4.4. Pest and diseases monitoring

Rice pests and diseases

The impact of pests and diseases was relatively moderate during mid to late July 2017 in the main rice regions of China. Affected by severe convective rain and storms, the habitat conditions in the fields were conducive to rice planthopper and rice leaf roller migration. In addition, for Lower Yangtze River and east Southern China, there was more precipitation and higher temperature than during the previous years, which provided appropriate conditions for rice sheath blight reproduction.

Rice planthopper

The distribution of rice planthopper during mid to late July 2017 is shown in figure 4.13 and table 4.5. The total area affected by the planthopper reached 6.1 million hectares, with severe impact in central Guizhou, northern Guangxi, and most of Guangdong; the pest only moderately affected rice crops in northern Yunnan and northern Hunan.

Figure 4.13. Distribution of rice planthopper in China, mid to late July 2017

Table 4.5. Statistics of rice planthopper in China, mid to late July 2017

Rice leaf roller

Rice leaf roller (figure 4.14 and table 4.6) damaged around 2.7 million hectares, and even severely so in central Guizhou and northern Guangdong. Damage was only moderately in northern Guangxi and northern Hunan.

Figure 4.14. Distribution of rice leaf roller in China, mid to late July 2017

Table 4.6. Statistics of rice leaf roller in China, mid to late July 2017

Rice sheath blight

Rice sheath blight (figure 4.15 and table 4.7) damaged around 4.5 million hectares, severely so in southern Jiangsu and northern Zhejiang and moderately in central Sichuan, central Hunan, and central Jiangxi.

Figure 4.15. Distribution of rice sheath blight in China, mid to late July 2017

Table 4.7. Statistics of rice sheath blight in China, mid to late July 2017

Maize pests and diseases

Maize suffered slightly to moderately from pest and disease attacks during late July in the main production areas. Heavy rains and high humidity in north and northeast China were conductive to armyworm reproduction and sheath blight dispersal.

Maize armyworm

Its distribution in late July 2017 is shown in figure 4.16 and table 4.8. The total area affected reached 1.5 million hectares, with the pest mainly occurring in southwest Heilongjiang, northwest Jilin, southeast Hebei, central Shandong, and central and northern Shaanxi.

Figure 4.16. Distribution of maize armyworm in China, late July 2017

Table 4.8. Statistics of maize armyworm in China, late July 2017

Maize sheath blight

Maize sheath blight damaged around 0.4 million hectares. The disease mainly affected southwest Heilongjiang, northwest Jilin, and northern Hebei (figure 4.17 and table 4.9).

Figure 4.17. Distribution of maize sheath blight in China, late July 2017

Table 4.9. Statistics of maize sheath blight in China, late July 2017