4.3 Pests and diseases monitoring

(1) Rice pests and diseases

 At the time of reporting (mid-August) the impact of pests and diseases has been moderate in the main rice growing regions. Weather conditions so far varied markedly between regions: warmer than higher during the previous years in southern China and central China; above average precipitation in the middle and lower reaches of the Yangtze River. In north-east China, east China and south China typhoons and heavy rainfall provided suitable conditions for rice planthopper (Nilaparvata lugens) and rice leafroller (Cnaphalocrocis medinalis) migration, and the dispersal of rice sheath blight (Rhizoctonia solani).

Rice Plant-hopper

    The distribution of rice Plant-hopper during mid-August 2019 is shown in Figure 4.6 and Table 4.5.The total area affected reached 5.6 million hectares, with the pest severely occurring in Anhui, northern Zhejiang, Hunan and Guangxi, moderately in Heilongjiang, western Zhejiang and southern Hubei, and only slightly in Jiangsu,Jiangxi, southern Hunan and central Hubei.

Figure 4.6 Distribution of rice Plant-hopper in China (mid-August 2019)

Table4.5 Statistics of rice Plant-hopper in China (mid-August 2019)

Rice Leaf roller

    Rice Leaf roller (Figure 4.7 and Table 4.6) damaged around 4.4 million hectares, severely so in south-western Heilongjiang, central Anhui, northern Zhejiang and northeastern Hunan, but only moderately in south-eastern Heilongjiang, central Zhejiangand southern Jiangsu, and slightly in Jilin, Liaoning, Jiangxi and centralGuizhou.

Figure 4.7 Distribution of rice Leaf roller in China (mid-August2019) 

Table 4.6 Statistics of rice Leaf roller in China (mid-August 2019)

Rice Sheath blight

    Rice Sheath blight (Figure 4.8 and Table 4.7) damaged around 3.4 million hectares, with varying degrees of impact: severely in south-western Heilongjiang, central Anhui, Zhejiang and northern Hunan, moderately in Fujian, southern Hubei, north-eastern Heilongjiang and northern Anhui, and  slightly in Jiangsu, northern Jiangxi, central Guizhou and northern Yunnan.

Figure 4.8 Distribution of rice Sheath blight in China (mid-August2019) 

Table 4.7 Statistics of rice Sheath blight in China (mid-August 2019)

(2) Maize pests and diseases

    Maize had suffered moderate pest and disease attacks by mid-August in the main maize production regions. Compared with average, relatively cool temperature affected north-east China; weather was humid in south-west China and northern China, creating conditions favorable for the reproduction of maize Army-worm (Mythimna separata) and maize Fall army-worm (Spodoptera frugiperda), and the dispersal of Northern leaf blight (Setosphaeria turcica).

Maize Army-worm

    The distribution of maize Army-worm in mid-August 2019 is shown in Figure 4.9 and Table 4.8. The total area affected by Army-worm reached 2.9 million hectares. Severe infestation occurred in south-western Heilongjiang, southern Jilin, northern Shandong and south-eastern Hebei; moderate ones  in northern Jilin, and southern Shanxi, while "slight" ones in Henan, central Shanxia and northern Hunan.

Figure 4.9 Distribution of maize Army-worm in China (mid-August2019) 

Table 4.8 Statistics of maize Army-worm in China (mid-August2019)

Maize Fall army-worm

    The insect (Figure 4.10 and Table 4.9) damaged around 1.0 million hectares, with the pest severely occurring in southern Yunnan, Guangxi, Guizhou and southeastern Chongqing. Moderate impact  occurred in northern Yunnan, northern Hubei, southern Shaanxi, eastern Shandong and southern Henan. Guangdong, Hunan, southern Hubei, Zhejiang and northern Anhui suffered only slight attacks.

Figure 4.10 Distribution of maize Fall army-worm in China (mid-August 2019) 

Table 4.9 Statistics of maize Fall army-worm in China (mid-August 2019)

Maize Northern leaf blight

    Maize Northern leaf blight (Figure 4.11 and Table 4.10) damaged around 1.6million hectares, severely so in south-western Jilin, northern Shandong and southern Hebei. Moderate and slight impacts moderately in southern Liaoning and central Hebei, and in Henan and northern Hunan, respectively.

Figure 4.11 Distribution of maize Northern leaf blight in China (mid-August 2019) 

Table 4.10. Statistics of maize Northern leaf blight inChina (mid-August 2019)