The commercial preparations of 2,4-D are available in the 

 form of (1) esters, which are of two kinds: (a) high volatile 

 esters of methyl, ethyl, propyl, isopropyl, butyl, amyl and pentyl 

 alcohols, the use of which may be restricted in some states, and 

 (b) low volatile esters such as propylene glycol butyl ether ester 

 (Dow) , butoxy ethanol ester (AmChem) , ethyl hexyl ester and butoxy 

 ethoxy ester (Diamond Alkali); (2) water soluble sodium salts, and 

 (3) water soluble amines which are the liquid salts of the acids. 



2,4-D esters are readily introduced into oil solutions, which 

 make them effective on such waxy-coated plants as cattails, water 

 lilies, softstem bulrush, duckweeds and others. 



Esters are combinations of the 2,4-D acid and the alcohols. 

 Ester formulations contain emulsifiers for introduction into 

 water. They represent the most common contact herbicides on the 

 market for use on farmlands, lawns, golf courses, etc. The 2,4-D 

 content of ester formulations varies from about 14 to about 40 

 per cent. 



Wetting or spreading agents are sometimes added to 2,4-D 

 as a means of getting the insoluble compound introduced into water 

 as a carrier. In addition they aid adhesion to plant surfaces 

 and penetration. 



Several common detergents "Tide", "Surf", mahogany soap, and 

 sodium secondary-alcohol sulphate have been used as wetting agents 

 or spreaders. The detergent concentration runs about 0.25 per cent. 

 The amounts of wetting agents vary from 0.05 to 0.3 per cent, 

 depending upon the kinds of plants to be sprayed. Plants with waxy 

 coats require more of the wetting agent than do more succulent 

 species with relatively unprotected leaf surfaces. 



The sodium and amine salts are directly soluble in water and 

 are easy to handle, but they are less effective on the waxy-coated 

 species . 



A new technique in the application of organic chemicals, such 

 as the f ormagens , is the invert emulsion. This is the water- in- 

 oil instead of the conventional oil-in-water emulsion. The invert 

 emulsion is a viscous material with thick creamy appearance. It 

 is less likely to drift and falls to the water surface or ground 

 more quickly and with fewer fine particles than do conventional 

 sprays. Its distribution from aircraft is described by Kirch 

 (1959). Once the invert emulsion has been formulated, it must 

 be kept stirred to keep the components from separating out. 

 According to Seaman (1958) , these water-in-oil materials have 

 sticking and penetrating properties superior to many oil-carrier 

 sprays, with only 10 to 15 per cent of the oil being required. 



14 



