Calendula disease prevention and control methods

Calendula powdery mildew

symptom

Powdery mildew is the main disease of calendula, which seriously affects its ornamental value. In the early stage of the disease, white circular spots appear on both sides of the leaves. The spots further expand and become irregular circles. The leaf surface looks like it is covered with a layer of white powder, and the stems are also covered with white powder. The growth of the plant slows down, the flowers gradually become smaller, and finally, the diseased leaves and stems turn yellow, and the entire plant withers and dies.

Prevention and treatment methods

Strengthen water and fertilizer maintenance to enhance the plant's disease resistance. Plants maintained indoors need to be ventilated in time, especially in March and April when the weather turns warmer. They should be moved outdoors in time to reduce the humidity.

After the flowers fall, remove the fallen leaves and flowers in time, and trim the diseased plants.

After the disease occurs, spray the pesticide in time, 1500 times diluted thiophanate-methyl or oxycarb wettable powder. When spraying, spray the entire plant. Spray once every 10 to 15 days, and spray 2 to 3 times in a row.

Calendula mosaic disease

symptom

Mosaic disease mainly harms leaves. After being infected by this disease, the leaves will become mottled or mosaic-like, the leaves will turn yellow, the growth of the plant will be stunted and dwarfed, and the flowers will grow deformed. Mosaic disease is mainly spread by insects, and is often accompanied by insect pests when it occurs.

Prevention and treatment measures

When diseased plants are found, they should be removed promptly. Since there is currently no specific medicine to prevent and treat mosaic disease, the prevention and control of mosaic disease mainly focuses on preventing pests and spraying fungicides every month.

Calendula rust

disease

When temperatures rise in early summer, rust often occurs on marigolds. Rust-like spots will appear on the leaves, causing leaf fall, burnt tips, poor growth, etc. In severe cases, the spores accumulate in dense patches, and the marigold quickly dies due to the evaporation of a large amount of water in the body.

Prevention and treatment methods

Spray the pesticide in time, using 2000 times diluted 50% carboxin wettable powder. Once rust spots are found on the leaves, remove them in time to avoid spreading to other leaves.