Demonstration and Promotion of Integrated Management Technology of Wheat Sheath Blight and Wheat Crown Rot in Zibo City

Peng LI, Shilong WANG, Yi AN, Zhiji LIU

Zibo Digital Agriculture and Rural Development Center, Zibo 255000, China

Abstract Since 2014, Zibo Plant Protection Station has carried out a series of prevention and control tests in the city to solve the problem of increasingly aggravated root and stem diseases of wheat. According to the results of individual test, the technical procedures for integrated management of wheat sheath blight and wheat crown rot based on deep tillage, seed coating and chemical control in spring are integrated. The technique has been greatly promoted through on-site meetings, training and publicity, demonstration and promotion, unified prevention and control, and green prevention and control, which increases wheat yield in technology application area, reduces the use of chemical pesticides, and protects the ecological environment. The radiation drives increasing production and incomes of the surrounding farmers, receiving remarkable economic, social and ecological benefits.

Key words Wheat; Sheath blight; Crown rot; Strategy; Benefit

1 Introduction

In recent years, the root and stem diseases of wheat in Huang-Huai-Hai River basin have showed a trend of multiple, mixed and heavy occurrence due to continuous planting and straw returning, and the major disease is wheat sheath blight; wheat crown rot poses a great threat to wheat production and becomes an important limiting factor for high yield, high quality and high efficiency of wheat due to gradually increasing occurrence area and aggravated damage[1-3]. The incidence of wheat field is generally 10%-30%, or above 70% in severe cases, resulting in direct yield loss of 5%-30%;Fusariumspp. causing wheat crown rot can also produce toxins in the process of infection, which can be transmitted upward to wheat ears through stems, affecting human and animal health[1,4-5]. Such diseases generally attack the root and stem base, and it is difficult to find the diseases due to hidden site. In the middle and late stage, when the straw turns brown and white head appears, the time for prevention and control has passed. In view of the difficult situation of prevention and control of wheat sheath blight and wheat crown rot, Zibo Plant Protection Station has studied the integrated management technology of sheath blight and crown rot since 2014.

2 Developing technical procedures for integrated management

2.1 Seed coatingSeed coating with high quality special seed coating agent before sowing can get twice the result with half the effort. 27% Difenoconazole·fludioxonil·thiamethoxam FS (300 g/100 kg seeds), 31.9% tebuconazole·imidacloprid FS (500 g/100 kg seeds), or 23% imidacloprid·fludioxonil·difenoconazole FS (600 g/100 kg seeds) can be applied. The seed coating agent can be added with Haidaosu 1 500 times dilution or 0.01 brassinolide (10 mL/10 kg seeds), which can enhance the resistance to diseases and stress at seedling stage.Trichoderma(300 g/100 kg seeds) or 1 billion cfu ofBacillussubtilis(2 000 g/100 kg seeds) can be used to coat seeds.

2.2 Soil treatmentBefore tillage, 25% tebuconazole EC 3 000 g/hm2or 30% difenoconazole·propiconazole EC 3 000 g/hm2is mixed with 75 kg soil, or 20 billion cfuB.subtilisis mixed with 37.5 kg fined soil, broadcasted on soil surface, and ploughed into the soil, which can effectively reduce the damage of wheat sheath blight and wheat crown rot to wheat seedlings at the seedling stage and even before winter.

2.3 Sufficient and well application of basal fertilizer

2.3.1Increased application of organic fertilizer. Increased application of organic fertilizer is beneficial to reduce the occurrence of root and stem diseases. The high-yield key fields are applied with organic fertilizer at the dose of 45-60 t/hm2, and the common fields are dominated by straw returning. The straw should be crushed to 2-3 cm, so as not to affect the quality of land preparation. The straw returning plots should be broadcasted with appropriate amount of nitrogen fertilizer (45-75 kg/hm2urea or 90-150 kg/hm2ammonium bicarbonate) and deeply ploughed to adjust the C/N ratio and speed up straw decomposition. In conditional plots, biological bacteria or organic material decomposition agent can be broadcasted at the dose of 30 kg/hm2. Agricultural manure can be applied at the dose of 30-45 t/hm2in the field without straw returning, and commercial organic fertilizer or organic and inorganic compound fertilizer can be applied at the dose of 1 500-3 000 kg/hm2if there is no agricultural manure.

