Correct use of ethephon when cotton matures late this year

This year, due to the influence of low temperature, overcast and rain, cotton production in northern China has led to late sowing and emergence of spring cotton in a large area, and the budding and flowering period has been delayed by about 7 days than usual, and the cotton bolting maturity will also be delayed by more than a week. In addition, there are more overcast and rainy weather in North China from late August to early September, cotton is prone to greedy green late ripening phenomenon. Therefore, measures to promote early maturity are particularly important in the late management of cotton fields this year.

Years of practice shows that the correct use of ethephon to accelerate ripening in late-maturing cotton fields is a simple and easy measure to increase production and income. After spraying ethephon, cotton could open bolls 710 days earlier, increase the pre-frost flowering rate by 10% to 20%, and increase the yield by 6.4% to 10.2%. Moreover, the cotton field after ripening is also beneficial to the sowing and high yield of the next crop. However, ethephon is also a "double-edged sword". If it is not used properly, it will not increase production and income, but will lead to a reduction in production and income. Therefore, it must be used correctly.

First, to correctly select the cotton field of pesticide application, we should choose the cotton field with greedy green late maturity and strong late maturity, mainly interplanting cotton field, summer sowing cotton and post-mature hybrid cotton. If the boll period of more than 80% of the cotton bolls is 40-45 days late maturing cotton field, the effect of pesticide application will be particularly good. Ethephon should not be applied to cotton fields with normal development and maturity, especially those with a tendency of premature senescence, otherwise cotton plants will wither prematurely and yield and yield will be reduced. Ethephon can not be sprayed on the cotton in the improved seed breeding field. If it is sprayed, the seed maturity will be reduced, the germination rate will be reduced, and the utilization value of seeds will be greatly reduced.

Second, correctly grasp the effect of spraying ethephon in the appropriate period, which is closely related to the temperature. Because ethephon can decompose and release ethylene only at a temperature higher than 20 ℃. Therefore, after spraying in the cotton field, it is required that the daily maximum temperature above 20 ℃ can be about 15 days in order to get a good application effect. According to the requirement of this principle, the spraying time in the cotton area of northern China mainly refers to the frost falling period, which should be 20 days before the dry frost period. Specific spraying time, but also need to be flexibly used according to local conditions. In general years, the cotton area of Huang-Huai in China should be sprayed around October 5.

Third, pay attention to spraying methods and dosage to choose sunny days without wind or breeze, spraying from 9: 00 a.m. to 3: 00 p.m. The amount of pesticide should be determined according to the growth of cotton, the temperature at that time and the time of spraying. For the cotton fields with prosperous growth, late application period, low temperature and eager stubble, the amount of application should be increased appropriately, but the amount of application per mu should not exceed 200 ml; on the contrary, the amount of application should be reduced appropriately. In the Huang-Huai area, in early October, 40% ethephon pesticide was used in 100 ml per mu, 50 kg of water was diluted evenly and then sprayed; from the end of early October to the beginning of October, 150 ml per mu was needed and 60 kg of water was diluted evenly before spraying. Use a sprayer to aim at the green bolls on the cotton plant and spray evenly from top to bottom, so that the cotton bolls that need to be ripe are covered with liquid medicine.

Spraying 40% ethephon and 2% superphosphate mixture has a good effect on cotton spraying 2% superphosphate diluent in the later stage, which can promote precocious maturity, prevent premature senility, increase yield and increase income significantly, and generally increase production by about 5%. Because calcium superphosphate is an acidic chemical fertilizer, when mixed with acidic ethephon, it not only does not affect the efficacy of ethephon, but also has a synergistic effect on ethephon, which is worth popularizing according to local conditions. The method is as follows: first, 1 kg of high-quality calcium superphosphate fertilizer is opened with 50-60 kg clear water, the residue is filtered, and then ethephon pesticides per mu are added, mixed evenly and then sprayed.

There are several problems that need to be paid attention to in the use of ethephon: first, ethephon is an acidic pesticide, which is easy to decompose and fail when encountered with alkaline substances, so it must not be mixed with alkaline pesticides. Ethephon diluent prepared should not be stored, but should be used as soon as it is prepared. Second, after spraying ethephon in the cotton field, if it rains within 6 hours, it needs to be re-sprayed after the rain. Third, before application, the bolls of cotton bolls should be harvested so as to avoid the decline of cotton bolls caused by spraying. Fourth, ethephon solution is strongly acidic and has a strong stimulating effect on the human body, so it is necessary to do a good job of safety protection at work. When the skin is stained with liquid medicine, rinse immediately with soap and water. Fifth, do not buy fake and shoddy drugs by being biased in listening to and believing. In recent years, there have been many kinds of crop ripening agents on the market, and most of these ethephon products produced by regular manufacturers are unapproved and registered by the agricultural administrative department and belong to fake and shoddy products that can not be used. Cotton farmers should buy through formal channels.