This group includes a large number of different species. Most of them have tube-like mouthparts used to pierce the plant and remove sap. Some inject saliva during the feeding process, which causes a deterioration of the plant tissue. Some feeding damage causes a malformation of plant parts. Others, such as aphids, excrete a sticky material called honeydew. Sooty mold often grows on this honeydew on the leaf surface, reducing the penetration of sunlight and, therefore, photosynthesis.
These insects have only three stages in the life cycle: egg, nymph and adult. There is no resting stage like the pupa. The nymphal stage sheds the skin several times, gradually getting larger until it changes into the adult. Both nymph and adult stages can damage the plant.
Many sucking insects can be controlled by the use of systemic insecticides. All can be controlled by recommended foliar-applied insecticides. Some of these pests feed primarily on the undersurface of leaves, making good coverage essential for effective control.
Some important pests that fit into the sucking insect group are aphids (plant lice), thrips, stinkbugs, whiteflies, plant bugs, leafhoppers and spider mites (not an insect).