What are the methods for preventing and treating rose diseases
1. Symptoms. Black spot is most prevalent in the Beijing area during summer and autumn. Infected rose leaves develop dark brown spots 3-4 mm in diameter with a yellow halo around them, and the leaves drop off; when the disease is severe, only the stems and infected young shoots remain on the rose plant. 2. Early prevention (1) During the rose seedling stage, prevent the leaves from...
Powdery mildew A fungal disease that harms flowers in environments with high temperatures, poor ventilation and relatively high humidity. A white powdery appearance on young leaves is called powdery mildew; use a 600-fold dilution of triadimefon or a 400-fold dilution of tuijunte.
Black spot
Caused by fungi, it overwinters in the soil on diseased remnant branches or fallen leaves as mycelium or acervuli; the following spring, water absorption produces conidia, which spread mainly by wind and rain. Rainy, foggy and dewy weather favors spore germination, so the disease develops easily. When water droplets are present on the leaves, the spores can germinate and invade within 6 hours. Under conditions of high air humidity during the rainy season, the reproduction of the pathogen and the spread of the disease are favored. Use 0.10-0.20 degrees Baume lime sulfur mixture, or spray the leaf surface with a 50% carbendazim wettable powder 500-1000-fold dilution.
Integrated control
The pathogen must be eliminated early. In early spring, in the first ten days of April, after the roses are taken out of the cellar and before the tree vigor becomes active, first carry out 1 pruning; before bud break, spray the roses thoroughly and carefully (including the plant, the pot soil and the area around the pot) with 0.50-1 degree Baume lime sulfur mixture.
Spray the plants regularly for control; use a 75% wettable chlorothalonil 500-fold dilution and an 18% copper fungicide 150-fold dilution, spraying once every 10 days. If it rains after spraying, spray again promptly after the rain. The spraying time is from June to September, with frequent spraying to control the occurrence of black spot.