bluuebunny/crossref_metadata_2025 huggingface dataset:
Mechanism of Trifluralin Diffusion in Silt Loam Soil
Authors: Bode L. E. , Day C. L. , Gebhardt M. R. , Goering C. E.
Published: May 2019

Diffusion of trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine) through Mexico silt loam soil was measured in diffusion cells under laboratory conditions. Radiolabeled herbicide was extracted from each sample and counted by liquid scintillation. Fick's Second Law with a constant diffusion coefficient adequately describes trifluralin diffusion regardless of concentration or diffusing time. Solution diffusion increases directly with bulk densities to 1.1 g/cm3and then decreases. Vapor diffusion is decreased approximately 50% for every 10% decrease in air-filled porosity. Vapor diffusion contributes the major portion of total diffusion at bulk densities of less than 1.2 g/cm3. For bulk densities between 1.2 and 1.4 g/cm3, the magnitudes of vapor and solution diffusion are similar.
Prediction of Trifluralin Diffusion Coefficients
Authors: Bode L. E. , Day C. L. , Gebhardt M. R. , Goering C. E.
Published: May 2019

In the range of 4.4 to 49 C, there is an exponential relationship between temperature and trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine) diffusion coefficients. Diffusion is low in air-dry soil for all temperatures. It increases to a maximum value when the soil has between 8 and 15% w/w soil moisture content and then decreases steadily as moisture content increases. When the air-filled fraction of soil void space is reduced below approximately 40% v/v by either compression or addition of moisture, diffusion begins to decrease. An equation was developed to predict trifluralin diffusion coefficients from a factorial experiment with seven soil moisture contents, five soil temperatures, and two bulk densities. Diffusion coefficients range from 3.8 X 10-11 cm2/sec to 2.8 X 10-6 cm2/sec. Fifteen terms are required in the prediction model to describe accurately the response surface of trifluralin diffusion coefficients. With the equation it is possible to predict trifluralin diffusion coefficients for any combination of measured soil parameters as long as they are represented by the range of the variables used in the experiment.
Biotic Interactions between Different Species of Algae
Authors: Boyd Claude E.
Published: May 2019

Species of green algae seldom grew as well in two-species cultures with other green algae, or with blue-green algae, as when cultured alone. Several species of algae apparently excreted one or more substances into the medium which inhibited the growth of the second species. Inhibition of growth of green algae was particularly great in two-species cultures with the blue-green algae,Oscillatoria rubescensDecandolle,Anabaena flos-aquae(Lyngbye) Breb.,Microcystis aeruginosaKutz., andCoccochloris peniocystis(Kutz.) Dr. and Daily. Green algae also failed to grow at normal rates in media prepared from filtrates of water from ponds which contained blooms of blue-green algae. Inhibitory substances are apparently an important factor in the development and persistence of relatively unialgal blooms of various species.
Influence of Simazine and Atrazine on Free Fatty Acid Content in Isolated Chloroplasts
Authors: Smith A. E. , Wilkinson R. E.
Published: May 2019

Chloroplasts, isolated from fresh spinach (Spinacia oleracea L.) were treated with four concentrations of each 2-chloro-4,6-bis(ethylamino)-s-triazine (simazine) or 2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine (atrazine) to determine the influence of these herbicides on the free fatty acid content in isolated chloroplasts. The treated chloroplast solutions were sampled at 0, 5, 15, 30, 60, and 120 min following treatment. Results indicated that most herbicide treatments increased free fatty acid content in isolated chloroplasts when compared with the zero concentration treatments. The increased fatty acid content was similar for most concentrations of simazine and atrazine. Results of individual fatty acid analyses indicated that the increase in total fatty acids was a result of increases in concentration of unsaturated rather than saturated fatty acids.
Yellow Nutsedge Shoot Emergence and Tuber Longevity
Authors: Stoller E. W. , Wax L. M.
Published: May 2019

Tubers of yellow nutsedge (Cyperus esculentusL.) were buried in the field 2.5 to 30.5 cm below the surface in November 1969 and 1970 at Urbana, Illinois. In both years, shoots began to emerge the following May and continued emergence until July. Very few additional shoots emerged after July. Shoots emerged from less than 2% of the tubers buried at 2.5 cm; the maximum number of shoots emerged from tubers at the 10.2 and 20.3-cm depths. Tubers at the 2.5 and 5.1-cm depths were more susceptible to winterkill than tubers at lower levels, probably because of the differences in soil temperature at these levels during cold periods. Kinetic analysis of laboratory-determined tuber viability for periods up to 22 months revealed that the half-life was 4.4 and 5.7 months for tubers buried at 10.2 and 20.3 cm, respectively. The extrapolated minimum temperature required for initiation of tuber germination in the laboratory was 12 C. This temperature minimum could not readily be related to initial shoot emergence in the field. The temperature at which 50% of the tubers survived a cold treatment for 4 to 48 hr was −7 C.
Weed Control in Soybeans with Postemergence-Directed Herbicides
Authors: Wilson R. G. , Burnside O. C.
Published: May 2019

Greenhouse studies showed that common cocklebur (Xanthium pensylvanicum Wallr.), green foxtail (Setaria viridis (L.) Beauv.), sunflower (Helianthus annuus L.), and velvetleaf (Abutilon theophrasti Medic.) were selectively controlled with postemergence herbicides in soybeans (Glycine max (L.) Merr. ‘Ford’). In the field the control of velvetleaf in soybeans was obtained by applying a postemergence-directed herbicide when soybeans were 15 cm tall and had the second trifoliolate leaf present. Postemergence-directed herbicides did not adequately control grass weeds. It was necessary to use a preplant or preemergence herbicide for grass control. Mechanical removal of lower leaves of soybean plants grown in the greenhouse significantly decreased yield. However, with field-grown ‘Amsoy’ soybeans mechanical removal of cotyledons, unifoliolate, and the first trifoliolate leaves did not reduce yield.
Chemical Fallow in a Winter Wheat-Fallow Rotation
Authors: Wicks G. A. , Smika D. E.
Published: May 2019

