Cotton - Red spider mites

Description

Mites (Tetranychus species) are tiny animals (almost microscopic) related to spiders, living in large colonies on the underside of leaves. They feed on the plant sap. The young stage is a pale straw color. The adults are bright red.

Damage

Mites are particularly a problem in hot, dry conditions and are reduced by rain. Colonies of two-spotted spider mites spread between the large veins of cotton leaves and turn the infested areas yellow. Gradually, the top surfaces of the leaves turn reddish. The feeding injury eventually causes the leaf to fall to the ground.

Life cycle

Adult females can lay 200 eggs placed singly on the lower surface of cotton leaves. These hatch after 3-7 days producing larvae which after 3-7 days become protonymphs - the first of two nymphal stages. These moult to deutonymphs and after a nymphal period of 6-10 days, the adult stage is reached. All the active stages feed together on the undersides of leaves between the main veins.