Prediction of diseases and insect pests in different stages of wheat

20 15 forecast of main wheat diseases and insect pests in China (from Baidu article)

The National Agricultural Technology Extension Service Center organizes experts from plant protection system, scientific research and teaching units to analyze and predict that in 20 15 years, the general occurrence area of wheat diseases and insect pests is 940 million mu, including 5 100000000 mu of pests and 430 million mu of diseases. Aphids recur in a large area, and the epidemic risk of scab is high. Sheath blight, powdery mildew, stripe rust, midge and wheat spider occurred in some areas.

I. Trends

(1) disease. The epidemic risk of scab is high, with the medium and above epidemic area of about 85 million mu and the area to be prevented of more than 654.38+0 billion mu. Among them, eastern Hubei and Jianghan Plain, Anhui and Jiangsu along the Huaihe River and its south, central and northern Zhejiang, Shanghai coastal areas and other places are threatened by epidemic, and other wheat areas in the Yangtze River basin, Huanghuai wheat area, Yili River Valley in Xinjiang and other places are more likely to be moderately prevalent, while wheat areas in southern North China are slightly prevalent. The occurrence area of stripe rust is 20 million mu; Among them, the "Three Rivers and One River" basin in the northwest of Sichuan, the late-maturing wheat areas in Longnan, Gansu, the areas along the Yangtze River in the south of Shaanxi and the northwest of Hubei are popular. Most of southwest China, most of Gansu, Guanzhong of Shaanxi, Jianghan Plain of Hubei, southern Henan, southern Ningxia, eastern Qinghai, northern Xinjiang and other places are moderately prevalent, and there are wheat areas in northern Henan, Anhui along Huaihe River and its south, southwestern Shanxi, southwestern Shandong, Jiaodong Peninsula and southern Hebei. The occurrence area of sheath blight is 65.438+0.4 billion mu; Among them, high-yield wheat areas in eastern Hubei and Jianghan Plain, Anhui and Jiangsu along Huaihe River and Huaibei River, southwestern Shandong and northern Henan reappeared, moderately occurred in Jianghuai, Huanghuai and other wheat areas in North China, and slightly lighter and lower in southwest and northwest wheat areas. The occurrence area of powdery mildew is 85 million mu; Among them, the stubble wheat in Henan and the high-yield wheat areas in central and northern Huangdao, central and southern Hebei, southwestern Shandong and southwestern Shanxi occurred seriously, while the Huanghuai and other wheat areas in North China, Jianghuai, the middle and lower reaches of the Yangtze River, southwestern and northern Xinjiang occurred moderately, and the northwest wheat area occurred slightly. Leaf rust and root rot are on the rise in Huanghuai and southern North China, and leaf blight, root rot, cyst nematode disease, take-all disease, smut and virus disease will cause certain harm in some wheat areas.

(2) pests. The occurrence area of aphids is 240 million mu; Among them, Hebei and Shandong are more serious, and other wheat areas in North China and Huanghuai, Jianghuai, the middle and lower reaches of the Yangtze River, Sichuan and Ningxia are moderate. The occurrence area of midges is 30 million mu; Among them, the wheat area in Hebei plain is re-developed, and it occurs moderately in the central and eastern Shaanxi Guanzhong, northern Henan and northern Tianjin, and it is light in other wheat areas in North China and Huanghuai, and light in northwest China. The occurrence area of wheat spiders is 65.438+000 million mu; Among them, the dry wheat in the mountainous areas of western Henan, southwestern Shanxi, south-central Shandong and south-central Hebei is heavier, most of the wheat areas in North China, Huanghuai and Northwest China are moderate, and most of the wheat areas in Jianghuai and Southwest China are light to mild. The occurrence area of underground pests such as needle flies, grubs and crickets is 70 million mu; It occurred moderately in Henan, Shanxi, Tianjin, Gansu and Ningxia, and slightly in other wheat areas in North China, Huanghuai and Northwest China. The first generation of armyworm, Laodelphax striatellus, wheat leafhopper, grasshopper and wheat stem bee will cause certain harm in some wheat areas; New pests such as white-browed borer, beet armyworm and Marcello Malpighi turtle are increasing.

