Uganda, April 20 -- Farming has been carried out for thousands of years and mankind has all along been struggling to overcome pests. Any organism that is destructive to crops may be described as a pest. They are a nuisance to farmers because they destroy what the farmer is struggling to grow for food or for cash.

The damage caused may be direct if they eat or destroy the crop or indirect if they cause a disease that eventually kills or weakens the crop.

Pests are mainly insects such as nematodes, mites, weevils and worms but birds and rodents are also referred to as pests. Today pests include those human beings who visit other people's farms to steal crops.

The Food and Agriculture Organisation (FAO) estimates that pathogens, wild anim...