Ethrel

Ethrel is a trade name for ethephon, a plant growth regulator used in agriculture to release ethylene in plant tissues. Ethephon is a phosphonic acid ester that, upon uptake by plants, hydrolyzes under acidic conditions to produce ethylene, phosphate, and chloride. The ethylene acts as a gaseous plant hormone, triggering responses such as fruit ripening, colour development, abscission, and flowering in various crops.

Applications include promoting ripening and uniform colouring of climacteric fruits (for example bananas, citrus, apples, mangoes) and facilitating harvest operations. It is also used as a defoliant in some crops, notably cotton, to promote leaf drop prior to mechanical harvesting. The magnitude and timing of the response depend on species, developmental stage, and environmental conditions.

Ethrel is typically applied as a foliar spray, although some crop uses involve soil drench or other methods, all according to the product label. Rates, timing, and pre-harvest intervals are specified on the label to minimize quality loss and residue concerns. Safety guidelines require appropriate protective equipment, careful handling, and adherence to withholding periods; exposure can irritate skin and eyes and accidental ingestion or inhalation should be avoided. Ethrel is regulated as an agricultural chemical in many jurisdictions, and its use is subject to local regulations and environmental considerations.