Spider mites are small arthropods that feed on the underside of cotton leaves using their piercing mouthparts to suck out the contents of leaf cells. This removes chlorophyll from the leaves and causes a reduction in photosynthesis. There are three types of spider mites twospotted spider mites (the main pest species; pale green with two distinct dark green spots on either side); bean spider mite (red in colour) and strawberry spider mite (pale green with three dark green spots on either side). They all cause different amounts of damage, so correct identification is important to help you make the correct control decision.