Detailed Explanation of the Causes of Dead Wheat Heads and Control Measures
In recent years, many farmers have found that dead heads often occur in the late growth stage of wheat, resulting in lower wheat quality and yield, with yield reductions of more than 50% in severe cases, bringing huge economic losses to farmers. So what are the causes of dead wheat heads? How should they be controlled? Let's take a look together.
I. Causes of Dead Heads
1. Sheath blight. When the disease occurs, oval brown lesions appear on the leaf sheaths of the 1st to 3rd nodes at the stem base. After the pathogen invades the stem, brown oval eye-shaped spots form, causing necrosis of the stem and ultimately leading to death of the plant due to insufficient supply of fertilizer and water.
2. Take-all disease. The main symptoms are black feet and white heads. When the disease occurs, the roots turn brown or black, the plants are short and sparse, and the leaves gradually turn yellow. After flowering, the awns turn white, and the entire wheat head gradually becomes a white head. The roots rot until the plant dies.
3. Root rot. The main symptoms are root rot and white, withered wheat heads. It can occur throughout the entire growth period of wheat. The pathogen invades the root system and seedlings and spreads with wind and rain. Damage is most severe after wheat flowering, ultimately leading to root rot, and the leaves wither and turn yellow until death.
4. Fusarium head blight. In the early stage, it appears as seedling rot and stem rot, and in the later stage as head rot. At the initial stage of the disease, water-soaked light brown lesions appear on the glumes of the spikelets, and after gradual spread, a pink mold layer is produced.
5. Underground pests. Underground pests bite and damage the roots and stems, causing dead plants. Many farmers do not carry out timely chemical soil treatment when planting, so the number of underground pests gradually increases, especially wireworms, which have become more severe, often causing dead seedlings and missing seedlings.
⟦NL>6. Mechanical damage. Carelessness during intertillage weeding, topdressing, and irrigation operations can cause stem breakage, leading to destruction of the transport tissue and causing dead wheat seedlings or dead heads. In addition, natural factors such as strong wind and rain and hail can also cause mechanical damage to wheat, resulting in dead heads.
II. Control Measures
1. For dead heads caused by sheath blight, seed treatment with chemicals at sowing can effectively delay the onset of sheath blight by more than 100 days and also reduce the severity of later disease development; second, spraying Heguoli or triadimefon from the wheat green-up stage to the jointing stage can effectively control the degree of disease development and reduce the number of later deaths.
2. For dead heads caused by take-all disease, promptly handle wheat straw and stubble after harvest to reduce the amount of inoculum in the field. At sowing, do not use seeds carrying take-all disease, or treat seeds with chemicals at sowing. Both can provide good preventive effects and reduce the severity of the disease.
3. For dead heads caused by root rot, first, rotate crops; second, treat the soil by mixing carbendazim with soil and broadcasting it before plowing; third, treat seeds with chemicals, or spray Heguoli and fenoxanil for control when the disease occurs.
4. Fusarium head blight. Spray chemicals in advance for prevention and control. Carbendazim or Heguoli can be mixed with 450 kg of water and sprayed evenly on wheat heads. After rain, spray once more to ensure good results.
5. For dead heads caused by underground pests, chemical seed treatment and soil treatment can be used for control. Before plowing, mix isofenphos-methyl granules or phoxim granules with fine soil and broadcast evenly, which gives good results.
6. For those caused by mechanical damage, during intertillage weeding, topdressing, and irrigation operations, artificial mechanical damage should be avoided as much as possible. At the same time, rational close planting and scientific management should be carried out to prevent lodging.
The above is an introduction to the causes of dead wheat heads and control measures. We hope it can help you. To learn more related knowledge, please stay tuned to us.