Abstract

Land pressure and increased costs of of insect pests’ management in sole cotton and cowpea crops limit production of cotton and cowpea in Malawi. In this regard, experiments were conducted at Bunda College Crop Science Student Research Farm and on farmers’ fields in Rivirivi and Mpingu Extension Planning Areas (EPAs) in Balaka and Lilongwe districts respectively during 2011/2012 season to assess performance of different intercropping systems and effectiveness of foliar pesticides applied on cotton on incidences of intercropped cowpea pests. The experiment at Bunda College had 10 treatments: sole sprayed cotton, sole unsprayed cotton, sole sprayed cowpea, sole unsprayed cowpea, 1:1 strip (same time) intercropping, 1:1 strip (delayed) intercropping, 2:2 strip (same time) intercropping, 2:2 strip (delayed) intercropping, within row intercropping (Sudan) and within row intercropping (IT82E-16). Six treatments were evaluated on farm namely sole sprayed cotton, sole sprayed cowpea, 1:1 strip (same time) intercropping, 2:2 strip (delayed) intercropping, within row intercropping (Sudan) and within row intercropping (IT82E-16). Experiments at Bunda and in Mpingu EPA were laid out as Randomized Complete Block Design while at Rivirivi EPA farmers were taken as replicates. Data were subjected to analysis of variance in Genstat statistical software and significant means were separated using Least Significant Difference (LSD). Intercropping productivity was assessed using Land Equivalent Ratio, Area Time Equivalent Ratio and Crop Performance Ratio. Bunda results indicate that cotton and cowpea growth and yield parameters were significantly influenced by intercropping systems (<0.001). The 1:1 and 2:2 strip cropping gave seed cotton yields that were similar to sole sprayed cotton at all sites. Lowest seed cotton yields were registered from within row intercropping treatments at all sites. At Bunda, sole sprayed cowpea gave highest cowpea grain yields followed by 1:1 strip (delayed). In Rivirivi and Mpingu EPAs, strip 2:2 (same time) and within row intercropping (Sudan) gave highest grain yields respectively. Delaying cowpea sowing reduced cowpea grain yields by 19%, number of pods per plant by 18% and seed size by 10% at Bunda. All biological indices had values greater than 1.0 indicating more productivity of intercropping over sole cropping. Pesticides applied on cotton to control cotton pests significantly reduced pests populations of intercropped cowpea. Delaying cowpea planting significantly (P<0.001) reduced Maruca testulalis and Anoplocnemis curvipes but increased thrips damage at Bunda. Simultaneous sowing of cotton and cowpea is recommended for increased production of the two crops. Growers are encouraged to use either 1:1 or 2:2 strip cropping with the choice dependent of the objectives of the grower.

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School	: Bunda College of Agriculture
Issued Date	: 2014

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