Evaluation for attractiveness of four chemicals to the biting midge, Forcipomyia taiwana (Diptera: Ceratopogonidae).

Four chemicals (1-octen-3-ol [octenol], lactic acid, acetone, and carbon dioxide) were evaluated for their attractiveness to the biting midge, Forcipomyia taiwana. The attractiveness was based on the number of adult biting midges attracted to each chemical. Results showed that the attractiveness of each chemical changed with different release rates. The optimal attractive release rates for octenol, lactic acid, and acetone fell in the range 0.5-0.9 mg/h, 0.2-1.4 mg/h, and 3.4-10.9 mg/h, respectively. The most attractive release rates were 0.7 mg/h, 0.2 mg/h, and 4.8 mg/h, respectively. Octenol, lactic acid, and acetone were evaluated simultaneously but in separate traps, at the best attractive release rate mentioned above to compare their attractiveness efficacies. Octenol was the most attractive to F. taiwana, followed by lactic acid and acetone; however, there was no significant difference between the mean numbers of adults attracted by the 3 attractants. Carbon dioxide (CO2) with release rates of 100, 250, and 500 ml/min showed no differences in attractiveness. When combinations of CO2, octenol, and blue light (BL, lamda max = 405 nm) were evaluated, the number of adults attracted by the treatment of CO2 + BL was the lowest, and that of the CO2 + octenol + BL was the highest.