The occurrence trend of early rice diseases and pests in China in 2016 was particularly severe

Time:

2016-05-26


According to a comprehensive analysis of factors such as the current occurrence base of diseases and pests, climate conditions, and rice cultivation situation, organized by the National Agricultural Technology Extension Service Center from May 10 to 11, 2016, technical personnel and relevant experts from the main rice producing provinces in southern China, it is predicted that early rice diseases and pests will be more severe this year, with an occurrence area of 319 million mu per occurrence compared to the previous year. Among them, the main pests are rice planthopper, rice leaf roller, and rice stem borer, with an area of 220 million mu per occurrence; The main diseases are rice blast and rice sheath blight, with an area of 99 million mu per occurrence.

1、 Occurring trend

(1) Rice pest damage

It is expected that the occurrence of rice planthoppers will be more severe in most of South China, Jiangnan, and southwestern rice areas, with an area of 82 million mu per occurrence compared to the previous year; The rice leaf roller is particularly prevalent in central South China and the central and western rice regions of Jiangnan, with moderate occurrence in the eastern part of Jiangnan and the middle reaches of the Yangtze River, which is heavier than the previous year and covers an area of 70 million mu per occurrence; The occurrence of the rice borer is particularly severe in the central and northern parts of Jiangnan and the middle reaches of the Yangtze River, with a large occurrence in some single and double cropping rice mixed planting areas in the southeastern Hubei and Jianghan plains, and moderate occurrence in other rice areas in Jiangnan, with a heavier incidence rate than last year and an area of 50 million mu per occurrence; The occurrence of the rice borer in southern China, Jiangnan, and the middle reaches of the Yangtze River is generally mild, while in some areas of northeastern Guangdong, it is moderate, lighter than last year, with an area of 8 million mu per occurrence; Other pests such as giant borers occur to a certain extent in some rice areas, with an area of 10 million mu per occurrence.

(2) Rice diseases

Sheath blight occurs extensively in the central and western regions of Jiangnan and the middle reaches of the Yangtze River, with a high incidence in most of South China and the eastern part of Jiangnan, approaching a normal year, with an area of 76 million acres; Rice blast disease occurs moderately in the frequently occurring areas of South China, Jiangnan, and the middle reaches of the Yangtze River, with a high risk of recurrence in susceptible varieties and historical disease areas, which is more severe than the previous year, with an incidence area of 16 million mu per occurrence; Rice bacterial leaf blight, rice bacterial stripe disease, and southern rice black stripe dwarf disease have occurred to some extent in some rice areas, with an area of 7 million mu per occurrence.

2、 Prediction basis

(1) Most diseases and pests have a base of occurrence that is more severe than others

Affected by the early flood season in South China, rice planthoppers have migrated early and in large quantities this year. According to the monitoring of the regional station of the National Pest and Disease Monitoring Network, the first peak of rice planthopper migration with a single light attracting more than 100 insects per day was detected in Pubei, Guangxi on March 18th, which was 5-15 days earlier than usual; Subsequently, migration peaks were observed in the coastal areas of southern Guangxi and southwestern Yunnan from late March to early April, and in southern China, southwestern China, and southern Jiangnan from mid April to early May. The number of migratory insects was 40% -150% higher than the same period last year. Currently, the number of rice planthoppers in the field is 100-700, higher than the same period last year. Local fields in Qionghai, Hainan, Zhongshan and Yangjiang in Guangdong, Hepu, Qinbei, Rongxian, Cenxi in Guangxi, Yuanyang in Yunnan, and Dayu, Xinfeng, Anyuan in Jiangxi have exceeded the control targets, with a hundred to 4000 pests per hundred clusters. The rice leaf roller has been migrating to the southern rice region since early March, and a peak of migration was observed in western Guangdong in late April. The migration period was 10-15 days earlier than usual; The fields in western Guangdong, southern Guangxi, and southwestern Guangxi have a high number of insect eggs, with a general population of 100-400 moths per mu and a high population of 500-700 moths, with a maximum of 3000 moths in Yangdong, Guangdong; The average number of larvae per mu ranges from 500 to 2000, with a height of 3000 to 5500. In some areas such as Maoming and Yangjiang in Guangdong, Hepu and Pubei in Guangxi, there are as many as 20000 larvae; The average number of eggs per mu is 5000 to 10000, with a high of 40000 in Yangjiang, Guangdong. The population of Chilo suppressalis in the central and northern parts of the Yangtze River and the middle reaches of the Yangtze River after winter is generally 1500 to 4500 heads per acre, with over 10000 heads in Loudi, Hunan and Linchuan, Jiangxi. It has a population base of more than one generation of Chilo suppressalis.