Recently, the National Agricultural Technology Center held the 2021 National Middle and Late Rice Disease and Pest Occurrence Trend Conference Chamber of Commerce in Harbin, Heilongjiang Province, and the monitoring and reporting technicians and relevant experts from the plant protection agencies of 20 provinces (autonomous regions and municipalities directly under the central government) in the main rice producing areas are expected to have an overall heavy incidence of major diseases and insect pests in 2021 according to the comprehensive analysis of the current disease and insect occurrence base, cultivation conditions and climatic factors, with an area of 920 million mu, an area of 630 million mu of insect pests, and a disease occurrence area of 290 million mu. Among them, rice planthopper and striped blight are more severe, rice longitudinal leaf borer, dimorph borer and rice blast disease occur moderately to more severely, rice aspergillosis occurs moderately, and southern rice black strip dwarf disease occurs more lightly.
Trending occurs
One
Rice infestation
Rice planthoppers occur heavily, with an area of 270 million mu in the country. Among them, the white-backed planthopper occurs more heavily in the eastern southwest and jianghan plains, and in the middle and lower reaches of the Yangtze River in the southwest and most of the middle and lower reaches of the Yangtze River, south China, Jiangnan and Jianghuai rice areas, while brown planthoppers occur more heavily in the rice areas of eastern And southwest China, most of the southwest, Jiangnan and the middle and lower reaches of the Yangtze River, and moderately occurs in most of South China, southwest and eastern China, and Jianghuai rice areas.
Rice longitudinal leaf borer occurs more heavily in rice areas along the lake in the western part of Jiangnan and the middle and lower reaches of the Yangtze River, and moderately occurs in most of the rice areas of jiangnan and the middle and lower reaches of the Yangtze River, the eastern southwest and most of South China; The area of occurrence in the country is 160 million mu.
Erhua borer occurs heavily in the western part of Jiangnan, and occurs moderately in the north-southwest, eastern China, eastern Jiangnan, middle and lower reaches of the Yangtze River, Jianghuai, and the central and southern parts of the northeast; the occurrence area of the whole country is 130 million mu.
Other insect pests such as gray planthopper, sanhua borer, giant borer, rice stalk fly, armyworm, And Taiwan rice borer occur to a certain extent in some rice areas; the national occurrence area is 69 million mu.
Two
Rice diseases
Blight occurs heavily in rice areas in most of South China, eastern Southwest China, Jiangnan and the middle and lower reaches of the Yangtze River, and moderately occurs in rice areas in eastern, southwestern and northeastern China; the incidence area is 180 million mu nationwide.
Rice blast is at high risk in the hilly mountains of southwest and Jiangnan and northeast rice areas, and the occurrence of rice in most other rice areas is moderate; the occurrence area of the whole country is 56 million mu.
The overall incidence of aspergillosis is moderate, and there is a risk of heavy occurrence in rainy weather during the flowering period of panicle pumping; the national occurrence area is 38 million mu.
The overall occurrence of black-striped dwarf disease in southern rice was mild, and moderate in western Guizhou, southwestern Guangdong and parts of central and southern Hunan Province, with an area of 1 million mu.
Other diseases such as rice white leaf blight, ear rot, flax leaf spot disease, and root-knot nematode disease occur to a certain extent in some rice areas; the area of occurrence in the whole country is 15 million mu.
Forecast basis
(1) The base number of diseases and insects such as "two migrations" pests has medium or above conditions for occurrence
At present, the amount of rice planthoppers in the rice areas of South China, Jiangnan and Southwest China is generally 300-1100 heads, and the maximum number of 100,000 worms in the eastern part of the southwest and central Jiangnan is 600,000 heads; the number of 100 bush insects in the middle and lower reaches of the Yangtze River and the Jianghuai Rice Area is generally 100-300 heads, and the maximum number of insects in Shanghai is 4000 heads. The amount of larvae per mu in the field of rice longitudinal leaf borer is low, with 5000, 2700 and 1200 heads in Hunan, Guangxi and Chongqing respectively, and other rice areas are generally below 500 heads, but there are more than 100,000 heads in central and western Hunan and central Qianzhong. The amount of larvae per mu in the rice areas of the southwest and northern parts, eastern South China and the middle and lower reaches of the Yangtze River is generally 250-450 heads, but the average number of larvae in Hunan is 3500 heads, and the super large occurrence standard (1000 heads). Rice blast disease has a wide range of incidence points, and there is still a certain proportion of planting of disease-susceptible varieties. Striated blight occurs heavily throughout the year, and the source of bacteria in the field is sufficient.
(2) Host crops and field ecological conditions are conducive to the occurrence of diseases and insects
The mixed planting area of single and double-cropping rice in the rice areas of South China and Jiangnan is large, which is conducive to the migration of rice pests and borers. The uneven growth period of single-cropping rice in the rice areas of southwest china and the middle and lower reaches of the Yangtze River increases the chance of rainy weather during the susceptible growth period of rice, which is conducive to the prevalence of climatic diseases such as rice blast and rice aspergillosis. The medium and late rice varieties in various places are mainly high-quality rice, the resistance level of the main cultivars is still at a low level, the resistance of some varieties is degraded or lost, and under the cultivation mode of high water and fertilizer, the host nutrition conditions are good, and the rice field is depressed and conducive to the occurrence and epidemic of rice diseases and insect pests
(3) Meteorological conditions are generally conducive to the occurrence of epidemic diseases and the northward migration of "two migrating" pests
According to the forecast of the National Meteorological Center, the overall temperature in China is high in the middle of summer (July and August) this year, and the rainfall in the northeast, the eastern part of Jianghuai, the northeast of Jiangnan, the eastern and northern parts of the southwest region, most of Jianghan and southern China is conducive to the epidemic of rice blast, blight, rice koji and other diseases, which is easy to cause local sudden epidemic hazards. Southwest south, south China, Jiangnan and most of the middle and lower reaches of the Yangtze River precipitation is small, and the number of high temperatures (daily maximum temperature ≥35 °C) in Jianghuai, Jianghan, Jiangnan and other places is too large, there will be a stage of high temperature heat wave, which will have a certain inhibitory effect on the development of the "two migrations" pest population, but the number of typhoons that landed or significantly affected China in the second half of the year was 6-8, close to the perennial to more, and there may be northward typhoons that significantly affect East China and the north, which is conducive to the northward migration of "two migrations" pests.
Source: National Agricultural Technology Extension