Timely control of watermelon fruit spot
Recently, the Department of Agriculture of Shandong Province discovered watermelon fruit spot disease in nursery greenhouses in Liaocheng and Dezhou. The disease is a national phytosanitary object, a devastating disease that occurs on watermelons, and can generally cause a 50%-90 reduction in watermelon production. %, and seriously affect the quality of watermelon. In order to ensure the safety of watermelon production, various measures should be taken to prevent and control watermelon spotted disease in time. First, the harm symptoms During the seedling stage of watermelon, when the cotyledons were opened, the lesions were dark brown and developed into dark brown necrotic spots along the main vein. The lesions are small on the true leaves, dark brown, surrounded by yellow halos, and usually develop along the veins. 14-21 days after flowering, the fruit is easy to infect. In the epidermis with watermelon fruit facing upwards, small water spots with diameter of only a few millimeters appear first, and then quickly expand to several centimeters irregular large-scale olive water-stained patches. The color is deepened, and it is constantly expanding, covering the entire fruit surface in contact with the ground portion within 7-10 days. The early formation of lesions after the aging of the lesions of the epidermis crack, often overflowing thick, transparent amber pus, the fruit quickly rot. Second, the cause of the disease Melon vegetable fruit spot caused by gram-negative bacteria, the growth of the pathogen temperature 28 °C, 4 °C -41 °C can grow between. The pathogenic bacteria mainly overwintered on the surface of the seed and the soil surface and penetrated through wounds and stomata. The transport of bacteria seeds is the main route of long-distance transmission. Bacterial pus on lesions is transmitted through rainwater, wind, insects, and agricultural operations, which can harm watermelons, melons, pumpkins, cucumbers, zucchini, and bitter gourds. Third, prevention and control measures 1. Quarantine measures. Do not relocate, purchase, or use seeds or seedlings that have not been quarantined. Suspected symptoms were found, immediately reported to the local government, and effective measures were taken to block and extinguish. 2. Use resistant varieties. The degree of susceptibility between cultivars is quite different. In areas where the morbidity is relatively severe, resistant cultivars should be replanted. For example, the triploid is more resistant to disease than the diploid and dark green than the light green. 3. Seed treatment. When seeds are sown, they are fermented with fruit juice and pulp for 24-48 hours (or soaked for 6 hours), then soaked in 1% hydrochloric acid solution for 5 minutes, washed with clean water, and air-dried to kill germs on the seed surface. 4. Strengthen management. Rational rotation and dumping, and non-cucurbit crops for more than 3 years of rotation. Deeply tossing land, turning sick bodies, wild hosts and pathogens into the depths of the soil or destroying their living environment to reduce the number of bacteria sources and reduce the chance of infection. Soil preparations, diseased fruits, weeds and wild host plants, especially cucurbits, are cleared during site preparation. Disinfect agricultural tools to kill germs. With drip irrigation, the irrigation water is sprayed only to the roots, which can effectively reduce the spread of germs. From the seedling stage, it was found that the diseased plants should be eradicated immediately and moved to the field and burned. 5. Chemical control. Copper preparations or antibiotics have better control effects. Can be used 50% methicone wettable powder 600 times or 77% can kill WP 400 times stem and leaf spray, spray once every 7-10 days, 3-4 times in a row. Flavors & Fragrances,Essential Oil,Eucalyptus Oil,Chinese Mugwort Leaf Oil Xi'an XJeson Biotech Co., Ltd , https://www.xjesonbio.com