Pay attention to prevent vegetable diseases in haze days

In winter, the number of haze days, low temperature and light weather increased, especially in the central part of our province and Beijing-Tianjin area, which has a certain impact on vegetable production and will aggravate the occurrence of diseases. Here, it is suggested that the majority of vegetable farmers should prevent the occurrence of vegetable diseases from the following aspects.

First, add to the luster

In haze weather, the grass and quilt should be opened every day to allow vegetables to use scattered light for photosynthesis; select the greenhouse film with good light transmittance and clean the greenhouse film in time to enhance the light transmittance; if there are conditions, artificial light can be replenished by placing supplementary light lamps and hanging reflective curtains on the back wall.

Second, less watering

In haze weather, the root system of vegetables is weak and the metabolic level is low, so it is not suitable to water heavily. It should be watered reasonably according to the weather conditions, and drip irrigation under plastic film should be adopted to strictly control the humidity in the greenhouse to avoid the occurrence of low temperature and high humidity environment and prevent diseases.

III. Less fertilization

It is not suitable to apply a large amount of fertilizer in haze weather, but appropriate amount of carbon dioxide gas fertilizer can be applied. After the weather turns fine, proper amount of water and foliar fertilizer can be sprayed on the leaves, and normal water and fertilizer management can be carried out after the vegetables return to normal growth.

IV. Chemical prevention and control of common diseases

1. Tomato Botrytis cinerea. Botrytis cinerea is one of the most common diseases of greenhouse tomato in winter. Botrytis cinerea infects tomato leaves, stems, flowers and fruits, but harms green fruits more seriously. The control of tomato late blight should avoid excessive humidity in the greenhouse for a long time, timely ventilation, and timely removal of diseased plants at the initial stage of the disease. The pesticide control can be sprayed with 250 g / L azoxystrobin suspension, 70% propicin zinc wettable powder, 100 g / L cyanofrozole suspension and 72% urea manganese zinc wettable powder.

two。 Sclerotinia sclerotiorum. Humidity higher than 85% in the greenhouse is conducive to the incidence of Sclerotinia sclerotiorum. Young melons and stem vines in the middle and lower parts of the plant often suffer from serious diseases. Most of the young melons are infected from the top, showing water-stained dark green rot at the beginning, and then dense flocculent white mold is produced in the diseased part. when the environmental conditions are suitable, the white mold in the disease part is transformed into black mouse fecal sclerotia. When the stem was killed, the discolored water-immersed spot began to appear, then softened and rotted, and the diseased part produced white flocculent hyphae, followed by the formation of black mouse fecal sclerotia.

Using chemical control, 50% acetamidoxime water dispersible granules, 50% carbendazim wettable powder, 25% carbendazim wettable powder, 255 g / L isocarbamide suspension or 25% prochloraz EC can be sprayed.

3. Cucumber downy mildew. The disease mainly occurs in leaves. At first, the diseased leaves showed light green water soaking spots, but after expansion, they were polygonal and yellowish green turned to light brown. In the later stage, the disease spots converged into pieces, the whole leaves dried up, the gray-black mildew layer appeared on the disease spots on the back of the leaves when it was wet, and when it was serious, the leaves of the whole plant withered.

The prevention and control of cucumber downy mildew should make use of the closed characteristics of protected areas, and it is particularly important to create environmental conditions with high temperature and low humidity. Before the arrival of continuous haze overcast and rainy weather, spraying protective agents or chemical fumigation can play a better preventive effect, such as 45% chlorothalonil smoke remover and so on. At the initial stage of the disease, 20% flumorph wettable powder, 250 g / azoxystrobin suspension or 80% enoylmorpholine water dispersible granules can be sprayed for prevention and treatment.

Yu Lianguo of Yixian Agricultural Bureau