Control methods of common diseases of chrysanthemum

Chrysanthemum diseases mainly come from flower soil, old flowerpots, cuttings, seeds and seedlings, so the soil should be exposed to the sun before planting, or disinfect the soil and flowerpots with 1: 80 formalin solution, or mix a certain amount of mancozeb into the soil. Before cutting and transplanting, spray with 800 to 1000 times carbendazim. The following introduces the prevention and control methods of several common diseases after setting chrysanthemum seedlings.

Spot disease, also known as leaf spot, is mainly spread by soil. At the initial stage of the damage, the leaves of the injured plants showed round or oval spots of yellow and dark brown, then small black spots appeared in the center of the disease spot, the basal leaves were yellow and dry, and the upper leaves and buds gradually fell ill, affecting flowering. The disease is easy to occur when it is cloudy and rainy, wet and stagnant water, and the temperature difference between day and night is large. The prevention and control methods are as follows: reasonable stubble planting and virus-free plant grafting; avoid applying more nitrogen fertilizer, pay attention to drainage and ventilation, avoid muddy water touching the leaves when watering, and remove diseased leaves in time; use 80% wettable zinc 500 times or 1% Bordeaux solution 2 to 3 times a month, once a week when the disease occurs; when transplanting seedlings, disinfect with potassium permanganate or formalin.

The host of powdery mildew carried bacteria in dormant buds, mainly on the front and back of the middle and upper leaves. Yellow spots at the beginning, then frost, gradually expanded and connected into a large area of white powdery spots, serious leaves and shoots curl deformation, and even withered to death. The disease mostly occurred from August to October. The prevention and control methods include: removing overwintering weeds, reasonably watering and applying nitrogen fertilizer to prevent sudden growth, pruning and beating leaves to ensure ventilation and light transmission, and using carbendazim prevention, it can also be sprayed with 1000 times bacilli special liquid, or with 1000-0.5 degree lime-sulfur mixture. when the quantity is small, it can also be sprayed with edible vinegar.

Rust comes from seeds and weeds, which mainly harms the leaves and stems of chrysanthemum, and the leaves suffer more seriously. Disease spot gray protruding small spot, and then the disease spot from the back of the leaf through the leaf surface crack, there is withered yellow disease powder, can be transmitted with the air flow, and the spots turn black in the later stage. The disease is easy to occur when there is much rain and high humidity. Prevention and control measures include: reasonable fertilization, appropriate application of phosphorus and potassium fertilizer to improve plant disease resistance; potted chrysanthemum should often dredge drainage holes and strictly prevent stagnant water in the basin; remove weeds and remove diseased leaves in time to ensure ventilation and light; in rainy season, the application of 65% Daimen zinc 500 times solution or Baume 0.3 to 0.5 degrees stone sulfur mixture can effectively prevent the spread of the disease, and can also be prevented by topiramate and carbendazim.

Root rot root rot, dry rot or hemp-like, leaves withered and withered. It often occurs before and after flowering. The prevention and control methods are as follows: proper irrigation, waterlogging and drought irrigation, loose soil; garlic water irrigation of diseased plant roots, quick-acting fertilizer has a certain effect.

Virus diseases are mainly transmitted by aphids and green blinds. The young part of the plant is wrinkled and deformed, and there are "willow leaf head" and "yellow leaf", which is difficult to cure. Control methods include: selecting branches and seeds of disease-free plants, using root tip and stem tip virus-free tissue culture seedlings, early removal of "willow leaf head", using side branches to blossom to control aphids.