What causes distorted corn whorl leaves?

    1. Main causes

    1. Damage by thrips and the Swedish fly. Peeling back the outer leaves reveals that the base of the whorl leaf has already shriveled and has holes. The main symptoms are distorted whorl leaves, damaged and shriveled leaves, and rows of holes on the leaves. The upper leaf surface has a transparent film-like substance, some whorl leaves contain mucus, and a few whorl leaves have already broken off.

    2. Phytotoxicity from post-emergence herbicides. Leaves damaged by thrips and the Swedish fly are more or less broken; if the distorted leaves are not broken, it is caused by the use of a post-emergence herbicide containing nicosulfuron.

    2. Control methods

    1. Immediately use scissors to cut off the upper 1/4 of the leaves, or manually break open the twisted whorl, and apply fertilizer and water, and spray the leaves with a 1000-fold dilution of the plant growth regulator “Tianfengsu” (brassinolide), or the high-efficiency foliar fertilizer “Shuangxiao Wang&rdquo, 1 bag of 40 milliliters mixed with 30-45 kilograms of water, or 6000-fold Aiduoshou + 0.2%-0.3% monopotassium phosphate + 1% urea solution + micro-fertilizer containing zinc and boron, once every 5-7 days, spraying 2 times in succession.

    2. If the twisted whorl is caused by insect pests, the main approach should be to timely control thrips and the Swedish fly when summer corn has 5-6 leaves, and also spray pesticide at the large trumpet stage of corn to prevent and control the disease. The formula is: 10% imidacloprid 1000-fold solution or 5% acetamiprid 1500-fold solution plus agricultural streptomycin 500-800-fold solution, plus some high-efficiency foliar fertilizer, spray again at an interval of 5-7 days, spraying 2 times in succession.

    3. For whorl leaves deformed and twisted due to herbicide phytotoxicity, attention should be paid to selecting high-quality post-emergence corn herbicides, and to avoiding application during high temperatures, and applying at the appropriate time to prevent phytotoxicity caused by applying too late.