First, downy mildew
Characteristics: The disease mainly infested the leaves of lettuce. After the onset of disease, the seedlings turned yellow and died, and the adult plants became onset, and the leaves developed from the bottom up. At the beginning of the period, yellowish-yellow subrounded or polygonal lesions appeared on the leaves. When the damp spots appeared, white moldy leaves grew, and sometimes the moldy layer could spread to the front of the leaves. The late lesions turn into yellow-brown and connect into pieces, causing the whole leaves to dry, and sometimes the bacteria can infect the stems and cause the stems to become dark.
Control methods: Field plants were 2-3 times tilled before mulching. After planting ridges, the number of waterings was reduced, the field humidity was reduced, the water in the fields was prevented, plant growth was promoted, and the development of pathogens was inhibited. After the illness was found, the diseased leaves were immediately removed and burned. In particular, the lower leaves were removed to increase the permeability. Spray 600-800 times fluid M-45, can play a very good preventive effect. In the early stage of disease, medication is used once every 7-10 days to prevent and treat. The agent can be sprayed with 72% DuPont Kelu 800x or Kimreda Meer 600-800x. Several pesticides are alternately applied alternately, spraying once every 7-10 days, spraying 2-3 times in succession.
Second, black spot
Characteristic characteristics: Alternaria also known as ring disease or leaf blight, mainly harm lettuce leaves. The typical symptom is the formation of round or nearly round brown patches on the leaves, 3-15 mm in diameter, with concentric rims, and the appearance of black mold on the back of the lesion when wet. The disease is spread by wind and rain, warm and rainy, long time for dew condensation, lack of fertility, and plant weakness.
Control methods: to strengthen the cultivation and management, increase phosphorus, potash fertilizer. Rotation is carried out to remove old, sick and leaves in time. In the early stage of disease, use 50% acetaminophen wettable powder 1500 times solution or 10% Shigao water dispersible granule 1000 times solution, etc., rotate the drug, spray once every 7 days, spray 2-3 times continuously.
Third, Sclerotinia
Characteristic characteristics: more than the incidence from the base of the stem, and gradually extended upward and downward, causing skin rot. The surface of the lesions were cotton-like hyphae with black murine bacillus nucleus inside, and the upper part of the diseased plants quickly wilted and died. The pathogens spread through the wind and rain and invade from the senescent parts of plants. They are low-temperature, moist and dense and can promote disease.
Control methods: Reasonable fertilization, avoid partial nitrogen fertilizer application, and increase phosphorus and potassium fertilizers. Diligently cultivating and weeding, remove the diseased plants and diseased leaves in time, and perform deep plowing after harvesting so that most of the sclerotia are buried below 6 cm. At the early stage of disease, 70% thiophanate-methyl WP can be used 700 times, 50% skeletal WP 1500 times, or 40% sclerotin WP 500 times every 7-10 days. 1 time, continuous control 3-4 times.
Inner Mongolia Hengxintonghui Supply Chain Management Services Co.,LTD , https://www.hxthfood.com