To understand the dynamics of major diseases and insect pests in northern China this year, to guide local prevention and control of pests and diseases, and to promote the study of public welfare industries such as corn borer and armyworm, the National Agricultural Technology Center organized plant protection promotion, research and teaching on July 17-21. Experts from the field went to Tongliao City and Xing'an League in Inner Mongolia to carry out investigations and technical guidance activities for the pests and diseases of corn. Through on-the-spot field investigations, we learned about the types and hazards of local corn pests and diseases, and popularized the identification of diseases and pests, the causes and investigation techniques for prevention and control of diseases and insect pests, and exchanged and discussed the impact of planting structure of northern corn on pests and diseases and countermeasures.

The expert team took a deep and intense heat into the depths of Tongliao City, Kailuo County, Horqin District, Kezuozhong Banner, Zalut Banner, Xingquan League Tuquan County, Keyouzhong Banner, Keyouqian Banner, Ulanhot City and other 2 cities (the League). Representative maize fields in more than 20 villages in 14 towns and counties in counties (districts, flags) have conducted field surveys on the occurrence and damage of pests and diseases. The survey found that pests and diseases on spring maize are predominantly affected by the ecological trend, which poses a greater threat to the production of corn in the middle and later stages. Among them, corn borer generally occurs, field mosaics and stem bores are visible everywhere, and individual field block strains rate more than 50%. The double-leaf beetle beetle is high in quantity and heavy in weight. The highest single plant is more than 20, and the leaves from the lower part to the middle part of the leaf are fed with white net spots and holes, and a large number of adults are gathered from the newly extracted filaments of the ear. Filaments are severely bitten and severely pollinate. Corn borer has occurred in both Tongliao and Xing'an League. The pest population in Kailuo County is relatively high. The succession, if any, cover the tassel, upper leaves and bales, and the coverage becomes dark, which affects photosynthesis. The bandits invaded the corn field in Kezuozhong Banner and Zalurt Banner in Tongliao City. The plant leaves were severely nicked. When the large spot disease enters the initial stage, all field plots can be inspected, and the lesions in the middle and lower parts of the plant are more common. In the most serious occurrence of disease, the disease rate of the Wulanmadu Sumuyi field in the Kerouzhongqi is 70%. Plants can be seen on the tripe lesions. In the past, brown spot occurred in the Huanghe, Huai, Haixia and Maize areas in the cities of the two cities. The disease rate of some fields in Kailu county and Kezuo Zhongqi reached 50%-80%. Dwarfing disease was investigated in Tongliao City and the disease-affected strains in Xingyou Mengxuezhongzhong Banner. The plants were dwarfed, and the leaves were longitudinally striped and mosaic-shaped, and the base of the stem was tearing. Investigation of gray spot disease with suspected symptoms of small leaf spot in many Qixian County, Tongri County, Tongliao City, and Xingan Mengqianqianqian Banner See the diseased leaves of northern anthracnose and common rust similar to Curvularia leaf spot disease. The pathogen spores were confirmed to be inspected. Investigation team experts and local technicians agreed that the currently cultivated high-yielding varieties have poor resistance to diseases and insect pests. Maize continuous cropping and straw returning resulted in the accumulation of field diseases and insects. Close planting and high fertilizer and water management led to increased humidity in the field. Plant greening, climate warming and unequal precipitation are all conducive to the occurrence of a variety of diseases and insect pests, resulting in increased damage to northern corn pests and diseases in recent years. It is proposed that countermeasures should be taken to strengthen the cultivation and application of pest resistance, rational close planting and water and fertilizer management, and to strengthen early drug prevention; in addition, some counties (districts, flags) government financially put into effect the use of Beauveria bassiana and release Trichogramma Such measures as controlling corn borer are obvious and worth promoting.

Experts also explained to the local agricultural technicians on the occurrence and control laws of maize pests and diseases, especially the new brown spot, dwarf disease and other details were introduced, and based on the investigation, proposed to replace the brown spot disease Varieties, selection of carbofuran (effective content of 7% -10%) for corn seed coating before sowing, reasonable arrangements for planting density and other prevention and control suggestions. The chief expert of National Agricultural Technology Center Zhang Yuejin plant protection also gave grass-roots agricultural technicians a book entitled “Color Map of Corn Pests and Diseases Prevention”. This activity played a technical guiding role in the prevention and control of corn diseases and pests in the local area. The survey experts exchanged information and shared information. It also plays an important role in promoting the research of related topics to better serve the production practice. The activity is generally acknowledged and welcomed by local agricultural departments, grass-roots technicians and participating experts.