In the middle and late June, the early rice in the south will gradually enter the heading stage, which is a crucial period for the prevention and control of pests and diseases. At present, the occurrence of rice planthoppers is lighter than that of the previous year, and the occurrence area is concentrated in the south China and Jiangnan rice areas. The amount of gray locusts is high in some areas; the rice leaf roller is generally lighter, and the southern part of the country is heavier; After the warping, the insect population density decreased. The incidence of rice sheath blight and rice blast is close to normal.

Recently, there have been obvious rainfall processes in the southern rice area, which is conducive to the occurrence of rice pests and diseases. The local plant protection departments need to strengthen monitoring, and scientifically guide the prevention and control work according to the occurrence and control indicators of pests and diseases.

I. Rice planthopper

The cumulative area of ​​rice planthoppers was 272.375 million mu, which was 2.7 times that of the previous two weeks, but decreased by 40.1% year-on-year. Since the end of late May, rice planthoppers have continued to move in, and the main descending areas are concentrated in northern and southwestern China. In the southern rice area of ​​the south of the Yangtze River, many places have moved into the peak, and the number of single-light traps on the peak day has exceeded 1,000. Among them, Yunnan Yuanjiang and Qiubei have a peak of over 10,000 single-day insects, Dahua and Fengshan in Guangxi, and Fujian Xinluo has a peak of more than 50,000 single-day insects.

The types of immigrants are mainly white-backed planthoppers, and the proportion is generally 60%-93%. However, the total amount of insects in the field is not high. The amount of worms in the field after treatment is generally 100-800 heads, the height of 1400-2500 heads is high, and the number of insects in Yunnan is high. For example, the highest number of worms in Honghe Prefecture exceeds 20,000. .

In the middle and lower reaches of the Yangtze River, the number of insects is high, and the average number of insects in Jiangsu dry nursery field is 206,000 heads, and in some areas, it is over 1 million heads. The average number of insects in the water nursery field is 176,000 heads, and in some areas more than 800,000 heads. .

Second, rice leaf roller

The cumulative area of ​​rice leaf roller is 12.651 million mu, which is 2.4 times of the previous 2 weeks, but it is reduced by 37.5%. Since the end of late May, the number of insects in the field has been increasing. The amount of moths in the South China rice area is generally 200-500 heads, and the height is 1500-3500 heads. The amount of larval larva is generally 1800-4500 heads, the height is 11,000-63,000 heads, and the number of larvae in individual fields in southeastern Guangxi reaches 128,800 heads.

Compared with the same period of last year, the average amount of moths and acres of larvae in the field increased by 30.6% and 55.1%, respectively; the rate of leaf rolling was generally 0.2%-3%; the height was 5%-13%. The amount of moths in the Jiangnan rice area is generally 160-300 heads, 630-2500 heads high, 1000-4000 heads of larvae, and 5000-8000 heads high. The field is lighter, the leaf rolling rate is generally 0.1%-2%; the high 4%-13%.

Third, the second

The area of ​​stem borer was 50.939 million mu, down 3.9% year-on-year. The amount of larval larva was generally 500-1800 heads, and the average number of larvae in Anhui was 1780, an increase of 17.6%. The rate of the sheath of the sheath is generally 1.1%-3%; the rate of the sheath of Zhejiang and Anhui is relatively high, generally 5%-12%, and the rate of the sheath of the elephants in the severe mountain of Zhejiang is 92.3%.

Fourth, sheath blight

The area of ​​sheath blight was 31.374 million mu, which was 4.3 times that of the previous 2 weeks, which was basically the same as that of the previous year. The current strain of sheath blight in the early rice in the south is generally 12%-20%, and the high is 40%-70%; the disease rate is generally 25%-35%, and the high 42%-60.7%, the southeastern Guangxi is heavier. The rate of diseased plants in local fields is as high as 72.0%-89.0%.

V. Rice blast

The cumulative incidence of rice blast was 4.32 million mu, which was twice that of the previous two weeks, but decreased by 34% year-on-year. At present, the average diseased leaf rate in the field is generally 1.8%-5%, and the high is 10%-38%. The rate of diseased leaves in Jiangxi Xiajiang and Ji'an re-emergence fields is 40%-65%, and there are obvious disease centers and acute diseases. Spot and sitting phenomenon.

6. Future trends and analysis

According to the analysis and forecast of the Central Meteorological Observatory, it is expected that there will be strong rainfall in most parts of the south of the Yangtze River, southern China and southern Guizhou, and eastern Yunnan in the 13th to 16th, north of Zhejiang, southwestern Jiangxi, most of Fujian, central and eastern Guangdong and northern, central Guangxi There were heavy rains in southern Guizhou and eastern Yunnan, and heavy rains occurred in the local area.

Affected by the typhoon "Miaobai", there were heavy rains in the eastern part of South China and the eastern part of the south of the Yangtze River. Strong convective weather is conducive to the migration and migration of "two-shifted" pests. The high-temperature and high-humidity environment is also conducive to the aggravation of diseases such as sheath blight. All localities need to strengthen monitoring, comprehensively grasp the dynamics of pests and diseases, and effectively prevent and control the work. . (Pawn and disease survey office feed)

This article URL: June 2017, early rice pest and disease prediction, key prevention and control, rice planthopper, rice leafroller

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