Sometimes when we look around, we see bronze branches being dried by layers of white wax filaments, what is the reason? It turned out that a stinging pest called the tung psyllid was harming the tung. The green tree lice, also known as the sycamore split lice, is often distributed in North China, Central China, East China, Shaanxi, Gansu, Ningxia and Yunnan. The occurrence of this insect is very disorderly, and a variety of different insect states can be found during the same period. Both adults and nymphs are clustered , often more than a dozen or dozens of them on young shoots or branches , and are particularly numerous on young shoots ( nymphs ) and leaf backs ( nymphs and adults ) . Today, share about the identification and prevention of tung psyllids!
[1] Morphological characteristics
Adults are 5.6 to 6.9 mm long, coarse, coated, yellow-green, with black or black-brown markings; the head is wide, the apex is deeply lobed, yellow, the sides and leading edges are dark yellow, the middle slit is black, the forehead is exposed, the compound eyes are brown, the hemispherical prominence, and the wings are colorless and transparent. The eggs are spindle-shaped, 0.5 to 0.8 mm long, slightly transparent, yellowish or yellowish-brown at first birth and reddish brown before the eggs hatch. The nymph initial hatchery is rectangular, with a slight greenish tinge of tea yellow, and the wing buds are slightly emerging; the old mature body is oblong, 3 to 5 mm long and dark, and the wing buds are obviously visible.
[2] Occurrence law
Sycamore lice occur in 2 generations per year and overwinter with eggs. The nymphs are all submerged in the white waxy flocculents they secrete, moving quickly and have no jumping ability.
From late April to early May, the first generation of nymphs appeared, crawled to the tender or leaf back, and secreted wax hairs and mucus, contaminating the leaf surface and ground. The first generation of adult insects begins to appear in early June, and in late June, the adults are good at jumping and flying.
The second generation of nymphs appears in late June, the peak of activity is in mid-July, and the second generation of adults feathers in early August.
In early September, the third generation of nymphs is infested, and in September adults gradually lay eggs on the branches.
[3] Harmful symptoms
The main hosts are sycamore, catalpa and catalpa. During the occurrence period, it secretes white wax filaments, covered with trees and leaves, flutters with the wind, and is shaped like a flying fog, which seriously pollutes the surrounding environment and affects the appearance of the city. Sycamore lice are monophagous pests, and nymphs and adults suck sap on the back of sycamore leaves or on young stems, destroying the transport tissue, especially young trees. The white cotton flocculent wax secreted by the nymphs blocks the stomata of the leaf surface, affects the normal photosynthesis and respiration of the leaf, and makes the leaf surface appear pale and atrophied; the secretion contains sugar, which often causes mold parasitism. When the damage is serious, the leaves fall early, the branches dry, the epidermis is rough and fragile, and it is easy to break in the wind.
[4] Prevention and control measures
1. From late autumn to the following spring, spray the trunk and branches with 65% soap mineral oil milk diluted to 8 times the liquid to eliminate the winter eggs. Spraying 15 times the liquid in the nymph stage is effective.
2. Combined with winter pruning, remove excess side branches or combine with Qilin Kebai to smear the trunk to eliminate winter eggs.
3. Protect natural enemies such as ladybirds, grassflies, insectivores and parasitic bees.
4. Medicinal control selection of Qilin Qifa and Royal Moth.