Early warnings for major pests and diseases of food crops are now available.

High risk of recurrence of wheat scab and aphids.

It is projected that in 2019, major wheat diseases and pests will occur at a generally severe level, affecting a total area of 900 million mu‑times, with diseases accounting for 480 million mu‑times and pests for 420 million mu‑times. Fusarium head blight poses a high risk of widespread outbreaks, particularly in the middle and lower reaches of the Yangtze River and the Huanghuai wheat region; aphids are expected to be severely prevalent across much of North China and the northern Huanghuai wheat area; stripe rust will occur at moderate levels in the Jianghan Plain, the Han River basin, and parts of the southwestern and northwestern wheat regions; and sheath blight and powdery mildew are likely to be widespread in the high‑yielding wheat areas of the Jianghuai and Huanghuai regions.

[Diseases]

The risk of severe to very severe outbreaks of scab is high, with an estimated affected area of 150 million mu and a total preventive and control requirement exceeding 250 million mu‑times. Specifically, major epidemics are expected in the middle and lower reaches of the Yangtze River, the Jianghuai region, and southern Huanghuai; moderate to severe epidemics are anticipated in northern Huanghuai; and moderate epidemics are forecast for other wheat-growing areas.

Stem rust is generally expected to occur at a mild level, with an estimated affected area of 30 million mu. Specifically, moderate outbreaks are anticipated in northwestern Hubei and the Jianghan Plain, southern Shaanxi and western Guanzhong, southern Henan, southern Gansu, the riverine and valley regions of Sichuan, Yunnan, and the Ili River Valley in Xinjiang, with localized areas experiencing heavier infestations.

Overall, stripe rust is expected to occur at a moderate level, affecting an estimated 120 million mu. Specifically, it is forecast to be more severe in Hubei, Anhui, Henan, Jiangsu, and the Jiaodong Peninsula of Shandong, while in the wheat-growing regions of Northwest and Southwest China, its incidence is expected to be relatively mild.

Powdery mildew is generally at a moderate incidence, with an estimated affected area of 90 million mu. Locally, it is expected to be relatively severe in northern Jiangsu and the Jianghuai region, central and northern Henan, southern Shandong, southern Shanxi, and southern Gansu.

Stem base rot is spreading and causing increasingly severe damage in the wheat-growing regions of the Huanghuai Plain and southern North China, while leaf rust is widespread across most wheat areas. Additionally, diseases such as take-all, root rot, leaf blight, viral diseases, smut, cyst nematode disease, and snow mold can inflict significant harm in certain wheat-growing regions.

[Insect Pests]

Aphid infestations are generally expected to be severe, with an estimated affected area of 220 million mu. Severe outbreaks are anticipated primarily in the wheat-growing regions of the Jianghuai, Huanghuai, and most of North China, while moderate outbreaks are likely in other major wheat-producing areas, including much of Northwest and Southwest China.

Wheat spider mites are expected to occur at moderate levels overall, with an estimated affected area of 90 million mu. Specifically, heavier infestations are anticipated in western Henan and the northern Hubei hilly regions; moderate outbreaks are forecast for southern North China, the Huang-Huai Plain, and eastern Northwest China; while other wheat-growing areas are expected to experience lighter infestations.

Overall, the rice leafroller is expected to occur at a relatively mild level, with an estimated affected area of 15 million mu. In particular, moderate outbreaks are anticipated in central and southern Hebei, while localized areas in Cangzhou and Xingtai in Hebei, as well as in Zhumadian, Nanyang, and Puyang in Henan, may experience high-density infestations.

A generation of pests—including the armyworm, cotton bollworm, wheat stem sawfly, gray planthopper, wheat leafhopper, white‑browed grass moth, and locust—can cause significant damage in certain wheat-growing regions.

Local resurgence of migratory rice pests and epidemic diseases

It is projected that in 2019, rice diseases and pests will occur at a relatively severe level, affecting a total area of 1.19 billion mu‑times. Pest infestations are expected to be more serious than disease outbreaks, with pest damage covering 780 million mu‑times and disease damage covering 410 million mu‑times. Specifically, brown planthopper, stem borer, and sheath blight are anticipated to occur at a severe level, with localized outbreaks; rice leafroller, blast, and false smut are expected to occur at a moderate level, with some areas experiencing severe outbreaks; stem borers and rice viral diseases are forecast to occur at a mild level; and other diseases and pests are expected to occur at low levels.