Five fallow treatments in an alternate winter wheat (Triticum aestivumL.) fallow rotation experiment were compared over a 6-yr period at North Platte, Nebraska. During the 14-month fallow period from winter wheat harvest until winter wheat planting, plots receiving no tillage (weeds were controlled by herbicides) had the least weed growth, most soil water stored, and highest amount of surface mulch maintained. Also, the plots receiving only herbicides had the highest grain yields of all treatments. However, an average of 3.8 herbicide applications were needed to control grass weeds missed by 2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine (atrazine) during the last 5.5 months of the fallow period. Greatest weed growth during the fallow period was on plots that received only tillage and occurred during the first 3 months after harvest.
Penetration of Amine Salt Formulations of 2,4-D into Sunflower
Authors: Que Hee S. S. , Sutherland R. G.
Published: May 2019

Sprayed aqueous emulsions of long chain amine salts of (2,4-dichlorophenoxy)acetic acid (2,4-D) penetrated faster into sunflower (Helianthus annuus L. ‘Peredovik’) leaves than did sprayed dimethylamine salt aqueous emulsions at 21 C and 5% relative humidity (RH). The initial absorption (65 to 70% in 13 hr) was independent of light, but the following much slower absorption was strongly light dependent. The long-chain amine salts sprayed in diesel oil as carrier were 90% absorbed in 4 hr. It was concluded that long chain amine salts should be sprayed in this carrier to facilitate penetration into leaves and to reduce possible environmental contamination.
Pregermination Treatment of Black Seed of Halogeton
Authors: Cronin E. H.
Published: May 2019

Only 24% of black seed of halogeton (Halogeton glomeratus (M. Bieb.) C. A. Mey.) germinated 2 weeks after collection in October. After 11 weeks of dry storage germination had increased to 60%. During the additional 12 weeks of pregermination treatment, germination did not vary significantly from 60% except for seed stored moist at low temperatures. Ninety to 95% of moist seeds stored at −6 C for 6 weeks or longer germinated within 48 hr; this rate of germination was superior to that of seed collected in December.
Effects of 2,4-D and Amino Acids on Field Bindweed in Vitro
Authors: Harvey R. G. , Muzik T. J.
Published: May 2019

Two clones of field bindweed (Convolvulus arvensisL.) which differed in their susceptibility to (2,4-dichlorophenoxy)acetic acid (2,4-D) under field and greenhouse conditions also exhibited similar differences when stem cells were cultured in liquid and agar media. Amino acids added to the culture media altered the response to 2,4-D. Glutamic acid increased the tolerance of the susceptible (S) clone, but reduced the tolerance of the resistant (R) clone. Glutamine increased the susceptibility of the S clone to a much greater degree than it did the R clone. No significant differences were noted in the rates of absorption of metabolism of 2,4-D by the two clones. Glutamine increased and glutamic acid decreased 2,4-D absorption by both clones. Levels of nitrate reductase activity (NRA), soluble protein (SP), and gross RNA (GR) increased in the S tissues but decreased or remained constant in the R tissues exposed to 4.5 × 10−5M 2,4-D. Correlations between 2,4-D susceptibility and NRA demonstrated a relationship between the effects of 2,4-D and nitrogen metabolism. Differential binding of 2,4-D within the cells appears to be the most likely explanation for the differences in response to 2,4-D.
Evaluation of Seedling Progeny of Soybeans Treated with 2,4-D, 2,4-DB, and Dicamba
Authors: Thompson L. , Egli D. B.
Published: May 2019

Seed were harvested from soybean [Glycine max(L.) Merr. ‘Cutler’] plants treated at flowering and pod filling with (2,4-dichlorophenoxy)acetic acid (2,4-D), 4-(2,4-dichlorophenoxy)butyric acid (2,4-DB), and 3,6-dichloro-o-anisic acid (dicamba). Progeny of plants treated at flowering with 2,4-D and 2,4-DB or at pod filling with the lowest rate were normal. When higher rates were applied at pod filling, these phenoxy herbicides caused appreciable injury to the progeny in the form of reduced emergence and dry weight and malformed unifoliate leaves. Dicamba was much more injurious to the progeny of treated plants than 2,4-D and 2,4-DB. Even at low rates dicamba caused reduced germination, emergence, and dry weight and malformed first trifoliate leaves.
Sorption of Some14C-Herbicides by Isolated Plant Cells and Protoplasts
Authors: Boulware Margaret A. , Camper N. D.
Published: May 2019

Isolated plant cells (Zinnia elegansJacq. leaf tissue) and protoplasts (immature tomato fruit,Lycopersicon esculentumMill.) were obtained by hydrolysis of pectic substances in the middle lamella and the primary cell wall, respectively. Both types of cells were stabilized in an inorganic salt solution and used to study absorption and distribution of four14C-herbicides. Intracellular distribution within the protoplast was determined by ultracentrifugation in a discontinuous Ficoll gradient. Marked absorption ofp-nitrophenyl-α,α,α-trifluoro-2-nitro-p-tolyl ether (fluorodifen) and α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine (trifluralin) by the isolated cells was observed; absorption increased with time. Trifluralin was retained within the cell more strongly than fluorodifen. Similar absorption patterns of fluorodifen and trifluralin by protoplasts were observed. Trifluralin was incorporated to a greater extent than fluorodifen by the cells and protoplasts. Trifluralin was distributed evenly between the mitochondrial and the chloroplasts-nuclei fractions; whereas fluorodifen was concentrated in the chloroplast-nuclei fraction. No significant absorption of 1,1-dimethyl-3-(α,α,α-trifluoro-m-tolyl)urea fluometuron) or 3-(4-bromo-3-chlorophenyl)-1-methoxy-1-methylurea (chlorbromuron) was detected by either the isolated cells or protoplasts.
Delayed Incorporation of Trifluralin and Nitralin
Authors: Smith D. T. , Wiese A. F.
Published: May 2019

Trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine) required more thorough soil incorporation with a disk, probably to prevent loss by volatility, than did 4-(methylsulfonyl)-2,6-dinitro-N,N-dipropylaniline (nitralin). Mechanical incorporation of nitralin could be delayed for 96 hr after application, whereas trifluralin needed to be incorporated within 24 hr to control weeds. Gas chromatographic analyses of soil showed that trifluralin decreased rapidly during the first 24 hr that incorporation was delayed. Application of trifluralin with undiluted crop oil on dry soil did not prolong the persistence prior to incorporation compared to applications with water.
Effects of Auxin-Like Herbicides on Nucleohistones in Cucumber and Wheat Roots
Authors: Chen L. G. , Ali A. , Fletcher R. A. , Switzer C. M. , Stephenson G. R.
Published: May 2019

Roots of susceptible cucumber (Cucumis sativusL. ‘Chicago pickling’) and tolerant wheat (Triticum aestivumL. ‘Manitou’) seedlings were treated with 3,6-dichloro-o-anisic acid (dicamba) or (2,4-dichlorophenoxy)acetic acid (2,4-D) for either 10 or 46 hr. The roots were excised and nucleohistones were isolated and fractionated by polyacrylamide gel electrophoresis. In untreated cucumber roots there were four major nucleohistone fractions. Two of these fractions decreased or were not detectable 10 or 46 hr after treatment with dicamba or 2,4-D. In wheat, the nucleohistone fractions of the treated roots were similar to those of the controls. This suggests that in cucumber more of the DNA template is available for transcription. This suggestion was supported by the fact that the incorporation of14C-adenine into RNA in cucumber roots 10 hr after treatment with dicamba was increased by 50%, whereas in wheat there was no difference. Furthermore, the incorporation of14C-leucine into protein in cucumber roots 10 hr after treatment with dicamba was inhibited by 70%, indicating that the increased RNA produced was incapable of translating for protein synthesis. It is proposed that selective phytotoxicity of auxin-like herbicides is based on a differential alteration of RNA species and interference with protein synthesis.
Influence of Cropping and Activated Carbon on Persistence of Atrazine in Sand
Authors: Harvey R. G.
Published: May 2019

The persistence of 2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine (atrazine) residues under greenhouse conditions was affected by levels of activated carbon added to a silica sand potting medium and by up to four consecutive crops of corn (Zea maysL.). Degradation of atrazine within the sand and removal by the corn crops were both reduced by activated carbon. Atrazine removal by successive crops of corn reduced injury to oat seedlings grown on the sand alone, and absorption by 1.2 g of carbon per kilogram of sand prevented oat injury both with and without cropping. Although 0.4 g/kg of activated carbon inhibited atrazine removal by corn, oat seedlings were not protected from the residues remaining. When exposed to alternate freezing and thawing, the ability of 0.4 g/kg of activated carbon to deactivate atrazine was reduced causing increased oat injury.
Bentazon Mobility and Adsorption in Twelve Illinois Soils
Authors: Abernathy John R. , Wax Loyd M.
Published: May 2019

Investigations of the behavior of 3-isopropyl-1H-2,1,3-benzothiadiazin-(4)3H-one 2,2-dioxide (bentazon) in water solutions have shown that it was anionic in neutral solutions by exhibiting a strong movement toward the anode in an electrical field. The herbicide was not adsorbed by any of twelve selected Illinois soils or by the cation exchange resin, carboxymethylcellulose (CMC), but was almost completely adsorbed by charcoal and by the anion exchanger, diethylaminoethylcellulose (DEAE). Bentazon moved with the water front on soil thin-layer plates as well as through soil columns.
Responses of Peach Trees to Herbicides, Mulch, Mowing, and Cultivation
Authors: Lord W. J. , Vlach Edward
Published: May 2019

A 6-year study was conducted to compare the influence of 1,1′-dimethyl-4,4′-bipyridinium ion (paraquat), a mixture of paraquat and 2-chloro-4,6-bis(ethylamino)-s-triazine (simazine), frequent mowing, hay mulch, and cultivation on growth, yield, and nutrition of peach (Prunus persica(L.) Batsch ‘Jerseyland’) trees. The growth and yield of trees which received two annual applications of paraquat or one application of paraquat plus simazine were comparable to those of trees maintained under cultivation or hay mulch. Hay mulched and cultivated trees responded comparably. Hay mulched trees had higher leaf potassium (K) and lower leaf magnesium (Mg) than the other trees. Where grass was controlled only by mowing, trees were generally lower in nitrogen (N), made less growth, and produced less fruit.
Influence of Temperature on Absorption, Translocation, and Metabolism of Pyrazon in Sugar Beets
Authors: Koren Ephraim , Ashton Floyd M.
Published: May 2019

Autoradiographic studies showed that regardless of whether 5-amino-4-chloro-2-phenyl-3(2H)-pyridazinone (pyrazon) was applied to the leaves or to the roots of sugar beet (Beta vulgarisL.) plants, it moved in the apoplastic system. The pattern of pyrazon distribution from root absorption in sugar beet seedlings was identical at either 35 or 18.3 C. However, root absorption at 35 C was twice as great as at 18.3 C; and translocation of pyrazon into the shoot was more rapid at the high temperature. A major metabolite of pyrazon, a pyrazon-glucose conjugate, was produced in leaves and cotyledons but not in roots of sugar beets. A minor metabolite, less than 5%, was found in sugar beet leaves. Pyrazon was not metabolized by the susceptible species common lambsquarters (Chenopodium albumL.). The rate of pyrazon-glucose conjugate formation in pyrazon-infiltrated sugar beet leaf discs was practically identical at 35 and 18.3 C. Therefore, it was concluded that the increased susceptibility of sugar beets to pyrazon at higher temperatures was due to an increase in absorption and translocation of the herbicide at higher temperatures which was not accompanied by a parallel increase in the conversion of pyrazon to its glucose conjugate.
Interaction of Propanil with Insecticides Absorbed from Soil and Translocated into Rice Plants
Authors: El-Refai A. R. , Mowafy M.
Published: May 2019

