Question 6

This question was not popular with the candidates and their performance was woeful. In question 6(a), many candidates were unable to describe the nature of damage caused by bean beetle, grasshopper and yam beetle on crops. Also, in question 6(b), most candidates could not state the effects of the damage caused by each of the  insect-pests on crops .
The expected answers include:
Nature of damage caused by insect - pests:
(i)  Bean beetle
-       1. The larva bores into the beans where it feeds and  Pupates

1. The larva destroys the cotyledons
2.  Damages the embryo

(ii) Grasshoppers

1. Causes defoliation of plants
2.  Destroys/eats the bark and the growing apex of plants

(iii) Yam beetle:

1. The larva and adult bore and feed inside yam tubers
2. Creates holes on yam tubers

Effects of the damage caused by insect pests:
Bean beetle

1. Quality of the stored beans is reduced/Market  value is reduced
2. Shelf life of the beans is reduced
3. Palatability of the beans is reduced
4. Viability of stored beans is reduced
5. Quantity of stored beans is reduced

Grasshopper:

1. The wounds created predispose the tissues to secondary infection
2.  The photosynthetic area of the leaves is reduced·
3.  Reduces the market value/quality of  leafy vegetables
4.  Yield is reduced
5. Growth is reduced.

Yam beetle:

1. The holes created on yam tubers expose them to .secondary infection
2. Reduces the quantity of tubers                   
3. Reduces the market value/quality of yam tubers
4. Shelf life is reduced.
5. Palatibility is reduced

However, in question 6(c), most candidate  were able to state the side effects of chemical control of pests on the environment.