2.3.2Formula fertilization by soil testing. Nitrogen and zinc are the main nutrient elements affecting the incidence and severity of crown rot. Excessive application of nitrogen fertilizer and zinc deficiency of plants are beneficial to the occurrence of wheat crown rot. In areas severely attacked by crown rot, appropriate application of zinc fertilizer can effectively reduce the occurrence of crown rot. Formula fertilization by soil testing was implemented. In the whole growth period of high-yield field, one hectare of field is applied with 210-240 kg of pure nitrogen, 112.5-150 kg of phosphorus (P2O5), 75-112.5 kg of potassium (K2O) and 15 kg of zinc sulfate are applied one hectare; one hectare of field is applied with 210 kg of pure nitrogen, 105 kg of phosphorus (P2O5) and 75 kg of potassium (K2O) in medium-yield field.

2.4 Intensive farmingDeep tillage can turn the diseased body below 30 cm and compacted soil causes pathogenic bacteria to die of hypoxia, which can effectively reduce the density of pathogenic bacteria on soil surface and reduce the occurrence of root diseases. For the high-yield plots with straw returning, the plowing depth should be as deep as possible to 25 cm or more. Before deep tillage, the stubble of corn should be broken down, and the soil is flattened and compacted by rototiller after ploughing. For the plots with less straw returning, especially the plots with no-tillage planting for more than consecutive 3 years, mechanical deep loosening operation can be adopted. Local deep loosening or comprehensive deep loosening can be selected, and the operation depth is 25-40 cm. After deep loosening, the soil surface should be prepared with a rototiller in time, or the soil is compacted with compacting machine. Deep ploughing or deep loosening can be conducted once every 1-2 years. All kinds of ploughing plots, especially straw returning and rotary tillage plots should be thoroughly cracked and suppressed, so as to crush the soil and eliminate the clods.

2.5 Improving sowing quality

2.5.1Determining reasonable sowing date and sowing rate. Sheath blight occurs more heavily in the plots with early sowing date and large sowing rate. The suitable sowing date in central Shandong area is from October 1 to October 10, and the best sowing date is from October 3 to October 8. Wide width precision sowing technology of wheat is mostly used for sowing, with more tillering number. The sowing date should be strictly controlled in the appropriate range, while too early sowing will lead to flourishing growth before winter, severe winter freezing damage and root diseases. The sowing rate varies according to varieties, sowing date, and soil fertility level. Under proper sowing date, the basic seedlings of medium ear type cultivars with high heading rate are 1.5 million-1.8 million seedlings/hm2, while the basic seedlings of large ear type cultivars with low heading rate could be increased appropriately.

2.5.2Standardized sowing. Using wheat wide width precision sowing technology, the sowing depth is 3-5 cm, and too deep sowing will cause weak seedlings and increase the chance of disease infection.

2.6 Root and stem disease control in springIn spring, the best control period from turning green to standing stage (early and middle of March) should be grasped to carry out control work in time. Agents are sprayed in a sunny afternoon. It is recommended to use self-propelled sprayers, UAV and other efficient operating instruments to increase water consumption. 30% Difenoconazole·propiconazole EC 300 mL/hm2or 5% jinggangmycin AS 2 250-3 000 mL/hm2or 6 450 g/L tebuconazole SC 300 mL or 3 600 g/L thifluzamide SC 300 mL diluted with 900-1 050 kg of water can be sprayed on the stem base of wheat. Fungicides can be mixed to control wheat aphid, wheat spider or wheat sawfly. The drug can be added with Haidaosu 800 times dilution or 0.01% brassinolide at the dose of 150 mL/hm2, which can significantly improve the efficacy.

