Crop Diversification for Sustainable Management of Leucinodes orbonalis Guenée in Brinjal and Preparation of Sequential Sampling Plan
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Date
2019
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DIVISION OF ENTOMOLOGY ICAR-INDIAN AGRICULTURAL RESEARCH INSTITUTE NEW DELHI
Abstract
The present study entitled “Crop Diversification for Sustainable Management of Leucinodes orbonalis Guenée in Brinjal and Preparation of Sequential Sampling Plan” was performed at Division of Entomology, Indian Agricultural Research Institute (IARI), New Delhi during Kharif season of 2018. All experiments were carried out at research field of Division of Entomology, IARI, New Delhi. Brinjal is considered as one of the most common and popular vegetable crops in India and is being grown throughout the country except at higher altitudes. Damage caused to brinjal crop by insect pests mainly reduces the market value of produce and sometimes may lead to failure of entire crop. Farmers rely mostly on application of various insecticides to protect the crop from the insect pests which leads to contamination of harvested produce with harmful and toxic pesticide residues which leads to the destruction of beneficial fauna. As a part of sustainable pest management there is a need to look at the design of the agroecosystem and consider what ecological concepts can be applied to the arrive at better management of pests and conservation of their natural enemies. So, the present investigation was carried out with more emphasis on habitat management, natural control of pests and conservation of natural enemies in brinjal ecosystem.
A field experiment was laid out in randomized block design to identify the influence of different intercrops and border crops on incidence of insect pests and abundance of their natural enemies. Mean insect numbers and abundance of natural enemy counts were determined at regular intervals. The diversity created by introduction of intercrops (marigold, amaranthus, cluster bean and sunflower) and border crops (maize and French bean) in various combinations of planting, significantly reduced the insect pest population and enhanced the abundance of natural enemies compared to monocrop of brinjal. All the cropping systems proved to be superior over the monocrop of brinjal in significantly reducing the populations of
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Leucinodes orbonalis, Amrasca biguttula biguttula and Bemisia tabaci. Intercropping system of brinjal with amaranthus as intercrop and maize as border crop recorded lowest incidence of L. orbonalis. Intercropping system with marigold as intercop and maize as border crop with brinjal as maincrop recorded the lowest infestation and reduced the population of Amrasca biguttula biguttula significantly over the sole crop. In the case of Bemisia tabaci, the lowest incidence was observed in brinjal crop with marigold as intercrop and french bean as border crop. The abundance of coccinellids was the highest in the brinjal crop intercropped with amaranthus and bordered by maize while the abundance of spiders was the highest in brinjal crop intercropped with marigold and bordered by french bean.
Observations on population of insect pests and their natural enemies were recorded at weekly intervals during the experiment on seasonal abundance of insect pests and their natural enemies like coccinellids and spiders in relation to changing weather parameters. Peak infestation of Leucinodes orbonalis occurred from 36th to 40th standard week while that of Amrasca biguttula biguttula and Bemisia tabaci occurred during 31st standard week and 38th standard week respectively. Peak populations of coccinellids occurred during 35th to 38th standard week while the peak population of spiders occurred during 34th standard week. Correlation studies indicated that abiotic factors like maximum temperatures, minimum temperatures, evening relative, rainfall, windspeed were the factors that mainly influenced the incidence of L. orbonalis; sunshine hours, minimum temperature, average wind speed and evening relative humidity significantly influenced the incidence of A. biguttula biguttula and the factors like sunshine hours, maximum temperature, morning relative humidity and evening relative humidity influenced the incidence of Bemisia tabaci. Coccinellid population was influenced by maximum temperature, wind speed, minimum temperature and evening relative humidity.
Spatial distribution parameters were found out and sequential sampling plans were developed for the three major pests facilitating better management decisions. For
L. orbonalis, the lower and upper decision line values after first sample unit were 0 and 12 percent infestation, respectively. For A. biguttula biguttula, the lower and upper decision line values after first sample unit were 1 and 9 number of cumulative leafhopper population, respectively. In the case of Bemisia tabaci, the lower and upper decision line values after first sample unit were 1 and 9 number of cumulative whitefly
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population, respectively. A minimum of three samples are expected to be taken before arriving at management decision. Sequential sampling plan would be useful in helping the farmers take accurate management decisions besides reducing their efforts, time and money thereby provides a better benefit cost ratio to growers.
Keywords: Crop Diversification in brinjal, Sustainable Management of Leucinodes orbonalis, Sustainable Management of major insect pests of brinjal, Sequential sampling plan for Leucinodes orbonalis, Seasonal incidence of major insect pests of brinjal, Sequential sampling plan for major insect pests of brinjal.
Description
T-10268
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