According to statistics, there are more than 100 kinds of mulberry tree diseases that have been found in China, of which more than 40 kinds of mulberry tree diseases can cause greater harm. Therefore, doing a good job in the prevention and control of pests and diseases in the process of mulberry cultivation is a very important agricultural management measure. In principle, in the prevention and control of mulberry tree diseases and insect pests, it is necessary to implement the principle of "prevention first, comprehensive prevention and control", and actively take corresponding control measures to control the occurrence and development of diseases and insect pests under the condition of fully studying the occurrence and development of mulberry trees, so as to ensure the normal growth and development of mulberry trees and the high yield and quality of mulberry leaves. Today, stop tea with you to talk about what adverse effects of mulberry yellowing atrophy disease will bring to mulberry trees? How should it be prevented? I hope to provide some useful references for Sannon friends in need.
<h1 class= "pgc-h-arrow-right" > First, what is mulberry yellowing atrophy? </h1>
Yellowing atrophy can also be directly called atrophy disease, because the mulberry leaves after the disease will curl and shrink, so some sangnon figuratively call it cat ears. This is a disease that is harmful to the whole mulberry tree and can occur in all areas where mulberry trees are planted in China. In general, yellowing atrophy occurs after the summer harvest of mulberry trees, around May to August, of which the disease begins in early May, and after entering June, it will gradually become ill and enter the peak period, which can last until August. If the mulberry tree suffers from the disease, it will normally die after 2 to 3 years. What is even more frightening is that if a mulberry field has a mulberry tree disease, it is likely that the infection will cause more than 60% of the mulberry trees in the entire mulberry field to be seriously ill, and it may even reach 90%, so that the entire mulberry garden is completely destroyed and must be replanted.
The symptoms of mulberry yellowing atrophy are typical, at the beginning of the disease, the young leaves at the top of the mulberry tree will shrink and thin, the leaf veins are very thin, the leaves will curl and shrink to the back, and the color will be yellow. By the middle of the disease, the leaf shrinkage becomes more pronounced, and the successive curls are more severe, the internodes are shortened, the leaf order becomes chaotic, and even the phenomenon of fruitlessness occurs. Later in the course of the disease, the leaves become curled and atrophied like kitten ears, and the axillary buds continue to germinate, and many broom-like clusters of fine branches appear. At first, there may be a single branch that begins to occur, but then it will gradually expand to the entire mulberry plant, and the overall tree declines quickly, and generally after 2 to 3 years, symptoms of death will occur. Therefore, mulberry yellowing atrophy is a more serious mulberry disease, which must be prevented and treated in time at the beginning of the disease, otherwise it will lead to the infection of the entire mulberry garden.
<h1 class= "pgc-h-arrow-right" >2. What are the infection routes of mulberry yellowing atrophy? </h1>
1. Infection through mulberry grafting
In the process of grafting mulberry trees, if the rootstock has been infected or the scion has been infected, it may cause the grafted mulberry tree to suffer from mulberry yellowing type atrophy. But there is a big difference in the rate and time of infection between the two. If the rootstock itself is already sick, the mulberry tree after grafting with healthy scion grafting may become ill at any time. However, if the rootstock itself is healthy and the scion has a source of infection, then the possibility of the mulberry tree infection after grafting is different depending on the timing of the scion selection. Generally speaking, if the scion is cut from May to October, the infection rate can reach 100%, while the scion is almost non-contagious from December in winter to April of the following year. Under normal circumstances, we can see whether there are symptoms of infection after 2 to 3 weeks of additional connections.
2. Infection through insect vectors
Many diseases are transmitted by insect vectors, and according to research, the insect transmission vectors of mulberry yellowing atrophy disease mainly include two kinds of concave-edge rhombus leafhopper and quasi-rhomboid leafhopper. Under normal circumstances, these two insects can be smoked on the disease mulberry for 2 to 4 days to obtain the source of poison, and the disease begins to spread after a cycle of about 20 days. The spread of these two insects in the mulberry garden is about from mid-June to mid-October, of which mid-September is the peak period of transmission. And once poisoned, its ability to spread can last until death. It is worth noting that it is impossible to develop the disease immediately after the mulberry infection, because it has a latent period, which varies from 20 to 300 days. In other words, after the mulberry tree is infected, it may become ill in the same year, or it may not appear until after the summer harvest of the mulberry tree in the second year.
<h1 class= "pgc-h-arrow-right" >3. How to effectively prevent mulberry yellowing atrophy? </h1>
1. Prevention and control methods for grafting infection of mulberry trees
If mulberry yellowing atrophy is infected because of mulberry grafting, we need to start from the source and strictly control the source of the poisonous strain.
