ABSTRACT
The quality of the environment has been a major concern of the Corps of Engineers as part of the basic mission to improve river and harbor transportation, to provide more adequate flood control, and to plan for appropriate water resource development. While mechanical methods were first used for this purpose, chemical methods have since been developed for most situations. The most effective water hyacinth killing chemical yet discovered is 2,4-dichlorophenoxy-acetic acid, commonly called 2,4-D. This herbicide is an organic chemical belonging to a group of substances known as plant hormones or growth regulators. Direct effects of repeated use of herbicides such as 2,4-D on the aquatic environment are relatively minor if the herbicides are used properly. Indirect effects may conceivably result in particular changes in the environmental system over a period of time. These changes, however, are not necessarily detrimental, for single organisms are not indispensable to an ecological community and many different organisms compete for the same niche.
