Scab is a common disease in wheat producing areas in China, which not only seriously affects the high yield and stable yield of wheat, but also causes mycotoxin (DON) to contaminate wheat grains after onset, which affects the quality and safety of wheat and poses a potential threat to human and animal health. According to local monitoring and expert consultations, the field of bacteria in most wheat fields is widely distributed and large in quantity, satisfying the conditions of pandemic, and the lack of resistance of most of the main varieties, combined with the increase in the probability of rainy weather during wheat heading and flowering, is expected to be 2017. The annual wheat scab continues to be a pandemic trend in the Yangtze River Basin, Jianghuai and Huanghuai wheat areas, and it needs to implement a prevention and control area of ​​nearly 200 million mu. In order to promote scientific prevention and control and ensure the safety and quality of wheat production, the Ministry of Agriculture Plantation Management Division organized experts to propose the following prevention and control guidance.
First, the prevention strategy
Adhere to prevention-oriented, comprehensive management, classification guidance, district policy, scientific use of drugs, cost-effective. The perennial recurrence area of ​​wheat scab in the Yangtze River Basin, Jianghuai, Huanghuai, etc., insists on “actively attacking, seeing flowers and fighting drugs†and unshakable, grasping the critical period of wheat heading and flowering, comprehensively spraying the prevention of road chemicals and reducing the occurrence of diseases. degree. In the middle and north of Huanghuai, North China, Northwest China and other perennial wheat areas, adhere to the "prevention of prevention, timely medication" does not relax, the wheat heading flowering period, once the rain or long-term condensation and other suitable disease prevalence, immediately organize the spraying of "insurance drugs" ", reduce the risk of disease epidemics.
Second, prevention and treatment technology
While strengthening the management of fertilizer and water and reducing the humidity in the field, timely spraying of the pesticides on the road is the key measure to control the occurrence of scab and reduce the pollution of toxins. In order to improve the effectiveness of prevention and control, all localities should strive to achieve "four adherences."
(1) Adhere to the appropriate use of drugs. The wheat from the ear to the early stage of flowering is the best time to prevent and control the occurrence of wheat scab. The Changjiang River Basin, Jianghuai, Huanghuai and other Changfa Districts have comprehensively implemented the prevention and control measures of “seeing flowers and fighting drugs†(5-10% of Yanghua). In case of epidemic weather such as continuous rain and long-term condensation, a second prevention is required. It should be applied again 5-7 days after the first dose. In the northern part of Huanghuai, North China, Northwest China and other occasional areas, once the climatic conditions of the disease occur, the wheat flowering period should be seized and the drug should be prevented in time.
(2) Adhere to rational drug selection. It is the key to ensure the prevention and control effect by selecting the type of the agent and the effective dose. Cyanide, tebuconazole, prochloraz and other pharmaceutical preparations and their compound preparations should be preferred. Especially in areas where the pathogens such as the middle and lower reaches of the Yangtze River and Jianghuai have developed resistance to carbendazim, it is necessary to use more bacteria. Spirit and its compound preparation.
At the same time, try to use rain-resistant ultra-fine powder, plastic suspension and other dosage forms; pay attention to the rotation of drugs, the second prevention and treatment should use the first variety of different mechanisms of action to prevent drug resistance, improve control effect, reduce Mycotoxin contamination.
(3) Adhere to scientific application of medicine. The selection of efficient application equipment, suitable additives and stabilizers is the basis for ensuring the effectiveness of prevention and control. It is recommended to use self-propelled wide-format application machines, drones, hot fog machines, motorized misters, electric sprayers and other application machines. Stretcher sprayers should be avoided as much as possible.
Use a small-aperture nozzle spray as much as possible, and add the corresponding functional additives to ensure the proper droplet size and uniform distribution of the liquid. The spray of the mobile mist spray machine should be controlled within 2/3; the hot fog machine should be used with the stabilizer; the drone, especially the multi-rotor drone, should be added with a settling agent.
(4) Adhere to a multi-effect. The wheat earing stage is a promising period for a variety of diseases and insects in wheat, and it is also a critical period for prevention and control. All localities should focus on the prevention and control of wheat scab, adapt to local conditions, rationally select and scientifically mix anti-control agents, and take into account the prevention and control of major pests such as larvae, mites, stripe rust and powdery mildew. At the same time, pay attention to the combination of disease prevention and control of pests and control of Wang and anti-aging, classification guidance, mixed fertilizer and fertilizer, and weight gain.