Second, the forecast basis

(1) The disease base of autumn seedlings is low, and the base of aphids and wheat spiders is high. The occurrence area of autumn seedlings of stripe rust is small, and the overall condition is mild. Gansu, Ningxia, Shaanxi and other major areas in the northwest are 25 1 10,000 mu, the smallest year since 2006, 5438+0. Among them, the incidence of disease in Longnan, Longdong, Longzhong, southern mountainous areas of Ningxia and Shaanxi Guanzhong is mainly from single diseased leaf to small diseased heart, with an average diseased field rate of 20%-40% and an average diseased leaf rate below 0.65438 0%. Only some fields in Zhuanglang County of Pingliang City, Lintao County of Dingxi City, Lintan County of Gannan Prefecture, Yuanzhou District of Ningxia and Pengyang County were affected. Sporadic diseased leaves and minor disease centers have been found in Ledu, Jianzha, Hualong, Guide and Xunhua counties in eastern Qinghai, with an average diseased leaf rate of 0.5%-2.0%, which is a serious year in recent years. Sporadic cases, covering an area of 300 mu, occurred in Yili and Aksu counties in Xinjiang, and the illness was the lightest in the past five years. As of 20 15,65438+10,15, diseases occurred in 57 counties (cities, districts) in Sichuan, Yunnan, Hubei and Shaanxi provinces in winter, covering an area of 52,000 mu. The epidemic diseases in winter are more serious than 20 13, close to 201,20 12, 20 14, lighter than 20 10 and much lighter than in 2009. The overall situation of powdery mildew seedlings in autumn is 20 13 lighter than normal and the same period. Gansu, Shaanxi, Ningxia and other northwest regions are more common, covering an area of 2.6 million mu, with an average diseased leaf rate of 0.5%. The average rate of diseased leaves in Shanxi is 2.5%, which is 67% higher than that in 20 13 years and 150% higher than that in the same period of normal years. Incidence was sporadic in the western mountainous areas of Henan Province and Jiaodong Peninsula of Shandong Province, but it did not occur in most wheat areas in North China, Huanghuai, Jianghuai and Yangtze River valley before winter. Autumn seedling sheath blight is often young, and it is heavier in some areas than in 20 13. Huanghuai and North China wheat areas are common, with an area of 865,438+10,000 mu. The average rates of diseased plants in Shandong, Henan, Anhui, Hebei, Shanxi and Jiangsu were 3.6%, 2.9%, 65,438+0.4%, 65,438+0.2%, 0.9% and 0.5%, respectively, and most wheat areas were lower than normal. Compared with the same period of 2065,438+03, Henan, Anhui. The number of aphids in autumn seedlings in most wheat areas is close to normal, which is higher than 20 13 in the same period. It is common in Jianghuai, Huanghuai, North China and Northwest China, with an area of 6.5438+0.55 million mu. The average number of aphids per 100 plants in Shanxi, Henan, Anhui, Shaanxi, Shandong, Beijing, Hebei and Ningxia were 7.4, 6.5, 5. 1, 5.0, 4.6, 4. 1, 2.7 and 1.9 respectively. Compared with the same period of 20 13, except Beijing, which is 68% lower, most other wheat areas are 50%-200% higher. In 20 13, the amount of autumn seedling mites of wheat spiders in most wheat areas was higher than that in normal years and the same period. It is common in Jianghuai, Huanghuai, North China and Northwest China, with an area of 1 1 10,000 mu. The average number of insects per foot in Anhui, Shandong, Henan, Shaanxi, Shanxi, Hebei and Ningxia were 63.5, 65,438+09.0, 65,438+07.0, 65,438+00.0, 7.2, 4.0 and 65,438+0.8 respectively. The population density of midge in most wheat areas decreased obviously. In autumn, the average number of insects per square meter in Tianjin, Hebei, Shaanxi, Beijing, Henan, Ningxia and Shanxi is 7.9, 2.5, 2.0, 1.5, 1.6, 1.2 and 0.2, respectively, which is different from that in normal years and 20 18. However, there are still some areas where the population density of local fields is relatively high. The highest population per cubic meter is Pucheng, Shaanxi, Luanxian, Hebei, Anyang, Hebi and Nanyang, with 237 people, 86 people, 182 people, 108 people, 96 people and 78 people respectively. The population density of underground pests in most wheat areas is low. The average number of mixed insects per square meter in Shaanxi, Shanxi, Henan, Beijing and Hebei were 4.5, 3.2, 2.9, 1.6 and 1.2, respectively, which increased by 12% and 23% compared with 20 13 in the same period. The damage rate of autumn seedlings in Huanghuai, North China and Northwest China is 0.5%-2%. Compared with the same period of 20 13, Hebei and Shanxi are 89% and 5% higher, respectively, while other regions are lower.

(2) Wheat planting structure and variety layout are beneficial to the occurrence of diseases and insect pests. The planting area of winter wheat in China is 335 million mu, and the wintering period is a good year in recent years, which basically realizes the wintering of strong seedlings. Moreover, Henan, Hebei, Shandong, Shanxi and other major wheat producing areas are all over-sown and have a large population. Recently, the trend of individual fields is obvious, which is conducive to the occurrence of many diseases and insect pests. The distribution of wheat varieties has not changed obviously, and the resistance level is still low. Except for a certain proportion of stripe rust-resistant varieties planted in Gansu, Sichuan and Shandong, most wheat varieties have poor resistance to stripe rust, especially since 20 10, the emergence and development of a new pathogenic group of stripe rust "Guinong 22" has accelerated the loss of disease resistance of wheat varieties; Except for some varieties of Emai, Young Mai and Ningmai series, the main varieties in the middle and lower reaches of the Yangtze River, Jianghuai, Huanghuai and North China are not resistant to scab. In addition, the introduction of high-yield varieties from northern China into Jianghuai wheat region increased the epidemic risk of scab. In addition to the large planting area of powdery mildew resistant varieties in Shandong, the resistance of main wheat varieties in Jianghuai, Huanghuai and North China to powdery mildew, sheath blight, aphids and other major pests and diseases is generally poor.

(3) Meteorological conditions are conducive to the occurrence of pests in most wheat areas and diseases in some areas. According to the forecast of the National Climate Center, the temperature in the middle and lower reaches of the Yangtze River and most of the northern winter wheat areas in October15+0-February is close to normal, which has no obvious adverse effect on the overwintering of pests and diseases. The high temperature in most winter wheat areas in southwest China and less precipitation in south China are conducive to the occurrence of pests such as aphids in winter. In the spring of 20 15 (March-May), the temperature in most of China's wheat growing areas is close to the same period of normal or higher, especially in Huanghuai and North China, such as northern Henan, most of Shandong, south-central Shanxi, southern Hebei and most of southwest China, which is beneficial to the population rise and occurrence of aphids, wheat spiders and other pests. The precipitation in most wheat areas in China is close to the same period of the year or more, especially in the middle and lower reaches of the Yangtze River, Jianghuai and Huanghuai wheat areas 1-20%, and in eastern Hubei, southeastern Henan, Anhui, Jiangsu, Shanghai and northern Zhejiang, which is very beneficial to the occurrence and development of scab, stripe rust, sheath blight and powdery mildew. For example, it rained for two consecutive days when wheat was heading and flowering.