Theory question 105
Crop PestsDescribe 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
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(a) Stem borers: larvae tunnel in maize/sorghum/rice stems causing dead heart, lodging and lower yield; control – early planting, crop rotation, burning stubble, systemic/granular insecticides, resistant varieties
(b) Grain weevils: bore into stored grain, reduce weight and quality, cause heating and mould; control – dry grain well, clean stores, fumigation, storage insecticides (e.g. Actellic), airtight storage
(c) Cotton stainer: sucks developing seeds, stains lint, spreads boll rot; control – spraying insecticides, removing alternative host plants, hand picking, crop rotation
(d) Cassava mealybug: sucks sap, causes stunting, bunchy top and leaf loss, lowering tuber yield; control – biological control with parasitic wasp (Epidinocarsis lopezi), resistant varieties, clean planting material, insecticides
For each pest give the damage (economic importance) and at least two control methods.