3 Measures

3.1 Striving to make technological breakthroughSince 2014, a number of tests have been carried out on the prevention and control of wheat sheath blight and wheat crown rot. First, it is clear that deep tillage can effectively reduce the occurrence of wheat sheath blight and wheat crown rot. Second, 5 kinds of seed coating agents with high efficiency and low toxicity are screened, including 27% difenoconazole·fludioxonil· thiamethoxam FS, 31.9% tebuconazole·imidacloprid FS, 23% imidacloprid·fludioxonil·difenoconazole FS, 11% pyraclostrobin·triticonazole FS, and 4.8% difenoconazole·fludioxonil SC; 5 spraying agents with high efficiency and low toxicity against crown rot are screened, including 125 g/L epoxiconazole SC, 240 g/L thifluzamide SC, 18.7% propiconazole·azoxystrobin SE, 30% difenoconazole·propiconazole EC, and 430 g/L tebuconazole SC. Third, the prevention and control effects of different application instruments on root diseases are comparatively studied, and the results prove that self-propelled sprayer is superior to UAV and artificial control. Fourth, the influence of different water consumption on the effect of plant protection UAV spray against wheat sheath blight is studied, and the most suitable water consumption to achieve the best control effect without affecting the operating efficiency is identified: the water consumption of 10 kg and 15 kg small plant protection multi-rotor UAV is controlled at 18-24 L, and the control effect reaches 72%-75%.

3.2 Actively seeking financial supportAll units can actively strive for the projects, such as integration pilot project of green control and unified control of agricultural pests in Shandong Province, major pest specialized prevention and control system construction project, special plant protection project of modern agriculture program, guide district and county plant protection to make coordinative use of financial disaster relief funds from the central government, and actively apply for local financial support. Unified wheat spraying control has been carried out, with a total investment of more than 60 million yuan, which effectively promotes the promotion and application of green and efficient prevention and control technology against wheat pests and diseases in the city. Huantai County is at the forefront of the whole city. In view of the occurrence of wheat root diseases, the spring prevention and control of wheat root diseases has been organically promoted since 2014, and the government has procured control agents against wheat root diseases through unified bidding and distributed them into households. Linzi, Gaoqing, Zhangdian and other districts and counties also actively coordinate central, provincial, city, district and county levels of financial funds for prevention and control of spring wheat root diseases. In 2019, Zibo Plant Protection Station undertook the projectDemonstrationofIntegratedApplicationTechnologyfortheWholeGrowthPeriodofWheatin2019-2020issued by the National Agricultural Technology Extension Service Center. A 26.67 hm2demonstration field was established in Huantai County, focusing on the demonstration and popularization of quality seed coating agent + spring root disease control technology, and good demonstration results were received. The implementation of these projects greatly promotes the popularization and application of integrated management technology of wheat sheath blight and crown rot.

3.3 Accelerating the establishment of specialized plant protection prevention and control teamsThe specialized plant protection prevention and control service teams are actively expanded, with pesticide business households, farmers’ specialized cooperatives, large farms with comprehensive agricultural machinery services, large farms, and agricultural food processing and production enterprises as the main bodies, and the special plant protection prevention services are extended within the scope of their own services. Young and middle-aged workers who are interested in serving agriculture and farmers are encouraged to participate in plant protection service organizations, and regular technical training is carried out to improve their service skills and level. At the same time, the leading role of Huantai County as the demonstration county for integration of professional unified prevention and control and green prevention and control of wheat and Gaoqing County as the demonstration county for green prevention and control of wheat should be brought into full play, to comprehensively improve the professional level of wheat pest and disease control and prevention in the city.

3.4 Demonstration and promotion, extensive publicitySeveral demonstration areas of million hectares are established in the wheat centralized planting area in Zibo City every year, which are widely publicized and demonstrated by holding spring root disease prevention and control on-site meetings, wheat unified prevention and control on-site meetings, spring production on-site meetings,etc.The first is to publicize to leaders; leaders are invited to visit the site during and after the demonstration process, and the situation of increasing production and the social benefits obtained are reported to leaders, in order to arouse leaders’ attention and to obtain strong support. The second is to publicize to the masses; the practical effects that can be seen and touched will help the masses deepen their understanding of new technologies through the intuitive forms of on-site meetings, technical consultation, and issuing technical materials. The third is the technical guidance in the field. Every year, technical guidance is given during the key period from spring regreening stage to jointing stage, and on-site meetings for the unified prevention and control of root and stem diseases are held in the demonstration area to observe the use effects of large-scale spraying machinery, UAV and other efficient plant protection machinery.