Third, prevention and control measures
The effective prevention window of wheat scab is short and time-sensitive, and requires a high degree of organization. All localities should give full play to the administrative superiority, the advantages of the agricultural sector, the technical advantages of plant protection institutions, and the service advantages of specialized prevention organizations. "Four enhancements."
(1) Strengthen the implementation of responsibilities. Party committees, governments and agricultural departments at all levels must fully understand the great significance of prevention and control of wheat scab, strengthen organizational leadership, increase financial support, refine work plans, arrange deployments at an early stage, implement responsibilities at all levels, and strengthen supervision and inspection. Ensure that prevention and control work is carried out in a powerful and orderly manner.
(2) Strengthen monitoring and early warning. Entity monitoring and investigation of plant protection organizations at all levels, comprehensively grasp the situation of the seedlings, disease, and public opinion, pay close attention to the weather changes, timely analyze the epidemic situation of the consultation, accurately publish the forecast and warning information, and clarify the key prevention and control areas, key prevention and control fields and the best prevention Control time, scientific guidance and prevention actions.
(3) Strengthening the rule of unified defense. All localities should play a leading role in the demonstration of specialization and defense, and vigorously promote the unified organization and launch, unified technical programs, unified pharmaceutical supply, unified application time, unified prevention and control actions, "five unified" prevention and control, and effectively improve the degree of prevention and control organization, Comprehensively improve the effectiveness, efficiency and effectiveness of prevention and control.
(4) Strengthening guidance services. Organize cadres and technicians to conduct technical guidance in the main wheat producing areas and the scab recurrence areas. In the critical period of prevention and control, we will take the form of “shoulder face†and “hands-on†to carry out technical training and guidance services to ensure the implementation of prevention and control technical measures.
Extended reading: on the prevention and control of wheat scab and common misunderstandings
(1) Selection of resistant (resistant) disease varieties, as of 2013, no immune or high resistant varieties were found, but there are some resistant varieties with good agronomic traits, such as Sumai No.3, Sumai No.2, Xiangmai No.1, Yangmai No. 4, Wanya No. 2, Yangmai No. 5, No. 158, Liaochun No. 4, Zamai No. 5, Xingmai 17, Xi Nong 88, Xi Nong 881, Zhou Mai 9 No. 1 iaoyou 688, Xinbao Feng (7228) Mianmai 26, Qumai 27, Wannian 2, Zheng Yin 1 , 2133, Ning 8026, Ning 8017, etc. Spring wheat has Dingfeng No. 3 and Ningchun No. 24. All localities can be selected according to local conditions.
(2) Agricultural irrigation and control should be rationally drained and drained, and wetlands should be drained and drained. After harvesting, we should deepen the mites and reduce the source of bacteria. Sowing at the right time, avoiding the rain during the flowering period. It is recommended to apply compost with enzymes, using formula fertilization technology, rational fertilization, avoiding partial application of nitrogen fertilizer, and improving plant disease resistance. Lime water soaking before planting, see wheat smut.
Chemical control
1 Seed dressing with stimulation bacteria. Spray the seeds with 100-150 g of solid microbial agents or 50 ml of liquid microbial agents per 667 m^2, mix well, and dry them for sowing.
2 The key point of prevention and control is to prevent the occurrence of ear rot during the flowering stage of wheat. Spraying at the beginning of flowering period, it is necessary to use the medicine in the early stage of wheat stalk and flowering (the rate of flowering plants is 5-10%). For pesticide control, pesticides with good permeability, rain-resistant scouring and long-lasting effect should be selected. For each acre, 25% cylamella suspension can be used, 100-200 ml, or 40% ethiazole/imilian aqueous emulsion 20~. 25 ml, or 28% enamel·carbendazim wettable powder 50-95 g, sprayed on 30-45 kg of fine mist of water.
Depending on the weather conditions, variety characteristics and the growth period, the second dose of medicine should be sprayed about 7 days later, paying attention to alternate rotation. In addition, in the middle and late stage of wheat growth, scab, wheat bran, and armyworm mixed area, 667m^2 with 40% chlorpyrifos 30ml or 10% anti-carbocarb 10g plus 40% chlorhexidine 100g or 60% anti-mildew 70g plus phosphoric acid 150g of dihydrogen potassium or urea, high-yield, etc., excellent in control effect.
