Plain tree is a very common kind of green tree species in the garden, its canopy is wide and perfect, the branches and leaves are luxuriant, and it is often used as a landscape tree and a shade tree in the northern garden; and in many areas of the south, it is directly used as a street tree.
The picture shows the application of pu trees in the garden landscape
However, in the planting process of the simple tree, in addition to the daily maintenance and management, it is also necessary to pay attention to the prevention and control of some diseases and insect pests. Just a few days ago, a friend sent me a few pictures, saying that he found some small long-horned bumps on the leaves of the simple tree.
Long horn-like bumps on leaves
In fact, this is caused by the harm of the park shield wood lice, and the long horn-like deformed bulges we have seen are the insect galls formed after the park shield wood lice harm the leaves of the plant.
<h1 class="pgc-h-arrow-right" data-track="5" > so what is park shield lice? What are the characteristics of the hazard? </h1>
Park shield lice belongs to the family Pycnidae, which is an obligate parasitic pest that specifically harms the tree, mainly by sucking the leaves of the tree and sucking the sap in the leaves of the leaves.
The picture shows the nymph of the Park Shield wood lice
When the pudding of the leaf flakes is harmful, the cell tissue of its leaves will be stimulated by the hormones secreted by it when feeding and laying eggs, and then accelerate the division and rise outward, thus forming the kind of cone-shaped or horn-like galls we see on the leaves.
The gall horns formed after the damage of the wood lice are generally 4 mm to 8 mm long, and after the gall is formed, its nymphs will continue to feed inside the gall, secrete wax, and then form a disc-shaped white wax cap, which tightly covers the orifice on the back of the leaf.
The picture shows a white disc wax cap
<h1 class="pgc-h-arrow-right" Data-track="5" What are the hazards to garden plants when > the damage of the park shield lice? </h1>
After being harmed by the pu dun lice, the leaves will be covered with insect galls and round white wax covers, and the value of its landscape viewing is greatly reduced; and these insect galls formed on the leaves will also hinder the accumulation and transport of nutrients in the leaves of the plant, resulting in the depletion of the branches of the treetops, the early fall of the leaves, affecting its normal growth and development.
In addition, the nymphs of the P. park dun lice will also secrete white flocculent wax when they are harmed, and these white flocculents can block the stomata on the leaves of the plant, thus affecting the normal photosynthesis and respiration of the pu tree, resulting in the pale and atrophied appearance of the leaf surface of the pu tree; Moreover, the secretions of the Pak Dun wood lice nymph also contain a large amount of sugar, which can also induce mold parasitism, thereby causing the occurrence of coal pollution, which seriously affects the landscape value and normal growth of the tree.
<h1 class="pgc-h-arrow-right" data-track="5" >what are the characteristics of the occurrence of park shield lice? </h1>
Park dun psyllid is an obligate parasitic pest on the park tree, so it mainly occurs in henan, Shandong, the middle and lower reaches of the Yangtze River and Jiangnan, where the tree is planted more.
Pictured here are the larvae of the wood lice of the park shield inside the wax lid
The park shield lice occurs in 1 or 2 generations a year, overwintering in the buds with eggs. Generally around the beginning of April in the spring of the following year, the temperature rises, when the young leaves of the tree first unfold, a generation of nymphs (summer type) hatch from the overwintering eggs, the nymphs begin to move to the back of the leaves to fix the stinging hazard, stimulating the accelerated division and proliferation of leaf tissue; in late April and early May, the funnel depression is caused on the back of the leaf, forming a horn-shaped gall on the leaf surface, and secreting wax filaments, forming a white irregular round wax shell on the back of the gall, and the nymph lurks in the gall; with the increase of age, the wax shell and the horned gall also continue to increase. At this point, the nymphs are nearly ripe.
Around mid-May, the adults are feathered in large numbers, the adults crawl out from the edges of the wax shell, rest on the leaves, and can fly up after being alarmed, and after the adults have crossed their tails, they continue to lay eggs in the buds for the winter, so that the next year will continue to be harmful.
<h1 class="pgc-h-arrow-right" data-track="5" > how can we do effective prevention and control? </h1>
The picture shows the larvae of the Park Shield wood lice
The main reason why Park Dun wood lice is not easy to control is that its nymph exposure period is short, most of the time is in the insect gall in the harm, due to the protection of the gall and wax cover, it is difficult for the general drug to contact the insect body when spraying drugs, which makes our control work more difficult.
Therefore, in the prevention and control of Park Dun wood lice, we must start to prevent and control before the gall is fully formed; and when using drugs, we must also choose some drugs that are both aspiring and tactile, and the penetration ability of the drugs is also best to be stronger.
Specific prevention and control measures are as follows:
(1) When the eggs of the overwintering insects have just begun to hatch in early April, select oxidized fruit or imidacloprid, high-efficiency cypermethrin, etc. to spray to kill some of the newly hatched nymphs.
(2) In the middle of April, when the gall first occurs, there are fewer leaves in the gall at this time, and the leaves with the gall can be removed in time by artificial means and burned in time. The leaves of the tree are then sprayed holistically using avermectin, etc. to kill the nymphs inside those newly formed galls.
(3) At the end of April and the beginning of May, when there is more gall, you can choose a compound agent of thiamethoxine and prazidazone for spraying, so that the purpose of touch killing and gastric poisoning can be achieved at the same time.
Of course, in addition to the above methods of drug control, if conditions permit, we can also use parasitic bees, ladybirds, grasshoppers and other natural enemies for biological control.
Well, about the prevention and control methods of Park Dun wood lice, I will briefly share it with you here today.
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