Canada thistle (Cirsium arvense Scop.), a widely distributed weed in northern United States, according to Dewey (3), was introduced from Europe in 1777. In 1901 Blankenship (1) reported it to be rare in Montana having been identified in only five locations. However, a report issued in 1956 by Heikes (6), showed an estimated 625,000 infested acres in Montana. Another report of a survey of the four northwestern states including Montana, Idaho, Oregon, and Washington estimated their total of Canada thistle at more than 1.5 million acres infested (4). This was considerably more than any other weed of this region. Control measures for this weed are, therefore, of primary importance.

Grains of wild oats (Avena fatua L.) may remain dormant in the soil for several years or even for decades. The reasons for this dormancy are not known, but various hypotheses have been advanced to explain it, such as that the hull acts as a barrier to oxygen (1,7), and that a toxic substance is present in the hull as in cultivated oats (5). The tests here reported were undertaken to further explore some aspects of the problem of dormancy in wild oats.

Kochia (Kochia scoparia L.), also commonly called fire weed, is one of the most widespread annual weeds in Kansas and the Great Plains region. The origin of the weed in Kansas is obscure but it was introduced into the United States from Europe (1). The plant had been cultivated as an ornamental and apparently much of its present wide distribution is a result of escape from ornamental plantings.

In Part I of the present study, the effects of amount, intensity, and frequency of simulated rainfall on the distribution of monuron [3–(p–chlorophenyl)–1,1–dimethylurea] in Lakeland sand soil were studied (9). Part I also indicated the general importance of leaching in herbicide usage. The present study includes consideration of soil temperature, soil organic matter, soil moisture content, and amount of herbicidal application as they influence monuron distribution.

The use of herbicides among nursery crops has been practiced only to a limited extent. Possibly this is because: slight herbicidal damage is serious in an expensive crop of nursery plants; the diversity of plants in a nursery makes it difficult to find suitable selective herbicides; the relatively small area of many nurseries makes cultivation and hand hoeing more practical than for large acreages; and damage to foliage of nursery crops makes the plants unsaleable whereas in farm crops foliage damage is less significant.

Previous studies by Bruns and Rasmussen (1, 2) showed that the longevity of the seeds of certain noxious weeds may range from several months to 5 years or more when stored in fresh running water. In order to gain information of this nature on additional weed species, a third test was initiated on April 4, 1952. The results of this study are reported herein.

Sun (2) reported that pith cells in the hypocotyl of soybean (Glycine max (L.) Merr., variety Monroe) became meristematic and vascular strands developed in the pith after treatment with 2,4–dichlorophenoxyacetic acid (2,4–D). Later (3), he found a retardation in elongation of roots from treatment with 2,4–D. The pericycle produced a mass of dense meristematic tissue extending to the periphery of the root. Even non-conducting cells of the primary phloem of roots became meristematic.

In contrast to the great development of chlorophenoxyacetic acids as herbicides, the fluorophenoxyacetic acids have received very little attention in weed control work, chiefly because they were difficult to synthesize. In addition until recently, they were not widely available. Thompson et al. (5) listed 2–fluorophenoxyacetic and 2–methyl–4–fluorophenoxyacetic acids as plant growth inhibitors. Crane and Blondeau (1) reported 4–fluorophenoxyacetic acid to be as effective as 4–chlorophenoxyacetic acid for inducing parthenocarpy in figs. A 100 ppm spray gave 88% fruit set with no foliar damage. Edgerton and Hoffman (2) stated that the same compound was moderately effective in delaying leaf abscission on apple trees and produced a 2,4–D-type formative effect on treated shoots. Weintraub et al. (6) showed with a bean leaf-area repression test that some of the fluorophenoxyacetic acids have a very high formative activity comparable to that of the most active chlorophenoxyacetic acids.

The application of small samples of various weed seeds or seed mixtures to greenhouse flats for herbicidal studies is usually a manual operation. Various size flasks, beakers or test tubes are employed for the distribution of weed seeds to the soil surface of the flats. However, this method is time consuming and often results in uneven distribution of the seeds.

The National Highway Program, recently approved, represents the largest peacetime construction program in history. The 41,000 mile network of interstate highways will be built on an average 300 foot right of way and will place over one million acres of land along the pavement subject to landscaping and maintenance.

In the recent past, the various plant species which are lumped together in the general class of aquatics have received considerable attention from workers in the field of weed control because of their importance in affecting water usage in irrigation, water reservoirs, transportation, and recreational facilities.

The herbicide isopropyl N–(3–chlorophenyl)carbamate (CIPC) has been found to be effective in controlling annual grasses when applied as a pre-emergence treatment. This herbicide is also very effective in controlling chickweed (1, 9, 12) and grasses in dormant alfalfa (11).

Goatweed, Hypericum perforatum, has long been considered among the most serious of weeds attacking the western ranges. It not only dominates large areas of range land, thus reducing the kind and amount of native forage, but it has poisonous properties as well. Livestockmen had good reason to bless the Chrysolina family of beetles and the men who pioneered their introduction into the goatweed infested range county. They are doing a marvelous job of reducing this weed.

The 4th Annual Convention of the Hawaii Weed Conference was held in Honolulu May 27 and 28, 1957. It was attended by personnel interested in weed control from the sugar and pineapple plantations, ranches, utilities, industry, the Armed Services, the Board of Agriculture and Forestry, the Hawaii Agricultural Experiment Station and Extension Service, Pineapple Research Institute and Hawaiian Sugar Planters' Association.