Occurrence and control of wheat sheath blight

According to the investigation of the measuring and reporting stations in various counties (cities and districts), at present, wheat sheath blight has been widespread and will enter the stage of epidemic damage, and all localities must seize the appropriate period and organize the broad masses of farmers to carry out prevention and control in time.

I. Analysis of occurrence and trend

The occurrence characteristics of wheat sheath blight this year are as follows: first, the occurrence period is normal, due to the low temperature last winter and spring, the growth of wheat seedlings is weak, which is not conducive to the occurrence of wheat sheath blight. The earliest Xiangshui in the city was first found in mid-February, and a large area was found at the end of February and early March. Second, the prevalence rate and the disease are slightly milder than those in the same period last year. According to the systematic survey of Xiangshui on March 15, the diseased plant rate was 21.25% (7-35.5%) and the disease index was 4.25 (1.4-7.1). According to the systematic survey of Xiangshui on March 15, the diseased plant rate of wheat was 2% (0-4%). 165 fields were investigated in the city from March 16 to 18, including 143 wheat fields, with a diseased rate of 40.6%, a diseased plant rate of 3.25% (0-62.5%), and 22 barley fields, with a diseased rate of 31.8% and a diseased plant rate of 0.73% (0-7%). Third, there are great differences in different regions and different crops. As far as the whole city is concerned, the northern region is heavier than the central and southern regions, the dry stubble field is heavier than the rice stubble field, and the wheat is heavier than barley. 20 fields were investigated in Xiangshui on March 18, including 10 dry stubble wheat, 100% diseased field rate, 28.5% diseased plant rate (4-62.5%), 10 rice stubble wheat, 70% diseased field rate and 4.6% diseased plant rate (0-18%). Funing investigated 22 fields, including 17 wheat fields, the diseased plant rate was 17.7%, the diseased plant rate was 1.85% (0-9.5%), 5 barley fields, the diseased field rate was 20%, and the diseased plant rate was 1.4% (0-7%). Dongtai investigated 26 fields, the diseased field rate was 30.8%, and the diseased plant rate was 0.85% (0-7%). Sheyang, Tinghu and other places are sporadically found.

Wheat has entered the jointing stage one after another, and sheath blight will also enter a critical period of stem invasion. With the rise of temperature, it will accelerate the development of the disease. If there is more overcast and rainy weather in the future, it will be more conducive to the development of the disease. It is expected that wheat sheath blight will occur in moderate degrees this year, with heavy weight in local areas, and some fields with high density, large population, good growth and weeds will occur greatly.

II. Opinions on prevention and control

1. Make full use of agricultural measures to create environmental conditions that are not conducive to the occurrence and development of the disease. All localities should make full use of agricultural measures, clear ditches and regulate soil moisture, improve drainage capacity, reduce field humidity, remove field weeds in time, improve light transmittance, and increase the application of phosphorus and potassium fertilizer to improve plant disease resistance, so as to inhibit the occurrence and development of diseases.

2. Organize chemical prevention and control in time to control the development of the disease. The application of pesticides at the jointing stage of wheat is the key to control the development of the disease, prevent stem invasion and reduce damage. All localities should seize the jointing period from late March to early April, and fields with sheath blight disease rate of more than 20% or sporadic disease of stems and stems should be sprayed immediately. 40% Bote wettable powder 30-40 grams per mu or 20% Jinggangmycin powder 50 grams per mu, 50 kg coarse spray with water. When spraying, the middle and lower parts of the plant should be sprayed evenly and thoroughly, and the number of times of drug use should be increased according to the development of the disease. The fields with early onset, serious disease and rapid development after medication must be used more than 2 times, with an interval of 7 min and 10 days.