Identification Methods and Control Techniques for the Tea Black Spiny Whitefly

The black spiny whitefly, also known as the citrus spiny whitefly, belongs to the order Homoptera, family Aleyrodidae. It can damage tea plants, citrus, pomelo, oil tea and many other plants, with omnivorous feeding habits. The larvae settle on the undersides of leaves, piercing and sucking sap, and excrete "honeydew", which leads to sooty mold, hinders photosynthesis, weakens tree vigor, causes sparse buds and leaves, and can even cause branches and leaves to wither. The adult of this insect is 0.95-1.35 mm long. Apart from the orange-yellow abdomen, the body and wings are purplish brown. The front wings have 7 white spots along the margin, while the hind wings are light brown and spotless. The body surface is thinly covered with white waxy powder, and the compound eyes are red. The eggs are banana-shaped, 0.21-0.26 mm long, milky white to yellowish brown, attached to the undersides of leaves. The larvae are black and have 3 instars. The first-instar larva is elongated oval, about 0.25 mm long, flat and smooth, with legs, and has 2 slightly curved white wax lines on its back. The second-instar larva is about 0.5 mm long, slightly raised on the back, pitch-black, with a distinct white wax ring around the margin, 10 pairs of spines on the sides of the back, and the legs have disappeared. The third-instar larva is about 0.7 mm long and has 14 pairs of spines on its back. The pupa is oval, 1.0 mm long, with 19 pairs of black spines on both sides of the dorsal ridge, and 10 pairs (male) or 11 pairs (female) of black spines around the margin.

To control this insect, first strengthen tea garden management, and combine pruning to thin out low branches to reduce the pest population. Second, pay attention to protecting natural enemies; an important part of this is not to spray pesticides blindly. To protect parasitic wasps and ladybugs, release whitefly black wasps where conditions permit. That is, in fields where parasitism by whitefly black wasps is found, do not apply pesticides. After the parasitism rate increases, pick leaves bearing eggs and move them to other tea gardens. When the pest situation is severe or the population rises and chemical control is needed, adhere to three principles: first, apply pesticide during the peak hatching period of the larvae; second, ensure spraying quality, focusing on spraying the undersides of leaves in the lower part of the tea bush; third, choose good pesticides. Pesticide options include Tianwangxing, Actara, Pujiaya, Yousheng, etc. If managed well, applying them at the peak hatching period of the first-generation larvae, using pesticide only once in the whole year can basically solve the problem.