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sur le développement des zones arides et semi-arides

Titre : Impact of groundnut crop based intercropping system on insect pests and their natural enemies

Auteur : Girija T.

Université de soutenance : University of Agricultural Sciences, Dharwad

Grade : Master of Science in Agricultural Entomology 2014

Résumé
Impact of groundnut crop based intercropping system on insect pests and their natural enemies were studied during Kharif 2013 at Main Agricultural Research Station, Dharawd. The intercrops such as bajra, sorghum, cowpea, lucerne, foxtail millet, chilli and sunflower were sown at 3:1(groundnut : intercrop) ratio to study their impact on the population of insect pests and their natural enemies on groundnut. The lower incidence of insects (Spodoptera, leafhopper, thrips) were recorded in groundnut + foxtail millet, followed by groundnut + bajra and groundnut + sorghum intercropping. Groundnut+ sorghum intercropping recorded least Percent Disease Index (PDI) of both early and late leaf spot disease, which was followed by groundnut +foxtail millet and groundnut+bajra intercropping. The highest population of coccinellids and predatory spiders were recorded in groundnut+foxtail millet followed by groundnut+bajra and groundnut+sorghum intercropping. Highest percent parasitisation (22.33%) due to Apanatlees. ssp and Campolities chlorideae and higher natural incidence of N. rileyi (14.05%) was found at 60 days after sowing (DAS). Highest percent parasitisation of Spodoptera larvae was recorded in groundnut + lucerne, followed by groundnut + foxtail millet, groundnut + bajra and groundnut + sorghum intercropping. Where as highest incidence of N. rileyi was recorded in groundnut + cowpea intercropping and was at par with groundnut + lucerne intercropping. The highest Spodoptera larval mortality was recorded at 10 days after N. rileyi spray in groundnut + cowpea intercropping was at par with groundnut + lucerne intercropping. Groundnut + foxtail millet intercropping yielded maximum (27.33q/ha) followed by sole groundnut crop (26.20q/ha), groundnut + bajra (26.00q/ha) and groundnut + sorghum (24.33q/ha). The present result indicates that some of the crop combinations will enhance the epizootics of N.rileyi by providing suitable microenvironment for their higher activity. The highest economic return was recorded in groundnut + foxtail millet, followed by groundnut + bajra and groundnut + sorghum.

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