Introduction to the Latest Control Methods for Corn Seedling Blight
Corn seedling blight is a fungal disease of corn at the seedling stage. In the early stage of the disease, it often causes the heart leaves of corn seedlings to curl and wilt, and in severe cases causes seedling death. In recent years, the occurrence of corn seedling blight has shown a worsening trend, becoming one of the main diseases on corn seedlings, with a relatively large impact on corn yield. Let us take a look below at the control methods for corn seedling blight!
Damage Characteristics
After corn becomes diseased, the root tips first turn brown, and after spreading, this leads to poor root development or reduced root hairs, few or no secondary roots, aging of primary roots, necrosis of the cortex, and the root system turning blackish brown. Necrotic spots also form at the first internode of the stem, causing water-soaked rot in the stem that is prone to breaking, and the leaf sheaths also turn brown and split. The leaves turn yellow, the leaf margins scorch, and the heart leaves curl and break easily. In severe cases, death occurs, and when a small number of secondary roots form, weak seedlings appear. In lightly affected seedlings, the aboveground part shows no obvious symptoms. Generally, from the 2 to 3-leaf stage, the leaf tips of the 1st to 2nd leaves begin to turn yellow and gradually develop toward the middle of the leaves, and in severe cases the heart leaves gradually wither and wilt.
Occurrence Pattern
Corn seedling blight generally occurs from after sowing to early July. Under long-term drought conditions, from after corn sowing to the root development period, a sudden moderate to heavy rain causes soil compaction, creating an environment with low soil temperature and high humidity, making infection with this disease easy. Disease is severe in low-lying fields, poor soil, clay soil, saline-alkali land, and plots where corn herbicides are applied. In addition, poor seed quality and overly deep sowing also make the disease more likely. In fields with wheat-corn as the main rotation pattern, because wheat root disease has occurred severely in recent years, pathogens such as Fusarium moniliforme, Fusarium graminearum, and Rhizoctonia have accumulated, and the occurrence of summer corn seedling blight is also relatively severe.
Control Measures
1. Select high-quality, disease-resistant varieties, and choose corn seeds that are large, plump, and have strong germination vigor.
2. Promote formula fertilization, apply more farmyard manure, and cultivate strong seedlings, with special attention to supplementing phosphorus and potassium fertilizers. Promote root growth so that the plants grow vigorously, thereby improving disease resistance.
3. Strengthen intertillage management, reduce the use of herbicides, and weed and hoe in time to enhance soil permeability.
4. For prevention, use 1000-fold carbendazim plus 2 to 3 jin of potassium chloride to drench the roots.
5. Choose 70% thiophanate-methyl 800-fold solution, or 20% triadimefon 1000-fold, 75% chlorothalonil 1000-fold, and other pesticides, and spray continuously 2 times (with an interval of about 7 days between each application).