fixed insecticide schedules. The observations were recorded by counting the damaged shoots and fruits, total number of shoots and fruits observed at each picking. The mean lowest leafhopper population (1.10 nymph/leaf) was recorded in treatment schedule S 3 (seed treatment with imidacloprid 600 FS @ 5 g/kg seed + 1 st foliar spray with Prempt 20 EC @ 750 ml/ha + 2 nd foliar spray with imidacloprid 17.8 SL @ 100 ml/ha). Similarly, the lowest mite population (4.34 mites/cm 2 ) was recorded in treatment schedule S 2 (seed treatment with imidacloprid 600 FS @ 5 g/kg seed + 1 st foliar spray with Prempt 20 EC @ 750 ml/ha). The lowest shoot damage (1.11%) was recorded in treatment schedule S 8 (S3 + 3 rd foliar spray with thiamethoxam 25 WG @ 100 g/ha + 4 th spray with spinosad 45 SC @ 190 g/ha + 5 th spray with carbaryl 50 WP @ 1.125 kg/ha). The lowest fruit damage on number basis (1.95%) was recorded in treatment schedule S 4 (S2 + 2 nd foliar spray with spinosad 45 SC @ 190 g/ha). On weight basis lowest damage (1.84%) was recorded in treatment schedule S4 . Schedule S 5 (S 2 + 2 nd foliar spray with thiamethoxam 25 WG @ 100 g/ha) was most economical with highest cost to benefit ratio (1:10.25). The population dynamics of the major insect pests and mite on okra were carried out by counting the nymphs of leafhoppers, adults of whiteflies, adults and nymphs of mites at weekly interval from three leaves each from upper, middle and bottom canopy of the plant on randomly selected 50 tagged plants. The leafhopper population was remained throughout the cropping season with minimum population of 1.6 nymphs/leaf in 27 th standard meterological week and the maximum population of 13.9 nymphs/leaf in 32 nd Standard meterological week. Whitefly population was observed during early cropping season with maximum population of 3.4 adults/leaf on 28 th standard meterological week. Mites population was found during later stage of crop growth and the maximum population of 18.2 mites per square cm of leaf in 34 th standard meterological week. The fruit damage by Earias spp. was observed between 31 st to 36 th standard meterological weeks. The maximum fruit damage of 13.9 per cent was recorded on 36 th standard meterological week. There is no significant effect of weather parameters on whitefly and the leafhopper population had negative correlation with maximum temperature and positive correlation with morning relative humidity. Red spider mite population and fruit borer damage caused by Earias spp. was significantly and negatively correlated with minimum temperature. |
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Date |
2016-09-19T10:21:10Z
2016-09-19T10:21:10Z 2014 |
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Type |
Thesis
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Identifier |
http://krishikosh.egranth.ac.in/handle/1/77303
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Language |
en
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Format |
application/pdf
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Publisher |
CCSHAU
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