Protected Tomatoes in Winter Protected Areas against Late Blight

Tomato late blight is a disease of low temperature and high humidity. The temperature in the greenhouse is 22 to 24Â°C during the day and 10 to 13Â°C at night. The relative humidity of the air above 80% can infect the plants, especially in conditions of continuous rain and light. Under the more prone to happen and popular, tomatoes in winter protected areas should pay attention to timely prevention and treatment.

Late blight can harm tomato leaves, stems, and fruits, with severe damage to leaves and green fruits. Leaf victims usually start from the tip or the leaf margin of the lower middle leaf, and gradually spread to the upper leaf and fruit later. The initial stage is dark green irregular water-stained lesions. There is no obvious boundary between disease and health, and the humidity is high. The spot quickly spreads and a white mold layer appears on the edge of the lesion. Damage to the culm, water-stained depression in the diseased area, and then turned brown, disease stem tissue becomes soft and easy to break. The fruit is affected, and the disease starts from the near fruit stalk. The lesions are oily and gradually develop into four weeks. They gradually turn dark brown later, and are slightly sunken. The diseased fruit is not soft and soft, and the diseased surface is white and moldy when wet. Things. After the fruit is harvested, it will continue to suffer during storage and transportation.

To control the late blight of tomato, it should be used in the early stage of disease to cure 52.5% of ketones, urea cyanide wettable powder 2000 times, or 50% of enoyl ethylene phosphate aluminum wettable powder 600 times, or 72% of frost urea manganese zinc. WP 600 times, or Amisida 250 g/liter azoxystrobin suspension 1500 times spray, once every 7 to 10 days, continuous control 3 to 4 times. In addition, measures such as rational rotation, selection of disease-resistant varieties, disinfection of seeds and seedbeds, and enhancement of cultivation and management have a good preventive effect.

YT-T15

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