Describe briefly the economic importance and the control measures of the following: (a) Stem borers of cereal, (b) Grain weevils of stored produce: (c) Cott...

Answer Details

(a) Stem borers of cereal: Stem borers are a group of insects that cause significant economic losses to cereal crops such as maize, rice, and sorghum. They bore into the stems of these plants and feed on the vascular tissues, causing stunting, wilting, and even death of the plants. This can result in reduced yields and quality of the affected crops. Control measures include the use of resistant varieties, cultural practices such as crop rotation, and the application of insecticides.

(b) Grain weevils of stored produce: Grain weevils are a common pest of stored grains such as maize, rice, and wheat. They feed on the kernels of these grains, reducing their quality and making them unsuitable for consumption or sale. Control measures include proper storage techniques such as drying and fumigation, as well as the use of insecticides.

(c) Cotton stainer: Cotton stainers are insects that feed on cotton plants and stain the fibers with a reddish-brown color, reducing the value and marketability of the cotton. They also reduce yields by damaging the developing bolls. Control measures include the use of resistant varieties, cultural practices such as crop rotation and weed control, and the application of insecticides.

(d) Cassava mealy bug: Cassava mealy bug is a serious pest of cassava, a staple crop in many African countries. It feeds on the leaves and stems of cassava, causing stunting and reduced yields. Control measures include the use of resistant varieties, cultural practices such as intercropping with legumes, and the application of insecticides. In addition, the introduction of natural enemies such as parasitic wasps has been successful in controlling the pest in some areas.