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Because of the limited water supplies, it is imperative that the non- beneficial use of water be reduced. Our primary concern in the last few years has been the control of tamarisk (saltcedar) which is one of the principal phreatophytes infesting the Southwest. Other phreatophytes which are creating problems to a certain extent include cottonwood, willow, arrowweed, wild rose, Russian olive, and baccaharis. Tamarisk has been of concern to the Bureau and, during the last 15 years, there has been much activity in trying to devise methods for its control. Since these plants grow in quasi-dense jungle, individual plant treatment is impossible. Thus, it has been necessary to remove the plants with mechanical equipment as a first step toward initiating a control program. We have reported before of early work which the Bureau of Reclamation has accomplished but, for review, I mention it again. As early as 1948, 200 acres of tamarisk were aerial sprayed with a formulation of 2,4-D at the rate ~f 1 pound per acre. One hundred acres of this area were res prayed in the spring of 1949. Kills ranging up to 85 percent were observed on the tamarisk plants which received these two applica- tions of herbicides (photograph 2). From this early work, it appeared that a "cure-all" for control of tamarisk plants had been obtained. An ~dditional 2,600 acres of adult tamarisk were sprayed in 1951 using ~ similar formulation plus additional new herbicides. The results from these applications were very disappointing. In fact, nowhere since the original spraying in 1948 and 1949 have we obtained any comparable kills. Since 1958, approximatelv 12,OOO acres of phreatophyte-infested areas on the Rio Grande, in the ~pper reaches of Caballo Reservoir and between Elephant Butte and Bernardo, New Mexico, have been cleared. Other agencies have cleared phreatophyte growths in Arizona, California, and Nevada. The methods and costs for clearing phreatophytes have varied consider- ably depending on the density of the plants and the type of equipment used. The cost for clearing approximately 6,000 acres in the Caballo Reservoir averaged approximately $20 per acre. This work was done by force account. On an additional 6,400 acres near Bernardo, the cost for clearing was $45 per acre when accomplished by contract. Some of this difference in cost was because the infestation at Bernardo was dense and luxuriant, the soil was sandy and unstable, and the contrac- tor was required to stack the debris. Since the early work with tamarisk, we have continued to explore and evaluate a variety of mechanical control methods and to experiment with new chemicals. The Bureau laboratory at Denver is conducting investigations relating to the effects of adjuvants. Preliminary tests indicate that herbicidal activity of certain chemicals may be improved with the addition of these "helpers" although they are not herbicidal themselves. 28