What are the common pests and diseases of roses? A detailed guide to prevention and control methods
Common rose diseases include rust, black mold, and powdery mildew. Rust often affects rose leaves, young branches, and flowers. In the early stage of the disease, rust-red spots appear on the leaves, and in severe cases the leaves wither, scorch, and drop off, affecting flowering the following year. Diseased leaves should be removed promptly and destroyed in a centralized manner. You can also spray once every half month from May to August...
Common rose diseases include rust, black mold, and powdery mildew. Rust often affects rose leaves, young branches, and flowers. In the early stage of the disease, rust-red spots appear on the leaves, and in severe cases the leaves wither, scorch, and drop off, affecting flowering the following year. Diseased leaves should be removed promptly and destroyed in a centralized manner. You can also spray 150-200 times equal-strength Bordeaux mixture once every half month from May to August for prevention. During the disease period, spray 300 times fenaminosulf solution for control.
Black mold mainly affects leaves and the base of flower buds. It is severe in rainy, muggy weather and can cause massive leaf drop. Before the plants sprout in early spring, spray 3-5 degree lime sulfur mixture for control. In the early stage of the disease, you can also spray 50% thiophanate-methyl wettable powder at 600 times dilution, once every 10 days, and spray 3-5 times continuously depending on the condition for control.
Common rose pests include rose stem sawflies, rose noctuid moths, cottony cushion scales, and red spider mites.
Rose stem sawflies are wood-boring pests that mainly damage rose stems, causing branches to wither and leading to plant death. When pruning plants in winter, check the pith at the base of the stubs. If bored tunnels are found, drip in 1-2 drops of 80% dichlorvos emulsifiable concentrate, then seal the opening with mud. If young shoots are found to be infested, cut them off and destroy them.
Rose noctuid moths damage leaves with their larvae and also bite and feed on flower buds and flowers. Spray 90% crystallized trichlorfon at 1000-1500 times dilution, or 50% fenitrothion emulsifiable concentrate at 1000 times dilution for control.
Red spider mites damage both the front and back of leaves, causing leaves to dry up and drop off. In the early stage of infestation, spray 20% dicofol emulsifiable concentrate at 1000-1500 times dilution or 20% tetradifon wettable powder at 800-1000 times dilution. Both the front and back of the leaves must be sprayed. Spray once every 15 days; generally 1-2 sprays are enough.