[Harmful symptoms]
Nymphs and adults suck sap on the back of the leaves, and at the same time secrete white wax filaments and cotton flocculent ash, cover the back of the leaves, discharge honeydew, pollute the leaf surface, induce soot disease, resulting in weak tree potential and reduced flowers and fruits.
[Prevention and control methods]
Chemical control: (1) In winter, 99% mineral oil 100-150 times liquid, pine resin mixture 8-10 times liquid, stone sulfur compound 0.8-1 baume degree. (2) In the spring of the following year, the adult insects are in full bloom, and 5% high-efficiency cypermethrin is sprayed with 1500 times + 30% thiamethoxenide 1500 times for control.
[Morphological characteristics]
Adult insects are pale brownish yellow, body length 0.5-0.6 mm, wingspan 1.5-1.8 mm, anterior and posterior wings pink white, forewing outer edge arc, the middle of the leading edge has 3 lilac spots diagonally to the middle of the posterior margin, the apex has a lilac spot pattern, obliquely inward, to the open chamber and folded to the hip angle, 5 spots are faintly visible, there is also a lilac spot at the base of the wing, compound eye black, 1 pair of antennae, 4 segments of the female, 3 segments of the male, pink white. The eggs are small, about 0.3 mm, long ovate, with one end fixed by the stalk, and dark yellow-green before hatching. When mature, the nymph is about 0.8 mm long and about 0.6 mm wide, short oval, dark yellow-green, and covered with a thin white wax powder. The pupa is about 0.6 mm long, with a slight midside bulge on the back and a pale dark green.
[Life Habits]
It prefers to live in shaded, unventilated orchards, and also likes to work with the leaves of black bettorius or citrus whitefly. At any time in the field, three insect states can be seen at the same time, the generations overlap, the number of one year is unknown, it can be seen that adults, nymphs and eggs overwinter at the same time, mainly eggs overwinter. Adults have weak flight ability, secrete white flocculent waxy substances on the tail, and form a circular or irregular "nest" around the insect body, with a dense inner circumference and an outer evacuation, in which the adult nest lives. The eggs are scattered on the back of the leaves around the adult rest, oval, milky white, and fixed with an egg stalk. Nymphs are scattered, occasionally gregarious, after fixed feeding, the worm body secretes a very fine glassy wax filament, the wax filament is slightly curved, the length is not equal or slightly curved, radially intertwined around the nymph body, like a bird's nest, the nymph is fixed in the center, and the nymph develops, pupates and feathers into adults. After the citrus spring shoots turn green, the adults move to the back of the new spring leaves to feed and lay eggs.