The Control of Grass Weeds in Sugar-Cane Fields in Puerto Rico

Abstract

Effective control of grasses was obtained with 2,4-D (150 ml. of 40% ester/gal. of diesel oil) at the rate of 40-50 gals./acre. Two other treatments at the same rate per acre were very effective: (1) dinitro-o-secondary butyl phenol in combination with 2,4-D and diesel oil, and (2) pentachlorophenol with 2,4-D and diesel oil. Firing of the surface parts of a grass weed stand was ineffective. All treatments were injurious to cane when the spray was applied to plants younger than 4 months of age. Aromatic oils (Shell) are far more effective than diesel oil. 2,4-D, which alone has little effect on grasses, is a very active grass herbicide when dissolved in diesel or aromatic oils and applied as a fine spray. The spray should not be ap- plied on a windy day. Two methods of application have been developed[long dash]preplanting application and applying the oil spray to fields of growing cane when this is over 3 months of age.