(a) Distinguish between a field pest and a storage pest. [2 marks] (b) Give two reasons for early harvesting of maize from the field. [2 marks] (c) Describe...

(a) Field pest versus storage pest

A field pest is a pest that attacks and damages crops while they are still growing on the farm (in the field), for example the grasshopper and stem borer, whereas a storage pest is a pest that attacks and damages harvested farm produce kept in storage, for example the weevil and rat.

(b) Two reasons for early harvesting of maize

1. To avoid damage and losses caused by field pests, birds and rodents.
2. To reduce spoilage from rain, mould and rotting and to prevent lodging of over-mature plants (early harvest of green maize also fetches a good market price).

(c) Methods of crop improvement

(i) Introduction: this is bringing in crop varieties or planting materials from another area or country where they have desirable qualities, and growing them in a new environment. If they perform well, they are multiplied and released to farmers.

(ii) Cross breeding (hybridisation): this is the deliberate mating (crossing) of two crop plants of different varieties, each having desirable qualities, so that the offspring combines the good qualities of both parents, for example high yield with disease resistance.

(d) Six factors to consider in selecting a crop variety

1. High yielding ability.
2. Resistance to pests and diseases.
3. Suitability to the local soil and climate.
4. Early maturing ability.
5. Market demand and consumer preference.
6. Tolerance to drought and adverse conditions (good storage/keeping quality is also acceptable).