Investigations were undertaken to ascertain whether residues of soil-applied carbaryl (1-naphthyl N-methyl carbamate) and diazinon [O,O-diethyl-O-(2-isopropyl-4-methyl-6-pyrimidyl) phosphorothioate] insecticides may be absorbed from the soil and translocated to foliage of rice (Oryza sativa L. ‘Nahda’) and to determine the phytotoxic interaction between them and foliar-applied propanil (3′,4′-dichloropropionanilide). Results from greenhouse studies showed that carbaryl and diazinon were translocated and affected hydrolytic activity in rice shoots at all rates of application. Carbaryl was more inhibitory but diazinon persisted longer in the soil. When propanil was applied in the presence of diazinon, no additive phytotoxicity occurred on rice plants over that occurring from propanil alone. Synergistic effects in rice, resulting in dry weight loss, were marked when soil was treated with 5 mg of diazinon per kilogram of soil and subsequently sprayed with propanil. Synergistic phytotoxicity was apparent when propanil was applied 1 day after carbaryl treatment and most plants were killed. Slight injury was noticed on plants treated with propanil 2 weeks after carbaryl treatment at 1 and 5 mg/kg.
Comparative Effects of Diquat plus Copper Sulfate on Aquatic Organisms
Authors: May B. E. , Hestand R. S. , Van Dyke J. M.
Published: May 2019

Effects of herbicide combinations on aquatic invertebrates were evaluated in Inglis Reservoir, which is located in west coastal Florida. The addition of 6,7-dihydrodipyrido [1,2-a: 2′1′-c]pyrazinediium ion (diquat) plus the triethanolamine complex of copper sulfate (TAC) and diquat plus copper sulfate pentahydrate (CSP) for control of hydrilla (Hydrilla verticillata Casp.) decreased the number of invertebrates inhabiting the treated areas. The diquat plus CSP combination exerted the greatest effect upon invertebrate numbers. Both herbicide combinations, however, did alter significantly the number of taxonomic groups in the areas. Invertebrate declines were due more generally to resultant habitat changes (i.e., loss of hydrilla) than to direct herbicide toxicity. The response of fish to the effects of the herbicide treatments on invertebrates could be ascribed to dietary changes, decreased growth rates, and possible mortality.
Herbicide Effects on Parasitism of Tomato by Hemp Broomrape
Authors: Saghir A. R. , Foy C. L. , Hameed K. M.
Published: May 2019

Thirteen soil-incorporated herbicides, mainly of the dinitroaniline and carbamate groups, were evaluated in the greenhouse for selective control of hemp broomrape (Orobanche ramosaL.) in tomato (Lycopersicon esculentumMill. ‘Rutgers’). Hemp broomrape readily parasitized tomato roots and competed vigorously with the host. Shoots of the parasite emerged within 6 weeks after inoculation. Herbicides at 0.1 to 10.0 ppmw, with one exception, significantly reduced shoot dry weight of tomato measured at 10 weeks after treatment, in comparison with untreated, noninoculated controls. Generally, the degree of inhibition of establishment of the parasite was correlated with herbicidal injury to tomato. None of the treatments prevented the establishment of the parasite without causing severe crop injury. However,N-n-propyl-N-tetrahydrofurfuryl-4-trifluoromethyl-2,6-dinitroaniline (CGA-14397, ER-9063) at 3.3 and 6.6 ppmw exhibited some degree of selectivity as indicated by relative shoot dry weights of the host and parasite. Activated charcoal applied as a root dip on tomato or in soil admixtures prior to transplanting had no effect on parasitism and growth of hemp broomrape.
Studies on the Mechanism of Resistance to Simazine in Common Groundsel
Authors: Radosevich S. R. , Appleby A. P.
Published: May 2019

Studies were conducted to determine the effect on photosynthesis, the absorption, and the metabolism of simazine [2-chloro-4,6-bis(ethylamino)-s-triazine] in two biotypes of common groundsel (Senecio vulgarisL.). Simazine inhibited photosynthesis in the susceptible (S) plants, but resistant (R) plants were unaffected. When the herbicide was removed from the S biotype after 24 hr, photosynthesis resumed. Both biotypes absorbed the herbicide equally well and were unable to metabolize simazine during 96 hr. The greatest concentration of14C activity (80 to 90%) was located in the chloroform-soluble fraction of the foliage of each biotype and was identified as simazine. Small amounts of radioactivity (10 to 15%) occurred in the water-soluble fraction, but there was no differential increase in water-soluble simazine metabolites. A different mechanism of resistance than previously reported for triazine-resistant plants may be operative in one groundsel biotype.
A Soil Profile Analysis for Puncturevine Fruit and Seed
Authors: Goeden R. D. , Ricker D. W.
Published: May 2019

The incidence of puncturevine (Tribulus terrestris L.) carpels and viable seed recovered from soil samples varied inversely and linearly with depths to 24 cm. Soil type and texture and method of tillage influenced the gradients of carpel distribution and their rate and degree of vertical migration. Evidence for enforced, induced, and innate dormancy in puncturevine seed is presented. Most seed germinated from depths of less than 4 cm in cultivated, sandy loam and clayloam soils. The intra-carpel pattern of seed germination was such that seed located nearest the stylar end of two, three, and four-seeded carpels tended to germinate first, with the other seed tending to follow in order of their position in the carpel from the stylar to the receptaclar end. However, all possible combinations of intra-carpel germination patterns occurred under field conditions.
Ozone-Herbicide Interactions in Crop Plants
Authors: Carney A. W. , Stephenson G. R. , Ormrod D. P. , Ashton G. C.
Published: May 2019