In the middle and lower reaches of the Yangtze River, the spraying period is often rainy or rainy, and it is necessary to rush to spray before the rain or after the rain stops. After spraying, the rain can be sprayed once every 5 to 7 days. In order to improve the control effect, it is necessary to focus on the wheat ears when spraying, and spray evenly.
1, the key to prevention is to seize the opportunity + sufficient amount of medication + sufficient water + secondary medication. The timing of prevention and control is from the beginning of heading to the beginning of flowering, 6-24 hours before the rain +5-7 days, and then the second time, the last 36 hours in the 24 hours after the rain stop or the spraying during the rain interval +5-7 days.
2. The water consumption is not less than 15 kg per mu. The spray is made of small hole spray to improve the atomization effect and the number of droplets per unit area, and improve the uniformity of the medicine in the ear.
3, with a straight nozzle or if there is no wind and wind, the nozzle leaves the top of the ear about a foot, which is conducive to drifting and falling of the droplets, increasing the chance and quantity of medicine in the ear. Low-volume spray or mister fogging works better (but lacks special preparations). The low-volume spray method uses a spray of 0.7mm or less, and the sprayed droplets are more than twice as fine as the ordinary spray (1-1.5mm spray), that is, the same volume of water forms more droplets than the ordinary spray method. -2 times.
4, pay attention to the amount of medication and water consumption. To scientifically understand the instructions for the use of pesticides, the correct use of pesticides, including accurate calculation of the amount of drugs and water consumption. Avoiding the use of pesticides will not achieve the effect, excessive use of drugs will cause waste, increase the selection pressure and rapidly increase the resistance of pests and diseases, environmental pollution and so on. The recommended dosage for each regular pesticide is the result of many years of testing by a professional agency (department), otherwise there will be no approval registration number.
However, the test was carried out according to a certain scientific method. The general water consumption is 50 kg of wheat (limited to spraying and spraying but not flowing), but the farmers save time and labor (50 kg of water per mu, for Daejeon) It is really unrealistic. When spraying, there is no reasonable amount of water. First, the water consumption is small. Second, the spray holes are getting larger and larger, resulting in poor dispersion of pesticides in the field, short wetting time to targets, and short absorption time. Reduce the chance of target drug administration, thus reducing the efficacy.
Therefore, I personally recommend the regular workers and peasants type 16 manual or electric sprayer, the water consumption of 15 kg is more suitable, not less than 10 kg, and it is necessary to call on manufacturers and farmers to reduce the spray nozzle to improve the atomization effect, in order to improve efficiency. Use one or three heads.
Another important point to note is that when the recommended dosage is a certain amount of water, the calculation method of the dosage is: the amount of the medicine used (commodity preparation) = 50,000 times (commodity preparation), for example, for 1000 times of liquid The dosage of the mu should be no less than 50 grams, and the amount of the 500 times liquid is 100 grams. Some pesticide instructions are the original amount of pharmaceuticals, but also converted into commercial preparations.
5. Arrange the watering time and avoid watering during the flowering period to avoid increasing the humidity and disease opportunities in the field. However, if the drought during the flowering period is also a factor in reducing production, it is necessary to have a flexible grasp and reasonable arrangement of watering time. However, it is necessary to prevent the use of sprinkler irrigation.
6. Prevention and control of new pesticides for scab. Oxazol, Mimiamide, Clostridium, Tebuconazole (Ricky), Cyanolide, Su Rui Ke, Suo Baoli, etc. Carbendazim also has different preparations, the effect of the suspension is good, and the wettable powder is prone to precipitation.
7. The time to prevent and cure scab is also the time to prevent and control the larvae, mites, powdery mildew and rust. The fungicide, insecticide, humic acid micro-fertilizer and potassium dihydrogen phosphate are sprayed together to achieve a spray-proof prevention. However, note that the dosage should not be too large, and the concentration should not be too high (the upper limit of the concentration is not reported, I don't know).
