First, the characteristics of major diseases. The major diseases of sesame are sesame stem blight, sesame wilt, sesame blight, and sesame blight. 1, sesame stem blight. Sesame stem blight, also known as sesame stem blight, sesame Heigen mad and so on. The main damage is sesame stems, roots and seedlings. At the seedling stage, the upper part of the diseased seedlings died of wilting and roots died of browning. After the stalk is damaged, the diseased stem appears yellowish-brown water-stained spots and develops rapidly. It turns into a wrap-around spot, and is dark brown in late stages. Afterwards, the stem is hollow and easily broken. After the roots were damaged, the main roots and branching roots gradually turned brown, and a large number of black sclerotia formed in the root cortex, causing the roots to die. The bacterium sclerotia winters on seeds, soil, and diseased plant residues. In the following year, conidia are transmitted by wind, rain, and steam in the field, and they mainly invade from the base, root, and petiole of the plant stem. Sesame seedlings and flowering stages are the most susceptible. Strain can produce conidia and spread infection. High temperature, high humidity, and more rain are conducive to disease epidemics, partial application of nitrogen fertilizer, planting too dense and continuous crop damage. 2, sesame wilt. The sesame wilt disease, also known as half yellow or yellow, is a typical vascular disease. Many pathogens invade the root tip and wounds of the seedlings. The pathogens enter the catheter after invading from the roots and spread along the catheters to the stems, leaves, pods and seeds, causing the disease to die. The base of the diseased plant stem was reddish-brown, the vascular bundle of the stem was brown, and the leaves turned yellow and wilted. Sometimes it is limited to half of the infection, the performance of the disease is half of the dead. When wet, the affected area has pink mold. The pathogenic bacteria overwinter in the soil, in diseased plant residues or inside and outside the seeds. The onset began in June and peaked in August. Even for sesame field, poor soil fertility and high humidity in the field, it is conducive to the occurrence of disease. 3, sesame wilt. Sesame bacterial wilt is commonly referred to as sesame meal and is a disease caused by bacteria. The bacteria invade from the root wound or invade from the natural orifice and spread from the bottom up in the plant duct. In the early stages, the diseased plants seemed to lack water, wilted during the day, returned to normal at night, and slept at night after a few days. The outer part of the roots of the affected plants was dark brown with brown spots, and the inner vascular bundle was brown with bacteria overflowing. The leaf veins of the affected leaves were dark green stripe, and the diseased fruit was dark brown. The disease bacterium spreads over the soil with the diseased plant residues in the soil and is transmitted by running water or agricultural operations. The peak incidence is mostly in summer 7-8 months. After the storm, the sudden increase in temperature is conducive to the epidemic of the disease. 4, sesame disease. Sesame is a devastating disease. The main damage to the sesame stem base, stem, capsule, leaves. After the victim's base was damaged, it developed dark green water stains, followed by reddish-brown, depressions, and longitudinal cortex. After the damage of stems and pods, the diseased part was dark green water stains, contracted and sunken, and there was cottony white mold. After the leaves were damaged, yellow-brown lesions appeared, and the lesions had inconspicuous rims. The pathogenic bacteria overwintered in the residue of the diseased plant with hyphae or oospore. The pathogens of the following year invade the stem base and produce sporangia, which are spread by wind, rain, and water to expand and re-infect. In July, the period of onset of budding sesame started to occur and peaked in August. Rainy and wet victims are heavy. Second, comprehensive prevention and control technology 1, selection of disease-resistant varieties and seed treatment. Choose high-quality, high-yield, stain-resistant and disease-resistant varieties such as Yuzhi No.8 and Yizhi No.1. Before sowing, soak in seeds with warm water of 55°C for 10 minutes or soak in warm water of 60°C for 5 minutes. Allow to dry after sowing. Or use quintozene (1:1) with quintozene and dosage of 0.5-1% of seed weight; or soak with 0.5% copper sulfate solution for half an hour, all have better control effect. 2, agricultural control. The sesame soil has serious pests and diseases, and it is not allowed to continue cropping. The 3-5-year rotation of sesame and cotton, sweet potato and grass crops can better control the occurrence of diseases. After the sesame seeds are harvested, they are promptly cleared of field sicknesses and burned or buried in depth to reduce the sources of overwintering bacteria. Timely removal of diseased plants and out-of-field destruction will prevent the spread of germs. Strengthen fertilizer and water management, increase base fertilizer, basal fertilizer with medium and late organic fertilizer as the main, and mixed application of phosphorus, potash fertilizer, no application or less nitrogen fertilizer seedlings, cultivating healthy seedlings, so that the bacteria is not easy to invade. The use of sorghum cultivation, timely ditch drainage, to prevent the accumulation of water in the field, reduce the humidity in the field. 3, chemical control. Prevention and control of sesame disease should be based on agricultural control, and chemical control must be controlled before the occurrence of disease spraying or during the initial stage of disease. The control agents include 37% of wilted rickmia WP 800 times, 40% of carbendazim suspension 700 times, 50% of thiophanate-methyl WP 800-1000 times, of 80% of copper sulphate WP 800 times. Liquid and so on.
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