Adult biting midge response to trap type, carbon dioxide, and an octenol-phenol mixture in northwestern Florida.

The efficacy of Centers for Disease Control, ABC PRO, and counterflow geometry (CFG) mosquito suction traps to sample populations of adult Culicoides was investigated in northwestern Florida. These traps were baited either with a 4:1:8 mixture of octenol, 3-n-propylphenol, and 4-methylphenol alone or in combination with carbon dioxide (CO2). Control traps were operated without the octenol-phenol mixture or CO2. Four species, in order of descending abundance, were collected in all traps regardless of treatment: Culicoides mississippiensis, C. barbosai, C melleus, and C. furens. Midge abundance from traps baited with octenolphenol alone was not significantly different, regardless of species, when compared with traps without the mixture. However, when CO2 or CO2 plus the mixture was used, trap collections of C. mississippiensis and C. barbosai significantly increased, with the latter mixture exhibiting a synergistic effect on trap catch for both species. When this combination was used, the ABC PRO trap collected significantly more C. mississippiensis, whereas the CFG trap caught significantly more C. barbosai compared with all traps powered with 6-V batteries (P < 0.05). The effects of CO2 plus the octenol-phenol mixture on C. melleus collections appeared to be additive only for ABC PRO and CFG traps. Populations of C. furens were sporadic and too low (<0.5% of total collection) to determine any statistically meaningful differences. On the average, CFG traps powered with 12-V batteries only increased midge collection 1.2 times compared with similar traps powered by 6-V batteries. This increase was not significantly different (P > 0.05).