On August 31, Ding Zhongtang, Qingyang Township, Jiangyan City, came to the telephone and said that after a recent rain, the land of 200 acres in the area had grown large and small tumors on its leaves, and there were many small knobs on the petiole. Now no one in the field is normal. At the beginning of the onset of disease, there will be a lump on the blade, and the latter will bulge at the rear and form a tumor. The last tumor will grow black and dry. After the onset of carbendazim, thiophanate-methyl control, the effect is very unsatisfactory. He asked which agents were effective. According to the preliminary diagnosis of relevant experts from the Department of Aquatic Vegetables of the Yangzhou University, Sagittaria showed nodules on the leaves and petioles, and later on it became dark, probably due to smut. Smut powder, also known as rickets, is the main disease of Sagittaria. It is widely distributed, with a general incidence rate of 20% to 40%. The rate of serious diseased field plants is more than 60%, which seriously affects the output and quality of Sagittarius, often resulting in 10%~ 20% reduction in production, severe disease fields can reduce production by more than 50%. The disease often occurs in hot and humid weather after June, and there are three types of symptoms on the leaf. The first is the appearance of light green round spots on the leaves, which gradually turn yellow-green blemish-like spots, so it is also called "caries." The diseased department often has a white slurry, and finally the disease is dying and yellow, and there are many black particles scattered. Sometimes the ridges fall off into holes. The second is the tan-colored swollen spots on the leaves. After the shrinkage, the punctures break off and form a broken mesh hole. The third is the appearance of brown green or orange lesions on the leaves, the edge is not obvious, many black dots are produced under the epidermis, the back of the leaves is yellow-white, and the epidermis ruptures to reveal the black spore heap. Petiole lesions were initially whitish, and later developed into green oval-shaped nodules and ascending longitudinal sulcus. Late orange-colored nodules showed many black granules after the epidermis ruptured. Root symptoms are not obvious. In severe cases, the entire leaf and petioles have numerous spots. The disease is a basidiomycotina aggregatum arrowhead fungus. The spores spore in the Sagittaria bulbs or remain in the soil as the residue of the disease overwinters, and after the next year the weather becomes warmer (the temperature is above 22°C), it spreads through air currents, rain, or irrigation to invade the plants and produces spores after about 1 week. Mission, reinfection. From June to July, when the temperature reached 26 to 28°C, the peak incidence occurred. After August, the temperature was too high and the drought caused the field disease to stop developing. During the growing season, it is hot and rainy, and there are many dew exposures. The disease is serious. Field plants grow green, apply nitrogenous fertilizer, and the density is too large. The disease occurs early and heavy, and the incidence of continuous crops is heavy. There are certain differences in resistance between varieties. After Ashton has developed smut, it should be sprayed and prevented at the early stage of the disease. It can use 80% Ethyl Iactin EC 1000 times, or 12.5% ​​fenfofenol EC 2500 times, or 25% Triadimefon WP 800 times. Liquid, or 50% carbendazim WP 500x, or 42% tebuconazole 8000x, or 10% difenoconazole 8000x, or 40% fluorosilicone Emulsion 8000 times, or 40% polysulfide suspension 500 times spray, 10 to 15 days once, continuous control 2 to 4 times. According to Ding Zhongtang’s report, the incidence rate of the diseased plots reached 100%, the condition was very serious, and the efficacy of the drugs was poor. It was appropriate to apply drugs repeatedly and alternately use different agents. In addition, the prevention and treatment of the disease should also be selected according to local conditions resistant to disease-resistant varieties, such as white arrowhead, scraping Laowu, purple round, Liancheng long arrowhead and other varieties. Pay attention to the selection of disease-free bulbs. Self-retaining seeds should be soaked with 10% triadimefon WP 1500 times, or 12.5% ​​fenfozolol 3,000 times, or 20% chloridrol 2500 times for 2 hours before germination. Or use 25% carbendazim wettable powder 500 times solution soaking for 3 hours, then wash germination with water. Clean the garden, completely remove the diseased tissue after harvest, and destroy it centrally. To avoid continuous cropping in severe wards, pay attention to the application of P and K fertilizers and rational planting, not too dense. Strengthen management of water and fertilizer, avoid long-term deep-irrigation and excessive application of nitrogen fertilizer, alter dry and wet late, promote root development, timely removal of old leaves, yellow leaves and diseased leaves. Soft Ice Cream Machine,Ice Cream Machine,Ice Cream Maker,Soft Cream Machine Guangzhou New Power Catering Equipment Manufacturing Co.,Ltd , https://www.gznewpower.com
The arrowhead of the Sagittaria is a smut disease.