Forecast of the occurrence trend of major diseases and insect pests in the middle and late stages of wheat in 2017

On April 6-7, the National Agricultural Technology Center held a national conference on the occurrence of pests and diseases in the middle and late stages of wheat in Jinan City, Shandong Province. The monitoring and technical personnel from the major wheat producing provinces (autonomous regions and municipalities) and the research and teaching units were planted and meteorological. Experts attended the meeting. Based on a comprehensive analysis of the bases of pests and diseases, the layout of wheat varieties and the farming system, combined with future weather trends, it is expected that the overall pests and diseases in the middle and late stages of wheat will be re-emerged in 2017, which is more serious than normal, and the disease is large. The prevalence risk is high, and stripe rust and aphid in the ear stage are biased and large.

First, the trend

Scab, stripe rust, powdery mildew, sheath blight, aphids and midges are the main pests that affect the growth of wheat in the middle and late stages. The estimated area is 990 million mu, including 520 million mu of disease and 470 million mu of insect pests (Table 1).

Table 1 Areas and regional prediction tables for major diseases and insect pests of wheat

Areas in which pests and diseases occur (10,000 mu)

Current total in the future

Scab is sporadic 1100011000 Jianghan, Jianghuai, Huanghuai, Northwest and North China

Stripe rust 111041505260 Jianghan, Huanghuai, Jianghuai, southwestern southwest, northwestern Xinjiang

Powdery mildew 7601060011360 Middle and lower reaches of the Yangtze River, Jianghuai, Huanghuai, North China, Northwest

Sheath blight 8290540013690 Huanghuai, southern North China, Jianghuai,

Leaf rust 16051905350 Jianghuai, Huanghuai, North China, Northwest

Other diseases, 53051705700, most of the wheat area

Subtotal 108504151052360

Maihao 29202070023620 Huang Huaihai, the middle and lower reaches of the Yangtze River, Northwest

Mai Spider 456053009860 North Huanghuai, North China, Northwest

The larvae sporadic 26002600 North China, Huanghuai, Northwest

Underground pests 120044005600 North China, Huanghuai, Northwest

A generation of armyworms sporadic 770770 in the middle and lower reaches of the Yangtze River, Jianghuai, Huanghuai

Other pests 50035004000 northern part of the wheat area

Subtotal 91803727046450

Total 200307878098810

(1) Major diseases

Scab: It is a pandemic trend, close to the previous year, and heavier than normal. The popular area is about 100 million mu, and the area to be protected is about 200 million mu. Among them, Jianghan and Jianghuai wheat areas are popular, and the southern wheat areas of Huanghuai are heavily prevalent, and most of them are popular in the southwest, north of Huanghuai, southern of China, and most of the northwest. The period of drug prevention is from the beginning of wheat to the early stage of flowering, Jianghan and Jianghuai are in the middle and late April, Huanghuai and southern China are from late April to early May, and most of the northwest is mid-May.

Stripe rust: The overall bias occurs, which is more important than the previous year and recent years, with an area of ​​about 50 million mu. Among them, the Hanshui River Basin occurred greatly, and most of the southwestern part, the southern part of Huanghuai and the southwestern part of Xinjiang and the northern part of Xinjiang were popular. The northern part of Huanghuai and the northwest part of the wheat area were moderately popular, and other wheat areas such as North China were lightly affected. In the prevailing period, the southwest and Hanshui River Basins are in April, the Huanghuai and southern China are from mid-April to mid-May, the northwest winter wheat area is from mid-May to mid-June, and the spring wheat area is from late June to late July. .

Powdery mildew: The overall occurrence is moderate, close to the previous year and perennial, with an area of ​​110 million mu. Among them, Jiangsu and Anhui along the Huaihe River, Huaibei and the coastal areas, and the northern part of Henan Province occurred heavily, and Huanghuai, Jianghuai, North China and most of the northwest occurred. In the peak period, Jianghan and Jianghuai wheat areas are from mid-April to early May, Huanghuai wheat area is from late April to mid-May, and North China and Northwest wheat areas are in May.

