The new flower friends panicked. Why are there so many black spots on rose leaves?

In late May, the weather is getting hotter and hotter, and the temperature in some areas has reached more than 30 degrees. Recently, I have received a message from many flower friends that the rose leaves at home are yellow, and there is still a little black on the leaves. Can you treat them with your fertilizer?

In fact, I am very glad that you can consult me on this question, indicating that flower friends trust me, although my liquid fertilizer can not cure the black spot of rose. Look at the picture above, this is the picture sent by Hua you yesterday, the leaf already has obvious black spots, and the whole leaf is infected more seriously, so it must be treated as soon as possible.

So what is black spot? Symptoms: the disease mainly occurs in the leaves. The initial onset of the leaf surface appeared black or dark brown radial disease spot, the edge of the disease spot is not obvious, after the disease spot gradually expanded into a round right near round, the edge has a radial awn-like protruding, 4Mel 12 mm in diameter, surrounded by yellow halo. The damaged leaves or leaflets are yellow and easy to fall off. In serious cases, all the leaves will fall off, leaving only the branches, the plant will grow and decline, and finally the whole plant will die.

Black spot is a fungal hazard, which is easy to occur in rainy and hot seasons, and is the most serious in April and May and late August and September in summer. Because the black spot is highly dependent on humidity, it is easy to occur at a high temperature of more than 85% humidity, especially when there is a water film on the leaves, such as the sun comes out after rain, so there is an environment of high temperature and high humidity. If it is no longer ventilated, it is easy to develop the disease, so the prevention of black spot is better than the treatment.

How to prevent it? Select varieties with strong disease resistance for planting, usually mainly lies in prevention, and pay attention to fungicide prevention before and after continuous rainy days. In addition, do not plant too closely, maintain a ventilated environment, clean up the old leaves in time, and do not water the leaves all help to prevent black spot.

Usually, if you fertilize the rose, it is best to choose a good nutrient solution, strengthen the cultivation management, and enhance the growth potential of the plant, which will help to enhance the disease resistance of rose. The rose special organic nutrient solution understood by flowers is rich in a variety of organic matter and active factors, which can greatly improve the internal structure of soil, decompose soil harmful substances, dredge plant nutrient transport channels, and promote plant photosynthesis.

If the rose is already sick, the diseased leaves should be removed and burned in time to prevent it from spreading. Wait until after autumn, thoroughly remove the withered branches and leaves, cut off the diseased branches and burn them centrally, which can reduce the incidence of the following year.