In 2018, the overall incidence of major crop diseases and pests remained stable; however, next year’s outbreak is expected to be more severe than usual.

In 2018, the overall incidence of major crop diseases and pests in China remained stable and was milder than in recent years. The total area affected nationwide reached 289 million hectares (4.335 billion mu), a decrease of 8.3% compared with 2017; the area treated totaled 384 million hectares (5.76 billion mu), down 6.6% year on year. Among these, Wheat Fusarium head blight has been severely prevalent in wheat-growing regions including the middle and lower reaches of the Yangtze River, the Jianghuai area, and southern Huanghuai, with a more severe incidence than in 2017. Corn Stem borers, cotton bollworms, two-brooded stem borers, and potato late blight have re-emerged in some areas; rice planthoppers, armyworms, locusts, and grass cutworms are occurring at high densities in localized patches, and the grass cutworm has entered another outbreak cycle. Wheat 、 Corn The incidence of soil-borne diseases, such as stem base rot, has continued to expand.
　　In 2018, the overall incidence of major crop diseases and pests remained stable; however, next year’s outbreak is expected to be more severe than usual.
　　It is projected that in 2019, the overall incidence of major crop diseases and pests in China will be more severe than usual, with a cumulative affected area of approximately 4.8 billion mu‑times. Among these, Wheat Fusarium head blight, the “two‑migration” rice pests, and the cotton bollworm all face a high risk of resurgence; the stem borer and rice sheath blight, … Wheat Aphids, Corn The stem borer has a wide distribution and causes severe damage; the armyworm, rice blast, Wheat Stripe rust, Corn Large spot disease and potato late blight are occurring at relatively severe levels in some areas; locusts remain generally stable, while the grass webworm has entered a new outbreak cycle, with localized patches potentially reaching high densities.
　　1. Major rice diseases and pests
　　1.1 Rice planthopper
　　Rice planthoppers are a major migratory pest of rice, with an average annual affected area of 24.46 million hectares from 2001 to 2018. Since 2012, thanks to effective control measures, their incidence has generally stabilized, with an average annual affected area of 19.34 million hectares. For 2019, rice planthoppers are expected to occur at a severe level in the rice-growing regions of South China, the Jiangnan area, the middle and lower reaches of the Yangtze River, and eastern Southwest China, while other rice-growing areas are forecast to experience moderate infestations.
　　1.2 Rice Leafroller
　　The rice leafroller is an important migratory pest of rice. Since 2011, its incidence has generally remained stable, with an average annual affected area of 15.16 million hectares. For 2019, the rice leafroller is expected to occur at a moderate level overall, with heavier infestations anticipated in the lower Yangtze River rice-growing region.
　　1.3 Stem borer
　　From 2001 to 2018, the average annual area affected by the rice stem borer was 14.79 million hectares per year. In recent years, the pest has shown a marked resurgence in the southern rice-growing regions. For 2019, it is forecast that the rice stem borer will occur at moderate to severe levels across much of the rice-growing areas in the southwestern and northeastern parts of China, as well as in the Jiangnan region and the middle reaches of the Yangtze River, with potentially widespread outbreaks in some localities.
　　1.4 Rice sheath blight
　　Rice sheath blight is a common and recurrent disease of rice, with an average annual affected area of 16.6 million hectares from 2001 to 2018. In recent years, the incidence of this disease has remained generally stable. For 2019, rice sheath blight is expected to occur at a relatively severe level overall, with most areas in the southern rice-growing region experiencing moderate to severe outbreaks, while much of Northeast China and the southern part of Southwest China are anticipated to see moderate levels of infection.
　　1.5 Rice Blast Disease
　　Rice blast is a widespread and highly destructive disease of rice, with an average annual incidence of 4.56 million hectares from 2001 to 2018. In recent years, its occurrence has remained generally stable. Rainfall during the booting stage is a key factor driving the epidemic. For 2019, rice blast is expected to occur at a moderate level overall, with a high risk of severe outbreaks in parts of eastern Southwest China and localized areas along the middle and lower reaches of the Yangtze River.
