Control methods of Fusarium wilt of chrysanthemum

First, the symptoms of damage: at the beginning of the disease, the leaf color became light yellow, wilted and drooping, the base of the stem also became light brown, the vascular bundles of the stem base became brown, and the vascular bundles of the upward expanding branches gradually became light brown, which led to root bark necrosis or blackening and rot, and some stems split at the base. When the humidity is high, white mold is produced, that is, pathogen hyphae and conidia. The spread rate of the disease is slow, and the branches and leaves on one side of some plants turn yellow and wilt or rot. Second, the characteristics of the disease: mainly chlamydospores overwintering in the soil, or saprophytic life for a long time. In the field, it can be propagated mainly by carrying bacteria in soil and taking cuttings from diseased plants or transmitted by irrigation water, or it can also be blown away by wind with the diseased soil. The optimum temperature for the development of the pathogen was 24-28 ℃, the highest was 37 ℃, the lowest was 17 ℃, and the disease was not found when the temperature was below 15 ℃. The fungus only harms the chrysanthemum, and the plant will die when the disease course is 2 weeks under the suitable conditions. Dampness or water stains are easy to occur, especially stagnant water after rain, high temperature and rain, excessive application of nitrogen fertilizer, and acidity in the soil. Third, prevention and control methods: (1) promote the application of Baode biological fertilizer or enzyme bacteria retting compost or mature organic fertilizer. (2) strengthen management, implement crop rotation, select sandy soil suitable for drainage, reasonable irrigation, strengthen the management of planting ditches, and avoid excessive humidity in the field or water accumulation after rain as far as possible. (3) at the initial stage of the disease, 50% carbendazim wettable powder or 50% methyl thiophanate sulfur suspension, 10% Zhiweiling water agent, 12.5% carbendazim concentrated solvent, 50% carbendazim wettable powder, 50% carbendazim wettable powder, 50% carbendazim (chlorobromaisocyanuric acid) water-soluble powder 1000 times.