First, strict quarantine measures should be taken. In the mulberry grafting process, the scion is best local, if it is transferred from other places, it must be strictly quarantined to ensure that there is no source of virus. For parks where mulberry yellowing atrophy has already occurred, scion and seedlings are not allowed to be transferred outward. Strict inspections should also be carried out for rootstocks, and diseased seedlings should be completely removed.
Second, it is necessary to promote disease-resistant varieties in a timely manner. In the process of comprehensive prevention and treatment of mulberry yellowing atrophy, the use of varieties with excellent disease resistance is a very important measure. At present, "Husang No. 7", "Yu No. 2" and "Husang No. 199" are all very good varieties that resist yellowing type atrophy and can be promoted in a timely manner.
Third, detoxification technology should be adopted in a timely manner. The so-called detoxification technology is to use artificial methods to remove the virus in the mulberry seedlings, such as heat treatment, stem tip culture and other detoxification methods, etc., in order to cultivate healthy and non-toxic mulberry seedlings, which can effectively cut off the source of infection of mulberry grafting.
2. Prevention and control methods for insect-borne infections
If the mulberry yellowing atrophy is transmitted by insect vectors, the vector must be cut off from the source and the insecticide must be done. Overall, vector insect eradication is carried out at least three times a year.
The first killing of nymphs was around mid-to-late April. We can use 80% dichlorvos emulsion or 50% malathion emulsion 1500 times liquid, or 50% octyl thion emulsion 1000 times liquid, or 40% Lego emulsion 1000 times liquid, the first generation of newly hatched rhomboid leafhopper and concave edge rhododendron nymph nymph for extermination.
The second killing of the first generation of adult insects takes place after the summer harvest of mulberry trees. Generally, 90% dichlorvos crystals are used to effectively kill the first generation of adult insects.
The third and fourth generations of adult insects were killed, after the end of the Mid-Autumn Silkworm. The variety of pesticides can be selected according to the drug source, and attention should be paid to the collocation of drugs to prevent drug resistance. In addition, in the winter, the mulberry garden should be re-pruned in winter, and the plants containing insect ovulation diseases should be cut off and taken out of the park for destruction to reduce the source of insects in the coming year.
3. Prevention and control methods of mulberry garden with mulberry yellowing type atrophy disease
Whether it is transmitted through mulberry grafting or through insect vectors, for mulberry gardens that already suffer from mulberry yellowing type atrophy disease, practical and effective measures must be taken to actively prevent and control them, reduce the spread of the virus, and reduce the economic losses of farmers planting mulberry silkworms.
First, the use of oxytetracycline control. Mulberry trees with mulberry yellowing type atrophy disease after the use of oxytetracycline treatment, can make the mulberry leaf disease temporarily disappear, the effect of treatment is closely related to the oxytetracycline administration method and concentration. Generally, the effect is best with root maceration and rhizome punching injection, followed by stem and leaf spreading. Impregnation of diseased seedlings with 2000mg/kg oxytetracycline liquid for 3 hours has obvious therapeutic effect, and spraying the diseased strain with 500mg/kg oxytetracycline liquid, spraying 2 to 3 times continuously, at intervals of about 15 days, can also control the cause of the season.
Second, thoroughly dig up the diseased strains. For mulberry trees that are already diseased, the most effective solution is to dig them up directly, so as to completely remove the source of the disease. In particular, for mulberry gardens with an incidence rate of more than 60%, it is necessary to dig up and replant them as a whole. In this process, we must follow a principle, that is, "early detection, early digging, digging clean", so we must strengthen the inspection of the wounded, especially in June and August, the high incidence of mulberry yellowing atrophy.
Third, strengthen fertilizer cultivation management. This is an adjunctive measure that, although it does not directly treat mulberry yellowing wilt, it can reduce the incidence of mulberry disease. After the summer harvest of mulberry trees, field management operations such as summer fertilization and tillage and weeding should be carried out in time to improve the fertility of the soil. In the fertilization process, we should pay attention to the ratio of nitrogen, phosphorus and potassium, and must not apply nitrogen fertilizer partially, so as to be conducive to the healthy growth and development of mulberry trees and improve the disease resistance of mulberry trees.
In short, mulberry yellowing atrophy disease is a disease that has a greater impact on mulberry trees in the process of mulberry planting management, so we must pay close attention to the growth and development of mulberry trees, especially in the high incidence period of disease from June to August. Cut off the transmission path in time, do a good job in field management and disease prevention and control in mulberry gardens. Only by "focusing on prevention and combining prevention and control" can we truly reduce the possibility of mulberry disease and improve the economic benefits of mulberry planting.