Forecast of occurrence trend of diseases and pests in middle and late rice
By: Date: 2022-07-29 Categories: foodtechnology Tags: ,
From July 14 to 16, the National Agricultural Technology Center held the 2022 national autumn grain pest occurrence trend conference in Yinchuan City, Ningxia Autonomous Region. The chamber of Commerce organized the forecasting technicians and relevant experts of plant protection institutions in 20 provinces (autonomous regions and municipalities directly under the central government) in the main rice producing areas. Based on the comprehensive analysis of the current pest occurrence base, cultivation conditions and climatic factors, it is estimated that the main pests and diseases of middle and late rice in 2022 will generally occur, with an area of 900million Mu times, The occurrence area of pests is 620million Mu times, and the occurrence area of diseases is 280million Mu times. Among them, rice planthopper, Chilo suppressalis and sheath blight are more likely to occur, rice leaf roller and rice blast are moderately to more likely to occur, rice false smut is moderately likely to occur, and rice black stripe dwarf disease is less likely to occur in southern China.
 
I. occurrence trend
 
(I) rice pests
 
Rice planthoppers are prone to occur, with an area of 260million mu in China. Among them, brown planthopper mainly occurs in South China, the eastern part of the Yangtze River and the middle and lower reaches of the Yangtze River, and moderately in the Yangtze Huaihe River and southwest rice areas; White backed planthoppers occur mainly in western South China, Eastern Southwest China and Jianghan Plain, and moderately in other rice areas in the south.
 
Rice leaf roller is more likely to occur in rice areas along and south of the lower reaches of the Yangtze River, and moderately in other rice areas in the south; The area of occurrence nationwide is 150million mu.
 
Chilo suppressalis mainly occurs in most rice areas in the north of Southwest China, Jiangnan, the middle and lower reaches of the Yangtze River and the Yangtze Huaihe River, of which the occurrence of rice borers can be large in some rice areas in central and southern Hunan and Northern Hunan, and moderate in most rice areas in southern China, southern Southwest China and Central Northeast China; The occurrence area in China is 140million Mu times.
 
Armyworm, stem borer, rice borer, gray planthopper, rice stalk Liriomyza sativae, Taiwan rice borer and other pests occur to a certain extent in some rice areas; The occurrence area in China is 70million Mu times.
 
(II) rice diseases
 
Sheath blight occurs in most of South China, the north of Southwest China, the south of the Yangtze River, the middle and lower reaches of the Yangtze River and the Yangtze Huaihe River, while it occurs moderately in other rice areas; The occurrence area in China is 180million Mu times.
 
Rice blast generally occurs moderately, and the risk of recurrence of susceptible varieties is high in the lower reaches of the Yangtze River, the southwest, the hilly areas of the south of the Yangtze River, and the northeast; The occurrence area in China is 48 million mu times.
 
Rice false smut occurs heavily in some rice areas along and south of the middle and lower reaches of the Yangtze River, and moderately in most rice areas in the southwest, Jiangnan and middle and lower reaches of the Yangtze River, but there is still a risk of serious occurrence in continuous rain, condensation or haze during heading and flowering; The occurrence area in China is 36 million mu times.
 
The occurrence of black streaked dwarf disease of rice in southern China was generally mild; The occurrence area is 1million Mu times.
 
Rice leaf blight, ear rot, flax leaf spot, root knot nematode disease, stem rot and leaf blight and other diseases occur to a certain extent in some rice areas; The occurrence area in China is 15million Mu times.
 
II. Prediction basis
 
(I) the number of pests and diseases such as”two migration” pests meets the conditions for occurrence of medium or above
 
At present, the number of rice planthoppers in 100 clusters in the southern rice region is generally 150-800, but the number in Northeast Guizhou, Northeast Guangxi and East Guangdong is 8000-12000. The number of larvae per mu in the field of rice leaf roller is relatively low, 7200, 6000 and 1200 in Guizhou, Hunan and Guangxi respectively, 700-800 in Jiangxi and Jiangsu, and less than 350 in other rice areas, but there are more than 50000 fields in central and Western Hunan and Southeast Guizhou. The number of larvae per mu of Chilo suppressalis in the northern southwest, Eastern South China, the middle and lower reaches of the Yangtze River and the Central Northeast rice region is generally 200-800, but the average number in Hunan is 1700. The incidence of rice blast is widespread, and there is still a certain planting proportion of susceptible varieties. Sheath blight occurs heavily all year round, and there is sufficient bacterial source in the field.
 
(II) host crops and field ecological conditions are conducive to the occurrence of diseases and pests
 
There is a large area of mixed cultivation of single and double cropping rice in South China and Jiangnan rice regions in China. The long sowing period and irregular growth period of single cropping rice in the southwest and the middle and lower reaches of the Yangtze River are conducive to the spread of pests and climatic diseases such as rice blast and rice false smut. The middle and late rice varieties in various regions are mainly high-quality rice, and the resistance level of the main varieties is still at a low level. The resistance of some varieties is degraded or lost, and the planting density of rice is high. Under the cultivation conditions of high water and fertilizer, the covering of paddy fields is conducive to the occurrence and prevalence of rice diseases and pests. In addition, when the water consumption for pesticide application of plant protection UAV is insufficient, it may lead to incomplete prevention and control of diseases and pests at the stem base such as brown planthopper, so it is necessary to be vigilant against the risk of accumulation of disease and pest sources.
 
(III) meteorological conditions are generally conducive to the occurrence of epidemic diseases and the northward migration of”two migration” pests
 
According to the prediction of the National Meteorological Center, the temperature in the main rice producing areas in midsummer (July August) this year is generally high, and there is more rainfall in South China, south southwest and northeast, East northeast and south, which is conducive to the occurrence and prevalence of rice”two migration” pests and rice blast, sheath blight, rice false smut and other pests; There is less precipitation in the lower reaches of the Yangtze River, and the number of high-temperature days in eastern South China, Jianghuai, Jianghan, Jiangnan and other places is more than the same period of the year. There will be periodic high-temperature heat waves, which will have a certain inhibitory effect on the development of the”two migration” pest population. However, in the second half of the year, there are still 4-6 typhoons landing or significantly affecting eastern China and the north, which is conducive to the northward migration of rice”two migration” pests and the occurrence and prevalence of bacterial diseases.