Occurrence Trend Of Main Diseases And Pests In Middle And Later Stages Of Cotton

On July 11-12, the National Agricultural Technology Center held a cotton trade association in the middle and later stages of cotton in Nanjing City, Jiangsu province. Experts from production, research and teaching units comprehensively analyzed the occurrence of cotton pests and diseases, the layout and growth of cotton varieties and meteorological conditions, and predicted the trend of main diseases and pests in the middle and later stages of cotton production this year.

This year, because of the delayed harvest of summer harvest crops, the cotton planting period and growth period are generally late, and cotton growth is generally or slightly deviated.

In the middle and later stages, the insect resistance of pgenic cotton declined, and the main varieties generally did not resist diseases such as Verticillium wilt. Most of the cotton fields in the Yellow River and Changjiang River Basin had more precipitation. It was estimated that the main pests and diseases occurred in the middle and late stages of cotton in 283 million mu times. The pests such as cotton bollworm, cotton aphid, cotton spider mites, cotton bug and Bemisia tabaci occurred in 228 million acres, and the diseases such as Verticillium Wilt and bell disease occurred 55 million mu.

Trend of occurrence

(1) cotton bollworm

The three generation of cotton bollworm is expected to take 35 million mu.

The the Yellow River River Basin and Xinjiang cotton region occurred moderately, with most of Shandong and Xinjiang in southern Xinjiang.

The peak period of the second generation of adults (3 days after the peak of adult emergence is the three generation egg bloom) is 3-9 days longer than usual. The prediction period is as follows:

The four generation of cotton bollworm is expected to take 25 million mu.

The cotton growing areas in the Yellow River and the Yangtze River generally occurred moderately, and the larvae occurred in late August to mid September.

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(two) Aphis gossypii

The Aphis gossypii is expected to occur at 40 million mu.

The occurrence of cotton fields in Xinjiang is more serious than that in the southern part of the Tianshan Mountains and in the southern part of the Yangtze River. The occurrence of cotton plants in the the Yellow River river basin is moderate, with the emphasis on Hebei and Tianjin.

The peak period is from mid July to mid August.

(three) cotton spider mites

It is expected to happen 43 million mu.

The the Yellow River River Basin, the Yangtze River Basin and the Xinjiang cotton region generally occurred in moderate occurrence, and Hunan, Jiangxi, Shaanxi and other places were more important.

The peak period is from mid August to early September.

(four)

It is expected to happen 45 million mu.

The cotton area in the the Yellow River river basin is more serious. The cotton area in the Yangtze River Basin is moderate and the cotton area in Xinjiang is lighter.

The three generation takes place from late July to mid August.

(five) Bemisia tabaci

It is expected to happen 20 million mu.

Slight occurrence occurred in the cotton area of the the Yellow River River Basin, where the cotton area in Henan occurred moderately and partially occurred. It occurred moderately in the Yangtze River Valley, where cotton and Hubei and Jiangsu cotton areas were more severe, and Sichuan, Jiangxi and Hunan took place lightly.

The peak period is from mid August to early September.

(six) Fusarium Wilt

It is expected to happen 25 million mu.

The the Yellow River River Basin, the Yangtze River Basin and the Xinjiang cotton region occur moderately, including Hebei, Hubei Jianghan Plain and Jiangsu coastal areas.

The peak period is 8-9 months.

(seven) other diseases and pests

Other pests are expected to take 20 million mu.

Among them, thrips thrive in Hebei and Anhui along the Yangtze River; Spodoptera litura occurred in Jiangxi, Hunan and Jiangsu, and occurred in Hubei and Anhui.

The occurrence of Boll disease is expected to occur in 15 million mu, and Hebei and Shanxi occur in Henan and Jiangxi. Cotton red leaf blight occurs in Hebei, and occurs in Henan, Shaanxi and Jiangxi. Other diseases occur in 15 million mu.

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Two. Forecast basis

(1)

The two generation of Helicoverpa armigera: partial occurrence in Shandong and Xinjiang. The occurrence of cotton bolls in other large and medium cotton plants is moderate or below.

The cumulative eggs of two generations in the two generations in Shandong, Hebei, Henan, Anhui, Hubei and Jiangsu were 450, 150, 72.6, 36.8, 36.6 and 7.8 respectively, all lower than the average of the previous year, but higher than last year.

Compared with the same period last year, Henan and Shanxi were respectively 63.9% and 71.4% higher than those of the same period last year. Tianjin, Shandong, Shaanxi, Jiangsu, Hunan and Sichuan were respectively 31%, 33.3%, 77.9%, 93.5%, 34.5% and 68.1% respectively.

(two) ecological conditions in the field are beneficial to pests and diseases.

Preliminary statistics show that the cotton planting area in China is nearly 70 million mu this year. The ratio of pgenic cotton planting in the the Yellow River River Basin and the Yangtze River valley cotton area is over 90%, and the cotton field intercropping area accounts for 30% of the planting area.

There is a great difference in insect resistance among pgenic cotton varieties popularized at present, and the resistance in the middle and late stages is generally declining, which is conducive to the occurrence of the three or four generation of Helicoverpa armigera. The use of pgenic cotton fields is reduced, and the simultaneous treatment of other pests is lost, which is beneficial to the occurrence of insect pests such as Aphis gossypii, cotton spider mites, cotton bug and Bemisia tabaci. The cotton field intercropping area is large, which is conducive to the occurrence, propagation and pfer of pests such as cotton bug, Helicoverpa armigera and whitefly.

The disease resistance of the main cultivars is generally poor, which is conducive to the occurrence of Fusarium Wilt and other diseases.

(three) meteorological conditions are favorable for diseases and cotton bug bugs.

According to the National Meteorological Center, in July, there were more precipitation in the northern part of the Yangtze River Basin and the the Yellow River River Basin. Besides the southeastern part of the mountain, northern Jiangsu, northern Anhui and the northeastern part of Hubei, the air temperature in most other cotton areas was basically flat, which was favorable for the occurrence of Fusarium Wilt and cotton bugs, and had a certain inhibitory effect on pests such as cotton bollworm, cotton aphid and cotton spider mites.

However, the precipitation in Xinjiang, Hebei, Shanxi, Shaanxi and Shandong is relatively small and the air temperature is high, which is favorable for the local cotton bollworm, cotton aphid and cotton spider mites.