One of the important steps in the maturing of a field of science is the establishment of a journal devoted to that field. A centralized means of publication is almost a necessity if a given branch of knowledge is to progress. “Weeds” is an attempt to fulfill that requirement for the science and art of weed control. If need is a measure of probable success, the success of “Weeds” is assured. Weed control literature has been published in every kind of journal — agronomic, horticultural, engineering, chemical, botanical, — and farm papers of all types, to make only a beginning.

A successful weed control program, whether it be Federal, State or County is involved with research, education and regulation.

Had laws been enacted and properly enforced in all states thirty or forty years ago to prohibit the introduction of noxious weeds the weed problems of today would not be so serious.

The control of roadside weeds and brush has always been a major problem of roadside construction and maintenance engineers. People charged with the responsibility of keeping our highways, county, trunk and local roads free of weeds and brush have heretofore found the control of unsightly weeds and brush a major and laborious problem and expense. For the control of many annuals such as hemp, giant ragweed, small ragweed, daisy fleabane, etc., a very thorough, systematic mowing program, coupled with the establishment of a heavy grass cover has in many instances sufficed to keep weed growth down to a minimum. However, for the control of such roadside weeds as Canada thistle, perennial sow thistle, poison ivy, etc., as well as for the control of all types of brushy growth, the mere mowing and laborious cutting of such plants has not resulted in eradication. The mowing of perennial weeds and brush is like “picking apples off a tree” — such picking does not kill the tree. Furthermore, programs of control involving brush have had to be repeated every two or three years at terrific expense to the tax payer. Laborious mowing and hand cutting is followed quickly by regrowth, which in a year or so is as bad or worse as the original stand which was removed.

Millions of acres in the United States are being chemically treated each year for the control of weeds. Weed investigators have generally accepted the fact that certain herbicides affect certain plants to a greater degree than others. Because of this, numerous chemicals are being used. Except for 2,4-D, there has been little work done on the bactericidal and bacteriostatic properties of the recent herbicidal compounds. It is the purpose of this paper to report a study of the influence that several recommended and experimental herbicides have on the microbial activity of the soil population and to establish the usefulness of a simple procedure outlined by Nelson in making preliminary determinations of this type.

In Louisiana approximately 300,000 acres of sugarcane are grown each year for the manufacture of sugar. Another 125,000 acres are necessary for the rotation program, making approximately 425,000 acres devoted to the production of cane. Of these, 100,000 acres were estimated in 1950 to be so badly infested with Johnson grass (Fig. 1) that a control program was necessary to obtain economic yields of cane. In addition to this acreage, headlands, ditchbanks, and roadsides of many additional plantations were infested with Johnson grass and constituted a potential threat to the cane fields.

Several workers have reported that the activity of certain plant-growth regulators is influenced by the particular carrier employed in applying the materials to the plants. The compound 2,4-D is more inhibitory to Kidney bean plants when applied in a Carbowax 1500 aqueous solution than in wholly aqueous solution. The inhibitory effectiveness of oil sprays of 2,4-D is reduced little by rainfall whereas wholly aqueous sprays may be rendered almost noneffective by rainfall a few minutes after treatment. Rice has reported a greater amount of absorption of NH4 2,4-D by leaves when Carbowax 1500 is included in aqueous solutions than occurs when wholly aqueous solutions are employed. The results presented herein are from additional studies on the effects of different carriers and formulations on the inhibitory properties of selected plant growth-regulators.

The announcement of the effectiveness of Isopropyl N phenyl carbamate as a graminicide received considerable interest by weed research workers. However, early attempts to control grasses with this chemical resulted in rather disappointing control. Subsequent work has shown that this can be largely attributed to improper usage of the material. Since this material is supposedly a growth regulating substance, it was reasoned that it should behave in a manner similar to 2,4-D. Study carried on in Oregon proved that this was not the case and that specific conditions are essential to maximum effectiveness of this chemical.

The herbicides 2,4-D and 2,4,5-T are used extensively in the Western States for killing Ribes, the noxious plants that spread the destructive blister rust (Cronartium ribicola Fischer) to white pines (Pinus L.). Tests of the thermal fogging unit here described relate to the broadcast application of low dosages of 2,4-D as a wet oil-fog designed to defoliate and damage ribes plants without significantly damaging associated white pines. Tests were made at Stockton, and near Pescadero, Calif., in 1950.