Control methods of celery spot blight caused by low yield of celery

Leaf spot blight seriously affects the quality and yield of celery. The symptoms and control methods of celery spot blight are as follows:

Celery spot blight

I. harmful symptoms

Leaf spot blight mainly harms the leaves, petioles and stems of celery. The disease starts from the lower leaves of the celery plant, and then extends to the middle and upper leaves. Leaf disease, the first light brown oil-soaked spots, gradually expanded to a diameter of 3-10 mm (mostly about 3 mm) round or irregular spots. The central part of the lesion is brown, light brown or grayish white. The edge is dark reddish brown and yellowish brown, with a yellow halo on the outer edge. In the later stage, there are scattered or a small number of small black spots on the plaque. Petiole and stem disease, the disease spot fusiform or long oval, slightly sunken, brown, light internal color, the spot is dense with small black spots. The disease is serious, the leaves are densely covered with disease spots, or the disease spots are connected into large areas, causing celery leaves to dry up and die. There are also large spot, generally round, larger 4-15 mm, the edge is mostly dark green.

II. Prevention and control methods

1. Select the varieties of celery with strong disease resistance.

2. Using seeds collected from disease-free celery plants or aging seeds every other year, using the new seeds of the previous year, celery seeds must be sterilized and the seeds can be soaked in warm water at 48 degrees Celsius for 30 minutes. This method has a slight effect on the seed germination rate and the sowing rate should be increased by 10%.

3. Make a good land and apply sufficient base fertilizer. From 7 to 10 days after planting, a small amount of fertilizer should be applied combined with frequent watering, and the vigorous growth period should be flooded and fertilized. Topdressing should pay attention to the combination of nitrogen, phosphorus and potassium, increasing the application of phosphorus fertilizer in the early stage and potassium fertilizer in the middle stage. Irrigation should be carried out frequently with small water to avoid flooding. The stagnant water in the field was discharged in time after the rain.

4. Timely harvest. In the early stage of the disease, the diseased leaves of celery, especially the lower leaves, were removed and buried deeply.

5. Crop rotation in the seriously affected area for more than 2 years.

6, celery spot blight in the early stage of the disease in time, such as 75% chlorothalonil (daconine) wettable powder 600 times liquid spray.