In the past two years, wheat scab has occurred frequently in many parts of our country and has a high frequency. Partially occurred in 1997. The diseased strain rate is about 3%. In 1998, this disease occurred generally, with an area of ​​158,000 hm2, accounting for more than 80% of the total area of ​​wheat sowing. Generally, the output of wheat is reduced by about 15%, and serious wheat production is reduced by more than 30%. l Occurrence patterns and environmental conditions The occurrence of head blight is related to factors such as climatic conditions, bacterial count, crop growth period, and disease resistance of the varieties. Their degree of interaction plays a decisive role in disease epidemics. When wheat heading, flowering and filling stage have high temperature and high humidity, it is beneficial to the occurrence of diseases. Under the suitable temperature of 25 °C and humidity saturation for more than 36 h, the incubation period of disease is only 2d. Under appropriate temperature conditions, when the relative humidity of the soil surface is more than 80%, the ascus shells are produced rapidly and the amount of bacteria is high. Before the heading of wheat, when the incidence of the ascus shell in the sick body rises to more than 10% to 20%, it reaches Epidemic bacteria levels. Because the invading panicle of the pathogen is an anther-mediated medium, wheat is most susceptible to disease within 20 days after heading, and the sensitivity rate is highest in the flowering stage. Because the wheat varieties have anterior and posterior stages of flowering, they have different levels of susceptibility. The susceptibility between varieties determines the weather conditions during the flowering stage and the sowing date and other factors. Generally, early wheat fields are sowed, heading and maturation are also early, and often they can escape the epidemic stage of pathogen infection to reduce the degree of disease. On the contrary, the wheat fields with late sowing have delay in earing maturity, and often encounter disease epidemic season at the heading stage. Long, the degree of disease increased. In addition, wheat fields with low topography, heavy clay, and poor drainage are also conducive to the occurrence of head blight due to excessive humidity in the field. Excessive application of nitrogen fertilizer, too late, but also lead to long wheat, reduce the plant's resistance to disease, and delay the maturity of heading, increased disease. 2 Symptoms and Diagnosis All stages of wheat growth can be affected, causing seedling rot, culm rot and ear rot, while ear rot is the most serious, followed by culm rot, seedling rot is not common. When the ear rot occurred, light brown blister spots appeared on the tip of the glume of individual spikelets, and then gradually expanded to all spikelets and spread to other spikelets. The diseased ear was yellow-brown or blue-green, with a pink sticky mould conidium layer attached to the ear. At the late stage of disease, purple and black dots appeared in the ear. The wheat grains in the diseased ear were more likely to be discolored or partially rotted. When the wheat ear is lightly damaged, symptoms usually do not appear, or only one or more spikelets occur locally. Seedling rot is mainly caused by seeding of diseased seeds, which often causes unripe or rot. Or after the emergence of seedlings, the root sheath has become rot. Although the seed with light damage can grow seedlings, it grows weakly and is vulnerable to adverse environmental conditions. It is yellow and rots and cannot head. 3 Control methods The prevalence of head blight has fulminant and intermittent characteristics. The prevention and control methods should be based on agricultural control. In combination with the selection of disease-resistant varieties, integrated prevention and treatment measures for pharmaceutical protection will be carried out during the key period. 3?l deep plowing smashing, sterilizing the source of wheat before sowing deep plowing, leaving the former remains on the soil surface of the debris buried soil, the unburied residual stalks. Burnout or fertilizer should be removed. 3.2 Strengthen field management Wheat fields need to be drained to reduce groundwater level and field humidity. To get rain and dry, there is no water in the ditch. Appropriate early sowing, multi-application of phosphorus and potassium fertilizer to promote robust growth of wheat straw and early maturation, can prevent and reduce the occurrence of diseases. 3? 3 selection of disease-resistant varieties is currently not immune and high resistance varieties. The wheat varieties that are relatively resistant or light in our city include Yumai 21, Yumai 24, Bainong 64, etc. 3.4. Seed treatment Seed treatment can be carried out in conjunction with the control of other diseases when wheat is sown. Seed diseased seeds can be first floated with 25% saline or 40% cement water and then soaked in 1% lime water. 3?5 The critical period for the prevention and control of chemical agents is wheat flowering to grain filling stage. The first spraying should be slightly earlier than when the spores of the disease sporadically spread, and the disease is about to prosper. Generally, when the rate of wheat flowering plants reaches more than 10%, when the temperature is higher than 15°C, weather predicts that there will be rain for 3 days, or more than 5 days of rainfall within 10 days, or there will be heavy fog and heavy fog, it is necessary to begin Fight drugs, spray once again every 7 days or so, can prevent and cure once in light wards, and control twice in intensive wards to control the occurrence of head blight. 3.5.1 Carbendazim (benzimidazole 44) used 25% or 50% carbendazim wettable powder, the former every 667 m. With 150 ~ 300 g, the latter every 667 rr,. z with 75 ~ 150 g. Add water 75 kg spray. 3? 5.2 carbendazim suspension for every 667m. With 40% carbendazim suspension 50 ~ 100 g, add 60 kg of water spray. 3.5.3 Carbendazim micropowder contains 80% active ingredient per 667 m. With 50 g, add water lO kg, spray with a low-capacity micropore (spray diameter 1.Oram) sprayer, control effect of 90% to 95%. 3.5.4 Topoxazine is sprayed with 50% thiophanate WP and 500-1,000 times dilution of water, which is slightly less than carbendazim. 3.5.5 sterilization Dan sprayed with 50% wettable powder and 200 times dilution with water, the effect is generally 70% to 80%. Dandan only has a preventive effect and no therapeutic effect. This medicine has a curative effect on wheat rust. Laundry Detergent,Organic Detergent Liquid,Laundry Liquid Detergent,Detergent Liquid Wuxi Keni Daily Cosmetics Co.,Ltd , https://www.kenidailycosmetics.com