Sheath blight: The overall bias occurred, close to the previous year, with an area of ​​140 million mu. Among them, most of Jianghan, Jianghuai and Huanghuai occurred heavily, most of them occurred in most of North China, and most of the wheat areas in the northwest occurred lightly. At the peak of the period, Jianghan and Jianghuai have begun to invade the stalks. The Huanghuai, North China and Northwest wheat areas are from mid-April to early May.

Leaf rust, root rot, total eclipse, leaf blight, smut, cyst nematode, etc. will cause some damage in some areas.

(2) Major pests

Aphids at the ear stage: The overall occurrence is large, which is heavier than normal, with an area of ​​240 million mu. Among them, the northern part of Huanghuai and the wheat area of ​​North China occurred greatly, and most of the Sichuan Basin, Jianghuai and Northwest China occurred, and other wheat areas occurred moderately. In the middle of the flood season, the southwestern part is in the middle and late April, the Jianghuai and Huanghuai are from late April to mid-May, the north and northwest winter wheat areas are from early May to early June, and the northwest spring wheat area is from late June to 7. Late in the month.

Sucking worms: The overall incidence is light, close to the previous year, lighter than normal, with an area of ​​26 million mu. Among them, some parts of the wheat areas in Beijing, Tianjin, Hebei, Shaanxi, Henan, Shandong and other provinces (cities) may be seriously damaged. The adult emergence period is from mid-April to early May.

Wheat spiders, underground pests, first-generation armyworms, gray planthoppers, wheat leaf bees, wheat stem bees, and bandits can cause certain damages in some areas.

Second, the basis of the forecast

(1) The distribution of scab and stripe rust is widespread, and the population of aphids is large.

Scab: The main producing area of ​​wheat is continuous with rice or corn, and the area of ​​straw returning is large. The stock of rice piles and corn stover in the field is large. The rate of straw infection was high in this year. The rates of rice straw in Hubei, Zhejiang, Anhui, Jiangsu and Shanghai were 7.3%, 5.8%, 3.4%, 1.7%, and 1.3%, respectively. The prevalence of corn stalks was 32.5% and 17.9%, respectively, and the amount of field bacteria met the pandemic conditions. The maturity index of the ascots in the Jianghan Plain, Jianghuai and its southern areas is generally 25-60, more than 60 in the Yanjiang wheat area, 10-20 along the Huaihe and Huaibei areas, the pathogen development progress is close to normal, the ascospores release time and wheat The flowering susceptibility is consistent with the disease.

Stripe rust: affected by the warm winter climate, stripe rust occurs early and has a wide range. At present, there are 11.1 million mu in 390 counties in 75 cities of Sichuan, Yunnan, Guizhou, Chongqing, Hubei, Henan, Anhui, Shaanxi and Gansu provinces, an increase of 2.2 times compared with the same period of last year, an increase of 43.8% over the same period of 2015. , an increase of 1.6 times over the same period of 2010-2016. The disease conditions in Hubei Jianghan Plain, southern Henan, and southwestern Shaanxi have entered the spring epidemic in advance, and Shaanxi Guanzhong, Gansu, and Anhui have also taken place.

Powdery mildew: The condition is lighter than last year and perennial. At present, 7.6 million mu has been accumulated, and the southwestern region is at the peak of the disease. The average diseased leaf rate is above 3% and the highest is 100%. Jianghan, Jianghuai and Huanghuai are in the initial stage, and the disease is earlier than the previous year. The rate is about 1%, most of the illness is lighter than that of the previous year. The average disease rate of the south of the mountain and the southwestern part of the mountain is 5% and 3.1% respectively. The incidence of sporadic disease in the northwest is not seen in most parts of North China.

