What Causes Dry Tips on Welsh Onions? Detailed Explanation of Causes and Control Measures
Welsh onions are grown fairly widely in China, mainly in the northern regions, but dry tips can occur during cultivation. Dry tips have become a major obstacle in Welsh onion production, often leading to declines in both yield and quality and directly affecting growers' income. So what causes dry tips on Welsh onions? How can they be controlled? Let's take a look.
1. Dry tips caused by disease
Disease is one of the main causes of dry tips on Welsh onions. When Welsh onions develop late blight, pale white spots appear on the affected areas and gradually spread into grayish-white patches, causing the leaves to wither from bottom to top and producing the dry tip phenomenon. When gray mold occurs, white spots also appear on the leaves, all developing downward from the leaf tip, and under high humidity gray mold also appears on the lesions. Root rot can also cause Welsh onion leaf tips to turn yellow and gradually wither and die. All three of these diseases can cause the dry tip phenomenon.
Control measures: For late blight, spray leaves or drench roots with for control; for gray mold, spray with procymidone or iprodione for control; for root rot, spray and drench roots with hymexazol or metalaxyl for control.
2. Dry tips caused by insect pests
Many pests can also cause dry tips on Welsh onions, such as thrips, which mainly damage Welsh onion leaves, causing irregular grayish-white spots to appear on the leaves and, in severe cases, withered leaves. Somewhat similar to thrips, leafminers and beet armyworms are the same: their larvae bore into the leaves and feed on the mesophyll tissue, leaving only the dried epidermis of the leaves.
Control measures: For thrips, spray with bifenthrin for control; for leafminers, spray with cyromazine for control, spraying once every 5 days for 2-3 consecutive treatments; for beet armyworms, spray with emamectin benzoate and chlorfenapyr for control.
3. Physiological dry tips
In addition to pests and diseases causing the dry tip phenomenon on Welsh onions, improper practices in routine management can also cause dry tips. When Welsh onions lack calcium or boron, their growth and development are hindered, leading to leaf withering and dry tips. A lack of water in the plant can also cause dry tips; using pesticides at too high a concentration can also cause the leaves to turn white or develop dry tips.
Control measures: Apply sufficient basal fertilizer, mainly organic fertilizer or farmyard manure, and when the plant is found to lack trace elements, supplement them by foliar spraying. Pay attention to water management: water promptly during drought, and also pay attention to drainage during the rainy season, keeping soil moisture content at 60%-80%. When using pesticides, strictly follow the instructions; they should not be too concentrated, and after pesticide damage occurs, promptly spray a remedy.
The above is an introduction to the causes of dry tips on Welsh onions and control measures. We hope it can help you. To learn more related knowledge, please follow us.