Evidence that β-alanine or calcium pantothenate partially reversed the inhibitory action of several chlorinated aliphatic acids on yeast growth (4) suggested the hypothesis that synthesis of pantothenate is one of the metabolic pathways sensitive to this group of herbicides. The objectives of the experiments reported herein were (a) to determine the mechanism by which the enzymatic synthesis of pantothenate was inhibited by these compounds, (b) to seek evidence for the contributions of this mechanism, in vivo, to the herbicidal effects of 2,2-dichloropropionic acid (dalapon), (c) to determine whether pantothenate treatments could overcome the effects of dalapon in plants and (d) to test chloro-substituted analogs of pantoate for herbicidal activity. To achieve the last objective it was necessary to synthesize several new chemicals.

The increasing use of toxic agents as pesticides for application contiguous to water areas has been viewed with trepidation by many fisheries workers. Herbicidal chemicals are viewed with particular alarm due to their increased use, both present and projected, for the control of aquatic vegetation where they are placed in direct contact with fish and other aquatic organisms.

The girdling of apple trees by field mice (Microtus spp.) is a common problem in most areas where this fruit is grown. Since these species of mice will seldom cross a bare area to feed, it is desirable to remove all vegetation at the base of the trees to help reduce the possibility of girdling. Many growers maintain such a bare area by slow and costly hand methods. Such methods are frequently employed in late fall, increasing the possibility that the newly exposed trunk area may incur winter injury.

One of the major costs in the production of woody ornamentals is for weed control by cultivation and hoeing. In nurseries, plants are grown in the same location for two to five years, and several species often are grown in mixed blocks. Thus, there is a need for a herbicide which is non-toxic to as many species as possible.

The commercial use of herbicides formulated on granular carriers has expanded rapidly and in many instances has preceded research on their development and properties. Experimental studies have been concerned primarily with field problems involving the control of weeds in a particular weed-crop situation. Conflicting results obtained in both the experimental and the practical use of granular herbicides have emphasized the need for basic information on the mode of action of granular-herbicide formulations and the effect of environment and cultural techniques on their use.

Herbicidal applications to mesquite in Arizona (17), New Mexico (21), and Texas (5) indicate that the low-volatile esters of 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) are usually more effective than amine salt formulations, but there have been instances where the reverse was true. This inconsistency has occurred only in isolated cases, but was of interest in that factors which affect differential susceptibility to the ester and the amine formulations are important and should be more fully understood. The purpose of this study was to determine whether mesquite has a different period of susceptibility to the ester than to the amine. Various biological and meteorological factors were also determined to test their relation to mesquite susceptibility.

The absorption and translocation of 2,4-D (2,4-dichlorophenoxyacetic acid) has been extensively studied by numerous investigators and a number of reviews have been written (3, 7, 8). The methods used in these studies have been critically evaluated (1, 5, 8) and the general conclusion is that in the study of the absorption and translocation of biologically unstable organic compounds, such compounds should be isolated and identified.

Recent investigations on the use of 2-chloro-N,N-diallylacetamide (CDAA), 2-chloroallyl diethyldithiocarbamate (CDEC), and ethyl N,N-di-n-propylthiolcarbamate (EPTC) for weed control have stressed soil incorporation rather than the more conventional application to the soil surface. By this treatment loss of the herbicides as vapors may be reduced, the risk of crop injury lessened, and weed control improved. Although both pre-planting and pre-emergence soil incorporation have been investigated, pre-planting treatments appear most promising. In many weed-crop situations the results obtained with EPTC have been especially promising.

Early patent records show that a rotary-hoe type of implement has been in existence since 1839 (2). The rotary hoe was used on soybeans as early as 1915, and important considerations for weed control were discussed in “Soybeans in Indiana, 1928,” (1) but its use did not become widespread until about 1929.

Cotton is the major cash crop in Missouri's seven southeastern delta counties, and is second in cash value for the entire state, even though it comprises only about 6 per cent of the total acreage. Heavy infestations of weeds late in the season materially complicate the defoliation process, reduce the efficiency of both mechanical and hand pickers, lower the grade of the lint by contributing stains and trash, and account for greatly diminished net returns. Despite advances in this field, weed control still constitutes the principal remaining barrier to complete mechanization of cotton production.

The control of undesirable woody plants is one of the biggest land management problems on non-crop land in the South. There are more than six million acres of pine sites in Louisiana alone that are in need of cull hardwood control (12). Large acreages of similar stands and sites are located in other southern states. Because of the competition for land and increased demand for raw materials, many landowners have realized the necessity of utilizing their land to the fullest extent.

Halogenoalkylcarboxylic acids such as monochlorocetic acid, trichloroacetic acid, dichloropropionic acid and 2,3–dichloroisobutyric acid, have well known herbicidal activities upon monocot plants. However, they are not effective in killing the seeds of weeds. This may be due to their inability to penetrate the seed coats.

Wild garlic (Allium vineale L.) continues to be an important problem weed of Eastern and Southeastern United States. It is spread principally by aerial bulblets mixed with seed. The present rules and regulations used by seed laboratories to determine bulblet viability seem inadequate. This paper will discuss the use of 2,3,5–triphenyltetrazolium chloride, referred to as TZ, as an indicator of bulblet viability.

Because nut grass is a weed problem, there is need for knowledge of the factors affecting the sprouting of tubers following conditions in which they are dormant. Similarly an understanding of the mechanisms involved in the control of dormancy along with information on the metabolism of tubers at different stages of growth is needed. The purpose of this series of studies was to obtain information on some of those problems. The purpose of the present study was to determine the response of nut grass to several oxygen levels as measured by germination habits and respiration of tubers.

To obtain information on the metabolism of nut grass tubers at different stages of growth, this study purposed to determine certain metabolic pathways of tubers at different stages of germination, which might aid in determination of the most sensitive stage to herbicides.

The purpose here was to study fundamental aspects of polyphenoloxidase in dormant tubers.

Several studies have been conducted concerning the action of amitrol (3–amino–1,2,4–triazole) upon certain enzyme systems. The activity of catalase from treated potato plants and barley leaves (7), leaves of potato, barley, and sunflower, and rats (2) has been reported. In all cases, amitrol depressed the activity of catalase.

Most people connected with the making, marketing and using of pesticides agree that the naming for common use of the stream of new chemicals could be better organised, especially on an international basis.