Tomato (Lycopersicon esculentumMill. ‘Fireball’), white bean (Phaseolus vulgarisL. ‘Seaway’), and tobacco (Nicotiana tabacumL. ‘Delhi 34’ and ‘White Gold’) were pretreated with herbicides at one of three rates prior to fumigation with ozone at 0, 7.5, 15, or 30 pphm (parts per hundred million) for two 1.5-hr period. The plants were harvested 5 to 7 days after ozone fumigation, dried, and weighed. The natural logarithms of the dry weight data were subjected to multiple regression analysis to test for synergistic or antagonistic interactions between ozone and the various herbicides. Synergistic phytotoxicity was definitely observed for pebulate (S-propyl butylethylthiocarbamate) and possibly for chloramben (3-amino-2,5-dichlorobenzoic acid) in combination with ozone on tobacco ‘White Gold’ and ‘Delhi 34’, respectively. For most of the other combinations (chloramben, trifluralin α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine) or monolinuron (3-(p-chlorophenyl)-1-methoxy-1-methylurea) on white bean, diphenamid (N,N-dimethyl-2,2-diphenylacetamide) or trifluralin on tomato, chloramben on tobacco ‘White Gold’, and pebulate on tobacco ‘Delhi 34’) the phytotoxicity in the presence of ozone was additive and no interaction was indicated. An antagonistic interaction between ozone and benefin (N-butyl-N-ethyl-α,α,α-trifluoro-2,6-dinitro-p-toluidine) was indicated on the two cultivars of tobacco.
Effect of Benefin and DCPA on Overseeded Grasses Maintained as Putting Greens
Authors: Coats G. E. , Ward C. Y. , McWhirter E. L.
Published: May 2019

Overseeded rough bluegrass (Poa trivialisL. ‘Danish common’) and Italian ryegrass (Lolium multiflorumLam. ‘Gulf’) maintained under putting green conditions were more susceptible to benefin (N-butyl-N-ethyl-α,α,α-trifluoro-2,6-dinitro-p-toluidine) and DCPA (dimethyl tetrachloroterephthalate) than creeping bentgrass (Agrostis palustrisHud. ‘Penn-cross’), red fescue (Festuca rubraL. ‘Dawson’), or perennial ryegrass (Lolium perenneL. ‘Medalist II’). February applications of 1.68 or 3.36 kg/ha of benefin and 6.72 or 13.44 kg/ha of DCPA caused significantly more discoloration and reductions in density than equivalent rates applied in March or April. Benefin was more injurious than DCPA to all overseeded species as judged by quality or density. DCPA caused significant delays in the breaking of dormancy of bermudagrass [Cynodon dactylon(L.) Pers. ‘Tifdwarf’].
Reducing Herbicide Injury to Sorghum with Crop Protectants
Authors: Spotanski R. F. , Burnside O. C.
Published: May 2019

Greenhouse and field studies were used to evaluate crop protectants with herbicides in order to obtain selective, broad-spectrum weed control in sorghum [Sorghum bicolor(L.) Moench ‘RS 626’]. Of the herbicides evaluated alachlor [2-chloro-2′,6′-diethyl-N-(methoxymethyl) acetanilide] was the only one causing sorghum injury that could be moderated with crop protectants. The crop protectant anhydride (1,8-napthalic anhydride) was most effective in reducing alachlor injury when applied as a seed treatment at 0.5% (w/w). Storage of anhydride-treated seed for 1 year did not increase anhydride damage to sorghum seedlings. Preplant applications of alachlor, incorporated into the soil, caused four times more injury to sorghum than did the same rate applied preemergence. Combinations of atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine] and alachlor did not increase sorghum injury or alter the effects of the crop protectants. In the field, anhydride was the most effective crop protectant used. Crop protectant R-28725 (2,2-dimethyl-3-dichloroacetyloxazolidine) at 0.5% w/w to sorghum seed and at 0.6 kg/ha as a tank mix was effective in reducing sorghum injury at the lower alachlor rates. Crop protectant R-25788 (N,N-diallyl-2,2-dichloroacetamide) was the least effective of those studied; however, seed treatment at 0.5% w/w was more effective than the tank mixes.
Predicting Sugarbeet Root Losses Based on Kochia Densities
Authors: Schweizer E. E.
Published: May 2019

The reduction in root yield (Y) of sugarbeets (Beta vulgarisL.) caused by specific densities (X) of kochia [Kochia scoparia(L.) Schrad.] was predicted by using the linear equation Y = 4.30 + 1.81 X. This equation was most accurate when the kochia density was 20 plants or less per 30.5 m of row. In 28 of 30 weed-control systems, where kochia densities ranged from 0.2 to 16.5 plants per 30.5 m of row, the predicted yield reductions were within 5% of the actual yield reductions.
Carbohydrate Reserves in Roots of Dalmatian Toadflax
Authors: Robocker W. C. , Schirman Roland , Zamora B. A.
Published: May 2019

Reserve carbohydrates of Dalmatian toadflax (Linaria dalmatica(L.) Mill.) in eastern Washington were at their highest levels in autumn at the end of the growing season, and the lowest point occurred at the beginning of flowering about June 15. A one-time removal of first-year floral stems (June 11, 1964) did not significantly lower reserve carbohydrates when measured in September, but similar clipping of floral stems the second year (June 16, 1965) did cause a significant reduction. Reserves were reduced by 2-(2,4,5-trichlorophenoxy)propionic acid (silvex) at 1.12 or 1.68 kg/ha but were not reduced by 4-amino-3,5,6-trichloropicolinic acid (picloram) at the same rates. Combinations of equal weights of the two herbicides to total 1.12 or 1.68 kg/ha caused a significant reduction in reserve carbohydrates. The combinations of silvex and picloram appeared to have an additive toxic effect, but the reduction of reserve carbohydrates was no greater than that caused by silvex alone at 1.12 or 1.68 kg/ha. Lethal action of the herbicides did not appear to be caused by reserve carbohydrate depletion. Glucose and fructose were the major reducing sugars detected in chromatographic analysis.
Leaching of Trifluralin and Oryzalin in Soil with Three Surfactants
Authors: Koren Ephraim
Published: May 2019

