Marigold often has spot disease, which is caused by fungi. It is easy to get sick in hot and rainy humid weather. At the onset of the disease, the leaves appear spots, which will expand and increase. At the serious stage, the leaves turn yellow, black and dry, and finally fall off.
In daily management, we should keep ventilation and do well in water and fertilizer management. When the disease occurs, the diseased leaves can be removed, and 50% tobuzin 1000 times solution or carbendazim 800 times solution can be sprayed for treatment, and 10% Bordeaux solution can be sprayed once every 10 days for 3-4 times continuously, which can control the disease.
The bacterial wilt mainly occurs in the seedling stage of marigold. When the disease occurs, there will be small oval brown spots at the base of the stem of marigold. The spots will gradually expand, causing the stem to dry up and the seedlings to die.
When Marigold is infected with bacterial wilt, it can be treated by spraying 50% carbendazim or 50% mancozeb 1000 times, once in 7-10 days.
Marigold outbreak of powdery mildew, generally in the humidity, light shortage, poor ventilation conditions are easy to infect the disease. When the disease occurs, the leaves, stems, branches and flower buds of marigold will grow white powder, and the leaves will wither and not bloom.
When the outbreak of powdery mildew occurs in marigold, it is required to ensure that the growing environment is ventilated and the air humidity is relatively small. During the growth of Tagetes, it can be controlled by spraying methyl 50% Tobu 800~1000 times or 200 times.
Aphid is a common plant pest. It can occur in the growth process of marigold, mainly tea brown aphid and green aphid.
In the growth process of marigold, the growth of plants should be observed at any time, and timely control. Aphids can be sprayed with 10% imidacloprid 4000-6000 times.
The leaf miner moth is a kind of harmful insect. The larva will eat the leaves, and when it is serious, it can make the whole leaves yellow and wither.
If Marigold is found to be harmful to marigold, it can be used to remove the damaged leaves at the early stage, and it can be prevented by spraying with 40% Omethoate and other insecticide.
