Technical Guidance on the Prevention and Control of Wheat Diseases and Pests in Autumn and Winter
Carrying out disease and pest control during the wheat sowing period is of great significance for reducing the initial amount of diseases and pests, preventing the occurrence of diseases and pests at the seedling stage, and ensuring effective control of wheat diseases and pests throughout the year. In order to implement the spirit of the 2015 Ministry of Agriculture autumn and winter planting conference and further strengthen the work of autumn sowing chemical seed dressing and autumn and winter disease and pest control for wheat, our center and the Disease and Pest Control Function Research Laboratory of the National Wheat Industry System organized relevant experts and, in combination with the occurrence of wheat diseases and pests in the spring and summer of 2015, put forward technical guidance on the prevention and control of major wheat diseases and pests in autumn and winter in different production regions of China.
(1) Highlight key regions and control targets. According to this year's winter wheat planting situation in China and the occurrence patterns of diseases and pests over the years, wheat disease and pest control in autumn and winter should focus mainly on the Huang-Huai-Hai wheat region, the middle and lower reaches of the Yangtze River wheat region, the Southwest wheat region, and the Northwest wheat region. In the Huang-Huai-Hai wheat region, the main targets are sheath blight, root rot, take-all, smut, cyst nematode disease, yellow mosaic disease, underground pests, and weeds, while also controlling seedling-stage rust, powdery mildew, aphids, and small brown planthoppers and other diseases and pests. In the middle and lower reaches of the Yangtze River wheat region, the main targets are sheath blight, take-all, loose smut, and stinking smut, with underground pest damage in a small number of fields. In the Southwest wheat region, the main target is wheat stripe rust, while also taking into account scab, powdery mildew, wheat aphids, wheat mites, and underground pests and other diseases and pests. In the Northwest wheat region, the main control targets are wheat stripe rust, powdery mildew, stinking smut, and underground pests.
(2) Plant resistant (tolerant) varieties to diseases and pests. Southern Huang-Huai is a frequent occurrence area of stripe rust, and in areas with early and severe occurrence year after year, rust-resistant and slow-rusting varieties such as Zhoumai 17, Yumai 34, Yumai 49, Yumai 69, Xinmai 19, Xinong 979, and Xiaoyan 6 should be planted. In areas with severe occurrence of cyst nematode disease, varieties with a certain degree of disease resistance such as Taikong 6, Zhongyu 6, and Xinmai 11 should be selected for planting. In frequent and newly occurring areas of wheat yellow mosaic disease, relatively resistant varieties such as Xinmai 208, Yumai 70-36, Fanmai 5, Yumai 70, and Zhengmai 366 can be planted. In the middle and lower reaches of the Yangtze River wheat region and areas with severe scab occurrence, varieties with a certain degree of resistance or tolerance to scab and other diseases should be selected to reduce the pressure of using chemical agents to control wheat scab later. The Southwest wheat region mainly relies on stripe rust-resistant varieties, and according to local conditions, disease-resistant varieties such as Mianzamai 168, Mianmai 37, Mianmai 39, Mianmai 41, Mianmai 43, Mianmai 45, Chuanmai 42, Chuannong 18, Xikemai 2, Emai 18, Yunmai 2, Qianmai 15, Zhoumai 17, and Wanmai 53 should be selected. The Northwest wheat region is the summering area of wheat stripe rust. At different altitudes in this region, selecting and planting good wheat varieties containing different disease resistance genes plays a very important role in controlling the spread of wheat stripe rust and the initial amount of pathogen inoculum. In wheat regions around summering areas such as the mountainous areas of southern Gansu and Liupan Mountain, resistant (tolerant) varieties should be planted according to the situation. In other areas of the Northwest wheat region, local varieties with high quality, disease resistance, and high yield should be selected as far as possible according to the situation.
(3) Chemical seed dressing. According to disease and pest conditions, choose and use high-efficiency suspension seed coating agents such as tebuconazole, difenoconazole, fludioxonil, and difenoconazole·fludioxonil to coat wheat seeds to prevent diseases, and use an appropriate amount of imidacloprid suspension seed coating agent for coating to prevent pests, yellow dwarf disease, and bushy dwarf disease; mixing the two can control major diseases and pests at the seedling stage at the same time. In the summering area of stripe rust and surrounding wheat regions, use seed coating agents such as triadimefon and tebuconazole for seed dressing to simultaneously control seedling-stage stripe rust and powdery mildew and prevent the occurrence of later stinking smut and other diseases. In areas where take-all occurs, focus on seed dressing or coating with difenoconazole suspension seed coating agent and silthiofam (Silthiopham) suspension; for underground pests, phoxim or chlorpyrifos can be used for seed dressing; for fields with particularly severe soil-borne diseases and underground pests, chemical soil treatment should be carried out. In areas where multiple diseases and pests occur together, according to the main local disease and pest types, seed coating agents or seed dressing agents compounded with fungicides and insecticides can be used for coating or seed treatment. The active ingredients of each single agent in the compound (mixed) agent should be roughly the same as when used alone. In areas where seedling-stage aphids, wheat mites, and underground pests occur and cause relatively severe damage, phoxim or imidacloprid suspension seed coating agents should be used for seed dressing.
(4) Agricultural measures. In areas of the Huang-Huai wheat region where corn straw is returned to the field, fine land preparation should be carried out, corn straw should be buried in the soil as much as possible, residual stalks at the field edges should be cleared, and after emergence, winter irrigation and compacting of wheat seedlings should be combined. In areas or fields with severe occurrence of cyst nematode disease, key measures of compacting after sowing and during the autumn seedling stage to control the disease should be promoted. In the summering area of wheat stripe rust, manual eradication and herbicide spraying should be used to remove volunteer wheat seedlings; at sowing time, according to soil moisture, appropriate delayed sowing should be adopted to reduce infection by seedling-stage stripe rust, reduce seedling-stage diseases, and lower the amount of pathogen inoculum in autumn seedlings.
(5) Control of autumn seedlings. According to the occurrence of diseases such as stripe rust, powdery mildew, and sheath blight on autumn seedlings, when the disease occurrence is severe, carry out spot treatment to protect the surrounding area. In southern Shaanxi, an area where stripe rust pathogens overwinter and reproduce, strengthen monitoring and carry out chemical control in early-diseased fields; triazole fungicides can be selected for spray control. In areas where sheath blight occurs at the seedling stage, strengthen monitoring and carry out control as early as possible; in the Weibei dry plateau area, the Longdong area of Gansu, the Longnan area, and the winter wheat area of southern Ningxia, on the basis of seed dressing prevention, attention should be paid to controlling seedling-stage aphids to prevent the occurrence of wheat yellow dwarf disease. Early winged aphids can be trapped and killed with yellow boards, and for chemical control, high-efficiency and low-toxicity insecticides such as imidacloprid and pymetrozine can be selected for spray control.
National Agricultural Technology Extension Service Center
Disease and Pest Control Function Research Laboratory of the National Wheat Industry System
September 25, 2015