Trapping the Stable Fly by Using CO2 or CO as Attractants1

Malaise traps baited with CO2 or CO (both gases released at 3 liter per minute) and experimental control traps without any gas released were operated on a dairy ranch on 3 consecutive days. The experimental design, a double 3×3 Latin square, was balanced for both site and day effects. The traps at which CO2 was released caught about 3 times as many stable flies, Stomoxys calcitrans (L..), as did either the traps at which CO was released or the experimental control traps. These results are significant at the 0.005 level. There were no significant differences between the numbers of flies caught at the CO-baited trap and the numbers caught in the experimental control traps.