Scanning electron micrograph of a glasshouse mealy bug, Planococcus citri, on the underside of a leaf. The picture shows an immature nymph, about 1mm long. Its body is covered with a wax layer in the form of helical springs (white). The covering is delicate; short broken lengthsare visible between intact clumps on its body, and also as small pieces on the leaf surface. The insect is facing to the right; two claws are visible on either side of the front of its body, and to its rear, two short caudal processes. P. citri and other pest species of mealy bug are of tropical origin and do not survive outside in cool climates. They feed on a variety of houseplants by sucking sap; and produce honeydew, that may attract aphids or ants.The wax coating renders chemical treatment difficult; some measure of control is possible by physical removal by using a fine brush dipped in methylated spirit.