How to Treat Rose Diseases? A Detailed Guide to Prevention and Control Methods
The rose is the queen of flowers, fragrant and blooming in all four seasons, and is a common ornamental flower. But roses are also very susceptible to diseases, so how do you treat rose diseases?
1. Rose powdery mildew
1. Symptoms: Diseased leaves first show chlorotic yellow spots, which then enlarge and become covered with white powdery growth, curling backward, shrinking and thickening. After the petioles and tender shoots are infected, they become slightly swollen and bend backward. After flower buds are infected, the flower shape becomes deformed. In severe cases, the leaves wither and yellow, and the plant becomes weak.
2. Prevention and control methods: To prevent this disease, pay attention to ventilation, do not plant too densely; do not let the air be too humid; increase light; apply more phosphorus fertilizer. Currently the best agents for controlling this disease are BASF's Collis (1 g diluted in 3 to 5 jin of water), Italy's Isabion (1 ml diluted in 3 jin of water); a syringe can be used as the mixing tool. For prevention, you can choose the low-toxicity Baolijing (1 g diluted in 1 jin of water).
2. Rose black spot
1. Symptoms: Rose leaves, pedicels and young branches can all be affected. The lesions are initially seed-brown to brown small spots, then expand and turn black or dark brown, often surrounded by a yellow halo. In severe cases, all the middle and lower leaves of the whole plant drop off, and branches die.
2. Prevention and control methods: Remove diseased leaves promptly, and heavily prune diseased plants in winter. Prune regularly during the growing season to maintain good ventilation. Isabion (1 ml diluted in 3 jin of water), 20% difenoconazole microemulsion (1 ml diluted in 3 jin of water), and Nativo (1 g diluted in 5 jin of water) can be used for control. For prevention, you can choose the low-toxicity Baolijin (1 g diluted in 1 jin of water)
3. Rose leaf blight
1. Symptoms: Occurs on rose leaves. In the early stage, yellow-green needle-point spots appear on the leaf surface. Later the lesions expand into round or irregular shapes with purple edges, and after expansion they merge into patches. The boundary between diseased and healthy tissue is obvious. In the later stage, small black spots appear on the diseased parts, and the edges of diseased leaves look scorched.
2. Prevention and control methods: Remove and destroy diseased leaves promptly. Choose disease-resistant varieties, plant at a reasonable density, and strengthen care. Spray with 75% chlorothalonil wettable powder at 500-800 times dilution. Dow AgroSciences' Daconil (1 g diluted in 1 jin of water), Bayer's Antracol (1 g diluted in 1 jin of water). Spray carbendazim and other agents in the early stage of the disease for control.
4. Rose mosaic virus disease
1. Symptoms: Mainly manifested as mosaic pattern, some showing ring spots or oak-leaf patterns, and some as chlorotic spots, yellow veins or stunting.
2. Prevention and control methods: Avoid using diseased plants as propagation material. Pull out and destroy diseased plants promptly when found. Choose disease-resistant varieties or tissue-cultured seedlings. During the growing season, pay attention to controlling aphids and other transmission vectors. Spray amino-oligosaccharin aqueous solution in the early stage of the disease to inhibit virus spread.
Roses need careful care. Although they are relatively easy to grow, they are prone to pests and diseases, so management work must be done well.