General-contact weed killers /
wsF^ General-Contact Weed Killers • • • are not selective. They destroy all kinds of vegetationboth weeds and crop plants. C^T hese herbicides are used to control unwanted plant growth along highways, rights-of-way, and fence lines, and around farm and industrial buildings. Sodium arsenite has been the chemical most commonly used for such purposes, but it is dangerous to humans and livestock. It is now being replaced by new sprays which are nonpoisonous, cheap, and easily applied. |^f There are
... lied. |^f There are three types of general-contact herbicides: 1 . Water-soluble materials, including common salts and corrosive chemicals, sodium chlorate, and salts of the phenol compounds. 2. Emulsions, made by combining water and oil. Additional toxic chemicals may be incorporated in either the oil or water base, or both. 3. Oils, including Diesel fuel, smudge-pot oil, stove oil, kerosene distillates, low-grade oils, proprietary weed-killer oils, and oils fortified by addition of phenol compounds or sulfur. f^} There are many conditions under which general-contact sprays are effective, and a variety of spray materials which are suitable. For this reason, the present circular is concerned with giving an overall picture of these different sprays and suggesting possible uses, without making hard and fast recommendations. \^E ach grower will have to decide for himself which type of spray is best for his purpose, after he has studied the materials available and their advantages and disadvantages.