Division weeding

Cell Division Inhibitors. The most common mode of action of soil-appHed herbicides is growth inhibition, primarily through dkect or indkect interference with cell division (163). Such growth inhibitory activity is the basis for most pre- or post-emergent herbicides intended to control germinating weed seeds. In germinating seeds, cell division occurs in the meristems of the root and the shoot. Meristematic cells go through a cycle... 

The 2-chloroacetanilides (Figure 2.22) are also suggested to inhibit cell division in susceptible weeds. These compounds have found a major commercial market for the pre-emergence control of grass and some small seeded broad-leaved weeds in crops such as maize and soybean. It is likely that 2-chloroacetanilides also alkylate the sulfhydryl groups of certain essential plant enzymes. 

Pesticide use and breast cancer risk among farmers wives in the agricultural health study. Am. J. Epidemiol., 161(2) 121-135. Fawcett, R.S. (2006). Two Decades of Atrazine Yield Benefits Research. North Central Weed Society Research Report, Atrazine Yield Data Summary, 1986-1995 and 1996-2005. Average Com Yield With and Without Atrazine. Prepared for the Atrazine Network for submission to Special Review Division, US Environmental Protection Agency. Available at http //www.ksgrains.com/triazine/ NC WS S % 20 Atrazine% 20 96-05 . pdf... 

FAO (Food and Agriculture Organization of United Nations) (2003). FAO Yearbook of Production. Rome, Italy FAO Statistics Division. Futch, S.H. (1997) Horticultural and environmental aspects of weed control in Florida citrus. Ph.D. thesis. University of Florida, Gainsville. 

Bearded irises tolerate drought very well when dormant (usually beginning about 6 weeks after bloom), but water them well until dormancy sets in and after division. Fertilize routinely in spring and early fall, keep weeds and other plants away from rhizomes, mulch loosely the first winter after division, and plan to stake tall-growing cultivars when in bloom. 

In the development of our most important single natural resource, water, the Bureau of Reclamation, at its Division of Engineering Laboratories, carries on research activities in nine areas concrete and concrete making materials hydraulics earth materials petrography protective coatings analytical chemistry bituminous materials saline water demineralization and special investigations, such as aquatic weed controls, cathodic protection, corrosion, and evaporation reduction. 

The selective toxicity of sulfonylureas to certain weeds without damage to the cereal crop arises from their rapid metabolism in the crop plant to inactive compounds, whereas in sensitive weeds the metabolism is much slower. The very high herbicidal activity suggests a specific biochemical mode of action, which is concluded to be the inhibition of plant cell division. Sulfonylureas block the enzyme acetolacetate synthase (ALS), which catalyses the biosynthesis of the essential branched chain amino acids valine, leucine and isoleucine. 

We first became interested in pyridazines as herbicides when a number of pyridazines synthesized in a CNS project at our Lederle division were evaluated in our primary herbicide screen. One of these compounds, AC 228,764, controlled eleven of the twelve weed species at 8 kg/ha in the preemergence test. All of the test species were bleached, emerging white from the soil. In our secondary evaluation at 4 kg/ha, AC 228,764 controlled ten out of eleven annual grass and broadleaf weed species with selectivity in cotton, soybeans and rice. This spectrum of activity and crop... 

In addition to exploiting the potential of polymer chemistry, Du Pont continued to commercialize new products in the divisions that had created their integrated learning bases before World War II. It did so in chemicals, including ammonia and methyl, and also in paints, finishes, and nonporous fabrics. After World War II, Du Pont began to build on its earlier potential in the production of insecticides and other agricultural chemicals (SIC 2879). Its innovative selective-weed-control products enabled it to capture 20 percent of the U.S. herbicide market by 1960. ... 

Propyzamide is effective mainly for the control of germinating weeds. It is absorbed through the roots, in Agropyron repens also through the rhizomes when applied in their vicinity. The absorbed herbicide inhibits the root and stem growth of sensitive plants. After treatment, normal cell division stops within a short time. Thus, primary action is manifested by the inhibition of mitosis (Carlson et al.,... 

Amicarbazone is a new herbicide for broad spectrum weed control in com and sugarcane. It belongs to the chemical class of carbamoyl triazolinones and acts as an inhibitor of photosystem II. It was discovered 1988 by the former Plant Protection Division of Bayer AG (now Bayer Crop Science) and developed under the internal code no. BAY MKH 3586 (Pig. 10.3). 

This book, based on presentations at three American Chemical Society symposia, has been organized into five divisions dealing with the control of insects and other animals, diseases, and weeds. The compounds, their activities, their biosynthesis, and their mechanisms of action are explored. 

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