Very small insects with a size of a few millimeters, which are subordinate to the large group of plant lice (such as aphids and cicadas ) represent. In contrast to the males, the mostly wingless females attack leaves, fruits and bark of various plants as well vines, They occur mainly in warmer areas, in Central Europe especially the crested lice (Coccidae). They have piercing, sucking mouthparts with piercing bristles, which are used to pierce vegetable tissue for food intake. This leads to growth disorders, discoloration, wilting phenomena and even death. The animals also excrete this as excrement honeydew that is often populated by black soot fungi. The insects develop from the egg to up to five larval stages and a nymph to the sex animals, which then have the typical protective cover (shield). The species Planococcus and Pseudococcus also transmit virus, those who Leaf roll disease and cause cork disease (see under Rugose Wood Complex ).
The "Rebenschildlaus" (Parthenolecanium corni), which is also known as "Zwetschgen-Napfschildlaus" or "Ordinary Napfschildlaus", is of particular importance for viticulture. This affects plums, apricots, gooseberries and currants and also vines, Wintering occurs as a second larval stage on branches and shoots and also in the soil. With the expulsion the larvae migrate to the young shoots, where they develop into six-millimeter females towards the end of May. At the same time, the back thickens and solidifies into a high-arched, brownish and lacquered shield, under which there are up to 3,000 eggs (hence the name). The larvae hatch towards the end of June, migrate to the underside of the leaves and suck on them. There is usually only one generation. The species "woolly vine insect" (because of salmon red eggs also "blood louse") also affects the roots. There are also other species like that Rebenschmierlaus, Are natural enemies lacewings. ladybug and parasitic wasps, some of which are deliberately exploited. See also under Vine enemies,