What Disease Causes Rose Leaf Curling
Abnormal curling of rose leaves often indicates that the plant is suffering from biological invasion or cultivation stress. This phenomenon not only affects the ornamental value but can also lead to the entire plant withering in severe cases. This article will systematically analyze the causes of rose leaf curling and provide professional-level solutions.
One, Pathological Mechanism Analysis of Leaf Curling
1.1 Fungal Disease Infection
Leaf spot disease is a typical fungal disease that causes rose leaves to curl, initially presenting as yellow circular spots on the leaf surface. As the mycelium spreads, the leaves gradually dehydrate and curl. The disease spreads 300% faster in high temperatures and humidity (25-30°C/RH>80%) and can be secondarily infected through rain splash.
1.2 Physical Damage from Pests
Red spider mites (Tetranychus urticae) and scale insects (Coccoidea) are the main harmful organisms. The former damages leaf mesophyll cells through piercing-sucking mouthparts, leading to chlorophyll loss, and when the pest density reaches 5 insects/cm², the leaf curling rate can reach 90%. The latter secretes honeydew that induces sooty mold, doubling the harm and accelerating leaf deformation.
Two, Analysis of Pathogenic Environmental Factors
2.1 Microclimate Imbalance
A closed planting environment reduces air circulation by 40%. When the day-night temperature difference is less than 5°C and the light intensity is less than 15,000Lux, the plant's resistance to diseases significantly decreases. Continuous soil moisture content greater than 70% can induce root rot, indirectly leading to leaf curling.
Three, Comprehensive Control Technical System
3.1 Physical Control Operations
• Remove Diseased Leaves: Use pruning shears disinfected with alcohol, making an oblique cut 2mm from the base of the petiole.• Environmental Regulation: Maintain a plant spacing of ≥50cm, install circulating fans to maintain a wind speed of 0.3-0.5m/s.• Light Management: Ensure an average of 4-6 hours of direct sunlight per day, with UV intensity ≥3μW/cm².
3.2 Chemical Control Plan
• Fungal Diseases: Alternate between using 25% azoxystrobin suspension (diluted 1500 times) and 50% carbendazim (800 times liquid), every 7 days.• Red Spider Mites: Spray the back of the leaves with 22% abamectin·spirodiclofen suspension (3000 times liquid).• Scale Insects: Apply 40% chlorpyrifos emulsion (1000 times liquid) + organic silicon additive, with a 10-day interval.
By establishing a preventive maintenance system, the incidence of rose leaf curling can be reduced by 85%. It is recommended to conduct EC value tests monthly (maintain 0.8-1.2mS/cm) and complement with amino acid foliar fertilizer (diluted 2000 times) to enhance stress resistance, fundamentally maintaining plant health.