Symptoms: this disease mainly damages the stem base of cornflower. In the case of high temperature, the stem of cornflower will appear light brown spots. When it is serious, it will turn gray white, and then part of it will rot. the stem and leaves will slowly wither and wither. This disease is most likely to occur in spring and autumn when the temperature is about 15 ℃.
Control methods: the plants should not be planted too densely, and the management of water and fertilizer should be strengthened. If any sick plants are found, they should be pulled out immediately; when the disease is serious, they can be sprayed with chemicals in the middle and lower parts of the plants.
Symptoms: the infected leaves will show irregular light gray green to light red spots on the surface, which will eventually lead to the death of the leaves of cornflower.
① observe more at ordinary times. Once the sick plant is found, pull it out in time and deal with it intensively.
② the planting of cornflower should not be too dense, and it should be ventilated frequently, and good ventilation and light transmission conditions should be kept.
③ chemical control: if the disease is serious, it can be properly sprayed with Bordeaux solution and other chemicals.
Symptoms: infected cornflower leaves will slowly distort, then shrink, eventually leading to vein necrosis.
Prevention and cure:
① at ordinary times, we should strengthen the management of water and fertilizer, timely ventilate and ventilate, and strengthen the illumination.
② observe more, if the disease is found, pull it out immediately and destroy it intensively.