What Causes Black Spots on Climbing Rose Leaves
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What Causes Black Spots on Climbing Rose Leaves
What Causes Black Spots on Climbing Rose Leaves
Black spot disease on climbing roses is mainly caused by fungal infections, belonging to the genus Actinomycetales, Cladosporium, and Hemipectoptera. This is a worldwide plant disease that is very common and extremely harmful to roses, affecting leaves, flowers, and buds.
Black spot disease on climbing roses may also be caused by high temperatures and high humidity, especially when ventilation is poor, which can easily breed bacteria. Therefore, during the cultivation of climbing roses, ensure good ventilation and avoid direct sunlight.
What to Do When Climbing Rose Leaves Have Black Spots
If climbing roses are infected with black spot disease, it is necessary to immediately cut off the diseased leaves and use fungicides such as carbendazim, polyoxysulfone, or Bordeaux mixture for spray control.
The black spots on climbing rose leaves are usually caused by black spot disease and need to be controlled with drugs like carbendazim. It is also important to pay attention to fertilization to improve the plant's disease resistance. In addition to this disease, plants may also suffer from rust and powdery mildew, which should be treated with triadimefon spray.
Moreover, climbing roses may encounter aphids and scale insects, which require spraying insecticides such as pymetrozine.
Preventing Black Spots on Climbing Rose Leaves
1. Diseased leaves on climbing roses that are severely affected can be directly cut off. Be sure to use a sharp, disinfected pair of pruning shears. After cutting the diseased leaves, do not cut any other branches with the same shears.
2. Clean up all the diseased leaves and branches on the soil surface of climbing roses, including fallen leaves, to prevent the onset of fungal diseases.
3. Climbing roses need to be regularly sprayed with fungicides, not just carbendazim, for prevention. When the fungal disease is truly induced by the plant, spray a solution of chlorothalonil, polyoxysulfone, or methyl thiophanate every 5-7 days, for about 4 consecutive applications.
The detailed explanation shared above about the causes of black spots on climbing rose leaves is hoped to bring you assistance in green plant management!