What are the prevention and control measures of cypress leaf blight?

Dragon cypress has dense branches and leaves, beautiful tree shape, green four seasons, strong resistance and long life, so it is an excellent landscaping and ornamental tree species, but dragon cypress is easy to suffer from leaf blight, so what are the control measures of dragon cypress leaf blight?

I. symptoms of cypress leaf blight

1. Symptoms

It mainly harms the leaves and green twigs of the year. At the initial stage of the disease, the leaves changed from green to yellowish green, without luster, and then turned to withered yellow, causing the leaves to fall early. The disease spot on the leaves spreads downward, harms the twigs, the twigs fade green, turn yellowish green, and then wither yellow, which is not easy to wither. the next spring is blown down by the wind, and the serious crown is covered with withered yellow branches and leaves, resulting in sparse crowns and weak growth in successive years. Reduce ornamental.

2. Pathogen

Through the isolation and culture of the diseased plants, it was confirmed that the pathogen was Alternaria, belonging to semi-known subphylum, Trichoderma, Alternaria and Alternaria.

3. The regularity of the disease

The pathogen overwintered with mycelium on diseased branches and produced conidia in the following spring, which became the source of primary infection. The conidia are spread by airflow and invade from the wound. The onset period is 4muri-May, and the peak period is 7murmuri-September. Light rain is beneficial to the formation, release and invasion of conidia.

II. Prevention and control measures of cypress leaf blight

1. Eradicate overwintering pathogens

After the leaves fell, the withered branches and leaves, especially the residual diseased branches on the crown, were removed, and the withered branches were treated centrally. And spray 100 times 200 times of copper sulfate once, and spray again before sprouting in March of the following year. The pre-bud scavenger can be sterilized by spraying dry branches with 3-5 Baumetu stone sulfur mixture.

2. Strengthen the management

While doing a good job in winter pruning, we should strengthen summer pruning, on the premise of improving light and reasonable load, timely remove branches that hinder ventilation and light transmission, worsen the conditions for the growth of bacteria, and increase the application of organic fertilizer and formula fertilization to enhance the tree potential and improve the ability to resist diseases.

3. Chemical control

Since the middle of June, internal absorption and protective fungicides have been sprayed alternately every 5-7 days to ensure that the leaves and branches are protected before continuous rain for more than 2 days each time. Considering the control of other diseases, Dyson can be mixed with other internal fungicides when sprayed.

Note:

Select regular enterprises to produce and sell drugs of up to the quality standards, and pay attention to the rotational use of drugs. Spray must be meticulous and considerate, no leakage, especially spray the inner branches of the crown, should ensure that the front, back and fruit of the leaves are evenly sprayed. At the same time, the higher the degree of atomization, the better the control effect.