Temperature - Often the most important factor that governs insect development is temperature.

Mono- culture of Crops - Generally crop monoculture is more vulnerable to pest because there is less resistance and fewer natural enemies of the specific pests attacking the crop.

Introduction of Plants to new locations - Some pest problems occurs when crops are introduced into new biological communities.

Weather pattern - For flying insects such as locusts, the prevailing winds are important in determining where they will fly and whether they will survive.

Migration- Movement to a different area with more favorable conditions allows some pests species to escape control and increase in number.