After land was plowed in the spring and prepared for planting, yellow nutsedge (Cyperus esculentus L.) was allowed to develop to heights of 10 to 12 and 20 to 25 cm. Either glyphosate [N-(phosphonomethyl)glycine] or paraquat (1,1′-dimethyl-4,4′-bipyridinium ion) was applied to emerged yellow nutsedge and other annual weeds at rates of 0.5, 1, 2, and 4 kg/ha. Half of the plots were double-disked 3 days after herbicide applications, and then all plots were planted with alfalfa (Medicago sativa L. ‘Cayuga’). Disking alone and application of glyphosate or paraquat alone did not satisfactorily control all weeds. However, the combination of a herbicide and disking controlled weeds enough to allow excellent establishment of alfalfa. In the year after establishment, the first cutting yields from the better combination treatments ranged from 3000 to 4400 kg/ha, which is normal for mid- to late-summer plantings in the region. Glyphosate was better than paraquat for control of grass weeds. Paraquat approached glyphosate in effectiveness when a supplemental disking treatment was added. Disking was as effective as the herbicide treatments for control of yellow nutsedge but not for control of broadleaf or annual grass weeds.

Chemical fallow with 2,2-dichloropropionic acid (dalapon) reduced the yield of non-seeded perennials more than mechanical fallow with sweep blades in the year of treatment. However, plants derived from seed left at the soil surface resulted in greater yields of nonseeded perennials on chemical than on mechanical-fallow plots the year following treatment. Each fallow method increased annual herbage yields the year after treatment as compared with directly-seeded plots. Litter was greatly reduced in the year of and in the year after mechanical fallow. However, the amount of litter on the chemical fallow plots was very high in the year of treatment and declined in the succeeding year. Success of seeding crested wheatgrass [Agropyron desertorum (Fisch, ex Link) Schult.] was slightly better after mechanical than after chemical fallow. Yield of crested wheatgrass in the year after planting was about the same for the mechanical fallow and the higher rate (10 lb/A) of dalapon. There was more available soil moisture to a depth of 30 inches in fallowed than in non-treated plots; but the small amount of moisture saved by fallow probably is immaterial to seeding success.

The specific and general postemergence herbicidal properties of N′-4-(4-chlorophenoxy)phenyl-N,N-dimethylurea [chloroxuron] were influenced by formulation and the carrier employed.

A small portable sprayer was found to be the most practical for applying experimental herbicides for the control of lambkill (Kalmia angustifolia L.) in lowbush blueberry plots. The standard knapsack sprayer requires a large volume of rinse water to clean the sprayer between treatments and this frequently has to be transported a considerable distance to the spray site. In order to reduce the amount of rinse water to a minimum a knapsack sprayer was modified so that the spray solution for each treatment could be held in an individual disposable polyethylene bag.

Six herbicides were applied to young stands of Kentucky bluegrass at weekly intervals in treatments beginning 5, 7, 9 and 11 weeks after seeding bluegrass. In both years the arsenical containing herbicides were effective when applications were started 7, 9 or 11 weeks after seeding. Applications started five weeks after seeding were unsuccessful in 1962 but gave excellent control in 1963. Reduced stands of Kentucky bluegrass and generally poorer crabgrass control were obtained with phenyl mercuric acetate than with the arsenicals.

Six-week-old honey mesquite [Prosopis glandulosa (Torr.) var. glandulosa] seedlings were treated with various concentrations of ethephon (2-chloroethylphosphonic acid) and 2,4,5-T [(2,4,5-trichlorophenoxy)acetic acid] alone and in combinations to determine effect on stem mortality under greenhouse conditions. Ethephon alone at 0.05 g/L brought about defoliation and a reduction in xylem tissue formation but did not affect the histological development of the stem tissue. Treatment with 2,4,5-T alone at 3.2 g/L resulted in 40% stem mortality along with the formation of abnormal xylem tissue of reduced thickness. A combination of ethephon (0.05 g/L) and 2,4,5-T (3.2 g/L) significantly increased mesquite mortality. This was associated with a further reduction in xylem thickness, abnormal development of the xylem, abnormal positional relationships of vascular tissues, and initiation of adventitious roots. This study showed that ethephon in combination with 2,4,5-T was more effective than either treatment alone in promoting the disruption of the tissue systems of the stem and in increasing control of mesquite seedlings.