Wheat scab, also known as wheat ear buck, rotten wheat head, red wheat head, is one of the main diseases of wheat, and one of the more serious diseases in the "three diseases and three insects" at the wheat ear stage. Wheat scab is common throughout the world and is mainly distributed in humid and semi-humid areas, especially in temperate regions where the climate is humid and rainy.
According to the relevant departments, in 2012, the area of ​​wheat scab in a province of Huanghuaihai Agricultural Area was about 24.6 million mu, accounting for 68.3% of the wheat planting area in the province, setting the highest history of wheat scab in the province. Although it has fully resisted and recovered more than 2 billion kilograms of production losses, it still causes some losses in wheat production. Farmers have caused huge losses and suffered huge losses. Wheat scab has become a major hidden danger affecting high-quality and high-yield wheat. Highly valued.
Wheat infection with scab affects wheat yield and quality. If improper control will cause wheat to reduce production, it will cause serious harvest. Some media reports that in 2012, some farmers in Anhui Province will harvest the immature wheat that has been infected with scab (confirmed to be extinct). It is sold to dairy farms at a price of 0.15 yuan/kg to feed the cattle. Such wheat straw is green and strong but the wheat ears are dead and white.
At the same time, the quality of wheat is reduced after infection with scab, the grains are dry and the flour yield is reduced. Wheat scab does not only cause serious yield loss and quality impact on wheat production, but more importantly, its phytotoxicity affects food safety and has attracted much attention.
Scab is caused by Fusarium fungi, causing loss of wheat yield, while also producing mycotoxin mainly deoxynivalenol (ie, vomiting toxin DON), which is harmful to humans and animals. Edible disease can cause symptoms of acute poisoning such as dizziness, fever, nausea, diarrhea, etc., causing bleeding in severe cases, affecting immunity and fertility, and directly posing a threat to human and animal health and life safety.
Therefore, when the content of wheat in wheat is more than 4%, it is inedible. At the same time, it indicates that wheat has lost its commercial value and needs to be treated separately. In 2012, some media reported that in some places in Jiangsu, wheat was infected with scab and the grain tube refused to accept wheat.
In short, wheat has no yield after infection with scab, or there is yield but wheat cannot be sold and there is no income. In view of the serious harm of scab, it has already attracted the attention of farmers and adopted a series of measures. According to reports, the effects of prevention and control are quite different. Through investigation, it is found that farmers' understanding of scab is still not enough, and there are still many misunderstandings in the control of scab.
One: I am lucky about the occurrence of scab and rely on old experience to solve new problems.
Wheat scab is a typical climatic disease caused by several species of Fusarium. Its epidemic is affected by various factors such as bacterial source, variety resistance, agro-ecological environment and cultivation management measures. The epidemic of diseases is closely related to meteorological conditions. When the average temperature in spring is above 9 °C and 3-5 days in rainy days, ascorbic spores are produced in the wintering source, and in the case of a large number of mature ascospores in the flowering stage of wheat, the rainfall occurs. Or the air is humid, the ascospores mature and scattered on the anthers, infested by the filaments, and the water-soaked light brown spots on the spikelets and glume initially expand to the entire spikelet.
In the rainy season of wheat heading and flowering, if there is a rainy weather with a certain amount of precipitation for more than 3 consecutive days, it can cause a pandemic of wheat scab. For three consecutive days of rainfall, the rainfall is over 12 mm, and the relative humidity of the field air is over 80%. Conducive to the release and infestation of ascospores, when the field air humidity reaches 80% or more, it is very likely to cause the occurrence and prevalence of wheat scab.
Therefore, in the prevention and control of wheat scab, we must look at it three times, "seeing the sky, seeing the seedlings, seeing the land", we must comprehensively consider the disease factors, some farmers can not comprehensively consider the above factors, fail to fully understand the symptoms of scab, Epidemic law, disease factors, only refer to the old experience to pay attention to weather changes (rainwater and temperature), while ignoring the influencing factors of field humidity and variety differences, although there is no large-scale disease occurrence, but also caused the occurrence of disease, affecting The increase in wheat yield and quality has been achieved.
Second: re-treatment and light prevention, see the disease medication, miss the best prevention period.
Wheat scab can be prevented from being incurable. It should be prevention-oriented, and the traditional practice of active defense and re-treatment of light and light prevention is not conducive to the prevention and control of scab. At the same time, the choice of the period of use in the disease prevention process will directly affect the level of control. Numerous data on the period of application of scab are “heading period to flowering stageâ€. During such a long period of drug use, there is a big difference in the effect of drug use in different time periods.
