Discuss briefly the side effect, preventive and control measures of diseases and pests of crops, under the following heading (a) chemical control (b) biological control (c) cultural method of control

Chemical control:
-The use of chemicals may destroy some useful insects and other organisms
-Nearly all the chemicals used to control pests of crops are toxic to man and farm animals
-Some chemicals can cause water pollution
-Pests and disease may develop resistance to chemicals

Biological control:
-The new organisms introduced may start to attack crops which were before free from attack
-The new organisms introduced may also feed on some beneficial insects

Cultural method of control:
-Bush burning can spread fire to other farms
-The use of fire to control pests can also result in the killing of other beneficial organisms
-Use of fire can also result in the loss of organic matter in the soil
-The use of fire can also destroy the soil structure