Agricultural system has undergone several changes in the past several decades. In order of priority to meet food needs and security, the agricultural lands have to be greatly intensified. Such intensification will consequently cause increasing pest issues thereby spreading of various diseases. Pests are those destructive or harmful living organism that causes damage to crops and hamper their growth. The damage caused by them can be very much devastating over a wide area and usually results in defoliation of the crop. The pests and their diseases affect food crops by causing significant losses to farmers and thereby threaten food security. Crop plant pests spread diseases mainly in three principal means such as environmental factors, through trading or other human migrating activities, and insects. Among all the pests, insects are the most common and cause maximum damage to the plant crop. Most of these pests spread several bacterial, fungal and certain other viral diseases to the crop plants. The two most widespread and vital methods of controlling pest and their ill effects are through chemical and biological processes, the principles behind each of these method has major differences.