These studies were an attempt to evaluate some of the factors affecting the detoxification of 2,2–dichloropropionic acid in soils. Residual toxicity is a factor that must be evaluated before effective use can be made of any herbicide. Stability is preferred for purposes of soil sterilization; rapid disappearance of the herbicide may be essential in preplanting treatments; and in foliar applications, rapid disappearance of the material that reaches the soil may be important. Detoxification is usually considered to be the result of one or more of the several processes, decomposition, leaching, adsorption, and volatilization.

The fast growing woody plant known as marabú, (Dichrostachys nutans), is native to Africa but it has found a favorable environment in Cuba. At present, dense stands of it, 20 feet and more in height, cover vast areas of the island, and a great deal of land has had to be abandoned on account of it. The ease with which it becomes established in turf or in neglected sugar cane lends exceptional interest to the development of methods of controlling, or, if possible of eradicating the plant.

The alkanolamine salts of 2,4–dinitro–o–secondary butyl phenol (DNBP) have been used frequently as a pre-emergence herbicide in cotton without causing injury. However, under some conditions the chemical has severely reduced the stand. This paper presents data that show the effects of rainfall, lime, soil type, and temperature on the phytotoxicity of dinitro to cotton seedlings.

Aquatic weed control in storage reservoirs and conveyance systems of certain domestic water supply systems is a challenging problem to the waterworks engineer. The problem concerns not merely the control or elimination of aquatic growths. It involves water quality factors which may be inconsequential in other phases of aquatic weed control, but are of major importance in drinking water supplies. Where adequate treatment facilities are available, water quality factors are subject to control. However, many domestic water supply systems lack treatment facilities, and the effect on water quality by the use of any materials in the supply must be subjected to critical review.

The way in which 2,4–D (2,4–dichlorophenoxyacetic acid) is most effectively used for controlling chamise is markedly different from that normally employed on woody plants. Old plants are difficult to kill, but young regrowth following cutting or burning is especially sensitive. The purpose of the present paper is to describe what is currently known (as obtained from hand sprayed plots) about the chemical control of chamise, and some of the factors that appear to be involved. Aircraft results will be published in a separate report.

The present report marks the completion of a 24-month study. The early phases have been described in brief in a progress report (3). Data contained in the earlier report are included in the present discussion to make the entire experimental record available as a unit.

Weed control is one of the principal problems of turf grass management. With the discovery that 2,4–D would selectively kill many broad-leaved weeds their control in turf has been minimized. As has been indicated by Grigsby (9), the widespread usage of 2,4–D may be an important factor in increasing the importance of crabgrass (Digitaria spp.) as a turf weed.

It has been shown that extracts of various weeds and crop plants inhibit germination and seedling growth (1, 4, 5, 7). In early experiments (7) it appeared that extracts of leafy spurge (Euphorbia esula) were particularly effective. For this reason it was of interest to more fully characterize the composition of leafy spurge. The present communication summarizes the results of qualitative paper chromatographic determinations for amino acids and sugars.