Abstract:
The most effective odour attractant for G. brevipalpis Newstead, namely a combination of octenol released at c. 9,1 mg/h, 4-methyl phenol released at c. 15,5 mg/h and acetone released at c. 350 mg/h, when used together with the smallest recommended colour target (as determined in previous studies), namely a 1,75 m wide x 1 m high black/pthalogen-blue/black target, was evaluated for the control of G. brevipalpis and G. austeni Newstead. This combination increased the catches of G. brevipalpis by 3,5 fold when compared to the number of those caught on a 1,5 m wide x 1 m high black target baited with a synthetic ox-odour as was used in a trial to control this species in the Hluhluwe-Umfolozi Game Reserve in 1992. There was an indication that odour (olfaction) plays a far more important role in attracting G. brevipalpis than does colour (vision). For G. austeni visual attraction appears to play the major role as the odours used were relatively unattractive to them. The odour-baited target should, however, attract G. austeni in sufficient numbers (visually) to achieve control to the fly.
