SUGGESTED GUIDE FOR CHEMICAL CONTROL 



OF WEEDS 1 



Herbicides are efficient and economical weed-control tools for many 

 weed-crop situations. However, they are precision tools which require 

 the best and latest information available for successful use. 



Chemicals still cannot be used for the control of all weeds in every crop. 

 But through research an increasing number of herbicides is being made 

 available, and the specific situations in which each is most effective are 

 being determined. Wider use of selective herbicides in crop production 

 will help bring about better harvesting methods, a greater degree of 

 mechanization, better yields, and fewer losses. 



Chemical weed control should be considered as a supplement to the use 

 of improved cultural and management practices. Good, clean seed is a 

 sound starting point for any weed-control program. Thorough tillage and 

 seedbed preparation, followed by clean, efficient, shallow, timely cultiva- 

 tion are extremely important. There are no substitutes for proper fertiliza- 

 tion and management of adapted crop plants. 



Suggestions given in this publication on rates of herbicides to use are 

 based upon the active ingredient or acid equivalent contained, and not upon 

 the total weight of any commercial formulation. 



SPECIAL NOTE 



All chemicals included in this report either are registered for one 

 or more specific uses or have received experimental permits under 

 the Federal Insecticide, Fungicide, and Rodenticide Act. With certain 

 exceptions (indicated in footnotes), the chemicals in this report may 

 be used as specified since such use will result in the production of 

 raw agricultural commodities meeting the requirements of Miller 

 Pesticides Chemicals Amendment (Public Law 518). Each chemical 

 should be applied in accordance with the directions on the manu- 

 facturer's label as to the crop specified, in the amounts specified, 

 and at the times specified. The excepted chemicals have been found 

 to be effective in controlling weeds, but (as of April 1, 1958) they can- 

 not be recommended for use on the crops specified since evidence 

 has not been developed to prove that they will leave no residues or/ and 

 tolerances have not been set under Public Law 518. 



Since the status of many chemicals is changing rapidly, and new 

 materials or new uses for older materials are being recommended, 

 it is important to keep in touch with the U.S. Department of Agricul- 

 ture, State agricultural experiment stations, or manufacturers of 

 specific products for up-to-date information. 



x The technical information in this publication was compiled and reviewed by D. L. Klingman, W„ G, Shaw, 

 F. L. Timmons, R. J. Aldrich, L.L.Danielson, and W. B. Ennis, Jr., of the Crops Research Division, Agricul- 

 tural Research Service. 



- 1 - 



