I would like to start with a premise, then discuss a bit of history as it applies to agriculture and food production, then relate food production to a country's total economy, and lastly, relate the profession of a weed scientist to a country's capacity to produce food.

I have enjoyed close and direct association with four different Land Grant Colleges. At the fourth, I served 20 years on the staff and became 50 years of age, giving me the privilege of retiring. If my comments appear critical of Land Grant Colleges as recently administered, these comments are intended to serve as constructive criticism. Contributions of the Land Grant Colleges are basic to our total United States welfare. Our society and our way of life continue to need these contributions. Perhaps the goals and objectives should be changed, but the contributions are still strongly needed.

Canada is a very large country with about 3,700,000 square miles of land surface but with only 100,000,000 acres of land in production and approximately 40,000,000 acres of virgin land capable of being used for crop production. Of the 100 million acres, about 80% of this is in the three western provinces of Manitoba, Saskatchewan, and Alberta. Saskatchewan alone has over 50% of this resource. Contrasted with this is the small area in the Maritimes of less than 2 million acres, some 6 to 7 million acres in Quebec, and 11 million acres in Ontario. Canada, therefore, has one major surplus resource and that is grain production in western Canada.

Preemergence applications of 3 lb/A of 1-(2-methylcyclohexyl)-3-phenylurea (siduron) plus 0.3 lb/A of 4-amino-3,5,6-trichloropicolinic acid (picloram) sufficiently suppressed competition from downy brome (Bromus tectorum L.) or medusahead (Taeniatherum asperum (Sim.) Nevski) and associated broadleaf species to allow the marginal establishment of intermediate wheatgrass (Agropyron intermedium (Host.) Beauv., var. Amur) seedlings. The technique was only successful on semi-arid range sites with above-average soil moisture and moderately dense stands of weed grasses. The range in tolerance of the three species to siduron is very similar, but downy brome is slightly more susceptible than medusahead or intermediate wheatgrass. There is a significant negative relation between plant moisture stress and root length of intermediate wheatgrass plants when root elongation is suppressed by low rates of siduron.

A small laboratory sprayer was designed to spray small quantities of chemicals on test plants. The sprayer apparatus consisted of a spray nozzle assembly, air line, and syringe to inject the test solution into the spray nozzle assembly. In operation, the sprayer provides good coverage of test plants and can be used to treat a large number of subjects rapidly.

Thirty variously substituted benzonitriles and derivatives applied at equimolar exponential rates were evaluated for their phytotoxic properties in nutrient solution. The order of activity of the variously substituted benzonitriles and derivatives was dissimilar to the benzoic acids and phenoxyalkylcarboxylic acids. Several of the materials evaluated were as active as, or more active than 2,6-dichlorobenzonitrile [dichlobenil]; namely, the 2,6-dibromobenzonitrile, 2,6-dichloro-β-benzaldoximeacetate, 2-bromo-6-chlorobenzonitrile, 2,3,4-trichlorobenzonitrile, and 2,3,5-trichlorobenzonitrile.

Potassium azide (KN3) was shown to have potential use as a soil fumigant based on the evidence that azide killed dormant seeds in laboratory and field experiments. Volatility was an important factor in the dissipation of KN3; an acid environment greatly increased volatility probably due to rapid conversion to HN3, whereas soil type exerted little influence on vapor loss. Increasing the soil moisture decreased volatility due to water solubility of NH3. KN3 was leachable and weakly adsorbed in various soil types and at different pH levels. From experiments using stoppered flasks to exclude volatility, it was concluded that the dissipation of KN3 was a chemical phenomenon accelerated by elevated temperatures. KN3 dissipated rapidly from an acid soil whether autoclaved or non-autoclaved; however, alkaline soils prevented dissipation of KN3. Apparently, KN3 is converted to HN3 before it is decomposed. Diffusion within the soil was restricted and occurred only in an acid soil. Covering the soil with plastic immediately after application reduced volatility and increased the biological activity of KN3.

Imbibition of pretreated velvetleaf (Abutilon theophrasti Medic.) seed was most rapid when the chalazal region was wetted, but submergence of the chalaza in water delayed seed germination. Respiratory measurements indicated that the seed coat did not inhibit gas exchange under our experimental conditions. Effects of 2,4-dinitrophenol on germination indicated that radicle emergence and radicle growth were distinct processes, and that radicle emergence was more sensitive to low concentrations of the uncoupler.

