What are the prevention and control methods of wheat scab? When is the best time to prevent scab?

At present, wheat has entered the heading and flowering stage, which is also the key period for the epidemic and control of wheat scab and stripe rust. What are the prevention and control methods of wheat scab? When is the best time to prevent wheat scab?

In addition, according to the prediction of experts, due to the previous freezing injury in some areas this year, the growth of wheat is weak and its resistance is poor. Therefore, if the prevention work is not done in time, it will lead to a massive reduction in wheat production!

What are the main symptoms of wheat scab?

Wheat scab, also known as wheat ear blight, rotten wheat head, and red wheat head, is one of the main diseases of wheat; it will be damaged from seedlings to heading, mainly causing seedling withering, stem base rot, culm rot and ear rot, and the most serious harm is ear rot, which reduces 1000-grain weight and affects yield; and the toxin secreted by the disease is harmful to the human body, and wheat with a diseased grain rate of more than 4% cannot be sold, so scab is extremely harmful to wheat!

Cause of scab

The pathogen of wheat scab can only infect some florets at flowering and filling stage, and then spread to the whole ear. What can really cause the disease is a transmission called ascospores, which are produced from the diseased remains left over from the previous year, including diseased wheat ears, rice stumps and corn stalks.

Secondly, it is a typical climatic disease. Only in the wheat flowering filling period encountered overcast and rainy weather, and there are a large number of bacteria (ascospores) in the air, the disease may occur. Due to the existence of a large number of germs every year, the weather from heading to filling stage of wheat, especially the rainfall and the number of rainfall, determine the severity of scab.

When is the best time to prevent wheat scab?

Chemical control of wheat scab should be mastered in the full heading to full flowering stage as early as possible spraying, miss this time, the control effect is greatly reduced.

In general, wheat heading first, and then flowering, should be applied at 10%-50% flowering; if the temperature at the spike stage is high, the wheat should be applied at the full heading stage. Pesticide application should be carried out before the rain, in the critical period of rain, should be sprayed in the rain gap.

Generally, it can be sprayed once in the critical period, and should be sprayed again 5-7 days after the first spraying when the variety is seriously susceptible, or the weather of continuous high temperature and high humidity is encountered after the first application, or the growth period of wheat is irregular and the flowering period is continuous for more than 7 days.

Prevention and control technology:

1. Select disease-resistant varieties and achieve reasonable close planting:

Recent market research found that the sowing amount of wheat in many places is too large, with sowing up to 60 jin / mu in some places, the wheat layer is thick after tillering, the field ventilation is poor, and when the air humidity reaches more than 80%, it is easy to cause a scab pandemic. In addition, if you catch up with the continuous rain for more than 3 days at the heading and flowering stage of wheat, it is easy to cause a pandemic of wheat scab.

2. the use of drugs in the critical period can achieve twice the result with half the effort:

According to years of control experience, it has been found that the best time for wheat scab control is when wheat ears are 4% Mel 6% and the best time to start spraying. At the same time, we should also pay attention to the temperature at the heading stage. If the temperature is high at the heading stage, the medicine should be used at the full heading stage. If the temperature is low, the wheat should be sprayed at the first flowering stage after heading.

3. drug selection is the key, and the combination of treatment and protection:

The choice of fungicides for the prevention and treatment of scab is 43% tebuconazole wettable powder or 20% cyanothrin hexazolol suspension or 40% tebuconazole thiram wettable powder or 40% tebuconazole water emulsion or 43% tebuconazole suspension, etc. For the control of aphids and trematodes, pesticides with long residual periods such as organophosphorus and pyrethroids can be selected, such as 48% chlorpyrifos 50-60 ml, 4.5% cypermethrin 60 ml and so on; at the same time, combined with "one spray, three prevention" plus 99% potassium dihydrogen phosphate 50-60 grams mixed spray, and prevent stripe rust, wheat ear aphid, powdery mildew and premature senescence, using 60 jin of water per mu.

4. Spray should be scientific and water consumption should be sufficient:

Especially after the wheat jointing, the plant density in the wheat field is high, so the whole wheat field must be evenly sprayed when spraying, and the atomized sprinkler should be selected when spraying. The lower leaves of wheat must be penetrated when spraying. Water consumption must be sufficient, between 50-60 jin per mu of field water, and secondary dilution must be carried out when dispensing medicine to ensure the effectiveness of the drug.

Note:

(1) when purchasing drugs, you must go to the regular stores with complete "three certificates", and the use of highly toxic organophosphorus pesticides and high residual pesticides and their compounding varieties are strictly prohibited.

(2) according to the occurrence characteristics of diseases and insect pests, choose the suitable scientific formula of pesticide, spray evenly, and prepare wettable powder pesticide, we must first use a small amount of hydration and then pour it into the application equipment and stir evenly, so as to avoid drug damage caused by uneven liquid.

(3) the dosage should be accurate. Prepare the liquid according to the amount of medicine per mu and water consumption, use the standard meter, do not add the medicine at will.

(4) spraying in the field should be carried out in the morning or in the afternoon without dew, and should be sprayed in case of rain within 6 hours after spraying.

(5) strictly abide by the safe operation rules for the use of pesticides, do a good job in the protection of personnel, and deal with the pesticide residues after application, do a good job in the cleaning of pesticide application equipment, and prevent the occurrence of unsafe accidents such as human and animal poisoning.