[Insect Pests]

Brown planthoppers are expected to occur at a severe level in the rice-growing regions of South China, the Yangtze River Basin, and eastern Southwest China; at a moderate level in western Southwest China, the middle and lower reaches of the Yangtze River, and the Jianghuai region, affecting 300 million mu‑times. Stem borers are forecast to be severe in northern South China, most of the Yangtze River Basin, and localized areas in the middle and lower Yangtze River region; moderate in southern South China and much of the Jianghuai area, covering 220 million mu‑times. Two-brooded stem borers are expected to range from severe to very severe in the Yangtze River Basin, southern Jiangnan, and northern Southwest China; moderate in northern South China, the lower Yangtze River, and the Jianghuai region; and mild in southern South China, southern Southwest China, and Northeast China, with an affected area of 180 million mu‑times. Three-brooded stem borers will be moderate in localized areas of South China and Southwest China, while elsewhere they are expected to be mild, covering 10 million mu‑times. Rice leafhoppers and rice stem flies are showing an increasing trend in damage across South China and the Yangtze River Basin.

[Diseases]

Rice sheath blight is expected to occur at moderate to severe levels across much of the rice-growing regions in South China, the Jiangnan area, the northern parts of Southwest China, and the middle and lower reaches of the Yangtze River; in some areas of Jiangnan and the middle Yangtze, it may reach epidemic proportions. In the southern and southwestern parts of Southwest China and in the northeastern rice‑growing areas, the disease is forecast to be at a moderate level, affecting 250 million mu. Rice blast is likely to prevail at moderate to severe levels in South China, the Jiangnan region, the hilly and mountainous areas of Southwest China, along the Yangtze River in the middle and lower reaches, and in parts of Northeast China, with an affected area of 70 million mu‑times. Rice false smut is expected to occur locally at moderate to severe levels during the mid- and late‑season rice crops in Jiangnan, the middle and lower Yangtze River basin, and the Jianghuai rice‑growing region, covering 40 million mu. Rice viral diseases are generally projected to be mild, with an affected area of 10 million mu‑times; among them, southern rice black streak dwarf disease poses a risk of moderate to severe outbreaks in localized rice‑growing areas of South China and Jiangnan. Bacterial diseases also carry a risk of moderate to severe occurrence in certain localized rice‑growing regions of the south.

Beware of the localized resurgence of migratory corn pests.

It is projected that, in 2019, the overall incidence of major corn pests and diseases nationwide will be close to the long-term average, affecting a total area of approximately 1 billion mu‑times. Specifically, pest outbreaks are expected to cover 730 million mu‑times, while disease outbreaks will affect 270 million mu‑times. Among the major pests and diseases in each corn-producing region: in Northeast and North China, these include the European corn borer, armyworms, underground pests, the two-spotted leaf beetle, and northern corn leaf blight; in the Huanghuai region, they comprise the European corn borer, cotton bollworm, two-spotted armyworm, and southern corn leaf blight; in Southwest China, the European corn borer, sheath blight, and small spot disease; and in Northwest China, the European corn borer, the two-spotted leaf beetle, aphids, and spider mites. The European corn borer poses a severe threat in Northeast China and the Huanghuai region; the cotton bollworm has seen increasing damage and an expanding geographic range in recent years; armyworms may cause high-density, localized outbreaks in parts of northern China; the grass cutworm population is showing a clear upward trend, with a potential for severe resurgence in certain areas of Northeast China; and southern rust carries a risk of widespread occurrence in the Huanghuai region.

[Insect Pests]

