The size of the needle tip of the back of the orchid leaf in the hot season

Sand spot disease is caused by Cercospora fungi. first, many needle-sized brown or brown sand spots are produced on the back of the leaves, and then expand to form many irregular spots. The disease only infects the old leaves near the base, and the central leaves are generally not harmed. Black spots are also produced on the front of the posterior leaves when the condition is serious, but the black spots are obviously less than those on the back of the leaves. The occurrence characteristics are that the occurrence of high temperature and humidity is serious, and the disease is not contagious. It only occurs once a year. There will be no more infection after July, and the seedlings are not susceptible to disease.

Prevention and treatment, because the incidence of sand spot is concentrated, there is no need to spray a large area, just spray a few leaves. Carbendazim 1000 times. Or chlorothalonil 1000 times.