Sheath blight: The disease is more serious than the previous year. It is currently widespread in Jianghan, Jianghuai and Huanghuai wheat areas, with an area of ​​82.9 million mu. The average disease rate of Henan, Shandong, and Anhui was 15.9%, 12.2%, and 9.9%, respectively. Jiangsu, Shaanxi, Shanxi, Hubei, and Hebei were 1.4%-5.8%, and some of southern Henan, central Shandong, Hubei, and Anhui were along the Yangtze River. The highest disease rate is over 85%.

Aphids: Population density is higher than last year and perennial. At present, there are a total of 29.2 million mu, and most of the southwestern part is the peak period, with an average of 168-640 heads; the Jianghan, Jianghuai and Huanghuai wheat areas are the beginning of the period, with an average of 100-67 heads. The North China and Northwest wheat areas are in the initial stage, and the average number of sputum is generally less than 5 heads. The wheat fields in the southwest, Jianghan and Huanghuai areas have been re-emerged in the field. The highest number of insects in the 100 plants is 5000-8000 heads, and the number of individual fields in Huaihe and Huaibei is more than 2000.

Sputum larvae: The density of the worms in North China, Huanghuai and Jianghuai is maintained at a low level, and is currently in the larval ascending activity period. In the spring soil survey, the average number of worms per plant was 6 heads, 4 heads and 2 heads in Tianjin, Gansu and Hebei, 1.6 and 1.3 in Shaanxi and Shanxi respectively, and 0.5-0.8 heads in Beijing, Shandong, Anhui and Henan. Except for Henan's year-on-year decrease of 34.9%, other regions increased by more than 15% from the previous year, and Tianjin and Shanxi increased by 2.6 times and 44.4% respectively. The highest insect populations in Shandong Bincheng and Qingyun, Hebei Zhengding and Julu, Henan Yanshi and Huaxian counties were 200, 168, 135, 75, 46 and 22, respectively.

(2) Wheat variety layout and farming system are beneficial to pests and diseases

There has been no significant change in the layout of wheat varieties in most of the wheat fields this year. The proportion of susceptible scabs accounted for 90%; the wheat varieties in the main producing areas were less resistant to stripe rust, the frequency of new pathogenic groups in Gansu and other places increased, and the rust resistance of some varieties was lost; powdery mildew and leaf rust , planting varieties of aphids and other pests of large area. And contiguous species monoculture, is conducive to pest infestation.

This year the North China wheat main producing area of ​​wheat growing well, each group generally too large wheat growing areas, coupled with emphasis on fertilizer and water management, increasing the field in the late canopy density of scab, stripe rust, powdery mildew, aphids and other pests and diseases is very beneficial . Jianghan, Jianghuai rice stubble Maibo date postponed without a fertility schedule big difference, and flowering very irregular, elongated cause of disease susceptibility, increasing the chance encounter even the rainy weather; and this area of ​​carbendazim resistance to Fusarium graminearum further enhance the control effect is reduced, scab increased threat of harm. The flowering stage of wheat in the Huanghuaihai wheat area is consistent with the emergence period of the midwater, which is beneficial to its spawning.

(3) The weather conditions are generally conducive to the occurrence of pests and diseases in the middle and late stages.

According to the forecast of the meteorological department, in the middle and late April, there will be multiple rainfall processes in Jianghan, Jianghuai, southern Huanghuai and the southwestern part of the country, which will be beneficial to the occurrence of diseases such as scab, stripe rust, powdery mildew and midge. In May, the precipitation in the upper reaches of Jianghuai and Jianghan was more than 2-5 percent, and the southern part of Huanghuai was more than 1-2%, which would aggravate the degree of damage caused by scab, stripe rust and powdery mildew; the temperature in the northern Huanghuai and North China wheat areas High and normal precipitation are less favorable, which is extremely beneficial to the occurrence of aphids at the ear stage. More weather such as smog and condensation will promote the spread of diseases such as scab and powdery mildew.

This paper URL: Forecast of the occurrence trend of major diseases and insect pests in the middle and late stages of wheat in 2017

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