Tropicultura (Jan 1991)
Comparison of seed yielding performance of deltamethrin unprotected and protected plants of five cowpea cultivars at Foumbot, Cameroon
Abstract
Losses in seed yields due to damage by seed insect pests were studied on unsprayed and sprayed cowpea plants at Foumbot, located in the western highland savanna zone of Cameroon, in 1988 and 1989. Major pests recorded in the study site were Melanagromyza vignalis Spencer (Diptera : Agromyzidae), Marucatestulalis Geyer (Lepidoptera : Pyralidae), Cydia ptychora Meyrick (Lepidoptera : Tortricidae), Heliothis armigera Hubner (Lepidoptera : Noctuidae), Aphis craccivora Koch (Homoptera : Aphididae), Apion species (Coleoptera : Curculionidae), Coreid bugs (Heteroptera : Coreidae), and Bruchids (Coleoptera : Bruchidae). Yields of undamaged cowpea seeds from unsprayed and sprayed plants of local cultivars acquired from Badun, Melong, Foumbot and Befang were comparable with those from MA 2/1, an improved cultivar from the International Institute for Tropical Agriculture that has been released in Cameroon by the Institute for Agronomie Research. Melanagromyza, Maruca and Coreid bugs caused 70-80 % of seed damage on unsprayed and sprayed plants. Fortnightly spraying of plants with deltamethrin at 12.5g. a. i./ha, significantly reduced yield loss due to damage by Maruca sp., the overall loss in seed yields/ha and % loss of potential seed yield, in all five cowpea cultivars used in this study. However, deltamethrin appeared ineffective in reducing seed yield loss caused by Melanagromyza and Coreid bugs.