Weed control as we know it today is a new field with frontiers and relationships that have not been clearly charted. Weed control workers are, in a sense, pioneers. The background of knowledge is still not great and many of the questions our farmers are asking have no unequivocal answer. The sources of information are still not clearly defined and many agencies are involved in the search for information. Within any one university or college one frequently finds information that the weed specialist needs developing in the departments of botany, agronomy, vegetable crops, horticulture, chemistry and agricultural engineering. Commercial organizations of many kinds are discovering new facts that we need to know. And not the least of these sources of information is the Extension Service itself because county men, and the farmers they work with, are constantly adding to our knowledge. It is a dull man indeed who can view field after field treated to control weeds without arriving at a good working hypothesis of what can be done and how to go about doing it. The role of the Extension Service in the development of weed control over the past ten years has been overlooked in our emphasis on research. I would not for a moment minimize the importance of the emphasis on research but I do decry the lack of parallel emphasis on encouraging the use of the knowledge so developed. And the Extension Service in the many states has been a potent force in developing the new information credited to research.

Along the lower Coastal Plain, from the western panhandle of Florida to the Carolinas, lie approximately ten million acres of deep sands. In northwest Florida the sandhills support chiefly scrub oaks and wiregrass (Aristida stricta). Oaks are mainly turkey oak (Quercus laevis) and bluejack oak (Q. incana). Once an understory to longleaf pine (Pinus palustris), the scrub oaks gained dominance as heavy, indiscriminate logging removed the pines. Today only scattered pines remain, and the oaks and wiregrass prevent seed from these pines from restocking the area.

Two parameters of physiological competence, rate of CO2 fixation and intraspecific competitiveness, were determined for one or more atrazine-resistant isolates of the photosynthetic bacterium Rhodobacter sphaeroides. Measured over a 2-h period under optimal conditions, two of the resistant isolates fixed CO2 at a greater rate than the atrazine-susceptible, wild-type organism. In a mixed culture study, an atrazine-resistant strain was able to grow and compete successfully with the susceptible, wild-type strain for at least 14 days.

Maximum activity of isocitric lyase (EC 4.1.3.1) was reached at 24 hr incubation of afterripened (nondormant) prickly sida (Sida spinosa L.) seed. Enzyme activity declined gradually with incubation times in excess of 24 hr. Actinomycin D (Act D) at 5 μg/ml had essentially no effect on 24-hr germination but inhibited development of isocitric lyase activity 83%. Cycloheximide (CH) at 10 μg/ml inhibited 24-hr germination of punctured seed only 7% but inhibited development of isocitric lyase activity 76%. Seed incubated in water 12 hr before being transferred to Act D at 5 μg/ml for an additional 12 hr did not escape sensitivity to the antibiotic. Isocitric lyase activity was inhibited when assayed at 24 hr total incubation. In the reverse experiment, seed incubated in Act D 12 hr before being transferred to water, isocitric lyase activity at 24 hr was not affected. Apparently prickly sida seed lacked a performed mRNA for isocitric lyase and transcription and translation of the mRNA occurred shortly after initiation of radicle protrusion (~8 hr).

The addition of a combination of methyl cellulose, sodium acetate and an alkyl aryl sodium sulfonate (sodium petroleum sulfonate) to spray solutions increased the toxicity of 2,2-dichloropropionic acid (dalapon) to oats and Cynodon dactylon L. The most effective combination tested on oats in the laboratory was 2.25% methyl cellulose, 1.75% sodium acetate, and 0.8% of an alkyl aryl sodium sulfonate. Lower concentrations of the three materials, combinations of any two of these additives, or any one added alone were less effective. Under field conditions, the response of Cynodon dactylon L. to dalapon was more rapid, control was more uniform and regrowth slower when dalapon sprays contained the three additives. Methyl cellulose increased and maintained the spray load on the grass foliage. Alkyl aryl sodium sulfonate probably increased penetration of dalapon. Sodium acetate increased the toxicity of the spray.

The morphological and physiological response of the slender oat (Avena barbata Pott ex Link # AVEBA) to the herbicides barban (4-chloro-2-butynyl 3-chlorophenylcarbamate) and difenzoquat (1,2-dimethyl-3,5-diphenyl-1H-pyrazolium) in conjunction with decreased water availability was determined for seven populations, representing three ecotypes, under greenhouse conditions. Generally, within the range of sublethal herbicide doses, with increasing herbicide rates, phytotoxicity ratings increased, but plant dry weight, tiller height, and number of spikelets were decreased. Also, the number of juvenile tillers decreased, while that of fertile tillers increased. Flag leaf area increased and flowering was delayed. The ratio of number of spikelets to plant dry weight and seed weight was influenced the least. Under the highest rates of difenzoquat, the within-plant variance of spikelet number decreased, indicating that there may have been a more equal partitioning of resources amongst tillers for spikelet production. The general influence of water stress was to amplify the effect of the herbicide. For example, the dry treatment reduced dry weight and tiller height, and delayed flowering. Within a particular herbicide treatment, the effect of the water stress was to cause reduced within-plant variance for days to flowering, flag leaf area, and number of spikelets. Three reactions were observed that could have helped buffer decreases in spikelet production: 1) An increased fraction of the dry weight of the plants was partitioned into the spikelets at the expense of other vegetative matter, 2) the increased leaf area of the primary tiller may have helped counterbalance any reduction in photosynthesis caused by herbicide action, and 3) an increased number of juvenile tillers was converted into fertile tillers resulting in an increased number of mature tillers. These data indicate that the slender oat has a remarkable “phenotypic plasticity,” which enables it to maintain reproductive structures under sublethal herbicide doses.

