Black spot of common diseases of canna

Canna

With the transformation of residents' way of life, potted flowers and ground flowers are becoming more and more popular. although canna with taller plants will try their best to dwarf and raise it at home, canna is easy to be infected with black spot in the case of improper conservation and management. infected plants affect the ornamental value, so how should flower friends take effective measures when canna is infected with black spot?

First, symptoms

Black spot damages the leaves of plants. In the early stage of the disease, yellow spots appeared on the susceptible leaves, which were round to oval, brown to dark brown after enlargement. Some of the disease spots are slightly wheeled. Disease spots can be connected to each other to form large disease spots, causing leaf death. In the later stage of the disease, a light black mildew is produced on the spot, which is the conidia of the pathogen.

Second, the law of the disease.

The pathogen overwintered on the fallen leaves with mycelium and produced conidia in the following spring. The conidia were infected by airflow transmission. The disease generally begins to occur from May to June, and is the most serious from July to August. High temperature and high humidity are beneficial to the occurrence of diseases.

III. Prevention and treatment

1. Reduce the source of infection and cut off the diseased leaves in time during the growing season, remove the diseased leaves in winter and destroy them centrally.

two。 Strengthen cultivation management, planting should not be too dense.

3. Chemical control: at the initial stage of the disease, after cutting off the diseased leaves, spray 65% Dysen zinc wettable powder 500mur800 times, or 1mer 1mer 100 Bordeaux solution, or 50% topazine wettable powder 500mur800 times, spray once every 10 times every 15 days, spray 3 times for 4 times.

Common diseases of canna and their solutions

Canna has bright colors and a long flowering period. it is one of the excellent flower varieties to beautify the environment. Some diseases will also occur in the conservation of canna. Let's learn about it below:

Canna disease:

Diseases of canna: 1. Black spot

Black spot is one of the common diseases of canna. In conventional cultivation, the disease is serious from June to August, with large withered spots and black fog on the back of the leaves, which occurs first from the leaf edge or leaf tip and then to the leaf center.

Solution: soak the bulb root with 50% methyl topiramate wettable powder 800 times for 5 minutes for 10 minutes before planting to prevent the disease. At the initial stage of the disease, the diseased leaves were cut off and burned, and 75% chlorothalonil wettable powder was sprayed once every 7 to 10 days for 2 to 3 consecutive times, which could inhibit the development of the disease.

Canna diseases: 2. Mosaic disease

Mosaic disease is a common disease of canna, when the disease occurs, there are mosaic or yellow-green spots on the leaves of the plant, petals become smaller and form a variety of colors, and when the disease is more serious, the leaves become deformed, involuted and plaque necrosis.

Solution: spray with 2000 times of 40% omethoate or 1000 times of 50% malathion, 20% diazinon and 70% aphid.

Diseases of canna: 3. Bud rot

Before the leaf development and flowering of the banana, the bud rot bacteria invaded through the stomata of the young leaves and flower buds. During the leaf development, many small disease spots appeared on the leaves, and gradually expanded, connecting with each other along the leaf veins to form large spots, and sometimes the disease spots formed stripes. The plaque is grayish white at first and soon turns black. The infected flower buds blacken and die before flowering. The disease spot can expand downward along the petiole, causing the death of young stems and buds. When the old leaf is damaged, the disease spot expands slowly, the shape is irregular, yellow, and the edge is watery.

Solution: soak in 500-1000 times solution of streptomycin for 30 minutes before planting, prevent and control bacteria, spray Bordeaux solution (1purl 200) or 77% can kill 500 times solution of wettable powder, 14% complex ammonia copper solution 400 times solution, etc., remove seriously diseased plants and remains in severe cases, and burn them.

Diseases of canna: 4. Leaf curling pests

Canna has strong adaptability, but it should pay attention to leaf curling pests from May to August every year, so as not to damage its young leaves and inflorescences.

Solution: it can be sprayed with 50% dichlorvos 800x solution or 50% prednisone EC 1000 times solution.

Canna has large flowers and bright colors, and breeding in the courtyard and other places will bring unexpected beautification results. In order to cultivate canna, it is necessary to pay attention to the occurrence and treatment of common diseases of canna. The solutions to common diseases of canna have been summarized to everyone. I hope it will be helpful to you.

Control of diseases and insect pests of canna

There is a big withered spot, and there is a black fog at the disease spot on the back of the leaf, which occurs first from the edge or tip of the leaf and then to the center of the leaf. This should be the black spot of canna. The primary disease is serious in Guangdong, Fujian, Hainan and Zhejiang. In recent years, it has also occurred in Beijing, Hubei and Tianjin, and the disease is serious in conventional cultivation from June to August.

Prevention and control methods: bulbs or seedlings introduced by ① should be strictly quarantined to prevent re-spread.

The ② bulb root was soaked in 50% methyl topiramate wettable powder for 5 minutes for 10 minutes before planting, and the disease could be prevented by taking out a little sun.

At the initial stage of the onset of ③, the diseased leaves were cut off and burned, and 75% chlorothalonil wettable powder was sprayed once every 7 to 10 days for 2 to 3 consecutive times, which could inhibit the development of the disease.