Describe briefly the economic importance and the control measures of the following: (a) Stem borers of cereal, (b) Grain weevils of stored produce: (c) Cotton stainer; (d) Cassava mealy bug
Explanation
The economic importance and control measures of:
(a) Stem borers of cereals: Economic importance (i) Larvae bore into stems and destroy the tissues. (ii) They make the plant to be weak. (iii) They reduce the quality an quantity of yield.
Control measures: (i) Spray with insecticides, e.g. vetox 85, to kill the larvae. (ii) Practice crop, rotation. (iii) Destroy affected plants.
(b) Grain weevils of stored produce: Economic importance: (i) Boring adult,. and larvae feed on the grains. (ii) They cause 3-5% losses and reduce farmer's profit. (iii) They reduce the grain tc powder. (iv) They reduce the quality and market value of grains.
Control measures: (i) fumigate store with BHC powder or phostoxin tablets. (ii) Ensure adequate storage. (iii) Early harvesting prevent weevils attack.
(c) Cotton stainer: Economic importance (i) It causes leaf distortion. (ii) It transmits viral disease to cotton. (iii) It destroys the content of the boll. Control measures: (i) By handpicking of insects (ii) Spray with insecticides
(d) Cassava mealybug: Economic importance: (i) It causes the disturbance of cassava growth. (ii) Plant becomes stunted deformed and twisted.
Control measures: (i) Early planting. (ii) Treat cuttings with hot water at 520c for 10 minutes