The leaching of α,α,α-trifluoro-2,6-dinitro-N,N,-dipropyl-p-toluidine (trifluralin) and 3,5-dinitro-N4,N4-dipropylsulfanilamide (oryzalin) with and without surfactants was studied in soil columns. In dry soil without surfactants leaching of trifluralin was less than that of oryzalin and did not amount to more than a few centimeters despite the use of light soil and large amounts of herbicide. In wet soil trifluralin leached more than twice as deep as in dry soil with the same amount of water. The addition of surfactants at a concentration of 2% of the spray volume increased both depth of water penetration and herbicide movement into the soil. The most pronounced effect of surfactants was the increase in movement of trifluralin in dry soil, but they also increased trifluralin movement in wet soil. There was no direct relationship between the ability of the surfactants to improve water penetration and their effects on leaching of the two herbicides. It was therefore concluded that increased leaching was due to an effect of surfactants on the sorption-desorption balance rather than on improved penetration of water. The improved movement of trifluralin into the soil as a result of surfactant action was also evident from another experiment in which surfactants increased the herbicidal activity of trifluralin sprayed preemergence on the soil surface.
Effect of Dinitroanilines on Solanaceous Vegetables and Soil Fungi
Authors: Eshel Y. , Katan J.
Published: May 2019

The phytotoxicities of four substituted dinitroanilines,N-butyl-N-ethyl-α,α,α-trifluoro-2,6-dinitro-p-toluidine (benefin), 2,6-dinitro-N,N-dipropylcumidine (isopropalin), 4-(methylsulfonyl)-2,6-dinitro-N,N-dipropylaniline (nitralin), and α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine (trifluralin), to eggplant(Solarium melongenaL. ‘Black Beauty’), pepper(Capsicum annuumL. ‘Vindale’), and tomato(Lycopersicon esculentumMill. ‘VF 145-B-7879′) were studied. Nitralin and trifluralin were most active in inhibiting root elongation and top growth of these plants, the effect of benefin was intermediate, and isopropalin was the least active herbicide. The order of crop tolerance was as follows: tomato > pepper > eggplant. The effect of these herbicides on two pathogenic fungi,Rhizoctonia solaniKuehn andFusarium oxysporumf. sp.lycopersici(Sacc.) Snyd. and Hans. was tested in culture and was found to be quantitatively and qualitatively different from that on plants. With both fungi benefin and trifluralin were more toxic than isopropalin, while nitralin showed a very low toxicity.R. solaniwas the less sensitive fungus.
Adsorption and Desorption of Picloram, Trifluralin, and Paraquat by Ionic and Nonionic Exchange Resins
Authors: McCall H. G. , Bovey R. W. , McCully M. G. , Merkle M. G.
Published: May 2019

We investigated the forces involved in the adsorption and desorption of 4-amino-3,5-6-trichloropicolinic acid (picloram), 1,1-dimethyl-4,4′-bipyridinium ion (paraquat), and α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine (trifluralin) using cationic, anionic, and nonionic exchange resins. The anionic resin (Cl-form) adsorbed 375, 0.08, and 0.67 mg of picloram, paraquat, and trifluralin, respectively, per gram of oven-dry resin. The nonionic resin adsorbed 4.0, 0.34, and 10.0 mg of picloram, paraquat, and trifluralin, respectively, per gram of oven-dry resin, while the cationic resin (H-form) adsorbed 2.3, 226, and 0.17 mg of picloram, paraquat, and trifluralin, respectively. Other cationic resins (Na-form and Ca-form) performed similarly to the hydrogen form. Desorption studies indicated that picloram was adsorbed mainly in the anionic form by coulombic forces (electrostatic) and to a lesser degree by weak physical bonding (van der Waal's forces). Paraquat was adsorbed as a cation through coulombic forces. Trifluralin was mainly absorbed by physical bonds at sites on the resins where there were no coulombic forces.
Effect of Trifluralin on Mitosis
Authors: Lignowski E. M. , Scott E. G.
Published: May 2019

The compound α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine (trifluralin) inhibited mitosis in onion(Allium cepaL. ‘Yellow Globe’) and wheat(Triticum aestivumL. Thorn’) root tips. Photomicrographs showed that trifluralin affected mitosis in the same manner as colchicine. Arrested metaphases, c-pairs, micronuclei, amoeboid nuclei, and polyploidy were observed at various times after treatment. An increase in the percentage of arrested metaphases and a decrease in anaphase and telophase figures after 3 hr showed that mitosis was being blocked at metaphase. Prophase did not appear to be affected. Centrifugation of treated root tips displaced the chromosomes of arrested metaphases indicating that the spindle apparatus was disrupted.
Effect of Herbicides on Alfalfa and Subsequent Crops
Authors: Swan D. G.
Published: May 2019

Three herbicides, 2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine (atrazine), 2-chloro-4,6-bis(ethylamino)-s-triazine (simazine), and 3-tert-butyl-5-chloro-6-methyluracil (terbacil), applied annually at 0.45, 0.90, and 1.80 kg/ha for 2 or 3 years to establish forage alfalfa(Medicago sativaL. ‘Ranger’), effectively controlled downy brome(Bromus tectorumL.), tumble mustard(Sisymbrium altissimumL.), and prickly lettuce(Lactuca serriolaL.). However, downy brome control decreased to less than half and broadleaf control ceased 18 months after the final herbicide application. Atrazine injured alfalfa most. Usually, annual applications of 0.45 kg/ha did not reduce yield. Greenhouse and field bioassay data indicated that the herbicides leached below the 0 to 32.5 cm soil zone and persisted. Residues were absorbed by roots of crops planted 2 to 3 years after the last application. Injury was similar whether the last application was made 18 or 30 months previously. The order of crop tolerance was sweet corn(Zea maysL. ‘Rugosa’) > potatoes(Solarium tuberosumL. ‘Norgold’) > winter wheat(Triticum aestivumL. ‘Nugaines’) > bush beans(Phaseolus vulgarisL. ‘Humilis’) ≅ sugar beets(Beta vulgarisL. ‘U. & I. hybrid No. 8′).
Microsite Requirements for Establishment of Annual Rangeland Weeds
Authors: Evans Raymond A. , Young James A.
Published: May 2019

