Control of powdery mildew of Euonymus tomentosa

Symptoms:

The disease harms leaves and shoots. Most of the disease spots were distributed on the front of the leaves. At the beginning of the disease, there are many small white round spots scattered on the susceptible leaves, which gradually expand, heal each other and become irregular spots. When the disease is serious, the infection rate of new shoots can reach 10%. White powder appeared on the whole leaf and shoot surface. The diseased leaves gradually fade green, turn yellow, and finally turn brown and black. The diseased part is deformed, the diseased leaf is shrunk, and the diseased tip is twisted and atrophied.

The regularity of disease:

The pathogen overwintered in the diseased plant by mycelium. In the spring of the following year, the pathogen produced a large number of conidia, which were spread by airflow and were harmful to infection. The conidia can be re-infected repeatedly. The pathogen parasites on the surface of the branches and leaves of the host and produces haustorium to penetrate into the epidermal cells to absorb nutrients. High temperature in summer is not conducive to the development of diseases. The disease of the plants planted in the shade was serious, while the disease of the adjacent sunny plants was little or no. The disease of young leaves and new shoots is serious, while that of old leaves is light.   

Prevention and treatment:

② medicament prevention and cure: at the initial stage of the disease, spray 1500-2000 times solution of 25% fenrucine wettable powder, or 80-1000 times liquid of 70% topazine wettable powder, or Baume 0.3-0.5 degree stone sulfur mixture, or 50% bacilli wettable powder 1500 times, spray every 10-15 days, spray 2-3 times.

Control methods of powdery mildew of Euonymus tomentosa

In the growth process of Euonymus tomentosa, Populus tomentosa is easily affected by powdery mildew. Powdery mildew is widely distributed in Populus tomentosa. When it is damaged, a layer of white powdery mildew is formed on the leaves and shoots, which reduces its ornamental ability. The following editor shares with you the prevention and control methods of powdery mildew of Euonymus tomentosa.

Incidence regularity of powdery mildew of Populus tomentosa

The pathogen overwintered with mycelium in the damaged tissue of Euonymus tomentosa and produced gray membranous bacterial layer. In the leaf spreading and growing period of Euonymus tomentosa in the next spring, a large number of conidia were transmitted and infected by airflow, which became the bacterial source of the disease for the first time. The pathogen parasites on the surface of the branches and leaves of the host, produces haustorium and absorbs nutrients deep into the epidermal cells, and produces a large number of spores to infect leaves and new shoots every spring, summer and autumn. High temperature in summer is not conducive to the development of the disease. Rainy season and high humidity conditions are conducive to the occurrence of the disease. Cool and rainy autumn is conducive to the disease. The disease of Euonymus tomentosa planted in the shade is serious, the disease of young leaves and new shoots is serious, and the disease is more serious when the branches and leaves of Euonymus tomentosa are too dense.

Control methods of Populus tomentosa powdery mildew

1. Improve the cultivation conditions, planted in dry, sufficient light, no stagnant water, deep and fertile soil.

two。 Strengthen the management of fertilizer and water, increase the application of phosphorus and potassium fertilizer and appropriate amount of nitrogen fertilizer, and pay attention to drought and drainage to make seedlings grow strong and improve disease resistance.

3. Combined with pruning, diseased branches and leaves are cut off.

4. Rational use of chemicals for timely prevention and control, pay attention to the alternate use of agents, so as to avoid drug resistance of powdery mildew; spray carefully and thoughtfully, pay attention to spraying the inner chamber and leaf back. It was treated twice with 3-degree stone-sulfur mixture in winter, with an interval of 1 month. During the leaf development and growth period of Euonymus tomentosa, especially from April to May and September to October, the following chemicals can be used for control: 1500 to 2000 times of 25% fenbuxine wettable powder, or 1000 to 1000 times of methyl thiophanate wettable powder, or 1000 to 1500 times of 50% benzoate wettable powder, or 1000 to 1000 times of 50% benzoate wettable powder, etc., as soon as the disease begins to appear and sprayed once every 7 to 10 days. Spray 4 to 5 times in a row.

The above is the article on the prevention and control of powdery mildew of Euonymus tomentosa, which is shared by the editor. I hope the above can help you.

Control of powdery mildew of Euonymus tomentosa

Euonymus tomentosa is a common hedge plant and modeling material in gardens, but its ornamental ability is reduced due to the widespread occurrence of powdery mildew, which restricts its application in landscaping.

Powdery mildew mainly harms the leaves of Euonymus tomentosa, the disease spots are mostly distributed on the leaf surface, resulting in powdery mildew spots; when the disease is serious, leaf back and new shoots can also occur, resulting in leaf shrinkage and deformity, new shoots twist, atrophy and stop growing, and cause fallen leaves and withered shoots. In the early stage of the disease, many small white round spots were scattered on the leaves, which gradually expanded and healed with each other, becoming irregular spots, even occupying all the leaves. For example, when the white powder layer on the surface of the disease spot is erased, it will show yellow round spots in the affected area. The pathogen overwintered in the damaged tissue or bud scale of Euonymus tomentosa with mycelium (i.e. gray membrane layer). In the leaf spreading and growing period of Euonymus tomentosa in the next spring, a large number of conidia were transmitted and infected by airflow, which became the bacterial source of the disease for the first time. The pathogen parasitized on the surface of the branches and leaves of the host, produced haustorium deep into the epidermal cells to absorb nutrients, and produced a large number of spores to infect leaves and shoots many times in spring, summer and autumn every year. High temperature in summer is not conducive to the development of diseases. High temperature is the main factor of disease occurrence.

Prevention and control measures:

1. To improve the cultivation conditions, the planting site should be high, dry, sufficient light, no stagnant water, and the soil should be deep and fertile.

two。 Strengthen the management of fertilizer and water, increase the application of phosphorus and potassium fertilizer and appropriate amount of nitrogen fertilizer, and pay attention to drought and drainage to make seedlings grow strong and improve disease resistance.

3. Combined with pruning, diseased branches and leaves are cut off. Do a good job of clearing the garden in winter, sweep the diseased branches and leaves and burn them in a concentrated way, and the diseased branches found in the growing period can be cut off and burned in time, which can effectively reduce the initial and re-infecting bacteria sources of the disease.

4. Rational use of chemicals for timely prevention and control, pay attention to the alternate use of agents, so as to avoid drug resistance of powdery mildew; spray carefully and thoughtfully, pay attention to spraying the inner chamber and leaf back. It was treated twice with 3-degree stone-sulfur mixture in winter, with an interval of one month. During the leaf development and growth period of Euonymus tomentosa, especially from April to May and from September to October, the following agents can be used for control: 25% trimethoprim 800-1000 times, 70% methyl topiramate 800 times, 50% benzoate 1000-1500 times, 50% chlorpheniramate 800 times, 40% thiazuron 600 times, 0.3 to 0.5 degrees stone sulfur mixture or 2% antimycin water agent 200 times.