Oxalic acid and oxalates occur in many plants. Consumption of plants containing high concentration of oxalates can be poisonous to animals. This has been reported by several investigators (5, 7, 9). However, in only a few plants are oxalates found in sufficient quantities to be lethal. Some species with a relatively high oxalate content are: sorrel (Rumex spp.), rhubarb (Rheum spp.), greasewood (Sarcobatus vermiculatus Torr.), soursobs (Oxalis cernus Thunb.), and halogeton (Halogeton glomeratus C. A. Mey.).

Weed problems in Alaska are relatively new because man's agricultural activities in this region have been limited until very recently to isolated clearings. These early clearings made by prospectors and homesteaders to produce feed for their stock also unintentionally served as increase plots for some troublesome weeds.

Since weeds in cranberry bogs cannot be successfully controlled by mechanical equipment, there has been considerable interest in chemical means of control. Among the chemicals that have been and are presently being used are iron sulfate, paradichlorobenzene, sodium chloride, sodium arsenate, sodium arsenite, copper sulfate, kerosene, and other herbicidal oils (2). All these chemicals have to be applied in relatively large quantities, which makes for a large per-acre cost of treatment and involves many problems inherent in the application of large quantities of materials. There is, then, considerable interest in a chemical which can be applied in relatively small quantities and which will provide satisfactory control of weeds in the bogs.

The cranberry (Vaccinium macrocarpum) is a low growing, perennial, woody plant of the boglands of the northern United States. Because cranberries are grown commercially on wet, low lying soils, the fields are often infested with a wide range of weeds common to such areas. Among the most common weeds of Wisconsin cranberry bogs are (1) sedge family: Carex oligosperma, Dulichium arundinaceum, and Eriophorum uirginicum; (2) rush family: Juncus effusus and J. canadensis; (3) horsetail family: Equisetum arvense and E. fluviatile; (4) fern family: Onoclea sensibilis and Osmunda regalis; (5) water plantain family: Sagittaria latifolia; (6) grass family: Leersia oryzoides, Glyceria canadensis and Calamagrostis canadensis; (7) composite family: Ambrosia artemisiifolia, Bidens connata, and Solidago graminifolia; (8) primrose family: Lysimachia terrestris and L. thyrsiflora; (9) buckwheat family: Polygonum sagittatum and P. amphibium; (10) rose family: Potentilla palustris and Rubus hispidus; (11) mint family: Lycopus uniflorus and Scutellaria epilobiifolia; (12) St. Johnswort family: Hypericum uirginicum; (13) gentian family: Menyanthes trifoliata; (14) willow family: Salix nigra and Populus tremuloides. Many other weed species occur in cranberry bogs, but they do not present a serious cultural problem.

The chloro-substituted benzoic acid compounds discussed here were included with a number of other chemicals tested in 1955, 1956, and 1957 as soil sterilizing herbicides at Hays, Kansas. The experiments were designed to yield information on the effectiveness of various treatments for field bindweed (Convolvulus arvensis) control. Results of the bindweed control studies have been briefly summarized by Phillips (9).

The question of direction and rate of movement of herbicidal chemicals in aquatic plants often arises in considering effective methods of chemical control for plants of this type. Results obtained from studies of solute movement within terrestrial plants are not directly applicable to totally submersed aquatic species for two reasons: a) A liquid medium, in which dissolved substances may be distributed uniformly, surrounds all parts of the aquatic plant, and b) Vascularization is minimal in leaf and stem tissues of submersed aquatics. Reports of experiments yielding quantitative data on translocation patterns in submersed aquatic plants are rare or nonexistent. It is probable that mechanical difficulties encountered in separating root systems from leaf or stem tissues of submersed plants have been of greater hindrance to translocation experiments with aquatic species than any other factors.

Simazin, 2–chloro–4,6–bis(ethylamino)–s–triazine, is a relatively new herbicide that has shown much promise for pre-emergence weed control in corn (3,4,7). It is a white crystalline compound with a solubility of 5 ppm in water and 900 ppm in chloroform. This compound is non-flammable, non-corrosive, and has an acute oral toxicity greater than 5 g/kg for mice. Simazin is said to be highly toxic to cucumber, of intermediate toxicity to cotton, and non-toxic to corn. Schneider (6) reported it to be effective only when absorbed through the root system. This study was begun to determine whether the differences in susceptibility of these plants and the limitation of effectiveness of simazin to the root system could be correlated with its absorption and translocation.

