Mealybugs belong to the scales family. However, they have no armours like other scales, the adult animals are powdered with a white waxy secrete. The edges of the body are covered with thorns and wax threads, occasionally very long, especially at the hind body. They usually lay eggs, but in favourable conditions some species are mainly viviparous.
In Central Europe two species are relevant on orchids.
Planococcus citri Risso:
3-5 mm long, oval, dark yellow to yellowish-brown, powdered with wax excrements, short and thick filaments on body edges. They live very polyphagous, and leave marked honeydew excrements. The yellow eggs are placed in mealy masses on the hind body, optimal temperatures around 24°C.
Longtailed mealybug ( Pseudococcus longispinus Targ.-Tozz. [= Pseudococcus adonidum L.]):
3-5 mm long, reddish to orange, oval mealybug. Characteristic is the length of the tail threads (filaments) that are about as long as its body. Extremely marked honeydew excrements.