Endosperm dry weight, protein, and fat losses accompanied rapid radicle growth of velvetleaf (Abutilon theophrasti Medic.) between 12 and 36 hr of germination at 31 C. Cotyledonary reserves were mobilized after 36 hr. Isocitrate lyase activity sedimented with a particulate fraction in varying degrees, but maximal activity developed at times coincident with fat mobilization. Respiration of excised endosperms reached maximal rates shortly after radicle emergence. The actions of hydrogen cyanide, carbon monoxide, and 2,4-dinitrolphenol indicated that respiration of endosperms excised from imbibed and germinated seed was due to cytochrome oxidase activity, and was coupled to phosphorylation.

We compared various rates of 2,3,6-trichlorobenzoic acid (2,3,6-TBA), 3,6-dichloro-o-anisic acid (dicamba), and 4-amino-3,5,6-trichloropicolinic acid (picloram), and various methods of application on persimmon (Diospyros virginiana L.). Single rates of 2,3,6-trichlorophenylacetic acid (fenac) and (2,4,5-trichlorophenoxy)acetic acid (2,4,5-T) also were included. In one experiment, 8 lb/A of dicamba injected into the soil killed significantly more persimmon than the same rate applied to the soil in 4-inch bands. Otherwise, with given herbicides at comparable rates, defoliation and mortality of persimmon were similar with all methods of soil application. Foliage applications of dicamba or picloram at relatively low rates caused defoliation and mortality of persimmon equal to soil applications of dicamba or picloram at high rates. Dicamba was more effective than equal rates of 2,3,6-TBA for killing persimmon. Picloram at 2 lb/A and dicamba at 4 lb/A, as foliage applications, defoliated and killed persimmon to nearly the same extent. Fenac was relatively ineffective for killing persimmon. Soil treatments with picloram and dicamba killed 22 to 30% more persimmon when applied in summer than when applied in spring. Spring and summer foliage applications of dicamba and 2,3,6-TBA caused similar defoliation and mortality of persimmon, but mortality of persimmon was somewhat higher with spring than with summer foliage applications of picloram. Summer basal treatment with 2,4,5-T killed more persimmon than spring basal treatment.

A relatively inexpensive, cold-temperature germination bar was constructed. The optimum temperature gradient of the bar for our low-temperature seed germination studies ranged from −4 to 11 C. An independent compressor and a chest-type deep freeze were compared for cooling sources. Alumnium foil Petri dishes were developed for use on the bar.

Excellent protection from 2-chloro-4,6-bis(ethylamino)-s-triazine (simazine) injury at twice the dose needed for weed control was obtained by dipping the roots of strawberry plants (Fragaria grandiflora Ehrh.) in a 10% slurry of activated carbon before transplanting. Protection was greater when the roots were dipped in the slurry of activated carbon than when activated carbon was applied in the transplant water. Protection was obtained from three different activated carbons. Protection from injury to varying degrees was observed when several other herbicides were used.

In preemergence application of six different substituted urea herbicides on coriander (Coriandrum sativum L.) and tomato (Lycopersicum esculentum Mill.), the monohalogenated compounds were more effective in the destruction of the plants than their dihalogenated counterparts. The relative difference in effectiveness was much greater in the resistant coriander which appears to take up less dihalogenated than monohalogenated herbicide. In postemergence application, the dihalogenated herbicides generally were slightly more toxic than their monohalogenated counterparts.

Economic evaluation of Scotch thistle (Onopordium acanthium L.) infestation of grazing land in northeastern California revealed potential annual losses to ranchers approximated $10.20/A for wet meadows, $6.70/A for wheatgrass (Agropyron spp.) stands, and $3.40/A on downy brome (Bromus tectorum L.) rangelands. Annual application of 0.06 lb/A of 4-amino-3,5,6-trichloropicolinic acid (picloram) provided the most economical ($3.57/A) means of suppressing Scotch thistle. Annual application of 0.06 lb/A also introduced less picloram into the environment than less frequent application of higher rates. Application of picloram to suppress Scotch thistle limits management options and reduces potential land values.

In laboratory studies, ethylene and an ethylene-releasing agent, 2-chloroethylphosphonic acid (hereinafter referred to as CEPA), stimulated germination of aged, pretreated but still dormant witchweed (Striga lutea Lour.) seed. Ethylene gas at 10−1 μl/L produced maximal (89 to 98%) seed germination. Witchweed seed also germinated when incubated directly in Eustis loamy sand treated with CEPA. A half-maximal response was obtained with 10 mg of CEPA per kg of soil. Vapors produced by apple (Pyrus malus L. Mill) slices, by an alkaline solution of CEPA, and by soil treated with CEPA also stimulated germination. Vapors from soil contained an inhibitor of the ethylene-induced seed germination. Exposure of the soil vapors to 20% potassium hydroxide removed the inhibitor. Germination studies with 10% carbon dioxide, carbon dioxide-free air, and ethylene indicated that carbon dioxide inhibited the ethylene-induced germination of witchweed seed.

