Schisandra chinensis stem base rot

The stem base rot of Schisandra chinensis can cause the base of the stem to rot, the root bark to fall off, and finally the whole plant to die.

With the expansion of artificial cultivation area, the incidence of stem base rot showed an upward trend. The general incidence rate is 2%-40%, and the serious one is more than 70%. It is a devastating disease.

1. The symptom of stem rot occurred in Schisandra chinensis in all years, and it was serious in 1 ~ 3 years old. The disease began at the base of the stem or at the junction of the rhizome. At the initial stage of the disease, the leaves wilted and drooped like a lack of water, but could not recover, the leaves gradually dried up, and finally all the aboveground parts withered. Peeling off the basal cortex of the stem at the initial stage of the disease can be found to have a little yellowish brown, but in the later stage, the cortex of the diseased part decayed and became dark brown, which was very easy to fall off. The disease was sectioned longitudinally, and the vascular bundles turned dark brown. When the condition is suitable, the disease spot expands upward and downward, which leads to the rot and peeling of the underground root bark. When the humidity is high, a pink or white mildew layer can be seen in the disease department, and a large number of Fusarium spores can be found by microscopic observation.

two。 According to the preliminary identification, the disease was caused by four species of Fusarium fungi, namely Fusarium oxysporum, Fusarium solanum, Fusarium oxysporum and Fusarium seminaked. These bacteria can be isolated from diseased plants, and the proportion is different in different regions. The pathogens were mainly spread by soil. Schisandra chinensis occurred from early May to late August. The disease began in early May and reached its peak in early June. The disease was serious in high temperature, high humidity and rainy years, and the disease showed an upward trend when it was sunny after rain. Underground pests, soil nematodes, wounds caused by transplanting and poor root development of plants are all beneficial to the occurrence of diseases. The freezing injury caused by continuous low temperature in winter can easily lead to serious disease in the following year, and Schisandra chinensis growing in the serious low-lying land with stagnant water is easy to occur.

The seedlings of Schisandra chinensis were bundled and stored underground for several months in autumn, and then transplanted to the field the following year. During this period, the pathogens in the soil are easy to invade the plants, resulting in carrying pathogens. Schisandra chinensis causes wounds in the process of transplanting and has a long slow seedling stage, during which the plant grows weakly and the pathogen is easy to infect the plant. As the phloem thickens, the branches become thicker, the tree potential increases, and the pathogen is difficult to invade. Schisandra chinensis has different degrees of disease in the planting area. Under the same cultivation conditions, the disease of 2-year-old Schisandra chinensis is the most serious, 3-year-old is the second, and 4-year-old and more than 4 years old Schisandra chinensis is the least.

3. Control technology ① strengthen field management, pay attention to pastoral cleanliness, remove diseased plants and burn them in time, and irrigate gonorrhea soil with 50% carbendazim 600x liquid; apply nitrogen fertilizer properly and increase phosphorus and potassium fertilizer to improve plant disease resistance; drain water in time after rain to avoid stagnant water in the field; avoid planting Schisandra chinensis on the land with serious Fusarium disease in the previous crop. ② seedlings were disinfected and healthy and disease-free seedlings were selected for planting. The seedlings were soaked in 50% carbendazim 600 times solution or mancozeb 600 times solution for 4 hours. ③ chemical control, the disease should be prevention-based, before or at the initial stage of the disease with 50% carbendazim wettable powder spray, so that the liquid can flow along the branches into the soil, spray once every 7-10 days, even 3 times 4 times, or with Luheng 1 (carbendazim) 4000 times solution for root irrigation.