The occurrence and control technology of wheat scab
Wheat is one of the most important food crops in the world, and the recent shortage of wheat has increased the recent world food panic. International wheat prices have been climbing and operating at high levels since July 2006. High quality and high yield of wheat is an important measure to ensure the sustainable development of wheat production in China. The sustainable development of wheat production in China also guarantees the stability of wheat prices in China. China has a vast territory, and the wheat growing area is covered by different ecological climate zones. Wheat production faces multiple disaster risks. The prevention and control of wheat scab is an important component of high quality and high yield. First, the impact and type of wheat scab. China's important wheat areas have suffered from scab. The frequency of occurrence of scab in the northern Henan area has been high in recent years, which has a great impact on the quality of wheat. The gibberellin problem. Fusarium can produce a variety of toxins. The group B toxin in trichothecene is a toxin that causes vomiting and abortion in animals. There are two types of toxin B: one is Fusarium enol (NIV) and the other is deoxynivalol (DON). Therefore, the prevention and control of wheat scab is not only related to food security but also to food safety. The gibberellin in the wheat area of ​​China has obvious differentiation, and the pathogen population of wheat scab in China. Many experts have studied the pathogens of scab in China, which are considered to be Fusarium graminiarum. With the progress of research and the expansion of the concept of species, Fusarium graminearum is no longer a species, but A family of 11 species. Among the 11 families, we identified them by molecular identification methods, and at least 6 distinct species caused scab in China. Therefore, the single drug control effect is poor now. Second, the prevalence of wheat scab. The most suitable temperature for the development of wheat scab is closely related to the temperature of 24-28 ° C, the lowest 8 ° C, the highest 32 ° C. It develops best at a relative humidity of 80-100%. The optimum temperature for the formation of ascospores and ascospores is 20-25 °C. The conidia produce the fastest temperature of 25 °C. In general, the temperature conditions after wheat heading are all to meet the growth and development of pathogenic bacteria. The key to the popularity is the rainy weather. Forecasting does not have to have a very complicated mathematical model! In fact, how many rainy days and rainfall in the weather forecast can be reported when the wheat is headed. The prevalence of wheat scab is also important. At present, some progress has been made in the breeding of resistance to scab, but it is not possible to obtain the ideal resistant varieties, which may not be available in the next decade. Varieties of resistance to scab are resistant to both infection and expansion. Agronomic traits other than resistant varieties are also associated with the prevalence of scab. 1 plant height. The dwarf species received much more species of ascospores that were ejected into the ear layer by the soil surface than the appropriate plant height. 2 The heading is neat or not, and the length of the head is long. If the heading is neat, the time for the ear is short, and there is less chance of encountering rainfall, which can reduce the epidemic. 3 The length of time remaining for anthers. Anthers play an assisting role in the invasion of pathogenic bacteria, and the remaining anthers can provide pathogens with nutrients like the medium to help the bacteria invade. 4 Whether the filling speed is fast or not. The filling speed is fast, reducing the range of spread of the bacteria. The prevalence of wheat scab is also closely related to cultivation management and planting methods. The terrain is low, the soil is sticky, and the drainage is poor, which causes high humidity in the wheat field and reduces the ability of wheat roots to breathe and resist disease. The corn-wheat cropping ground is not deep in tillage, and the large amount of corn-bar returning and the residue of the bacteria provide a large amount of fungus for the epidemic of wheat during the late growth stage. Third, the prevention and control of wheat scab. (1) Cultivation and control is the basis for the prevention and control of scab. 1. Deeply plowing and killing . Deep tillage and mites are important ways to reduce microbial bacteria. 2. Topdressing can not be too late. Late dressing tends to cause gluttony and late maturity, prolonging the time of infection and increasing the chance of infection, and causing more ineffective division and aggravation. (2) The selection of resistant and disease-resistant varieties is an important prevention and control measure. Although there are no varieties resistant to disease, there are still great differences between the varieties, especially the varieties that are resistant to expansion. In addition to resistance, the following principles should be considered in selecting the variety: 1 appropriate plant height, 2 heading consistent, 3 ear layer neat, 4 anther residual time is short, 5 filling speed is fast. (3) Chemical control is the key to the prevention and control of scab. Due to different climatic conditions, the period and speed of the heading and flowering of the wheat plants are different. Therefore, the date and frequency of application should be flexibly controlled according to the local climate change and the growth period of the wheat. Time principle of application: When the heading is fine and the temperature is high during the heading period, the wheat is plucked and the flowers are raised at the edge of the flowering period, and the application is best in the initial flowering period (10-20% of the flowering). At the heading stage, the temperature is low and the sunshine is small. The wheat is firstly flowered after the heading, and the medicine is used in the initial flowering period (10% flower). When the heading stage encounters continuous rain, it should be used at the heading stage. It is necessary to grasp the timing of the rain gap for medication. Pay attention to the problem: the medicine should be able to ensure the mist, the pressure and the orifice diameter should meet the fog requirements. Appropriate high concentration spray when there is rainy weather. Because scab occurs during the rainy season, mist and appropriate high concentrations prevent rainwater from scouring, which can result in secondary dilution of the agent without wasting and losing the agent. Especially when it is raining intermittently, it is necessary to emphasize fog and appropriate high concentration. It has been reported that Fusarium has a certain resistance to carbendazim , resulting in decreased efficacy. For example, Ma Zhonghua reported that 4.3% of the scab-resistant strains of carbendazim on the rice piles in Jingjiang, Jiangsu Province, and the proportion of resistant strains in Hai'an area was as high as 7.9%. However, carbendazim is still a good medicine for controlling wheat scab. 40g of carbendazim suspension per acre 120g, 80% of wettable powder 100g, 70% thiophanate-methyl wettable active ingredient 70g can be used for the control of scab. If there is carbendazim ultrafine powder or carbendazim suspension, it is best to use ultrafine powder and suspension, the effect is better than wettable powder . Pitch Angle Yaw Angle Rolling Angle,Machine Tool Positioning Laser Interferometer,Laser Measurement Machine Tool,Laser Interferometry Technology Automated Precision Inc. , https://www.apiasean.com