Studies on population dynamics and efficacy of chemical and botanical insecticides against insect pest complex of okra
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Date
2016
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JNKVV
Abstract
ABSTRACT
Present research work on “Studies on Population D ynamics and Efficacy of Chemical and Botanical Insecticides against Insect Pest Complex of Okra” Conducted at Department of horticulture Vegetable research farm, JNKVV, Jabalpur (M.P.) during kharif 2015. The experiments were conducted with the following objectives:
1. To study the succession of insect pests and their natural enemy insects in okra.
2. To study the population dynamics of major insect pests of okra in relation to weather parameters.
3. To study the efficacy of some new insecticides and botanical against insect pest complex of okra.
Five different species of insect pests and one natural enemy were recorded on the okra crop at experimental field of Department of Horticulture Vegetable research farm, JNKW, Jabalpur (MP.) during kharif
2015 which represented 3 orders (Hemiptera , Lepidoptera and Coleoptera) and 6 families (Cicadellidae, Aphididae, Aleyrodidae, Pyrrhocoridae, Noctuidae and Coccinellidae).
The jassid appeared when the crop age was about 16 days old i.e. during vegetative stage and remained available upto maturity stage of the crop. Aphid was the next insect pest to appeared on the crop during the vegetative stage and remained available up to maturity stage of the crop i.e.
22th to 28th October 2015. Whitefly was also appeared at vegetative stage and
remained available up to the maturity stage of the crop i.e.15th to 21st October
2015. Red cotton bug was appeared on the crop, when the crop age was about 77th day old and present for a very short duration (up to 96th day) i.e. during the maturity stage of the crop. Shoot and fruit borer was appeared on the crop, when the crop age was about 46 days old i.e. during reproductive stage and remained available upto maturity stage of crop. Lady bird beetle
appeared when the crop age was about 35th days old and remained available from vegetative to reproductive stage (68th day).
The jassid, Amrasca biguttula biguttula (Ishida) was first observed during 33rd SW (i.e.13rd to 19th August) and remained available upto maturity stage of the crop with peak activity during 40th SW (i.e. 1st to 7th October,
2015).
Correlation between various abiotic factors and jassid population showed that evaporation (mm) was found to be significant positive correlation. Further, maximum temperature, morning relative humidity sunshine and morning vapour pressure exhibited positive influence while minimum temperature, evening relative humidity, wind velocity, rainfall and no. of rainy days showed negative influence with jassid population but statistically found to be non-significant.
The activity of aphid, Aphis gossypii (Glover) was first recorded in the first week of August (33rd SW, 13th to 19th August 2015) with peak activity during 39th SW (i.e. 24th to 30th September 2015).
Correlation between various abiotic factors and aphid population showed that evaporation (mm) was found to be significant positive correlation.
Further, maximum & minimum temperature, sunshine and morning vapour pressure were found to be positive correlation, while morning & evening relative humidity, wind velocity, rainfall, no. of rainy days and evening vapour pressure showed negative correlation with aphid population but statistically found to be non significant.
The whitefly, Bemisia tabaci Genn. was first observed during 33rd SW
(i.e.13th to 19th August 2015) and remained available up to maturity stage of the crop 42thSW( i.e.15th to 21st October 2015).
Correlation between various abiotic factors and whitefly population was found non significant. Further, maximum temperature and sunshine, showed positive correlation while, minimum temperature morning & evening relative humidity, wind velocity, rainfall, no. of rainy days, morning & evening vapour pressure and evaporation showed negative correlation with whitefly population but statistically were found to be non- significant.
The activity of shoot and fruit borer, Earias vittella Fab. was observed from 38th SW (i.e. 17th to 23th September) with peak activity during 43rd SW (i.e. 22 to 28 October). Correlation between shoot and fruit borer, E. vittella and maximum temperature, morning & evening relative humidity, rain fall, no. of rainy days and evening vapour pressure showed positive correlation while, minimum temperature, wind velocity, sunshine, morning vapour pressure and evapouration showed negative correlation with shoot and fruit borer population but statistically were found non significant.
The various molecule evaluated in which emamectin benzoate 5 SG @
12 g a.i./ha and 10 g a.i./ha against shoot and fruit borer (Earias vittella F.) and imidacloprid 17.8% SL @ 35.6 g a.i./ha against jassid (Amrasca biguttula biguttula Ishida), aphid (Aphis gossypii Glover) and whitefly (Bemisia tabaci genn.) were found significantly more effective on okra (Abelmoschus esculentus L. Moench) during kharif 2015.
Maximum cost benefit ratio was obtained in imidacloprid 17.8% SL
@ 35.6 g a.i./ha (1:32.33) this followed by imidacloprid 17.8% SL @
17.8 g a.i./ha (1:22.55), thiamethoxam 25% WG @ 25 g a.i./ha (1:19.56), difenthiuron 50 WP @ 300 g a.i./ha(1:17.36), emamectin benzoate 5% SG @ 10 g a.i./ha (1:14.40), emamectin benzoate 5% SG
@ 12 g a.i./ha (1:12.65) and NSKE 5% g a.i./ha (1:3.65). respectively.
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