DIVERSITY AND ABUNDANCE OF INSECT POLLINATORS AND THEIR EFFECT ON YIELD AND QUALITY OF COWPEA AND CUCUMBER IN MAKUENI, KENYA

Abstract

Inadequate pollination is one of the key limitations in crop yield and quality of key vegetable crops. Cowpea and cucumber are crops of economic importance in Makueni county-Kenya. A study of insect pollinators and their role on yield and quality of cowpea and cucumber was conducted during the short and long rain seasons in 2017 and 2018 respectively in Kikome, Makueni- Eastern Kenya. The experiment was laid out as a split plot in a randomized complete block design with three replications and involved bagged and unbagged treatments. Eight insect pollinator species (4 orders, 7 families) were recorded on cowpea flowers and 10 species (4 orders, 8 families) on cucumber flowers. In cowpea, the abundance of Hymenoptera was maximum (5 species) while the orders Coleoptera, Lepidoptera and Hemiptera were each represented by a single insect pollinator. Apis mellifera was the most abundant of all insect pollinators observed (96.58% and 52.44% during the short and long rain seasons respectively). The peak foraging activity of Apis mellifera was recorded between 8:00am to 9:00am and 7:00am-8:00am during the short and long rain seasons respectively. In cucumber, abundance of Hemiptera was maximum (5 species) followed by Hymenoptera (3 species) and Lepidoptera (2 species), while Coleoptera and Diptera were each represented by a single species. Apis mellifera was the most abundant of all insect pollinators observed (96.50% and 64. 29% during the short and long rain seasons respectively). The peak foraging activity of Apis mellifera was recorded between 8:00am to 9:00am and 9:00am -10:00am during the short and long rain seasons respectively. Unbagged treatments had significantly higher yield and germination percentage than the bagged treatments in both test crops (p<0.05). This study highlights the importance of insect pollination as an additional input in enhancing the yield and quality of cowpea and cucumber in Makueni-Eastern Kenya.