Identification of Sphaerotheca fulva
Tomato tomato leaf spot disease, also known as tomato leaf spot disease, tomato gray leaf spot and brown spot disease, has become more prevalent in the Beijing and the suburbs in recent years, and has risen as a major disease in some tomato gardens. More than 90%, the output loss exceeds 50%. Before the disease occurred in this city, the farmers and grass-roots agricultural technicians generally lacked the experience of identification and prevention. To this end, I would like to tell you about the identification and prevention of the disease. ■Symptom identification The main damage leaves, in serious cases can also damage the petiole, stalk, stalk and calyx. In the early stages of damage, dark round or irregular round spots were produced on the leaf surface, and then they were restricted by the veins to expand around, showing a round, nearly circular or irregular shape. The middle chlorosis was pale to light brown. Micro-depression in the middle of the lesion, easy to break the perforation in the late and even the whole leaf dry, fall off. Petiole, stalk, stalk, and calyx lesions produced dark, near-circular lesions early in the lesion, microscopic spread in later stages, darker edges, and gray or white in the middle with a diameter of 2-4 mm. ■The incidence of the law The pathogenic bacteria is S. solanacearum and the wintering occurs when the mycelium adheres to the seed with the diseased body in soil or with conidia. When the conditions are appropriate, conidia are produced, and they are splashed on the tomato plants by air currents and rain, and invade from the stomata. Warm and humid, continuous rainfall and prolonged condensation are important conditions for the occurrence of diseases. Poor terrain, over dense planting, poor ventilation and light transmission, lack of soil fertility, and weak plant growth tend to occur. Under the same conditions, old leaves are susceptible to disease. ■Control methods Use resistant and resistant varieties. Varieties that have disease resistance or resistance to disease include pink fruit varieties such as Golden fruit 258, Garcia, and FA-1415, and pink varieties such as Sidong Shuangtian and L402. Seed treatment. The disease-free, coated seeds are selected and, if uncoated, they must be sterilized by soaking in warm soup. Put the seeds into hot water of 50°C-55°C, stirring constantly. When the water temperature drops to 30°C, stop stirring, continue immersing for 4-6 hours, knead with a clean, damp cloth, and soak with 10% sodium phosphate for 20 minutes. Then Rinse the liquid with water to germinate. Cultivation of disease-free seedlings. Use seedling-free seedlings (such as Daejeon soil) or plug seedlings. Before transplanting, spray 20% kresoxim-methyl water dispersible granules 1500 times or 10% difenoconazole water dispersible granules 3000 times. Cultivation and disease prevention. Before planting, add base fertilizer, nitrogen, phosphorus, and potassium fertilizers are used in a reasonable manner; use mulching or high ridge mulching to cover the cultivation; the sheds that once had this disease must be sterilized and sterilized on the surface of the shed before planting; timely watering and top dressing, watering After the improvement of ventilation, avoid stuffy sheds, and avoid stagnant water in the fields after the rain. Clean up the old leaves in time. Completely remove the diseased plants after harvest and concentrate on harmless treatment. Chemical control. Even after sporadic rain or a sporadic disease in the field, use 60% oxazoline-synthetic water dispersible granules 1500-fold, or 300-grams/litre ether bisporin suspension 1000-fold, or 10% phenyl ether Mepiconazole water dispersible granules 2000 times, or 50% iprodione suspension 1500 times, or 43% tebuconazole 2500 times, or 40% polysulfide 600 times, etc. Spray once every 7-10 days, continuous control 2-3 times. When the disease is severe, the application interval can be shortened by 4-5 days, and it can be controlled 2-3 times in a row. The medicaments should be used alternately and evenly sprayed on the positive and negative sides of the leaves. The medication should strictly observe the safety interval. Greenhouse Dutch Buckets,Dutch Bucket,Tomato Dutch Bucket,Plastic Dutch Bucket JIANGSU SKYPLAN GREENHOUSE TECHNOLOGY CO.,LTD , https://www.greenhousehydroponic.com