2,4-دی کلروفنوکسی استیک اسید-2,4-Dichlorophenoxy acetic acid

2,4-D is primarily used as a selective herbicide which kills many terrestrial and aquatic broadleaf weeds, but not grasses. It acts by mimicking the action of the plant growth hormone auxin, which results in uncontrolled growth and eventually death in susceptible plants.[11] Because it was discovered in the 1940s, there is no longer a patent governing the manufacture and sale of 2,4-D, and any company is free to produce it. Thus, it is sold in various formulations under a wide variety of brand names.[11] 2,4-D can be found in commercial lawn herbicide mixtures, which often contain other active ingredients including mecoprop and dicamba. Over 1,500 herbicide products contain 2,4-D as an active ingredient.[12]

A wide variety of different sectors use products containing 2,4-D to kill weeds and unwanted vegetation. In agriculture, it was the first herbicide found to be capable of selectively killing weeds but not crops. It has been used since 1945[13] to control broad-leafed weeds in pastures, orchards, and cereal crops such as corn, oats, rice and wheat.[14] Cereals, in particular, have excellent tolerance to 2,4-D when it is applied before planting. 2,4-D is the cheapest way for farmers to control winter annual weeds by spraying in the fall, often at the lowest recommended rate. This is particularly effective before planting beans, peas, lentils and chickpeas.[15]