Some farmers choose to use medicine at the booting stage or at the end of the flowering stage. Some even see the pink mold layer and then use the medicine. They do not have a good grasp of the best prevention period, and the control effect is low. Through field investigations, it was found that the best control period was from 5% wheat to 5%.
At the same time, there are several situations to be fully considered. The heading period is fine and the temperature is high. The wheat is plucked and the flowers are raised at the heading stage. The heading period can be used. The temperature at the heading stage is low, the sunshine is small, and the wheat is first taken after the heading, and the medicine should be used at the beginning flowering stage. When the heading period meets the rainy weather, when the scab is probable, the spray should not be late, don't wait until the weather is fine or when the flower is sprayed, the spray should be sprayed several times; if the system is good The period of long-lasting drug control can be advanced to the early stage of wheat heading.
Three: blindly choose the agent, ignoring the problem of complementary drug resistance and mechanism of action.
Currently, there are 248 pharmacies registered in the Ministry of Agriculture for the control of wheat and wheat scab (as of March 2013). Among them, carbendazim (97 registration certificates), thiophanate-methyl (50 registration certificates), polyketones (35 registration certificates), and Fumeishuang (21 registration certificates) were registered. The total number of registration certificates is 81.85%, and the registered control agents involve 14 components: carbendazim, thiophanate-methyl, oligosaccharide, triadimefon, sulfur, thiram, hexaconazole, jingji , prochloraz, enestrobin, diniconazole, tebuconazole, wax bud, epoxiconazole.
In recent years, farmers have generally reported that carbendazim is not working, and the effects of other agents are not good. It is impossible to rule out the problem of the quality of some pesticides. The relationship between resistant strains should also be considered, and it will be different from the farmers in the process of drug use. There is a close relationship between the use of the agent and the compounding mechanism.
The spraying of benzimidazole fungicides such as carbendazim is one of the key measures for the prevention and control of wheat scab in China since the mid-1970s. It has been reported that since 1992, Zhou Mingguo (Journal of Nanjing Agricultural University) discovered the world's first strain of Fusarium graminearum resistant strain in Haining, Zhejiang Province, and conducted continuous drug resistance test in Zhejiang, Jiangsu, Shanghai and Hubei. It has been found that the proportion of drug-resistant pathogens has risen rapidly, and has become a disease-causing species in Zhejiang and other places. At the same time, the distribution of disease-resistant pathogens has been expanding, and it has spread from the original Zhejiang to most of Shanghai and Jiangsu.
After a lapse of 20 years, the problem of resistance to benzimidazole fungicides has attracted the attention of people in the industry. In areas where certain drug control effects are reduced, it is recommended to actively pay attention to new varieties, such as tebuconazole. Mixture (Zammir), cymene ester (Jingnu), etc. At the same time, it is necessary to pay attention to the correct mixing of different mechanisms of action, to ensure that the drugs used have the multiple effects of systemic treatment, protection and eradication, and comprehensively prevent the spread of disease.
Four: The water consumption per mu is too small, which is not conducive to the efficacy of the drug.
According to the interview, some farmers in the wheat area use the conventional sprayer to spray more than 15 liters of water per mu, and the lesser is only 10 liters. Such a small amount of water will affect the normal function of the drug. In order to ensure the efficacy of the drug, if the use of conventional sprayer, the amount of water should be between 45 liters and 60 liters, or add a potency guarantee agent, such as spread.
Five: The number of medications cannot be correctly mastered.
There is no fixed standard for the number of medications. It is necessary to comprehensively consider factors such as the amount of bacteria, the incidence of the disease, and the effects of chemical control. It is necessary to carry out two prevention and control measures for the plots that have been seriously affected in previous years, and pay attention to the post-rain spray, for the first dose effect. If you are not good, you should take remedial measures in time. You can use the second agent about 7 days after the first dose to better control the spread of the bacteria and reduce the loss.
A comprehensive understanding of the pathogenesis of scab, master the law of onset, grasp the best prevention period, choose the right preventive agent and apply it correctly, and minimize the disease loss. (Author / Wang Guozhong)
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