Abundance and Diversity of Frugivorous Fruit Flies in Kandara, Murang’a County, Kenya

Abstract

Fruits and vegetables are important source of livelihood to farmers and major horticulture sub sector with high contribution to agricultural GDP in Kenya. This study was conducted to determine diversity and abundance of frugivorous fruit flies in Kandara sub county, Murang’a County in 2018, at a place where first area of low pest population was created in Kenya for Bactrocera dorsalis. Three sets of pheromone traps (Methyl-Eugenol, Cuelure and Trimedlure) were set in six trap stations within farmers’ orchards in four agro-ecological zones (LH1 (Lower Highland Zone), UM1 (Upper Mid-land Zone), UM2, and UM3). The trap catch data was collected fortnightly and data analyzed. Six fruit flies species namely; Bactrocera dorsalis, Ceratitis cosyra, Ceratitis capitata, Zeugodacus cucurbitae, Dacus bivittatus and Perilampsis sp were identified. Bactrocera dorsalis population was significantly (P<.001) different across the four agro-ecologies with lowest densities at LH1 and highest at UM3. Likewise, C. capitata recorded significant (P=0.042) difference densities across the agro-ecological zones, but no significant (P=0.386) difference was recorded for C. cosyra across the agro-ecological zones. Further, there was significant (P=0.012) difference in the number of Perilampsis sp across the agro-ecologies with the highest number recorded in UM1. Both Z. cucurbitae (P=0.061) and D. bivittatus (P=0.056) had low abundance across the agro-ecologies. The peak infestation period differed across the various fruit fly species, whereby B. dorsalis peaked in May, C. capitata in February and C. cosyra in January. The study shows that abundance for the fruit flies is probably related to their preferred hostplant and the weather patterns. We recommend continuous monitoring and intensifying trapping activities during peak periods in order to control the pest and protect fruits from damage. Farmers should be trained on the use of pheromone traps to reduce over-reliance on pesticides. Key words: Agro-ecologies, Bactrocera dorsalis, Ceratitis sp, fruit fly density, Pheromone