Control Methods for Common Diseases of Dahlia
Powdery mildew
Symptoms: Powdery mildew mainly attacks the leaves, flower stalks and flower buds of the plant. When the plant is affected, round white powdery patches appear on the plant, causing the leaves to twist and wither.
Control methods: Powdery mildew mostly occurs in autumn. When the disease breaks out, a diluted solution of antimycin can be sprayed, which has a very good control effect.
Brown spot disease
Symptoms: Brown spot disease mainly infects the leaves, causing yellow spots that gradually expand, and also produces black mold-like growth on the surface of the leaves.
Control methods: Plants generally become affected from June to August. Bordeaux mixture or chlorothalonil solution can be used for treatment.
The above are the post-bloom care methods for dahlias. We hope the dahlias you care for will be healthier and more beautiful.
How to control pests and diseases of dahlias
Dahlias have brilliant colors, shining brightly and displaying countless forms. They also have a long blooming period and are one of the world's famous flowers. With a short plant type and colorful flowers, their peak blooming period falls right around National Day, making them most suitable for household pot cultivation. How do you control pests and diseases of dahlias during cultivation?Dahlias like sunlight and prefer a mild climate. The optimum growth temperature is 10-25°C. They fear heat and are not cold-tolerant; at 0°C the tuberous roots freeze. In areas with high summer temperatures and abundant rain, plant growth stagnates and the plant enters a semi-dormant state. They are not drought-tolerant and are even more afraid of waterlogging, and they dislike heavy clay soil; after being waterlogged, the tuberous roots rot.
Powdery mildew harms leaves, flower stalks and flower buds. At first, nearly round white powdery patches appear, which expand into mottled white powdery layers, and the leaves twist and wither. The pathogen overwinters in diseased plant debris and spreads through airflow. The disease is severe from September to October. In the early stage of the disease, 2% antimycin 120 aqueous solution at 100-200 times dilution or 40% sulfur-carbendazim suspension at 800 times dilution can be used, sprayed once every 10 days for 2-3 consecutive sprays.
After brown spot disease infects the leaves, small pale yellow spots first appear, then expand and sink, finally forming nearly round spots with a grayish-white center and dark brown edges, with concentric rings, 1-5 mm in diameter, and a pale black mold-like growth on the surface. The pathogen overwinters in diseased leaf debris. The disease is severe from June to August. It can be controlled with 1% Bordeaux mixture or 75% chlorothalonil at 600 times dilution.
Viral disease shows symptoms such as mosaic patterns, chlorosis and dwarfing. The viral agents are dahlia mosaic virus, cucumber mosaic virus, tomato spotted wilt virus, tobacco streak virus, etc. Leafhoppers and aphids transmit the virus. For control, virus-free propagation materials can be selected and virus-transmitting insects controlled.
The dahlia stem borer moth larvae are pale yellow or pale red, with 2-3 generations per year. The larval damage period is from June to August. Fenitrothion 50% at 1000 times dilution can be sprayed. If the insects bore into the stems, omethoate at 100-200 times dilution can be injected.
Pests and diseases of dahlias and their control
Diseases of dahlias and their control
Powdery mildew
Powdery mildew is a relatively common disease of dahlias, mainly harming the leaves, flower stalks and flower buds of the plant. When dahlias develop powdery mildew, lesions appear on the plant as round white powdery patches, causing the leaves to twist and wither.
Dahlias usually develop powdery mildew in September and October. When the disease breaks out, some agents can be sprayed, such as a diluted solution of antimycin or a diluted solution of sulfur-carbendazim suspension, etc., sprayed several times in succession for a therapeutic effect.
Brown spot disease
Brown spot disease is also a common disease of dahlias. When brown spot disease occurs, it mainly infects the leaves, causing yellow spots that gradually expand, and also produces black mold-like growth on the surface of the leaves.
When dahlias develop brown spot disease, it is generally more severe from June to August. Bordeaux mixture or chlorothalonil solution can be used for treatment.
Viral disease
Viral disease is also a common disease of dahlias, mainly showing symptoms such as mosaic patterns, leaf chlorosis and plant dwarfing.
Dahlias develop viral disease mainly due to infection by certain viruses that cause pathological changes. When cultivating dahlias, choose pest- and disease-free planting materials and prevent pest damage.
Pests of dahlias and their control
Stem borer moth larvae
The common pest of dahlias is the stem borer moth larva. The larvae are pale yellow or pale red, and the damage period is mainly from June to August.
Control methods
When dahlias are attacked by stem borer moth larvae, some fenitrothion agents can be sprayed for treatment. Omethoate can also be injected.