Cowpea always faces damage caused by insect larvae. This damage can be eliminated or decreased using heat from the sun at about 50°C to kill the insects.
To kill the insects, spread materials like dry leaves and stumps on the floor to avoid heat loss to the ground and cover it with a black sheet to capture heat from the sun. Spread about 5 kg of cowpea per square metre on the black sheet leaving some space between the seeds and cover them with a transparent sheet, then fold the sides of the and secure them to the floor using stones.
Leave the seeds in the sun for about 2 hours. This kills the insects incase there is any and after, store the seeds in an air tight container. These seeds can be consumed at any time without fumigants.