4.3 Pest and Diseases Monitoring

The impact of pests and diseases was relatively moderate during mid to late September 2017 in the main rice regions of China. Rainfall in the southern China and southern Yangtze River regions created habitat conditions conducive to rice planthopper and leaf roller migration, as well as dispersal of sheath blight.

Rice pests and diseases

Rice planthopper

The distribution of rice planthopper during mid to late September 2017 is shown in figure 4.7 and table 4.5. The total area affected reached 5.9 million hectares, with severe impact in central Anhui, central Guizhou, most of Jiangsu, and most of Guangxi, but only moderate impact in western Guangdong, central Hunan, central Jiangxi, and eastern Yunnan.

Figure 4.7. Distribution of rice planthopper in China, mid to late September 2017

Table 4.5. Occurrence ratio of rice planthopper in China, mid to late September 2017

Rice leaf roller

Rice leaf roller (figure 4.8 and table 4.6) damaged around 4.9 million hectares, severely so in most of Jiangsu, most of Guangxi, and central Guizhou. The impact was moderate in eastern Yunnan, central Anhui, and central Hunan.

Figure 4.8. Distribution of rice leaf roller in China, mid to late September 2017

Table 4.6. Occurrence of rice leaf roller in China, mid to late September 2017

Rice sheath blight

Rice sheath blight (figure 4.9 and table 4.7) touched around 7.1 million hectares, severely affecting central Anhui, central Guangdong, and most of Jiangsu. The impact was moderate in eastern Guangxi, central Hunan, and central Jiangxi.

Figure 4.9. Distribution of rice sheath blight in China, mid to late September 2017

Table 4.7. Occurrence of rice sheath blight in China, mid to late September 2017

Maize pests and diseases

Maize suffered moderately from pest and disease attacks during late August in the main production areas. Abundant precipitation, some of it due to typhoons, created conditions conducive to the reproduction of armyworms and the dispersal of leaf blight.

Armyworm

The distribution of maize army worm in late August 2017 is shown in figure 4.10 and table 4.8. The total area affected reached 4.2 million hectares, part of it severely (central Shannxi, central Hebei, northern Shandong, and southwest Heilongjiang). The impact was moderate in central Jiangsu, northern Anhui, and southern Hebei.

Figure 4.10. Distribution of maize armyworm in China, late August 2017

Table 4.8. Occurrence of maize armyworm in China, late August 2017

Leaf blight

Maize leaf blight damaged around 2.0 million hectares, mostly in northwest Jilin, central Shannxi, central Gansu, and most of Ningxia (severe impact), and in southwest Heilongjiang and central Inner Mongolia (moderate impact). Figure 4.11 and table 4.9 present an overview.

Figure 4.11. Distribution of maize leaf blight in China, late August 2017

Table 4.9. Occurrence of maize leaf blight in China, late August 2017