Sucession and population dynamics of insect pest complex of onion and management of thrips
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Date
2016
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JNKVV
Abstract
Present research work on “succession and population dynamics of insect pest complex of onion and management of thrips” was carried out in the experimental field of Department of Horticulture, JNKVV, Jabalpur, (M.P) during 2015-16.
The experiment was conducted with the following objectives
1) To study the succession of insect pest complex on onion
2) To study the population dynamics of major insect pests of onion
3) Management of onion thrips :
a) To study the effect of planting dates on thrips incidence
b) To study the efficacy of insecticides and NSKE against onion thrips
Three different species of insect pests, one non insect pest and one natural enemy order were recorded on the onion crop at experimental field of Department of Horticulture, JNKVV, Jabalpur, (M.P) during rabi 2015-16. Which represented three pest orders viz. Thysanoptera (Family: Thripidae), Lepidoptera (Family: Noctuidae), Tetranychidae (Family: Trombidiformes) and a group of predators namely spiders, Order: Arachnida were also recorded.
The thrips appeared when the crop age was about 32 days old and their activity continued till the maturity of the crop. Cutworm appeared after transplanting when the crop age was about 32 days old and their activity continued till the reproductive stage of the crop. Fruit borer also appeared when the crop age was about 37 days old and their activity continued till the reproductive stage of the crop. Red spider mite appeared when the crop age was about 68 days old and their activity continued for a very short period (up to 106th day old crop). The first predation of spiders was observed during the vegetative stage of the crop i.e. about 12 days old crop (after transplanting) and remained available from vegetative stage to harvesting of crop.
The thrips T. tabaci Lindeman was first recorded in the first week of December i.e. 2nd December 2015 during the 48th standard week (SW) and remained available up to maturity stage of the crop with The peak activity during 1st SW (i.e. 1st to 7th January).
Correlation between various abiotic factors and thrips population showed that maximum temperature was found to be significant positive correlation. Further, minimum temperature, sunshine, morning vapour pressure and evaporation exhibited positive correlation. While morning & evening relative humidity, wind velocity, rainfall, no. of rainy days and evening vapour pressure showed negative correlation with thrips population but statistically found to be non-significant.
The activity of cutworm, A. ipsilon Hufnagel was first recorded in the first week of December i.e. 2nd December 2015 during the 48th standard week, with peak activity during 51th SW (i.e. 17th to 23rd December).
Correlation between various abiotic factors and cutworm population showed that, morning relative humidity, evening relative humidity, wind velocity was found to be positive correlation. While no. of rainy days and morning vapour pressure were found to be zero correlation. While maximum & minimum temperature, sunshine hour, rainfall, evening vapour pressure and evaporation showed negative correlation with leaves infested by cutworm but statistically found to be non significant.
The Fruit borer, H. armigera Hubner was first recorded in the second week of December (i.e. 7th December 49th SW), with peak activity during 2nd SW (i.e. 8th to 14th January).
Correlation studies revealed that maximum temperature, sunshine hours and evaporation showed positive correlation. Further, minimum temperature, morning and evening relative humidity, wind velocity, rainfall, no. of rainy days, morning and evening vapour pressure showed negative correlation with fruit borer population but statistically found to be non-significant.
The Red spider mite, T. telarius Linnaeus was first recorded in the first week of January (i.e. 7th January, 1st SW), with peak activity during 5th SW (i.e. 29th January to 4th February).
Correlation studies revealed that, morning relative humidity, and sunshine showed positive correlation. While maximum temperature, minimum temperature, evening relative humidity, wind velocity, rain fall and no. of rainy days, morning & evening vapour pressure and evaporation showed negative correlation with red spider mite population but statistically were found non significant.
The various molecule evaluated in which Imidacloprid 17.8% SL @ 29.37 ml a.i./ha was found to be significantly lowest thrips population than all other treatments but at par with Triazophos 40% EC @ 400 ml a.i./ha. Plots treated with Triazophos recorded significantly lower thrips population than other treatments except Profenophos 50% EC @ 500 ml a.i./ha. Against onion thrips, Thrips tabaci L. were found significantly more effective on onion , Allium cepa Linnaeus during rabi 2015.
Among the different date of transplanting evaluated, significantly highest population of thrips was recorded in D8 (December 15th) date of transplanting. The lowest thrips population was recorded in D2 (September 15th) date of transplanting.
The peak mean thrips population was recorded in the 4th week of March and lowest mean thrips population in fourth week of September.
Evaluation of Insecticide effect on population of thrips in the subplot (protected, Imidacloprid 17.8% SL @ 29.37 ml a.i./ha) revealed that significantly more effective against onion thrips, Thrips tabaci L., on onion, Allium cepa Linnaeus during 2015.
Interaction of the two factors i.e. planting dates and protected plot have a significant impact on the population of thrips. Among the different date of transplanting and protected plot evaluated, significantly highest population of thrips was recorded interaction (D4 x B1) i.e October 15th date of transplanting and protected plot. The lowest Thrips population was recorded in interaction (D2 x B1) i.e September 15th date of transplanting and protected plot was found significantly.
Interaction of the two factors i.e. planting dates and unprotected plot have a significant impact on the population of thrips. Among the different date of transplanting and unprotected plot evaluated, significantly highest population of thrips was recorded interaction (D8 x B2) i.e December 15th date of transplanting and unprotected plot, but at par with interaction (D7 x B2) i.e December 1st date of transplanting and unprotected plot. The lowest Thrips population (5.68 thrips/plant) was recorded in interaction (D1 x B2) i.e September 1st date of transplanting and un protected plot, but at par with interaction (D2 x B2) i.e September 15th date of transplanting and un protected plot.
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