Corn borer is generally at a moderate level of occurrence, affecting 300 million mu‑times. Specifically, the first generation is moderately to heavily prevalent in northern Northeast China, covering 110 million mu; the second generation is moderately to heavily prevalent in localized areas of Northeast and Southwest China, covering 120 million mu; and the third generation is moderately to heavily prevalent in parts of the Huanghuai region, covering 70 million mu. The second and third generations of armyworm are at a moderate level, with some northern areas experiencing high‑density, concentrated damage, affecting 58 million mu‑times. Cotton bollworm is generally at a moderate level; the third and fourth generations are moderately to heavily prevalent in the Huanghuai–Hai region, covering 90 million mu‑times. Underground pests are generally at a moderate level, with localized areas in Northwest and Northeast China experiencing heavier infestations, covering 85 million mu. Aphids are at a moderate level across most of Northeast, Northwest, and the Huanghuai–Hai region, affecting 52 million mu. The two‑spotted leaf beetle is moderately to heavily prevalent across most of Northeast China, and moderately prevalent in much of North China and Northwest China, covering 34 million mu. Thrips are moderately to heavily prevalent in localized areas of the Huanghuai region, covering 37 million mu. Grass webworm may re‑emerge heavily across most of Northeast China and in localized areas of North China, affecting more than 15 million mu. The two‑spotted armyworm is generally at a light level across the Huanghuai–Hai region, though some localized fields may experience high‑density damage, covering 11 million mu. Spider mites are moderately to heavily prevalent in central and western Inner Mongolia and northern Shanxi, and moderately prevalent across much of Northwest China, covering 23 million mu.

[Diseases]

Large spot disease is occurring at a moderate level across most of Northeast China, North China, and Southwest China, with localized areas in Northeast China experiencing heavier infestations, affecting 65 million mu. Southern rust is at a moderate level across much of the Huanghuai and Jianghuai regions, with a localized risk of severe outbreaks in parts of the Huanghuai area, covering 40 million mu. Small spot disease is occurring at a moderate level in localized areas of the Huanghuai–Hai region and in Southwest China, affecting 34 million mu. Brown spot disease is at a moderate level in the Huanghuai region, covering 30 million mu.

Localized areas in agricultural regions nationwide may experience high-density outbreaks.

It is projected that in 2019, locust outbreaks in agricultural areas will be near normal levels: East Asian migratory locust and Asian migratory locust are expected to occur at a slightly lower-than-normal intensity, while Tibetan migratory locust and the desert locust in northern agro-pastoral regions are anticipated to occur at a generally moderate level. The area affected by migratory locusts will total 16.8 million mu‑times, reaching the threshold for control measures on 10.3 million mu‑times; the area affected by desert locusts will total 30 million mu‑times, meeting the control threshold on 10 million mu‑times.

【Occurrence Trend】

Overall, the East Asian migratory locust is expected to occur at a relatively mild level. However, localized areas around the Bohai Bay and the Yellow River floodplains may experience moderate outbreaks, while newly colonized habitats near lakes, reservoirs, and wetlands could see high-density patches of nymphs. The projected affected area is 15 million mu‑times, with 9 million mu‑times reaching the threshold for control measures.

The Tibetan migratory locust is expected to occur at moderate levels across most of its common outbreak areas in Sichuan and Tibet, with localized outbreaks of moderate to severe intensity in the river valleys of the Jinsha, Yalong, and Yarlung Tsangpo Rivers. The projected affected area is 1.5 million mu, with 1.2 million mu meeting the threshold for control measures.

The Asian migratory locust is occurring at a mild level in Altay, Tacheng, Kashgar, and other areas of Xinjiang; the possibility of migratory locusts entering the region from abroad cannot be ruled out. In localized patches of reed marshes in central‑western Jilin and southwestern Heilongjiang, high‑density nymphal outbreaks may occur. The projected affected area is 300,000 mu, with 100,000 mu reaching the threshold for control measures.

In the northern agro-pastoral regions, locusts are generally at a moderate level of occurrence, with localized outbreaks of moderate to severe intensity in parts of Xinjiang—specifically Ili, Altay, Tacheng, and Bortala—and in Inner Mongolia—along the northern foothills of the Yinshan Mountains, in northern Chifeng, and in southern Xilingol. The projected affected area is 30 million mu‑times, with 10 million mu‑times reaching the threshold for control measures.

[Weather Conditions]

This spring, meteorological conditions and habitat in locust‑infested areas have been generally favorable for locust outbreaks. In the spring of 2019, temperatures across most locust‑prone regions were higher than average for this time of year, while precipitation was near normal or below normal, creating conducive conditions for egg hatching and nymph development. In areas where migratory locusts are commonly found, the overall ecological environment has remained largely unchanged; however, fluctuations in water levels in lakes, reservoirs, and wetlands near agricultural zones can readily give rise to new locust‑breeding hotspots.

   

Source: China Pesticide Network 。