Phytotoxicity of dalapon on bermudagrass as influenced by gibberellic acid, nitrogen and surfactants

In the past numerous cultural and biological methods have been utilized for controlling perennial grasses. Chemical methods have also been employed for specific problems. These include soil sterilants, herbicidal oils and other contact herbicides for non-selective control of grasses. Each of these foregoing methods has distinct advantages and well recognized limitations. Among the several chemicals recently developed and utilized as possessing herbicidal properties for controlling perennial grasses, dalapon is a promising recent addition to the family of chloro-substituted alkane carboxylic acids. Dalapon, 2, 2-dichloropropionic acid, exhibits a systemic action and is actively absorbed and translocated through the living grass foliage. Since its discovery in 1951, dalapon is proving to be unusually effective in controlling a wide range of grasses and several reports have appeared in the literature on the herbicidal action of this compound. Although considerable practical information pertaining to the use of dalapon has been accumulated within a relatively short period, there is a paucity of fundamental work on the synergetic effects of dalapon with other agents. In this connection the role of surfactants and gibberellic acid in influencing the effectiveness of dalapon has been studied by only a relatively few workers. Whereas numerous and extensive reports indicate the growth promoting properties and functional aspects of gibberellic acid on several plants, knowledge of interaction between the chemical and herbicide is limited. Because of more wide-spread use of dalapon in the control of grasses and the high cost of this herbicide, investigation of the effects of other chemicals and agents on the herbicidal behavior of dalapon is desirable in order to increase the efficiency of the material and reduce the per acre cost. The object of the present study is to determine the effectiveness of dalapon on common Bermudagrass (Cynodon dactylon) as influenced by gibberellic acid, nitrogen and surfactants