All the leaves of the Chinese rose have fallen off.

Common rose varieties can tolerate the low temperature of 65438 05℃. It needs rich organic matter and fertile and loose slightly acidic soil, but it has wide adaptability to soil. The relative humidity of air should be 75% ~ 80%, but it can also be slightly dry or slightly wet. It seems that the black spot disease should be controlled according to the following methods: 1. The diseased leaves of black spot disease first appeared small brown patches, which gradually expanded, and the epidermis showed large black-brown or purple-brown circular patches, and finally fell off due to necrosis. Control method: 200 times of Bordeaux mixture or 500 times of 60% mancozeb wettable powder can be sprayed; At the same time, it is necessary to clean the diseased leaves in time and burn them to reduce infection. 2. Powdery mildew covers leaves, petioles and tender tips of branches with a layer of white powder, which damages leaves and other places. Prevention and control methods: strengthen ventilation, reduce temperature, remove diseased leaves and branches, and burn them in time; Spray with 50% amobam 1000 times solution, or spray with 50% wettable powder and carbendazim 1200 times solution; Bordeaux mixture can also inhibit the development of diseases 200 times. Diseases: rose powdery mildew, rose green leaf disease, rose black spot disease.

Pest: Tetranychus schrenckii, a green blind stinkbug mite.

Rose powdery mildew

Symptoms: powdery mildew of rose is a worldwide disease, which harms rose, rose, rose and other plants. Pathogens infect leaves, floral organs and shoots of Chinese rose. In early spring, the leaves with diseased buds are covered with white powder on both sides. The leaves shrink, roll back, thicken, dry up and die gradually, and become the primary source of infection. In the growing season, when the leaves are infected, small white speckles first appear, which gradually expand into round or irregular white speckles. In severe cases, the white speckles are connected with each other. When shoots and petioles appear, the lesion is slightly enlarged and the internodes are shortened. Hualei was covered with white powder, shrinking and drying up. Mild buds produce deformed flowers.

In a word, powdery mildew is harmful to rose, causing early defoliation, dead branches, abnormal buds or failure to open, which seriously weakens the growth of rose when it occurs year after year. The pathogen of this disease is rose mononucleosis. Roses are only asexual, that is, powdery mildew fungi. Combined with pruning, diseased branches, diseased buds and diseased leaves are removed to destroy and reduce invasion. The methods of chemical control of rose powdery mildew are as follows.

(1) Spraying Pomei 2~3 degree stone sulfur mixture during dormancy to eliminate the overwintering hyphae in the diseased bud or the closed capsule shell of the diseased part.

(2) There are 65,438+0,500 ~ 2,000 times of 25% triadimefon wettable powder, 65,438+0,500 ~ 2,000 times of 50% benomyl wettable powder or 250 times of sodium bicarbonate commonly used in chemical control. Sulfur powder is often used for cold protection in greenhouses.

(3) Bio-pesticides such as B0-10 and antifungal agent 120 also have good control effects on powdery mildew.

The chemical name of antifungal drug 120 (Nong Kang 120, TF- 120) is called pyrimidine nucleoside antibiotics. It is a new variety of Streptomyces, which is white powder in appearance, soluble in water, insoluble in organic solvents, stable in acidic and neutral media, and unstable in alkaline media. Antibacterial 120 is a broad-spectrum antibiotic, which has a strong inhibitory effect on many plant pathogens. The control of powdery mildew of rose is to spray at the effective concentration of 100 mg/L, with the interval of 15~20 days, and spray continuously for 3 times. 3. Rose green leaf disease

Symptoms: Petals are thin and narrow, showing green sepals or leaves, corollas turn green and flowers turn leaves, which is a typical symptom of rose green petal disease. Under the same cultivation and management conditions, the plants suffering from this disease have shorter plant types, more lateral branches, narrower leaf shapes and less red petioles and stems. Flowers are prolific and flowery. Until winter, green flowers last for a long time, but in summer when the temperature is high, the base of the flower stalk is easy to delaminate and will fall off when touched.

Pathogen: Mycoplasma-like organism, which exists in phloem cells at the base of leaflike corolla and tender petiole of "green calyx", is oval and nodular, and new individuals formed after division are mostly spheroids, with individual diameter of 100-800 nm.

Transmission route: Recently, it is known that the main route of virus transmission is artificial grafting transmission, and whether there is still insect transmission in nature remains to be investigated.

Prevention and cure method

1, strengthen quarantine to prevent virus-free vaccines from being brought into disease-free areas.

2, timely prevention and control of tobacco pests and other suspicious media.

3. Use disease-free plants as propagation materials, remove diseased plants in time, and reduce the spread of bacteria. If the leaves fall in the north, but the situation is very weak, you must keep warm. The method is 10. After freezing water is poured in the middle of October, the branches are cut from the ground 1 10 cm above the ground, buried underground for heat preservation, pulled out before germination in the next spring, and fertilized once, preferably with decomposed organic fertilizer. If it is not necessary to apply NPK compound fertilizer, water is poured to germinate. Faith can grow well. Wish you success!