The pathogenesis of tomato leaf mold and its prevention and treatment
How to prevent and cure tomato leaf mold? Tomato leaf mold is also called black disease in some places, and it is also one of the common diseases of tomatoes. In severe cases, it affects tomato quality and yield. Let's learn about the occurrence and control methods of tomato leaf mold. First, the symptoms of harm Leaf mold mainly harms the leaves, and in severe cases, it also damages stems, flowers, fruit stalks and fruits. It usually begins to develop from the middle and lower leaves, and then gradually spreads to the upper leaves. Leaf disease: In the early stage, yellowish spots appear on the front of the leaves, and then the spots diffuse into irregular or elliptical yellowish chlorotic spots with inconspicuous edges; the surface of the leaves on the back of the leaves is grayish white, then becomes pale brown to dark brown. When the humidity is small, the mildew layer is not obvious; when the humidity is large, the black mold layer can grow on both the front and the back of the leaf. As the disease progresses, the leaves gradually curl from bottom to top. Generally, the leaves of the lower part of the disease plant first develop, and then gradually spread upward, and finally the whole plant leaves are yellow-brown and dry. Second, the law of incidence Foliar disease is a fungal disease caused by the genus H. oxysporum, which is mainly caused by mycelium or hyphae overwintering in the diseased body, or conidia attached to the seed epidermis or mycelium. Overwintering in the seed coat. When the environmental conditions are appropriate in the second year, conidia are produced and spread by airflow, irrigation water, etc., and can be invaded from the stomata on the back of the blade, or invaded from the sacs, stalks, etc., into the ovary, and lurking on the seed coat. The pathogen prefers high temperature and high humidity environment, and the optimal temperature for onset is 20-25 °C; at a certain temperature, the relative humidity is larger (more than 80%), the heavier the onset, the disease is prevalent when the relative humidity is above 90%. . Land plots with heavy ground, poor drainage, dense plants, poor ventilation, and high air humidity are prone to disease. Third, prevention and treatment methods 1. Choose resistant varieties. 2. Remove plant disease residues in time to remove them from the field and concentrate them on burning or deep burial. 3. Reasonable rotation: Rotating with non-solanaceae crops for more than 2-3 years, reducing the number of pathogens in the soil. 4. Seed disinfection: seed treatment is carried out by means of soaking seeds in warm soup, and after washing, drying, germination and sowing. 5. Field management: avoid partial application of nitrogen fertilizer, increase application of phosphorus and potassium fertilizer, prevent prolonged growth, enhance plant disease resistance; timely clean up the lower old leaves and yellow leaves, which is conducive to ventilation and light transmission; greenhouse cultivation area timely ventilation, control of watering, Drain in time after watering. 6. Chemical control: You can use the whole plant spray of Guoguang Pythium, Polymycin, Iprodione, Difenoconazole, etc. to control the leaves, and focus on the back and middle and lower leaves of the leaves. Note: It is easy to distinguish between leaf mold and gray mold, which can be distinguished from the following points. Leaf mold is easy to develop under warm and high humidity conditions, mainly in the middle and lower leaves, the leaf disease is irregular lesions, and the mildew layer is mostly on the back of the leaf; gray mold is easy to develop under low temperature and high humidity conditions, with leaves, The residual flower and the fruit stalk are mainly affected, and the leaves are "V"-shaped lesions when the disease occurs, and the mildew layer is mostly positive. The above content, the author of the article is Peng Guohao, I hope this content can help the vegetable farmers who have a headache for tomato leaf mold. In the process of planting, everyone can prevent it! Ultrasonic Cleaners,Ultrasonic Cleaner Machine,Dental Ultrasonic Cleaner Machine,Dental Distilled Water Machine Foshan Ja Suo Medical Device Co., LTD , https://www.jasuodental.com
