Fungicides are generally expensive to apply. The use of chemicals for insect control dates back to 1000BC when Homer referred to using sulfer to divert pests. One of the first synethic insecticides was Lethane marketed in 1932. Insectides are easy to apply to fields and cost effective. Their use creates a more affordable and more visually appealing crop.
Consumers desire healthy foods, but they buy with their eyes.
Often the best looking crop is the one best protected with insectides. An alternative method of pest control is introducing predatory insects. The predatory insects eat the pest insects. This method can be effective, but it is very time sensitive. If the predatory insects are not released during the currect stage of pest developement, then they fail to protect the crop.