(a) Discuss seven economic importance of insect pests in crop production.
(b) Name two hosts of cotton stainer.
(c) List two soil-dwelling insect pests of crops and state five general control measures of insect pests of crops.
Explanation
(a) The economic importance of insect pests in crop production are: (i) They destroy crops on the field through their sucking, burrowing and defoliation activities. (ii) They reduce the yield and in some cases attack may lead to total crop failure. (iii) They reduce the nutritional value of crops either on the field or in store. (iv) Farmers’ profits are drastically reduced. (v) Cost of production is increased as large sum of money is expended on their control. (vi) They render ‘ vegetables and fruits unattractive and unmarketable. (vii) They reduce viability of stored seeds. (viii) They serve as , vectors of diseases. (ix) Some are agents of pollination. (x) The wounds they create while feeding on plants predispose plants to infection.
(b) Hosts of cotton stainer are: (i) kenaf (ii) Okra (iii) silk cotton tree
(c) Soil-living insect pest of crops include: (rickets and termites. Control measures of insect pest of crops are: i) use of resistant or tolerant varieties, (ii) crop rotation practices, (iii) spraying crops with insecticides. (iv) dusting seeds or planting materials with powdered insecticides e.g. aldrin dust (seed treatment), (v) tillage practices. (vi) timely planting of crops; (vii) timely harvesting, (viii) farm hygiene / sanitation.