Farm crops insect pests

Insect pests of farm crops are difficult to control when necessary activities such as tillage weeding irrigation and harvesting increase the pest population and decrease the numbers of its natural enemies. 

Natural products can occasionally be used for crop protection purposes in their own right. The natural pyrethrins, such as pyrethrin I (Figure 1), are insecticidal compounds produced in the flowers of the plant Chrysanthemum cinerariaefoUum, and are well-known examples. They are used to control insect pests on various crops and on farm and domestic animals, but their use outdoors is limited by their poor stability in sunlight. Incidentally, this example is highly appropriate for this conference held at the University of Nairobi, because much of the world s supply of pyrethrins is produced in Kenya. 

As gardeners, we are most likely to notice the pest insects in our yards and gardens. However, entomologists estimate that more than 90 percent of all insects are beneficial. Wild and domestic bees and also some flies and moths pollinate crops this is essential for the development of many fruits, vegetables, and crops grown for seed. Honeybees are also farmed to provide honey, and silkworms are farmed to yield silk from their cocoons for fine clothing. 

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