What to Do When Black Spots Appear on the Leaves of桃花美人
桃花美人是 a star variety in the succulent world, and the appearance of black spots on the leaves is a common problem that困扰s many growers. These black spots not only affect the ornamental value but may also indicate a health crisis of the plant. This article will scientifically analyze the three main causes and guide you through a systematic black spot treatment plan.
Analysis of the Causes of Black Spots on桃花美人
Improper Watering
Leaf积水 is the primary factor triggering black spots. When water droplets remain on the waxy leaf surface, direct sunlight can create a magnifying effect, causing sunburn-like black spots. It is recommended to use a narrow-spouted pot to water along the edge of the pot, avoiding water accumulation in the leaf center. Water thoroughly every 15 days in winter and switch to misting in the morning and evening in summer to cool down, maintaining the substrate moisture at around 40%.
Metabolic Black Spot Characteristics
When the bottom old leaves naturally metabolize, they will show uniform brown spots, which is the normal replacement of old with new in the plant. Observe whether the spots are accompanied by leaf softening; healthy metabolic spots usually only change color without signs of rot. Retaining these leaves until they naturally fall off can help the plant regenerate.
Disease and Pest Infection Diagnosis
(T-J) disease and scale insects are the main pathogens. Infected leaves will show radially spreading black spots with a yellow halo around the spot edges. It is recommended to immediately isolate the diseased plants, wipe the insect bodies with 75% alcohol, and alternately spray with mancozeb and benzoylpropylazole, once a week for three weeks.
Comprehensive Black Spot Management Plan
Establish a preventive maintenance system: use red陶 pots to enhance breathability, and mix soil in a 4:3:3 ratio of akadama soil, kusakari soil, and pumice. Maintain an average of 4 hours of scattered light per day and keep the environmental humidity between 50-60%. Apply a slow-release trace element fertilizer once every quarter to enhance the plant's resistance to stress.
When the black spot area exceeds 1/3 of the leaf surface, surgical treatment is required: cut the diseased leaf with a craft knife sanitized with alcohol, and apply carbendazim powder to the incision. After the operation, place it in a shaded and well-ventilated area for two weeks, and gradually restore light after new buds sprout.