Brush species treated under field conditions have exhibited a variable response to growth-regulator type herbicides which cannot be explained by previous research findings. Light and temperature are known to influence the response of plants to these materials. Field observations have indicated that environmental factors such as relative humidity and soil moisture may also control to some degree the reaction of plants to herbicides. This chamber is being used to subject seedlings and small plants to controlled conditions of environment for evaluating the hypotheses suggested by field observations.

A recent paper (Shields et al. 2006) reports trapping seed of horseweed in the planetary boundary layer (PBL) of the lower atmosphere at heights up to 140 m above ground level. While it claims that seeds have not been trapped from the PBL before, it is shown here that seeds of other weedy composites were trapped at altitudes up to 610 m above ground level in southern Australia more than 40 yr ago.

Susceptible and resistant ecotypes of Canada thistle (Cirsium arvense L.) were grafted in various combinations of stock and scion to determine if the activity of 3-amino-l,2,4-triazole (amitole) was altered by passage through the plant tissue. It appeared that the differential susceptibilities of ecotypes of Canada thistle were not caused by a change in the activity of amitrole.

The alkanolamine salt of 2,4-dichlorophenoxyacetic acid (2,4-D), the dimethylamine salt of 2,3,6-trichlorobenzoic acid (2,3,6-TBA), and the sodium salt of 2,3,6-trichlorophenylacetic acid (fenac), were evaluated in controlling witchweed and toxicity to corn on germinating seed in petri dishes, as preplan ting, preemergence, and postemergence treatments in the greenhouse and as preplanting, soil-incorporated treatments in the field. Corn roots were affected more than the shoots by each herbicide. Fenac and 2,4-D inhibited root growth of corn seedlings in petri dishes more than 2,3,6-TBA. Fenac was the most effective herbicide for control of witchweed and weedy grasses when applied as a preplanting, soil-incorporated treatment and controlled witchweed at rates which significantly increased corn yields. Applied preplanting, 2,4-D did not control witchweed and 2,3,6-TBA at rates which gave witchweed control equivalent to that obtained with fenac was toxic to corn.

Legal protection of intellectual property is a requisite to the commercialization of the intellectual property and to the conferring of proper reward to the true owner of the property. Simplistically stated, this situation with regard to intellectual property is no different from the legal protection of a variety of properties, for example, home, land, or automobile. Laws have been established in the various countries of the world that are structured specifically to attain the desired goal of legally protecting property interests. In the intellectual property field, wherein we talk about property such as new inventions, we enter an area of not only protecting the legal rights of the property owner but also insuring the position of the public with respect to the eventual unlimited use of new inventions.

In four field experiments, acifluorfen {5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoic acid} applied preemergence at 1.1 kg/ha was not phytotoxic to peas (Pisum sativum L.) and increased the yield of shelled peas by an average of 25% compared to the weedy control. Yields were highest in all four experiments at the 1.1 kg/ha rate and tended to decline at higher rates of application. Growth chamber studies demonstrated that pea tolerance to acifluorfen was not affected by temperatures of 16/10 to 27/21C (light/dark) nor by stimulated rainfall of 0.5 to 5.0 cm. Peas and soybeans [Glycine max (L.) Merr.] were more tolerant of acifluorfen than were snap beans (Phaseolus vulgaris L.) and lima beans (Phaseolus lunatus L.) when acifluorfen was applied preemergence in the greenhouse or in hydroponic nutrient solution.

The preemergence herbicidal activities of 10 4-(methylsulfonyl)-2,6-dinitro-N,N-variously substituted anilines were determined on four plant species at four equimolar concentrations in nutrient solution. Several analogs were as active or slightly more active than 4-(methylsulfonyl)-2,6-dinitro-N,N-dipropylaniline [nitralin]. Most amino groups on these compounds were of a mixed nature. Preemergence toxicity decreased when the N-substituents contained more than six carbons or less than five.