Curling of leaf upwards and yellowing of terminal cotton shoots is characteristic symptom of presence of

Curling of the leaf upwards and yellowing of terminal cotton shoots is characteristic symptom of presence of Cotton Aphid (Aphis gossypii).
Cotton Leaf Curl Virus (CLCuV) illness is a major impediment to cotton production. It is caused by a genus of viruses known as Begomovirus, which is spread by whiteflies and poses a serious threat to the cotton crop.
The very characteristic symptoms include leaf curling, darkened veins, vein swelling, and enations that frequently develop into cup-shaped, leaf-like structures on the undersides of leaves.