What are the latest control methods for apple viral diseases?
Apple is a common fruit in our daily lives, and viral disease is a common disease during cultivation. If not controlled in time, it can lead to severe reductions in apple yield and cause huge losses to fruit growers. So how should apple viral diseases be controlled? Let's learn about it together.
1. Occurrence and harm
The apple viral diseases currently identified include mosaic disease, rusty fruit disease, wrinkle fruit disease, small fruit disease, ring spot fruit disease, rough-skinned fruit disease, yellow leaf disease, and others. Once infected by a virus, the tree will remain diseased for life and suffer lasting harm. The virus mainly spreads over long distances through grafting along with scions, rootstocks, and nursery stock. The more grafting propagation is carried out, the faster it spreads, and it is difficult to prevent and control with chemical agents. After a fruit tree is infected by a virus, all parts of the whole plant will carry the virus, disrupting and infecting the plant's normal growth, leading to problems such as weakened tree vigor, reduced yield, and deteriorated varieties, and in severe cases causing the death of the whole plant.
⟦NL>2. Disease symptoms
There are many types of viral diseases, and the symptoms of each disease differ. Mosaic disease mainly harms fruit trees and leaves. In the early stage, irregular bright yellow disease spots appear on the leaves. At first there are few, then they gradually expand and turn white, and chlorotic spots also appear. Rusty fruit disease mainly harms the fruit and can be transmitted through grafting, with an incubation period of 3-27 months. In the direction of the fruit stem cavity, 5 radial brown suberized rust spots appear. The epidermal cells at the rust spots become suberized and stop growing, causing the fruit surface to crack and the fruit to become deformed, seriously affecting fruit quality and marketability.
3. Control methods
For propagation, virus-free nursery stock must be selected. This is the most fundamental measure for controlling apple viral diseases. Attention must be paid to the selection of virus-free seedlings before planting. Regardless of whether the rootstock or scion carries the virus, after grafting they will form virus-carrying branches and plants, and will carry the virus for life. First, the rootstock should be selected from seedlings propagated by seed. Second, the scion should be selected from virus-free material. Third, avoid collecting scions from orchards where apples and pear trees are mixed or from apple orchards close to pear trees. Fourth, after planting and survival, regularly inspect whether there are virus-carrying plants, and promptly pull out and burn any found.
The above is an introduction to the control methods for apple viral diseases. We hope it can help you. To learn more related knowledge, please stay tuned to us.