Various combinations of crops, herbicides, and tillage were evaluated for field bindweed (Convolvulus arvensis L.) control in western South Dakota. Four crop rotations (continuous wheat (Triticum aestivum L.), wheat-fallow, wheat-sorghum (Sorghum vulgare Pers.), and wheat-sorghum-fallow) were modified by the application of (2,4-dichlorophenoxy)acetic acid (2,4-D) and/or the use of post-harvest tillage. Intensive cultivation and 2,4-D treatment were used to aid in the control of field bindweed in forage crops grown on a long-term basis and in conjunction with small grain rotations. Treatment with 2,4-D in a grain crop and with non-selective herbicides after harvest were tested. Crops were planted the succeeding 2 or 3 years and observed for effect of chemical residue. The established plants could be essentially eliminated while utilizing adapted crop rotations. The use of 2,4-D alone or in combination with cultivation made it possible to reduce the stand of field bindweed (20.7 to 22.2 shoots/sq yd) 90% or more in 3 years in all rotations. A ¾-lb/A rate of 2,4-D in June prevented seed production, killed susceptible plants, and weakened the remaining plants, but a follow-up treatment of 2,4-D in the fall, post-harvest cultivation, or post-harvest treatment with herbicides such as 2,3,6-trichlorobenzoic acid (2,3,6-TBA), 3,6-dichloro-o-anisic acid (dicamba), or 4-amino-3,5,6-trichloropicolinic acid (picloram) was necessary to kill them.

The interactions between copper (Cu++) and cyanide (CN−) with 1,1′-dimethyl-4,4′-bipyridinium ion (paraquat) on phytotoxicity to Chlorella pyrenoidosa Chick, IAC 251, were determined by measuring chlorophyll absorbance at 434 and 670 mμ. Cu++ inhibited phytotoxicity and CN− accelerated paraquat activity with highly significant mutually antagonistic interactions occurring between Cu++ (2 ppm) and CN− (16 ppm) at paraquat levels to 2 ppm.

One approach to the control of rhizomatous perennial weeds is to alter plant growth form to predispose the difficult-to-reach tissue to herbicides. Yellow nutsedge (Cyperus esculentus L.) was the test plant used in this study. Gibberellic acid induced erect rhizome growth whereas triiodobenzoic or naphthylphthalamic acids induced tuft-type growth as a result of a promoted and accelerated transformation of rhizomes to shoots.

Transformation of N-(1,1-dimethylpropynyl)-3,5-dichlorobenzamide (compound I) in soil occurs readily and two products are produced, initial cyclization giving 2-(3,5-dichlorophenyl)-4,4-dimethyl-5-methyleneoxazoline (compound II) followed by subsequent hydrolysis to N-(1,1-dimethylacetonyl)-3,5-dichlorobenzamide (compound III). These transformations can be brought about in vitro, the first step by means of acid or base, and the second by extended treatment with acid. The rate of cyclization and hydrolysis of compound I varies directly with soil temperature, being rapid at high temperature (37 C) and very slow at low temperature (5 C). The rate of chemical change of compound I in soil is influenced to a much greater degree by temperature than by soil moisture content. The effect of soil type on transformation of compound I was studied and compounds II and III were present in five of the six soils examined. The herbicidal activity of compounds II and III was negligible in comparison to compound I.

An 1130 IBM computer was used to process data from experimental plots to evaluate performance of preemergence herbicides in Hawaiian sugarcane fields (planted with varieties of four Saccharum spp.). The evaluation technique compares performance of experimental herbicides with the performance of three standard herbicides [2-(ethyl-amino)-4-(isopropylamino)-6-(methylthio)-s-triazine (ametryne), 2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine (atrazine), and 3-(3,4-dichlorophenyl)-1,1-dimethylurea (diuron)] under a wide range of environmental conditions. Under most conditions the substituted triazine 2-(sec-butylamino)-4-(ethylamino)-6-methoxy-s-triazine (GS-14254) gave better total weed control without crop toxicity than any of the three standards, and was particularly well-suited to regions of high rainfall.

The common purslane plant (Portulaca oleracea L.) flowered and produced seeds throughout the growing season. Seeds were mature about 15 days after flowering. Increased light intensity and temperature stimulated growth. In general greater yields were obtained under cool white light, followed by yields under green, blue, red, and yellow light, in that order. With high temperature during the light period and low temperature during the dark period, best growth occurred under green light.