Seedling emergence and growth of downy brome(Bromus tectorumL.), medusahead(Taeniatherum asperum(Sim.) Nevski), and tumble mustard(Sisymbrium altissimumL.) were favored by seed burial, pitting of the soil surface, and soil movement. These conditions maintained temperatures and soil and atmospheric moisture in the range required for establishment.
Effect of Atrazine on Chromatin Activity in Corn and Soybean
Authors: Penner Donald , Early Roy W.
Published: May 2019

Applications of 2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine (atrazine) at 10−4, 10−5, and 10−6M to 4-day-old etiolated soybean [Glycine max(L.) Merr. ‘Mark’] seedlings 6 hr before the isolation of chromatin enhanced the chromatin directed ribonucleic acid (RNA) synthesis by 16, 65, and 40%, respectively. The magnitude of this inductive effect increased with an increasing interval of time from 6 to 24 hr between application and chromatin isolation. The basis for the effect appeared to be an atrazine-mediated increase in chromatin template availability. The presence of atrazine during extraction and the assay was sufficient to evoke the response. This effect on chromatin activity was not observed for 2-hydroxy-4-(ethylamino)-6-isopropylamino)-s-triazine (hydroxyatrazine) or for atrazine on corn(Zea maysL. ‘Michigan 400′).
Influence of Dicamba on Development of Range Grass Seedlings
Authors: Halifax J. C. , Scifres C. J.
Published: May 2019

Seedlings of switchgrass(Panicum virgatumL. ‘Blackwell’), sideoats grama(Bouteloua curtipendula[Michx.] Torr. ‘Premier’), and native vine mesquite(Panicum obtusumH. B. K.) tolerated 0.28 kg/ha of 3,6-dichloro-o-anisic acid (dicamba) applied preemergence. After emergence, sideoats grama tolerated 0.56 kg/ha dicamba. Preemergence or postemergence applications of 1.12 and 2.24 kg/ha severely retarded shoot production of all three species. Soil residues in the surface 2.5 cm reduced root production of grass seedlings, whereas placement of dicamba 7.6 or 15.2 cm deep was not detrimental. All grass species germinated and grew for 21 days in soil containing up to 63 ppb of dicamba without reduction in shoot production. Overall order of susceptibility to dicamba was ranked as vine mesquite > switchgrass > sideoats grama.
Antagonistic Effects Between Picloram and Bromacil with Oats
Authors: Sterrett J. P. , Davis J. T. , Hurtt W.
Published: May 2019

Combinations of 4-amino-3,5,6-trichloropicolinic acid (picloram) and 5-bromo-3-sec-butyl-6-methyluracil (bromacil) pellets applied to the soil gave antagonistic responses on oats(Avena sativaL. ‘Clintland 64′) with either 5.6 plus 11.2 kg/ha or 11.2 plus 11.2 kg/ha of picloram plus bromacil. In nutrient culture a significant antagonistic response occurred over a 15-day period with a picloram to bromacil ratio of 30 to 1. Of the ratios evaluated, picloram appeared to interfere with the phytotoxic effect of bromacil. The uptake of14C-bromacil alone by oats from nutrient solution was nearly double that of14C-bromacil when combined with picloram. Thin layer chromatographic analyses revealed that 47% of the14C activity from bromacil in the oat was intact bromacil and that 70% of the labeled activity from picloram was unaltered picloram. The loss of nutrient solution by evapotranspiration was less from containers with picloram and bromacil than from those with bromacil alone. Picloramtreated roots were shorter than untreated or bromacil-treated roots.
Droplet Size and Phytotoxicity of Herbicides
Authors: McKinlay K. S. , Brandt S. A. , Morse P. , Ashford R.
Published: May 2019

An oil soluble formulation of the dodecyl (51% w/w) and the tetradecyl (13% w/w) amine salts of (2,4-dichlorophenoxy)acetic acid (2,4-D) was diluted with diesel oil and applied in homogeneous sprays of 100, 200, and 400-μ. droplets to seedlings of sunflower (Helianthus annuus L. ‘Peredovik’). At each droplet size all combinations of five dosage levels and five spray volumes were compared. For the same applied dosage the amount of stem curvature increased as droplet-size was decreased. When compared with 100-μ droplets, approximately three times and six times as much active ingredient was needed to produce the same effect with 200-μ and 400-μ droplets, respectively. For a fixed droplet-size, the effective dosage could be increased equally well by increasing the concentration or by increasing the number of droplets per unit area.
Control and Ecology of Weeds in Continuous Corn Grown Without Tillage
Authors: Triplett G. B. , Lytle G. D.
Published: May 2019

Corn (Zea mays L.) was grown continuously without tillage (no-tillage) and with conventional tillage for 7 years to evaluate several herbicides for use in both crop culture systems. The only consistently satisfactory herbicide combinations for the no-tillage corn were 2-chloro-4,6-bis(ethylamino)-s-triazine (simazine) and 1,1′-dimethyl-4,4′bipyridinium ion (paraquat) or 2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine (atrazine), simazine, and paraquat. Annual weed population shifted rapidly with different herbicide systems; fall panicum (Panicum dichotomiflorum Michx.) was the major annual weed where triazines were used as the residual herbicide. After several years of corn grown with no-tillage, hempdogbane (Apocynum cannabinum L.) became a significant problem in some plots. Corn yields with no-tillage were equal to yields in tilled areas provided weed control was satisfactory.
Inhibitor of Microbial Enzyme Prolongs Dodder Control with Chlorpropham
Authors: Dawson J. H.
Published: May 2019

