Leaf spot of eight Immortals

Symptoms and pathological changes: Baxian mosaic spot is mainly distributed in Sichuan, Henan, Guangdong, Taiwan, Jilin, Shanghai, Zhejiang, Hunan and other places. The disease mainly occurred on the leaves, the leaf spot was a light yellowish brown watery spot at first, and then expanded into a circle, nearly round, with a diameter of 2 to 5 mm, with a maximum of about 15 mm. Later, the center is light brown, the edge is dark brown, slightly raised, with inconspicuous wheel lines, and the disease produces small black spots, that is, the conidium of the pathogen. On the seriously susceptible leaves, there are a series of disease spots, which causes the leaves to turn brown and yellow until the plant dies. Its pathogen is fungus, which belongs to semi-known subbacteria, Cercospora, Cercospora and Cercospora.

The pathogen overwintered on diseased leaves and soil plant fragments. When the environmental conditions were suitable, the conidia were produced from the conidia, and the conidia scattered by wind and rain. A large number of conidia on the new disease spot spread through air flow, resulting in repeated re-infection. High humidity and heavy rain are conducive to the occurrence and spread of the disease. The disease occurred from August to September and decreased gradually in October, and the old leaves were easy to develop.

Control methods of leaf spot disease of Baxian flower: 1. Baxian flower likes fertile sandy loam and is not resistant to waterlogging. Sandy loam is suitable for planting to facilitate drainage, and diseased leaves and plants should be destroyed at the end of autumn to reduce the source of infection in the coming year. 2. Collect seeds on disease-free and robust plants and disinfect them with potassium permanganate or zinc benzoate before sowing. 3. Chemical prevention and treatment: spray prevention with 0.5% Bordeaux solution before the disease, even if the diseased leaves are removed in the early stage. Spray control at the initial stage of the disease or when the disease is serious, you can choose 50% carbendazim 500x solution, or 75% chlorothalonil 700x solution or 25% carbendazim wettable powder 300g / 600x solution, or 50% methyl topiramate 1000 times solution or 50% Dysen zinc 800g / 1000x solution.

In the process of growth, the eight Immortals will suffer from diseases, such as: eight Immortals Leaf spot disease, the disease will cause the leaves of the eight Immortals to gradually turn brown, gradually showing a withered yellow phenomenon, and even cause the death of the plant. The disease of leaf spot of eight Immortals mainly occurs on the leaves of eight Immortals. The foliar spot initially appeared as a light yellowish brown watery spot, and then gradually expanded into a circle. The center of the eight Immortals is light brown, the edge is dark brown, slightly raised, with inconspicuous wheel lines, the disease part of the eight Immortals mosaic leaf spot produces small black spots, that is, the conidium of the pathogen. In the case of serious leaf spot disease, the diseased leaves of the eight Immortals were stained continuously until the plant died. It is understood that in general, leaf spot lesions of the eight Immortals occur more seriously from August to September. The pathogen of eight immortal mosaic leaf spot survived the winter safely on diseased leaves and soil plant fragments. In the coming year, when the environmental conditions were suitable, conidia were produced from conidia, and conidia spread by wind and rain. A large number of conidia will be produced on the new disease spot to spread through the air flow, resulting in repeated re-infection of the leaf spot disease of the eight Immortals, which is beneficial to the occurrence and spread of the disease in high humidity and rain.

In order to control the leaf spot of eight Immortals in time, effective measures should be taken to control it. The flower growers strengthen the management of the eight Immortals. Because the eight Immortals prefer the moist and semi-shady growth environment, the best temperature for the growth of the eight Immortals is 18-28 ℃, which is more beneficial to the growth and development of the eight Immortals. In order to prevent and cure the leaf spot disease of Baxian flower in time, 0.5% Bordeaux solution should be selected for spray prevention before the disease occurs. The flower growers removed the diseased leaves of the eight Immortals in time after they found them. At the initial stage of the onset of the disease, you can choose to spray 50% carbendazim 500x solution, or 75% chlorothalonil 700x solution or 25% carbendazim wettable powder 300,600x solution, or 50% methyl thiophanate 1000-fold solution or 50% Desen zinc 800mol *-fold solution, or 50% carbendazim 600x solution. Or spray 40% polysulfide suspending agent 500600 times, 50% mixed sulfur suspending agents 500x solution, 1VRU 200Bordeaux solution, 77% wettable powder 500x liquid, 50% copper succinate (DT) wettable powder 400500x liquid, once every 10 days or so, control 2-3 times, can control the leaf spot disease of eight fairy flowers in time.