The control of submersed aquatic weeds is a major problem in the management of Missouri fish ponds. Dense stands of aquatic vegetation in ponds cause serious crowding and stunting of fish populations. Recreational values are impaired by the physical interference of weeds with fishing and boating. Even more serious are the occasional partial or complete kills of fish caused by oxygen depletion as plants decay. These kills may occur either in summer or winter.

Leguminous crops for hay, seed, pasture or soil improvement occupy a large portion of the total crop acreage. Plantings of legumes, particularly alfalfa, are often maintained long after production has dropped below an economic level. The reason may be reluctance of farmers to attempt establishment of new stands. In areas where fall seeding is possible but where mosture is often scant, spring seedings with the attendant hazard of annual weeds, must be relied upon for establishment of new stands.

The logarithmic, or variable-dosage, sprayer described by Pfeiffer, Brunskill, and Hartley (4) for use in experimental field plot studies appears to offer a means of materially reducing the time and space required to conduct field evaluations of herbicides in horticultural crops. The experiments described herein were conducted to determine the conditions necessary for the successful use of the sprayer in evaluations of this type.

In tests conducted at Prosser, Washington, during 1955 and 1956, DCB (orthodichlorobenzene), alone or in combination with xylene, showed considerable promise for controlling submersed aquatic weeds when introduced into irrigation channels. The first objective of the experiment reported herein was to determine whether irrigation water treated with DCB or DCB-xylene mixtures would injure certain crop plants. In other tests amitrol (3–amino–1,2,4–triazole) and sodium salt of dalapon (sodium 2,2–dichloropropionate) were effective in controlling certain emergent aquatic and ditchbank weeds. Frequently, the application of herbicides to control such weeds results in inadvertent or unavoidable contamination of water used to irrigate crop plants. Consequently, a second objective of this investigation was to determine the approximate quantities of amitrol and sodium salt of dalapon required to injure certain crop plants when applied in irrigation water, and to study the symptoms of injury.

The chlorinated phenoxyalkylcarboxylic acids are extremely valuable in affording a solution to many weed problems. On the other hand, the use of such herbicides may create problems since many crop or ornamental plants which are very sensitive to the phenoxy herbicides may be growing in close proximity to crops or areas in which treatments with such herbicides seems desirable. In the South, cotton may be planted adjacent to crops such as rice, sugarcane or corn or in areas bordering woods, highways or railways. On such areas, the application of phenoxy herbicides may solve the problem of weed control; however, they may create a new problem by causing injury to cotton.

Interest in the substituted urea compounds for their herbicidal properties was precipitated by Bucha and Todd's (3) report that 3–(p–chlorophenyl)–1,1–dimethylurea (monuron) was extremely phytotoxic. Freed (6) reported that only asymmetrically substituted ureas are effective as herbicides. Substitution on the para position was reported to result in greatest activity followed by meta. An ortho substitution reduced activity to half or less than that of the comparable para substitution.

Goosegrass, a widely distributed annual weed, creates difficult problems in heavily used turf areas. The seriousness of this weed problem, especially on golf course greens and tees, has suggested studies for its control. Very little research has been conducted in regard to this grass. Germination studies by Toole and Toole3 showed that 0.2% potassium nitrate was superior to water when used to moisten the substratum. Their work also indicated exclusion of light had little effect on germination at alternating temperatures of 20°–30°. The present study includes more complete temperature and light comparisons, and attempts to demonstrate light and temperature effects on seed germination.

The possible use of the phenoxybutyric acids as selective herbicides in the pea crop has been recognized from the beginning of their development (3) and preliminary experiments with the more important compounds of this series carried out in 1954 indicated that 4–(2–methyl–4–chlorophenoxy)butyric acid [4–(MCPB) showed the most promise (1). To date no results have been reported on the persistence of MCPB in peas; experiments were, therefore, undertaken to determine this under field conditions.

The herbicidal and desiccant properties of 1:1′–ethylene–2:2′–bipyridylium dibromide have been reported by Brian et al. (1). This substance appears to be a rapid acting translocated herbicide, effective on a wide range of plant species (1,2).