4.3 Pests and diseases monitoring

(1) Rice pests and diseases

The impact of pests and diseases was moderate during mid-late September 2019 in the main rice regions of China. The temperature of most cropland equaled or exceeded values of previous years and so did precipitation in Northeast China, South China and Southwest China. This provided suitable conditions for rice plant-hopper (Nilaparvata lugens) and rice leaf roller (Cnaphalocrocis medinalis) migration, and rice sheath blight (Rhizoctonia solani) dispersal.

Rice plant-hopper

The distribution of rice plant-hopper during the second half of September 2019 is shown in Figure 4.6 and Table 4.5. The total area affected reached 6.1 million hectares, with severe occurrence in Heilongjiang, North Zhejiang, central Anhui, North Hunan and central Guizhou. Moderate occurrence affected East Jiangsu, South Anhui, South Hubei, central Hunan and North Guangxi, and slight occurrence in central Jiangxi, central Hubei, South-west Liaoning and South-east Henan.

Figure 4.6 Distribution of rice plant hopper in China (mid-lateSeptember 2019)

Table4.5 Statistics of rice plant hopper in China (mid-late September 2019)

Rice leaf roller

Rice leaf roller (Figure 4.7 and Table 4.6) damaged around 5.2 million hectares, severely in South-west Heilongjiang, North Hunan, central Anhui and North Zhejiang, moderately in North-east Heilongjiang, central Jiangsu, central Guizhou and North Guangxi, and only slightly in South Hunan, central Hubei, central Jiangxi and South Henan.

Figure 4.7 Distribution of rice leafroller in China (mid-late September 2019)

Table 4.6 Statistics of rice leaf roller in China (mid-late September 2019)

Rice sheath blight

Of the 3.9 million hectares damaged by Rice sheath blight (Figure 4.8 and Table 4.7) South-west Heilongjiang, South Henan, North-east Zhejiang, North Hunan, central Hubei and North-west Jiangxi suffered severely. Moderate impact occurred in North-east Heilongjiang, central Anhui, central Jiangsu, central Guizhou and North-west Chongqing, while slight incidence occurred in West Hunan, North Fujian, central Jiangsu, South Anhui, central Hubei and central Chongqing.

Figure 4.8 Distribution of rice sheath blight in China (mid-late September 2019)

Table 4.7 Statistics of rice sheath blight in China (mid-late September 2019)

(2) Maize pests and diseases

Maize suffered moderate pest and disease attacks during mid-late September 2019 in the main production regions. Heavy rains and high humidity in Southwest China, Northeast China, North China and eastern China were conducive to maize army-worm (Mythimna separata) reproduction and maize northern leaf blight (Setosphaeria turcica) dispersal.

Maize army-worm

The distribution of maize army-worm in mid-late September 2019 is shown in Figure 4.9 and Table 4.8. Heilongjiang, central Jilin, East Inner Mongolia, North Shandong, central Shaanxi and East Hebei suffered severely, with more moderate impacts in North Jilin,South-west Liaoning, North Henan, North Jiangxi, South Shanxi and North Hunan, and only slight incidence in central Liaoning, South Hebei, central Henan and East Shandong. The total area affected by army-worm is estimated to have reached 3.2 million hectares.

Figure 4.9 Distribution of maize armyworm in China (mid-late September 2019)

Table 4.8 Statistics of maize armyworm in China (mid-late September 2019)

Maize northern leaf blight

Maize northern leaf blight (Figure 4.10 and Table 4.9) damaged around 1.8 million hectares, with the disease severely occurring in Heilongjiang, South Jilin, central Liaoning, North Shandong, central Shaanxi and East Hebei. Moderate impact is assessed for North Jilin, West Liaoning, East Inner Mongolia, West Hebei and North Anhui. Central Hebei, North Shanxi, South-west Henan, central Guizhou and North-west Hunan were only slightly impacted.

Figure4.10 Distribution of maize northern leaf blight in China (mid-late September2019)

Table 4.9. Statistics of maize northern leaf blight in China (mid-late September 2019)