Detailed Explanation of Common Diseases of Yellowhorn (Xanthoceras sorbifolium) and Their Control Methods
Yellowhorn is now one of the most important oil crops in our country. Its seeds and kernels contain a very high proportion of oil, and it is very easy to grow. It has no particularly strict requirements for growing environment, soil and other basic conditions, and its disease resistance is also relatively strong, although its incidence rate is relatively low. However, if it is not properly managed, some diseases can still occur. So what diseases can occur in yellowhorn trees? How should they be controlled? Let's take a look together below!
1. Yellowhorn root rot nematode disease
Symptoms: Root rot nematode disease is caused by nematodes parasitizing the root and stem parts. It mainly harms seedlings and young trees, and generally begins to occur after the seedlings emerge during sowing and seedling raising. Nematodes in the soil and residual roots invade, mainly under damp and shady conditions. The leaves will all turn yellow and withered, but will not fall off for a long time. The aboveground part shrinks and stops growing, and later gradually dies. After pulling out the diseased seedling, it will be found that below the root collar there is a swollen state, yellow water-soaked, and accompanied by a foul odor.
Control methods: In the relatively damp and shady seasons of autumn and winter, the seedling raising site should be plowed and earthed up to reduce the incidence of the disease. When sowing, the seeds should not be buried too deep, and the bottom water should be fully irrigated to avoid nematode transmission through water due to insufficient water later. During the emergence period, cultivating and earthing up should be strengthened. If any abnormal harmful conditions are found, the diseased plants must be removed and disposed of in time. When pests are found, pesticides such as fenamiphos or fensulfothion can be sprayed for control.
2. Yellowhorn stem rot
Symptoms: Stem rot is a disease that occurs in most plants. It is mainly a fungal disease caused by Fusarium and Verticillium. The pathogen overwinters in the soil and has extremely strong saprophytic ability. It is most likely to occur in environments with excessive waterlogging and excessively high temperatures, and generally begins to occur about two months after planting. It mainly harms the underground root part. The root will produce rotten dark brown sclerotia, and then begin to extend and spread around the stem base, causing the cortex to gradually rot. The leaves also begin to turn yellow and wilt, and finally the whole plant directly dies.
Control methods: Stem rot is mainly infected through root wounds, so during transportation and planting, damage should be avoided to prevent mechanical injury and give the pathogen an opportunity. After lifting the seedlings, try to soak them in solutions such as potassium permanganate to reduce pathogen infection of the seedlings. When the temperature is high and the weather is hot, cooling and shading work should be done well, and decomposed farmyard manure should be used. Control the planting density well, maintain soil moisture, and reduce the incidence rate. Agents such as oxadixyl can also be sprayed on the affected ground for control to prevent pathogen invasion.
3. Yellowhorn sooty mold
Symptoms: Sooty mold is mainly caused by psyllids sucking the sap of tender tissues. It often occurs on leaves and occasionally appears on young shoots. Small black spots will appear on the leaves, and then gradually expand and extend until all the small spots combine together, and the entire leaf is covered with a black mold layer. When young shoots are affected, it is almost the same as on the leaves. In severe cases, the whole tree will become charcoal black.
Control methods: During routine management of yellowhorn in the cultivation process, the planting density of yellowhorn should be well controlled, and the tree body should be properly pruned. Improve the permeability in the forest garden and reduce the humidity in the garden. Spraying can be used to control insects such as psyllids and aphids to prevent virus transmission. During the tree dormancy period in winter and when buds are about to sprout in spring, lime sulfur mixture can be sprayed on the tree crown to eliminate overwintering sources of disease.
The above three are the relatively common diseases when planting yellowhorn. Although there are more than these three, these three are the most representative. Therefore, everyone must pay attention to orchard management. During overwintering, disinfect the soil, centrally clean up diseased and residual branches, and treat affected tree bodies according to the symptoms. If there is no effect, they should be removed in time to prevent contagion. This article is for reference only, and I hope it is helpful to everyone!