Cotton matures late this year: how to correctly use ethephon

This year, cotton production in northern China has been affected by low temperatures, rain and other weather conditions, causing large areas of spring cotton to be sown and emerge late, with squaring and flowering stages delayed by about 7 days compared with normal years, and the boll-opening and maturation period will also be delayed by more than a week. In addition, from late August to early September, the North China cotton region had more rainy weather, making cotton prone to excessive vegetative growth and late maturation. Therefore, in this year's late-stage management of cotton fields, measures to promote early maturation are particularly important.

Years of practice have shown that for late-maturing cotton fields, correctly using ethephon for ripening is a good measure that is simple, easy, and increases both yield and income. After spraying cotton with ethephon, boll opening can be advanced by 7-10 days, the proportion of pre-frost cotton increases by 10%-20%, and yield increases by 6.4%-10.2%. Moreover, ripened cotton fields are also beneficial for sowing and high yields of the next crop such as @#@245@#@. But ethephon is also a “double-edged sword”. If used improperly, it will not only fail to increase yield and income, but will instead cause reduced yield and income. Therefore, it must be used correctly.

1. Correctly select the cotton field for application. Choose cotton fields that are prone to excessive vegetative growth, late maturation and strong regrowth, mainly intercropped cotton fields, summer-sown cotton, and hybrid cotton with strong regrowth. If a late-maturing cotton field is selected where more than 80% of bolls have a boll age of 40-45 days, the effect of application will be especially good. For cotton fields that develop and mature normally, especially those with a trend toward premature senescence, ethephon must not be sprayed, otherwise it will cause the cotton plants to wither and decline prematurely, resulting in reduced yield and income. For cotton in seed-breeding fields, ethephon must never be sprayed. If sprayed, it will lead to reduced seed maturity and a lower germination and emergence rate, greatly reducing the seed's use value.

2. Correctly grasp the suitable timing of application. The effect of spraying ethephon is closely related to temperature. This is because ethephon must be at a temperature above 20°C to decompose and release ethylene. Therefore, after spraying the cotton field, it is required that there be about 15 days with a daily maximum temperature above 20°C in order to achieve a good application effect. According to this principle, the spraying time in northern China's cotton region mainly refers to the frost period, and should be 20 days before the killing frost. The specific spraying time also needs to be applied flexibly according to local conditions. In ordinary years, in the Huang-Huai cotton region of China, it is suitable to spray around October 5.

3. Pay attention to the spraying method and dosage. Choose a sunny day with no wind or light wind, and spray from 9 a.m. to 3 p.m. The amount of pesticide used should be determined according to the cotton's growth vigor, the temperature at the time, and whether the spraying period is early or late. For cotton fields with vigorous growth, a later application period, lower temperatures, and an urgent need to clear the field for the next crop, the dosage should be appropriately increased, but the dosage per mu must not exceed 200 milliliters; otherwise, the dosage should be appropriately reduced. In the Huang-Huai region, when applying in early October, use 100 milliliters of 40% ethephon pesticide per mu, mix with 50 kg of water, dilute evenly, and spray; when applying from late early October to early mid-October, use 150 milliliters per mu, mix with 60 kg of water, dilute evenly, and spray. Use a sprayer aimed at the green bolls on the cotton plants, spraying evenly from top to bottom, so that all bolls needing ripening are covered with the liquid.

Spraying a mixture of 40% ethephon and 2% superphosphate has a good effect. Spraying a diluted 2% superphosphate solution in the late cotton stage promotes early maturation, prevents premature senescence, and significantly increases yield and income, generally increasing yield by about 5%. Because superphosphate is an acidic fertilizer, mixing it with acidic ethephon not only does not affect the efficacy of ethephon, but also has a synergistic effect on ethephon, and it is worth promoting according to local conditions. The method is: first dissolve 1 kg of high-quality superphosphate fertilizer in 50-60 kg of clean water, filter out the residue, then add the amount of ethephon pesticide needed per mu, mix evenly, and then spray.

Several issues to note when using ethephon: First, ethephon is an acidic pesticide and readily decomposes and becomes ineffective when it encounters alkaline substances, so it must never be mixed with alkaline pesticides. The prepared diluted ethephon solution should not be stored; it should be used immediately after preparation. Second, if it rains within 6 hours after spraying ethephon on the cotton field, the pesticide needs to be sprayed again after the rain. Third, before application, cotton bolls that have already opened should be harvested to avoid the quality of opened bolls being reduced by spraying. Fourth, the ethephon stock solution is strongly acidic and has a strong irritating effect on the human body, so safety protection must be taken during work. If the liquid gets on the skin, immediately wash it clean with soap and clean water. Fifth, do not buy counterfeit or inferior products based on hearsay. In recent years, many varied crop ripening agent products have appeared on the market. These ethephon products that are not from regular manufacturers are mostly unapproved and unregistered by agricultural administrative departments, and belong to counterfeit and inferior products that cannot be used. Cotton farmers should purchase through regular channels.