Fig. 1.

Design for testing of contact irritancy (a) and spatial repellency (b) of Culicoides midges to deltamethrin. To test contact irritancy, an insecticide treated paper was inserted in one end of the tube (red dot); a control paper was inserted in the other end (green dot). 20 Culicoides midges were released in the red end with the slider between the two tubes open (a). After 10 min, the number of Culicoides in each part of the tube was recorded. For the spatial repellency test, insects are released in a darkened centre tube (green dot); an insecticide treated paper or blank paper was inserted in the end tubes (red dots) (b). After 10 min, the number of Culicoides in each part of the tube was recorded