During the growth of green onions, you may notice symptoms such as white spots, dry leaves, curled wilting, and lack of growth. Some pesticides seem ineffective in these cases. What should you do? According to China Pesticide Network, here are some effective solutions.
There are several pests and diseases that can cause yellowing and withering of green onions, including downy mildew, gray mold, bacterial blight, viral infections, and onion fly infestations. Since treatments for downy mildew, gray mold, and bacterial blight don’t seem to work, it’s likely that the issue is either a viral infection or an onion fly infestation. The appropriate pesticide should be selected based on the specific symptoms observed.
Viral infections typically show as mottled yellow and green patterns or streaks on the leaves, which become twisted and thin. The tips of the leaves may gradually turn yellow. In severe cases, the growth of the green onions slows down or even stops completely. To manage this, you can apply a 1.5% phytocid emulsion diluted at 1000 times, 20% mancozeb wettable powder at 500 times, or a 10% mixed fatty acid emulsion diluted at 100 times. These should be sprayed every 7–10 days, and up to 2–3 applications may be needed depending on the severity.
Onion flies cause damage by laying eggs near the base of the plant. The larvae then burrow into the roots, leading to root rot and decay. This causes the above-ground parts to wilt, with yellowing leaf tips or entire plants turning yellow. In severe cases, the green onions may stop growing or die altogether. To control the larvae, you can use a 75% imidacloprid wettable powder diluted at 3000 times, 40% chlorpyrifos emulsifiable concentrate at 3000 times, 48% chlorpyrifos emulsifiable concentrate at 3000 times, or 5% hexaflumuron emulsifiable concentrate at 3000 times. Apply these directly to the root zone for best results.
If you're unsure about the exact cause, it's always a good idea to consult local agricultural experts or conduct a soil and plant test. Proper identification of the problem will ensure that you choose the most effective treatment and avoid unnecessary pesticide use. With the right approach, you can restore the health of your green onions and improve their yield and quality.
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