First, the occurrence of dynamics
According to surveys across the country, as of March 17, wheat stripe rust was found in 303 counties (cities and districts) in 72 cities in 9 provinces such as the southern part of Huanghuai, the southwest and the Hanshui River Basin, with an area of 10.28 million mu, an increase of 64.7% and 4.3 times over the same period in 2017 and 2019, respectively, which was the largest and heaviest occurrence in the same period in the past 10 years. Specific occurrences:
1. The spread of diseases in the Huanghuai River-Huaimai area has accelerated significantly, and the local disease is more serious. Henan Province has expanded to 30 counties (cities and districts) in 7 cities of Nanyang, Xinyang, Pingdingshan, Zhoukou, Zhumadian, Luohe and Xuchang, with an area of 446,000 mu and an occurrence period of nearly one month earlier than in 2017. The average disease rate in Nanyang is 4.1%, up to 25%, and the average severity is 20% and up to 100%. Funan County, Anhui Province, first seen on March 10, more than 10 days earlier than usual, the current area of 7 counties (cities, districts) along the Huai and Yanjiang cities is 45.3 acres, most of which are sporadic diseases, and the disease rate is generally 0.07%-0.45%. Hubei Province is in a period of rapid epidemic, which is the largest and most severe year of occurrence in the same period since the province has recorded. The area of occurrence reached 6.756 million mu, an increase of 2.1 times over the same period in 2017, and the average diseased field rate was 43.1%, an increase of 17.7 percentage points over the previous week; the general diseased leaf rate was 3%-16.7%, and the diseased leaf rate of the recurrent field disease center reached 100%.
2. The southwest wheat area has entered the peak of the epidemic, the average diseased leaf rate in most wheat areas is 4.8%-7.0%, the highest diseased leaf rate of locally recurrent plots is 60%-100%, and the average diseased leaf rate in Sichuan Province is 7.0%, 2.5 percentage points higher than that of the same period last year.
3. Sporadic diseases in the northwest wheat area, 6 counties (cities, districts) in Longnan and Tianshui cities in Gansu Province have an area of 10,300 mu. In Longnanwen County, the average diseased leaf rate and the average severity of the diseased field were 0.01%, and the average severity was 10%.
5. The area of occurrence in Shaanxi Province was 612,000 mu, an increase of 80.8% and 31.2% respectively over the same period in 2017 and the previous week. The average diseased field rates in southern Shaanxi and Guanzhong were 13.1% and 9.1%, respectively, the average diseased leaf rates in local pufa fields in southern Shaanxi were 1.6%, and the highest diseased leaf rates and severity were 10% and 40%, respectively, which was the year with the largest number of counties, the largest area and the most serious diseases in the same period since 2010.
6. Since the first discovery of Weinan City on March 5, more than 1,600 mu have occurred in 8 towns in 5 counties (cities and districts) such as Linwei, Huayin, Huazhou, Dali and Pucheng, which is the earliest and most serious spring disease in the past ten years. The area of Xiyang Village, Guanchi Town, Dali County, adjacent to our county, is 400 mu, with 27 disease centers and 130 single diseased leaves.
Second, the trend of the disease
Wheat stripe rust is a typical air-borne epidemic disease, which has the characteristics of wide spread area, fast spread speed and heavy local harm, and once a large-scale epidemic will seriously affect wheat yield. Although at present, our county has not found wheat stripe rust disease field before winter and early spring, but the epidemic of wheat stripe rust in our county in spring is mainly affected by foreign fungal sources, and there are many sources of wheat stripe rust in western wheat stripe rust in the province before winter, and more than 1600 acres have occurred in 5 counties of our city in early spring, and the occurrence of wheat stripe rust in neighboring cities and counties in our county occurs early and there are many fungal sources, which is conducive to the epidemic of wheat stripe rust in our county in spring, which poses a serious threat to wheat production in our county. In addition, since the early spring of February, there is more rain, the temperature is high, the weather forecast is more rainy in April and May, and the main wheat varieties in our county have poor resistance to stripe rust, and the climate and ecological environment conditions in the middle and late period of wheat are very conducive to the spread of wheat stripe rust, and it is expected that the stripe rust in the middle and late stages of wheat this year will be more serious, therefore, it is hoped that the town and street governments and the broad masses of farmers will pay enough attention to effectively strengthen the monitoring of wheat stripe rust, fully grasp the dynamics of wheat stripe rust, and make preparations for the prevention and control of wheat stripe rust as soon as possible Once the disease is found, the disease should be immediately applied to prevent and control the application to ensure the safety of wheat growth and the harvest of the first crop this year.
Third, prevention and control strategies
The key to the prevention and control of wheat stripe rust is early detection and early prevention, early prevention and small prevention, and it is necessary to strictly abide by the prevention and control strategy of "seeing the point of hitting the piece, seeing the piece of the noodles", "finding a point, preventing and controlling a piece", and "finding a piece, the field general defense". When spotting occurs, once the diseased field is found, the wheat field within a radius of 500 meters should be immediately centralized and unified prevention and control to minimize the number of initial bacteria sources. After the whole field is developed, it is necessary to carry out unified prevention and control of wheat fields within a radius of 2 kilometers of the field. Recurrent areas carry out emergency unified prevention and control, and implement joint prevention and control and group prevention and group control in large-area contiguous areas, and improve the coverage rate of specialized operations and the rate of prevention and disposal.
Fourth, prevention and control technology
1. Spotting occurs in wheat fields. When 1-2 disease centers or single diseased leaves are found in the field, the whole field is sprayed immediately, and the surrounding fields with hidden dangers are concentrated and unified prevention and control. The agent was selected per mu of 15% triazolone wettable powder 80-100 grams, or 43% texazol suspension 15-20 grams, or 25% propiconazole emulsion 35-40 ml, or 10% hexazol suspension 4-5 grams, mixed with water 25-30 kg evenly spray control.
2. Datian Pufa wheat field. After the wheat ear is extracted, the incidence of disease in the field increases, and when the leaf rate of wheat stripe rust disease reaches more than 0.5%, a large-scale general prevention is immediately carried out to achieve full coverage of the regional wheat field. Adopt the wheat "one spray, three prevention" technology based on strip rust control, taking into account wheat powdery mildew, leaf rust, wheat aphids, wheat long-legged spiders, wheat field underground pests, wheat strip leafhoppers and other diseases and insects. The fungicide can choose triazolone, enazol, pentazol alcohol, propiconazole, phenethicazole, etc., the insecticide can choose imidacloprid, acetamidine, thiamethoxazine, pyritone, matrine, etc., micro fertilizer can choose potassium dihydrogen phosphate, urea, humic acid, amino acids, growth regulators can choose acetylamine, chlorhenol, brassinolide, etc. The amount of spraying liquid per mu is 40-45 kg, and the spraying time is suitable for selecting 10 a.m. to 4 p.m. on sunny and breezy weather.
(Contributed by Fan Wugang, Agricultural Technology Center of Heyang County Agricultural and Rural Bureau)