Causes for outbreak of pests

Causes for outbreak of pests
    1. Destruction of forest or bringing forest area under cultivation – shift to cultivated crops. (eg) Hairy caterpillar attack on crop plants near forest areas.
    2. Indiscriminate use of pesticides leads to destruction of natural enemies, pest resistance,pest resurgence. (eg) Synthetic pyrethroids on sucking pests.
    3. Intensive cultivation (eg) Diamond backmoth on cauliflower in plains and extensive cultivation (eg) monoculture of rice leads to out break of leaf folder.
    4. Introduction of new crops (eg) gurkin crop leads more fruit fly incidence and improved strains (eg) many high yielding varieties are more susceptible to insects.
    5. Improved agronomic practices (eg) higher ‘N’, close spacing, weed control etc. improved crop growth and reduced competition for food to the insects.
    6. Introduction of new pest in a new area (eg) apple woolly aphid.
    7. Accidental introduction of foreign pests (eg) potato tuber moth, cyst nematode of potato, spiraling white fly on guava.
    8. Large scale storage of food grains (eg) outbreak of stored product pests, rat problem.

Last modified: Wednesday, 25 January 2012, 9:11 PM