<P> Another early technique involved complete removal of brush and woody vegetation from an area . Tsetse tend to rest on the trunks of trees so removing woody vegetation made the area inhospitable to the flies . However, the technique was not widely used and has been abandoned . Preventing regrowth of woody vegetation requires continuous clearing efforts, which is only practical where large human populations are present . The clearing of woody vegetation has come to be seen as an environmental problem more than a benefit . </P> <P> Pesticides have been used to control tsetse starting initially during the early part of the twentieth century in localized efforts using the inorganic metal - based pesticides, expanding after the Second World War into massive aerial - and ground - based campaigns with organochlorine pesticides such as DDT applied as aerosol sprays at Ultra-Low Volume rates . Later, more targeted techniques used pour - on formulations in which advanced organic pesticides were applied directly to the backs of cattle . </P> <P> Tsetse populations can be monitored and effectively controlled using simple, inexpensive traps . These often use electric blue cloth, since this color attracts the flies . Early traps mimicked the form of cattle but this seems unnecessary and recent traps are simple sheets or have a biconical form . The traps can kill by channeling the flies into a collection chamber or by exposing the flies to insecticide sprayed on the cloth . Tsetse are also attracted to large dark colors like the hides of cow and buffaloes . Some scientists put forward the idea that zebra have stripes, not as a camouflage in long grass, but because the black and white bands tend to confuse tsetse and prevent attack . </P> <P> The use of chemicals as attractants to lure tsetse to the traps has been studied extensively in the late 20th century, but this has mostly been of interest to scientists rather than as an economically reasonable solution . Attractants studied have been those tsetse might use to find food, like carbon dioxide, octenol, and acetone--which are given off in animals' breath and distributed downwind in an odor plume . Synthetic versions of these chemicals can create artificial odor plumes . A cheaper approach is to place cattle urine in a half gourd near the trap . For large trapping efforts, additional traps are generally cheaper than expensive artificial attractants . </P>

Diagram of life cycle of a tsetse fly