Effectiveness of pheromone traps in managing fruit flies (Diptera: Tephritidae) on mango (Mangifera indica) and cucurbits in Kenya

Horticulture contributes significantly to nutrition, food security and income in Kenya. Fruit flies (Diptera: Tephritidae) threaten fruits and vegetables production globally and are among the major pests of mangoes and cucurbits causing up to 80% losses if not controlled. Female fruit damage fruits by causing oviposition punctures and larvae feeding inside fruits. Further economic loss occurs due to quarantine restrictions imposed to limit pest spread through trade. For control of these pests, farmers in Kenya rely on chemical pesticides. However, pesticides are ineffective because the destructive stage of the pests are embedded deep inside the fruit. There is therefore need to identify alternative, environment friendly pest control methods that are also affordable to small scale farmers. This study determined the effectiveness of pheromone traps in the management of fruit flies. Four types of pheromone traps (Bactrolure (R), Cuelure (R), Ceralure (R), Torula track lure (R)) were installed in 40 mango and 15 cucurbit farms in Kiharu; and in 36 mango and 5 cucurbit farms in Kirinyaga West subcounties in central Kenya. Data on the abundance of fruit flies were collected fortnightly. To determine host preference mature cucurbits were incubated and emerging fruit flies monitored. Cumulatively, 49,545 and 5,582 fruit flies were recovered in all traps. Eleven fruit fly species were identified including Bactrocera dorsalis, Zeugodacus curcubitae, Ceratitis capitata, Ceratitis cosyra and Ceratitis fasciventris, Dacus bivitattus, Dacus ciliatus, Dacus punctatifrons, D. vertebratus, D. frontalis and T. nigeriimum. B. dorsalis was most abundant on mango while Z. curcubitae was most abundant on cucurbits. Bactrolure (R) (91%) was the most effective lure on mango and Cuelure (R) (70.6%) on cucurbits. There was significant difference in pupae (P=0.04) and adult emergence (P=0.024) in Kiharu but not in Kirinyaga west. These results show that pheromone traps can effectively substitute pesticides in controlling fruit flies on mango and curcubits.