A few days ago, a friend told me that there were many small white dots on the branches of the purple weed planted by his family, I don't know if it is a worm or a disease? Will it have any adverse effect on the normal growth of the ziwei tree?
The picture shows the purple weed velvet on the trunk of the purple weed
In fact, these small white spots are not a disease, but a very common pest on the ziwei tree - the ziwei velvet, a kind of insect that mainly harms the ziwei tree and the pomegranate tree. It is mainly parasitic in the form of nymphs and female adults on the branches of the ziwei tree for pricking hazards, and the bifurcation and axils of the ziwei are its favorite places to gather.
<h1 class="pgc-h-arrow-right" > what are the hazards of ziwei velvet to ziwei trees? </h1>
First of all, it will make Ziwei's tree weaken more and more.
Ziwei velvet worm mainly depends on the sap in the trunk of ziwei for a living, and the trees that are harmed by it do not show particularly obvious differences in the early stage, but with the prolongation of the damage time, the ziwei tree will gradually show symptoms of weakness, such as thin new branches, less flowering, early yellowing and falling leaves, and severe disease will also affect the dry death of branches.
Secondly, it will affect the ornamental value of the ziwei tree landscape.
Trees that are harmed by the purple velvet beetle not only have fewer flowers, but are also more prone to coal pollution disease. This is mainly because the secretions of the purple velvet beetle are very sticky, which can easily induce the occurrence of coal pollution. If the harm of ziwei velvet beetle is more serious, not only will the leaves be covered with oil stains, but even the branches distributed with ziwei velvet beetle will also turn black, which will seriously affect the landscape ornamental value of ziwei trees.
The picture shows ziwei whose branches have also turned black
Finally, if it is not prevented in time, it will cause the entire death of the ziwei tree.
Ziwei velvet borer sucks the sap in the trunk of ziwei tree branches will make the tree weaker and weaker, and the occurrence of coal pollution disease will affect the normal photosynthesis of the plant, if it is not controlled for a long time, the ziwei tree will dry up and die of the whole plant, causing landscape effects and economic losses to everyone.
<h1 class="pgc-h-arrow-right" > how can we prevent the occurrence of purple violet velvet beetle? </h1>
The picture shows the purple weed velvet beetle on the branches
First of all, it is necessary to understand the occurrence of purple velvet beetle.
The occurrence algebra of ziwei velvet in the north and south regions is slightly different, generally 2 to 4 generations can occur a year, and the specific generation algebra has a great relationship with the temperature and humidity in the local environment, and the more dry and hot the environment, the more conducive to its reproduction and development.
In the southern region, the first generation of purple weed velvet nymphs generally appeared at the end of March to the beginning of April, while the first generation of purple weed nymph nymphs in the northern regions generally appeared at the end of April to the beginning of May, so the peak incubation period of the purple weeds in different regions was not fixed, and local plant protection staff were required to summarize through 2 to 3 years of observation. However, in general, in May to June, August to September is the peak of the two nymph hatches of the purple weed velvet.
Secondly, it is necessary to determine the best prevention and control period for ziwei velvet beetle.
The best prevention period is mainly in the deciduous stage, before the germination of ziwei after soil thawing;
The best drug control period is mainly in the naked period of nymphs, because the waxy layer has not yet been fully formed at this time, and these exposed nymphs are not very resistant to drugs, which is very conducive to drug control. However, it should be noted that the nudity period of nymphs is only 8 to 10 days, and we must grasp them well. Once the wax layer is fully secreted, it will bring great difficulties to our later prevention and control work.
The picture shows a branch with a purple weed hopper
Finally, there are specific prevention and control measures.
There are three main preventive measures:
(1) At the defoliation period, prune the insect branches.
Purple velvet beetle is mainly in the form of eggs, nymphs and fertilized females in the form of cracks in the branches of the overwintering, in the deciduous period can be combined with winter shears to prune the branches of the purple weed trees carrying insect eggs, and then taken out of the park for destruction.
(2) Clear the garden twice after the leaves fall in autumn and before the budding in winter.
After autumn leaves fall, and before the budding of ziwei in early spring, a stone sulfur compound is sprayed on the whole of ziwei trees to clear the garden to eliminate the eggs hidden in the cracks in the branches and reduce the density of the insect population in the spring.
The picture shows the coal pollution disease induced by the purple weed velvet beetle
(3) In the early stage of germination of ziwei after soil thawing, insect infestation is prevented by root application of burial drugs.
Ziwei is relatively a plant that sprouts late in spring, after the soil thaws, we can bury some granular insecticides such as diazine phosphorus, octylthion, chlorpyrifos, etc. in the root of the ziwei tree by root application, so that the tree body can be absorbed and transported to the whole body of the tree, so as to achieve the purpose of preventing a variety of insect pests.
Prevention and control measures mainly have the following three points:
(1) During the period of stinging hazards of overwintering nymphs and female adults, timely spraying of drugs for prevention and control.
In the southern region from the end of March to the beginning of April, in the northern region from the end of April to the beginning of May, the nymphs and female adult nymphs began to sting, looking for places on the branches to fix the hazard, and when the harm first began, these nymphs did not secrete a white waxy layer, but a faint purple-red color. At this time, all branches and leaves of the aster tree are sprayed with acetamidium or thiamethoxam to control and reduce the hatching of pests.
The picture shows the purple weed velvet beetle when the waxy layer has not yet been fully formed
(2) Between the peak of nymph hatching and the adult stage, insecticide + osmotic silicone are used for control.
At the peak of nymph hatching, the waxy layer has not yet fully formed, and the resistance to drugs is still relatively weak. At this point 40% acetone can be used. Chlorpyrifos, or 40% spironium ethyl ester. Chlorpyrifos suspension agent, etc., compound penetrant silicone spraying, can effectively kill those newly hatched nymphs, or adult insects that have not yet fully formed the waxy layer, reducing the number of pests of purple velvet beetle.
The number of sprays is preferably 2 to 3 times, and the interval between each spray is preferably about one week.
(3) For trees with more purple velvet, you can use tools to scrape off the insects.
If there are many purple velvet ants distributed on the branches, and the waxy layer is thick, we can use steel wire brushes or iron brushes to scrape these waxy layers of insect shells, and then use some agents such as acetamidine, methic salt, and thiamethiazide to spray, which can also reduce the damage of purple weeds to ziwei.
<h1 class="pgc-h-arrow-right" >how to determine if the purple velvet worm has been killed after spraying? </h1>
If the purple weed velvet worm has not been killed, when we press the small white dots on these branches with our hands, there will often be red liquid flowing out, or some purple oval eggs;
The picture shows the purple-red liquid flowing out after pressing the hand
If the purple velvet worm had been killed, when we pressed the small dots on these branches with our hands, there would be no red liquid flowing out of them, but an empty wax shell.
<h1 class="pgc-h-arrow-right" > note here is:</h1>
The harm of purple velvet beetle to trees is not only related to temperature and humidity, but also has a lot to do with the ventilation and light transmittance of plants.
If you look closely, it is not difficult to find that the shade side of the purple velvet beetle is often more than the sunny side when the distribution of hazards on the branches is often more than the sunny side, and the plants with higher planting density are often more than those plants with better ventilation and light transmittance; so it is said that thinning, pruning, and enhancing the ventilation and light transmittance between the leaves of the purple weed can effectively reduce the occurrence of the purple velvet beetle on the tree.
Well, the knowledge about the purple velvet beetle will be briefly shared here today.
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