3.5 Training farmers through multiple channels and at various levels, and promoting the popularization of new plant protection technologiesAgricultural experts and professors from Shandong Plant Protection Station, Shandong Agricultural University and professional plant protection personnel from agricultural technology extension system have been invited to give lectures for many times, to expand the training teams for farmers. Field schools, farmer training centers, farmer cooperatives and other organizations have been set up to train farmers in various plant protection techniques through multimedia broadcasting, indoor lectures, field training, field operations and outdoor visits, so as to cultivate new types of farmers. The training work of village cadres, professional prevention and control workers, managers of professional cooperatives, production supervisors and other leaders are well performed. The ability of farmers to apply new plant protection technologies in their respective specialties is improved through the training, and agricultural productivity and income are increased.

3.6 Strengthening cooperation between schools and cities and overcoming technical difficulties in UAV applicationThe research group actively contacted with universities to explore the advanced technology of intelligent plant protection UAV in crop disease and pest control. In 2019, the research group signed theResearchCooperationAgreementonKeyTechnologiesandIntelligentAgriculturalMachineryEquipmentofPrecisionApplicationinAgriculturalAviationwith the College of Agricultural Engineering and Food Science, Shandong University of Technology, and explored key technologies suitable for different crops such as prevention and control speed, spray amplitude, droplet drift, auxiliary agents and pesticide reduction use of intelligent equipments (such as plant protection UAV), ensuring that the practical problems in production are solved, and realizing deep integrated development of "school and city". Subsequently, a seminar on key technologies of precision application was jointly held to study the experiments of spraying various types of plant protection machinery to control wheat root, weed and ear stage diseases and pests.

4 Achievements

4.1 Remarkable economic, ecological and social benefitsSince 2014, 6 demonstration areas of million hectares have been established in Linzi, Huantai and Gaoqing, with 110 demonstration sites and a total demonstration area of 26 700 hm2. Meantime, the green prevention and control technology of wheat sheath blight and crown rot was explored, and agricultural technology, ecological regulation and biotechnology were applied to prevent root diseases, so as to achieve the purpose of reducing drug use, efficient and sustainable disease prevention and treatment. Since 2014, it has been promoted in nearly 400 000 hm2fields, with reduced costs and increased benefits of 981 yuan/hm2, and the total economic benefit is 250 million yuan.

4.2 Effectively promoting the development of unified prevention and controlBy the end of 2021, there had been 75 unified prevention and control service organizations, and the total number of employees was more than 2 000 people. From 2020 to 2021, 12 professional cooperation organizations of unified prevention and control in Zibo City were rated as national star service organizations. Huantai County and Linzi District were guided to successfully apply for 2020 and 2021 national demonstration counties of "unified prevention and control".

5 Innovation experience

5.1 The way that governments buy services has greatly promoted the popularization of technologyUnified prevention and control of wheat root diseases in Huantai County adopts the way of government purchasing services. In accordance with the principle of fair competition and socialized operation, specialized service organization cooperatives are selected as the units to undertake the socialized service pilot projects through centralized government procurement and bidding. In the process of socialization service, county agricultural departments conduct random inspection on the operation quality of specialized service organizations, and specialized service organizations conduct whole-process supervision on the operation quality of agricultural machinery operators. Contract management is implemented, and the operation quality and area of agricultural machinery operators need to be signed and approved by farmers. This promotion method has also been recognized by Linzi, Gaoqing and other districts and counties, effectively promoting the large-scale application of technology.

5.2 Making full use of the demonstration and promotion role of large farmers and farmers’ specialized cooperativesIn the process of technology promotion, the technology is first demonstrated in large farmers and farmers’ specialized cooperatives in each district and county, and the radiation drives the surrounding retail farmers to use the new technology, playing a good promotion effect.