How to skillfully remove the black spots of rose

Black spot is one of the most common and destructive diseases in various places. It mainly infects leaves, as well as twigs, petioles, flowers, peduncles, buds and flowers. The disease spots on the twigs are long oval at first, dark purplish red, and slightly sunken. The spots on the pedicel are smaller. When the temperature rises to about 25 ℃ and the air humidity is close to saturation, the disease is the most serious. In the rainy season, the disease spreads most quickly and the infection is also serious. August and September is the peak. In addition, overdense planting or poor ventilation are also the main causes of the disease. The prevention and treatment of black spot is generally based on prevention and the combination of prevention and control. One is to select varieties with strong resistance, the other is to improve the cultivation environment, the cultivation site should be well ventilated, the light should be sufficient, and at least 6 hours of light should be guaranteed every day. The cultivated soil should be breathable, and those barren soil, plated soil and saline-alkali soil can not raise the rose well; the third is to remove fallen leaves, dead branches, weeds and wastes from the garden and burn them centrally so as to reduce the source of infection. At the same time, once diseased leaves are found, they should be cut off immediately. Do not touch the leaves of diseased plants casually to prevent human transmission. There are many drugs for the prevention and treatment of black spot, and 1% Fumei arsenic is used to disinfect the soil in early spring. Before the onset of the disease, spray 1000 times of chlorothalonil, once every two weeks, until the spread is controlled. It can also be sterilized with 800 times 70% thiophanate methyl solution. When the disease occurs, it can be sprayed with 800 times 50% carbendazim, which is resistant to Rain Water scouring. Practice has proved that the use of traditional Bordeaux liquid to control rose black spot is still an effective method. Because this medicine has strong adhesion in the wet weather of rose disease, it can form a thin film on the leaf surface, which can effectively kill germs. The efficacy of Bordeaux liquid can last for 2 weeks. Due to the long incubation period of black spot pathogen, the spraying time had better be mastered before the onset of the disease, and the effect will be better. Bordeaux liquid uses 100 times liquid lime equivalent formula, should be used now, not overnight. The spraying time should be in the evening, and it is easy to cause drug damage when spraying at high temperature at noon.