How to correctly use ethephon when ripening cotton

Many years of practice have shown that correctly using ethephon to ripen late-maturing cotton fields is a simple, easy-to-apply measure that increases both yield and income. Late-maturing cotton sprayed with ethephon can open bolls 7-10 days earlier, increase the pre-frost boll rate by 10%-20%, raise yield by 6.4%-10.2%, and increase income by 50-100 yuan per mu. Moreover, ripened cotton fields also help the sowing and yield increase of the next crop, such as wheat. But ethephon is a double-edged sword: if used improperly, it not only fails to increase yield and income, but instead causes reduced yield and income. Therefore, the use techniques of ethephon must be accurately mastered and used scientifically to achieve the expected results.

Choose suitable cotton fields for application. Choose cotton fields that stay green and mature late and have strong late vigor, mainly intercropped cotton fields, summer-sown cotton, and hybrid spring cotton with strong late vigor. If more than 80% of the cotton bolls in a cotton field have a boll period of 40-45 days, the effect of application will be especially good. For cotton fields that develop and mature normally, especially cotton fields with a tendency toward premature senescence, ethephon must not be sprayed, otherwise it will cause the cotton plants to wither and decline too early, resulting in reduced yield and income. For cotton in improved seed propagation fields, ethephon must not be sprayed even more; if sprayed, the utilization value of the seeds will be greatly reduced.

Correctly master the suitable period for application

The effect of spraying ethephon is closely related to temperature. Because ethephon can only decompose and release ethylene when the temperature is above 20°C. Therefore, after spraying the cotton field, it is required that the daily maximum temperature remain above 20°C for about 15 days before good results can be obtained. According to this principle, the spraying time in China's northern cotton region mainly refers to the frost period, and should be 20 days before the killing frost period. In ordinary years and under ordinary conditions, in North China, spraying should be done around early October.

Spraying method and dosage

For application in early October, use 100 ml of 40% ethephon per mu, mix with 50 kg of water, dilute evenly, and spray; if applying from late early October to early mid-October, use 150 ml per mu, mix with 60 kg of water, dilute evenly, and spray. Aim the diluted solution at green bolls on the cotton plants that have a boll period of more than 40 days, and spray evenly from top to bottom so that every cotton boll needing ripening is covered with the solution.

Spraying ethephon mixed with 2% superphosphate solution

Spraying diluted 2% superphosphate solution on cotton in the later stage has effects such as promoting early maturity, preventing premature senescence, and increasing yield and income, generally increasing yield by about 5%. Because superphosphate is an acidic fertilizer, mixed use with acidic ethephon not only does not affect the efficacy of ethephon, but can also have a synergistic effect, and is worth promoting according to local conditions. Method: first dissolve 1 kg of high-quality superphosphate in 50-60 kg of clear water, filter out the residue, then add the amount of ethephon required per mu, mix evenly, and spray.

Several issues to note when using ethephon

1. Ethephon is an acidic pesticide and easily 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 prepared and used immediately. 2. After spraying ethephon in a cotton field, if it rains within 6 hours, the pesticide needs to be sprayed again after the rain. 3. Before application, cotton bolls that have opened should be harvested to avoid a decline in cotton fiber quality caused by spraying.