　　2. Wheat Major pests and diseases
　　2.1  Wheat Fusarium head blight
　　 Wheat Fusarium head blight is a quintessential climate‑driven epidemic disease. Between 2011 and 2018, it averaged an affected area of 5.43 million hectares. Wheat Precipitation during the heading and flowering stages is a key factor influencing the epidemic of this disease. In recent years, the frequency of its recurrence has increased, and it has become… Wheat The most significant disease affecting it. It is projected that in 2019… Wheat Fusarium head blight poses a high risk of severe epidemics in the middle and lower reaches of the Yangtze River, the Jianghuai region, and the southern Huanghuai wheat-growing areas. Wheat Stripe rust is generally at a moderate incidence, with localized outbreaks of severe intensity in wheat-growing areas such as southern Gansu, the riverine basins of Sichuan, and the Han River basin.
　　2.2  Wheat Stripe rust
　　 Wheat Stripe rust is a regionally widespread disease. Through integrated management, its incidence has remained relatively stable over the past decade, with an average annual affected area of 2.3 million hectares. However, in 2017, extreme weather conditions led to widespread outbreaks and significant damage across most wheat-growing regions nationwide. It is anticipated that in 2019… Wheat Stripe rust is generally at a moderate incidence, with localized outbreaks of severe intensity in wheat-growing areas such as southern Gansu, the riverine basins of Sichuan, and the Han River basin.
　　2.3 Aphids
　　Aphids during the heading stage are a factor that affects… Wheat An important pest that significantly affects yield, it has recently been occurring at a relatively severe level across most wheat-growing regions of the Huang-Huai-Hai Plain. From 2011 to 2018, the average affected area was 15.93 million hectares, and it is… Wheat The most important pest in production. Estimated for 2019. Wheat Aphids are generally occurring at a severe level, with particularly severe outbreaks in Shandong and Hebei.
　　3. Corn Major pests and diseases
　　3.1  Corn stem borer
　　 Corn The stem borer is Corn The commonly occurring wood-boring pests have, in recent years, affected an average area of 18.8 million hectares, with a growing trend of increased damage in regions such as Northeast China and the northern parts of Northwest China. It is projected that in 2019… Corn The stem borer is generally occurring at a severe level. First generation. Corn In northern Northeast China and the Ili region of Xinjiang, the second generation… Corn In Northeast and parts of Southwest China, the rice stem borer has three generations. Corn The stem borer is occurring at a moderately severe level in parts of North China and the Jiangnan region.
　　3.2 Armyworm
　　The armyworm is a migratory pest; over the past decade, it has averaged 3.85 million hectares of infested area annually, and in 2012, three generations of armyworms caused severe outbreaks in northern China. For 2019, the overall incidence of the second and third generations is expected to be moderate, with localized areas in Northeast, North, Northwest, and the Huanghuai region experiencing relatively severe outbreaks, and some regions may see high‑density, concentrated damage.
　　3.3  Corn Large斑 disease
　　 Corn Large-spot disease is a widespread epidemic, with an average annual affected area of 4.5 million hectares in recent years. It occurs fairly commonly, with severe localized damage. It is projected that in 2019… Corn Large spot disease is expected to occur at moderate levels across most of Northeast China, North China, and Southwest China, with severely affected areas likely to see heavy outbreaks in susceptible varieties.
　　4. Other major pests and diseases
　　4.1 East Asian migratory locust
　　Following integrated management, the East Asian migratory locust has experienced generally stable outbreaks in recent years; however, the complex ecological conditions in locust‑infested areas have heightened the risk of locust proliferation. For 2019, moderate outbreaks are anticipated in parts of the Bohai Bay region and the Yellow–Huai Plain, with localized areas likely to see high‑density clusters of nymphs.
　　4.2 Cotton bollworm
　　Affected by structural adjustments and other factors, in recent years the cotton bollworm has… Corn The incidence and damage caused by this pest are trending upward. It is forecast that in 2019, the cotton bollworm will generally occur at a relatively severe level, with the second to fourth generations being particularly prevalent in northern regions. Corn 、 Peanut 、 Soybean It is severely prevalent in fields of sunflowers and other crops, with a marked escalation of damage in parts of Northwest and North China; in some areas, high-density, localized outbreaks may occur.
　　4.3 Potato Late Blight
　　Potato late blight is a quintessential climate‑driven epidemic disease, with rainfall during the budding to flowering stage serving as a key factor influencing its spread. For 2019, the overall incidence of potato late blight is expected to be moderate, with elevated risks of severe outbreaks in southeastern Southwest China, northern Northeast China, northern North China, and eastern Northwest China.

Author: Pest and Disease Monitoring Division, National Agricultural Technology Center Editor: xwbj1