Diseases and Pests of Marigold and Their Control

Diseases of marigold

Leaf spot

Marigolds often suffer from leaf spot disease, which is caused by fungi and is prone to occur in hot, rainy and humid weather. When the disease occurs, spots appear on the leaves and they will expand and increase in number. In severe cases, the leaves turn yellow, black, dry, and finally fall off.

Prevention and treatment methods

In daily management, ventilation should be maintained and water and fertilizer management should be done well. When the disease occurs, remove the diseased leaves and spray 1000 times diluted 50% thiophanate or 800 times diluted carbendazim for treatment. You can also spray 10% Bordeaux mixture once every 10 days for 3 to 4 times to control the disease.

Damping-off

Damping-off disease mainly occurs in the seedling stage of marigold. When the disease occurs, small oval brown spots will appear at the base of the marigold stem. The spots will gradually expand, causing the stem to dry up and the seedlings to die.

Prevention and treatment methods

When the disease of damping-off occurs in marigold, you can spray 1000 times diluted 50% carbendazim or 50% mancozeb for treatment, once every 7 to 10 days.

powdery mildew

When marigolds are susceptible to powdery mildew, they are usually susceptible to the disease in conditions of high humidity, insufficient light, and poor ventilation. When the disease occurs, white powder will grow on the leaves, stems, branches and buds of marigolds, the leaves will wither and the flowers will not bloom.

Prevention and treatment methods

When marigold is infected with powdery mildew, the growing environment must be ventilated and the air humidity must be relatively low. During the growth period of marigold, you can use 800-1000 times diluted 50% methyl thiophanate or 200 times diluted dinitrate to spray for prevention and control.

Pests of marigold

aphid

Aphids are common pests of plants and can occur during the growth process of marigolds. They are mainly light brown aphids and blue-green aphids.

Prevention and treatment methods

During the growth process of marigold, you should always observe the growth of the plant and take timely prevention and control measures. If aphids appear, spray with 4000-6000 times diluted 10% imidacloprid.

Leafminer

Leaf miners are a relatively harmful pest. Their larvae will eat the leaves, and in severe cases the entire leaf can dry up, turn yellow, and die.

Prevention and treatment methods

If marigolds are found to be infested with leaf miners, the affected leaves can be removed at an early stage. In severe cases, 40% omethoate or other systemic insecticides can be sprayed for prevention and control.