People harvesting cowpeas in Tahoua, NigerJake Lyell/AlamyHuman urine that has been matured in the sun for at least one month appears to be both a fertiliser and an effective pesticide. The findings could be particularly helpful for combatting insect infestations in West Africa, where soil quality is typically low and traditional pesticides are expensive.Farmers taking part in a previous trial in Niger to investigate the use of urine as a fertiliser discovered that it was also having a pesticide effect, as plants treated with it had less pest damage than those that werent.