Isopropylm-chlorocarbanilate (chlorpropham) at 6.7 kg/ha applied in mid April controlled dodder(Cuscuta campestrisYunck. andCuscuta indecoraChoisy) that emerged in May but did not consistently control dodder that emerged in June. Mid March applications sometimes controlled dodder that emerged in May but did not control that which emerged in June. Whenp-chlorophenylN-methylcarbamate (PCMC), an inhibitor of microbial enzyme activity, at 1.7 kg/ha was applied with chlorpropham at 6.7 kg/ha in mid March or mid February, dodder that emerged in May and June was controlled consistently. A reduced rate (4.5 plus 1.1 kg/ha) of the combined materials applied in mid March also consistently controlled dodder that emerged in May and June.
Effect of Time of Application of Diphenamid on Pepper, Weeds, and Disease
Authors: Eshel Y. , Katan J.
Published: May 2019

The effect of timing of preemergence application ofN,N-dimethyl-2,2-diphenylacetamide (diphenamid) on phytotoxicity to pepper(Capsicum annuumL.), efficacy of weed control, and damping-off incidence was studied in greenhouse and field experiments. Delay of application from day of sowing to close to emergence reduced phytotoxicity to pepper while only partially reducing herbicidal action. Addition of a mixture of the contact nonresidual herbicides 6,7-dihydrodipyrido[1,2-a:2′,1′-c]pyrazinediium ion (diquat) and 1,1′-dimethyl-4-4′-bipyridinium ion (paraquat) to a late preemergence application of diphenamid resulted in control of weed seedlings which emerged after sowing of pepper and significantly increased the yield. The increase ofRhizoctoniadamping-off incidence due to diphenamid was also reduced by delayed application.
Hormonal Aspects of Seed Dormancy in Yellow Foxtail
Authors: Kollman G. E. , Staniforth D. W.
Published: May 2019

Investigations with exogenous test solutions showed that abscisic acid (ABA) inhibited germination of nondormant seeds and that gibberellins (GA) promoted the germination of yellow foxtail(Setaria lutescens(Weigel) Hubb.) The effect of the promoters was much more readily demonstrated with excised caryopses than with intact seeds. Cytokinins reversed ABA inhibition of germination; GA did not, but the two promoters in combination were more effective than the cytokinin alone. The reversal occurred only at one end of the embryonic axis, the shoot end. An endogenous inhibitor was extracted from dormant and nondormant yellow foxtail seeds and compared with ABA by chromatography, electrophoresis, and bioassays. The extracted inhibitor was very similar to ABA in six paper-chromatography solvent systems, three paper electrophoresis runs at different pH values, and three bioassays. Paper electrophoresis was an effective means of separating the two plant hormones, ABA and gibberellic acid (GA3).
Movement and Persistence of Picloram in Soil
Authors: Hunter J. H. , Stobbe E. H.
Published: May 2019

The movement and persistence of 4-amino-3,5,6-trichloropicolinic acid (picloram) in an Osborne clay soil was determined over a 4-year period. Picloram concentrations were determined with soybean(Glycine max(L.) Merr. ‘Altona’) as the bioassay plant. Application rates ranged from 35 to 700 g/ha. Movement and dissipation of picloram were neglible under low soil moisture conditions, but under high rainfall conditions picloram was leached into the 30 to 60-cm depth. A greater percent of the picloram was leached at the higher application rates. Dissipation increased with temperature (days over 27 C) and decreased with increasing depth in the soil profile. Two applications of picloram at 70 g/ha applied in 2 successive years showed no detectable accumulation, but accumulation occurred from two applications of 350 g/ha; 32% of the activity remained after approximately 2 years.
Cocklebur Control in Soybeans with 2,4-DB and Chloroxuron
Authors: Gossett B. J. , Reinhardt L. R. , Byrd W. P.
Published: May 2019

Foliar-applied 3-[p-(p-chlorophenoxy)phenyl]-1,1-dimethylurea (chloroxuron), chloroxuron with dodecyl ether polyethylene glycol surfactant, and dimethylamine salt of 4-(2,4-dichlorophenoxy)butyric acid (2,4-DB) effectively controlled cocklbur(Xanthiumsp.) in soybeans(Glycine max(L.) Merr. ‘Hampton’ or ‘Lee’). While treatments caused crop injury, treated soybeans produced higher seed yields than untreated soybeans infested with cocklebur plants. Seed yields from soybeans growing free of cocklebur were not reduced by treatment with chloroxuron or chloroxuron with surfactant but in some cases were reduced by 2,4-DB treatment.
Broadcast or Banded Chloramben by Tillage Variables in Soybeans
Authors: Moomaw R. S. , Robison L. R.
Published: May 2019

The herbicide 3-amino-2,5-dichlorobenzoic acid (chloramben) was applied preemergence to soybeans [Glycine max(L.) Merr.] in 1969, 1970, and 1971. Herbicide band widths were 18, 36, and 53 cm, and there was a broadcast treatment. Cultivation and rotary hoeing were also imposed on the herbicide band widths as variables. A 36-cm band of chloramben was the minimum band width used which consistently maintained soybean yield when supplemented with mechanical tillage. Broadcast treated soybeans without mechanical tillage yielded as well as handweeded soybeans in 2 of 3 years. Each 4 kg/ha of weed growth reduced soybean yield 1 kg/ha. Average weed yield reduction due to cultivation was 100, 76, and 54% in 1969, 1970, and 1971, respectively, when average weed yields were 360, 1650, and 4720 kg/ha in successive years. Rotary hoeing reduced weed growth 48% and increased soybean yield 20% in 1970 but did not significantly affect weed or soybean yields in 1969 and 1971.