Disease and Pest Control of Emei Rose

1. Powdery mildew

It is likely to develop on leaves, petioles and young shoots as well as flower buds. Some irregular white powdery spots will appear on the mature leaves, and then the diseased leaves will slowly turn brown from the tip or the edge of the leaves, which will eventually cause the entire leaf to slowly dry up and fall off. If young leaves are accidentally infected, the infection will gradually expand and become less obvious on the edges. White powdery spots will appear on both sides of the young leaves, and then cover the entire leaf. The leaves also begin to turn light gray or purple-red. If the petiole is infected, its internodes will begin to shorten, the stem will begin to become thinner, and some diseased shoots will appear dry and then covered with white powder. If the flower buds are infected, the pedicels will become deformed, or even die in severe cases.

Prevention and control methods: Choose varieties that are resistant to powdery mildew. When pruning in winter, be sure to cut off all diseased branches and buds. In the early stage of the disease, you can apply less nitrogen fertilizer and more phosphorus and potassium fertilizers, so as to improve its disease resistance. In addition, attention should be paid to timely drainage after rain to prevent moisture from staying for a long time, thus reducing the occurrence of diseases.

2. Black spot

If the disease occurs, it usually affects its leaves, petioles and young shoots. When the leaves first start to become sick, some small purple-brown to brown spots will appear on the front. After expanding, they will become some round or irregular black-brown spots.

Prevention and control methods: We can choose some drugs such as carbendazim or daconil, and then spray them on the diseased areas.

3. Anthrax

The spots that appear are usually on the edge of the leaves, and are approximately semicircular in shape. The edges of the spots are dark brown, and the color turns brown to light brown in the middle. Later, many small black dots will appear on the spots. This pathogen can usually overwinter on diseased fallen leaves. In a relatively warm and humid environment, the spores will germinate and infect the leaves.

Prevention and control methods: You can carry out timely cleaning in late autumn and early winter, collect the diseased fallen leaves, and then burn them together. We also need to strengthen protection and provide appropriate repairs. Treat the denser branches and leaves, maintain good ventilation and ensure that the branches and leaves below receive light. Or you can use some medicines.