bluuebunny/crossref_metadata_2025 huggingface dataset:
A Cucumber Bioassay Test for the Soil Residues of Certain Herbicides
Authors: Dowler Clyde C.
Published: June 2019

A bioassay standard curve injury rating, using cucumbers (Cucumis sativusL.) as the indicator plant, was developed for quantitatively determining soil residues of 5-bromo-3-sec-butyl-6-methyluracil (bromacil), 6-dichloro-o-anisic acid (dicamba), 3(3,4-dichlorophenyl)-1,1-dimethylurea (diuron), (2,3,6-trichlorophenyl)-acetic acid (fenac), 4-amino-3,5,6-trichloropicolinic acid (picloram), and 2,4-bis(isopropylamino)-6-methoxy-s-triazine (prometone). The herbicide concentrations ranged from 0.001 to 2.187 ppmw. The presence of all the herbicides could be detected at 0.009 ppmw and the herbicides killed cucumbers at 2.187 ppmw. Cucumbers could be used to effectively measure a greater concentration range of fenac than the other herbicides. A highly significant negative correlation existed between injury rating and fresh plant weight. However, concentrations of the herbicides were more easily detected by a visual injury rating on abnormal growth characteristics than by fresh plant weight.
Translocation of Assimilates and Dalapon in Established Johnsongrass
Authors: Hull Richard J.
Published: June 2019

The influence of repeated clipping of the shoots on the translocation of 14C-assimilates and 2,2-dichloropropionic acid 2-14C (dalapon) into the rhizome system of established johnsongrass (Sorghum halepense (L.) Pers.) was studied when regrowth was in the preboot, boot, and flowering stages. Radioautography and radio-assay procedures were used to follow the distribution of label within the plants. Plants defoliated three times prior to treatment showed no increase in basipetal translocation over plants defoliated once. As plants matured to the flowering stage, assimilate translocation into rhizomes increased. This increase was closely related to the degree of secondary rhizome growth occurring at time of label application. During preboot, assimilate movement was restricted to rhizome apices with very little retention in intervening tissue. Labeled dalapon followed a similar translocation pattern to that of assimilates. The role of assimilate translocation and storage as correlated with life cycle changes in carbohydrate nutrition of established johnsongrass is discussed.
Effects of Pyrazon on Growth, Photosynthesis, and Respiration
Authors: Frank R. , Switzer C. M.
Published: June 2019

The herbicide 5-amino-4-chloro-2-phenyl-3(2H)-pyridazinone (pyrazon) had a ten-fold greater inhibitory effect on the growth of common lambsquarters (Chenopodium albumL.) than on sugar beets (Beta vulgarisL.), Production of dry matter was inhibited by accumulations of pyrazon in the tissues. When these accumulations reached a level approximately twice that which affected dry matter production, plants wilted, collapsed, and died. Pyrazon failed to affect the structural integrity of either chlorophyll or the chloroplast, but inhibited the Hill reaction of chloroplasts isolated from both sugar beets and common lambsquarters. The I50value was 6 × 10−6M pyrazon. There was no difference between sugar beets and common lambsquarters in the degree of inhibition in oxygen evolution by leaf discs placed in pyrazon. When plants were culturedin vivowith pyrazon, the rate of oxygen evolution was correlated with herbicide accumulations in the leaf tissues. Sugar beet leaves contained only one-third to one-fifth the level present in common lambsquarters. The rates of respiration of roots and leaf discs of both species were not affected by pyrazon treatmentsin vivoorin vitro.
Trifluralin Persistence as Affected by Depth of Soil Incorporation
Authors: Savage K. E. , Barrentine W. L.
Published: June 2019

Bioassay and chemical analyses of residual α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine (trifluralin) from greenhouse and field experiments indicated that the persistence of this herbicide is increased by deep incorporation as compared to shallow incorporation or surface application. Laboratory studies using a charcoal vapor trap indicated that trifluralin volatilization decreased with increasing depth of incorporation. Volatilization appears to be an important mode of trifluralin dissipation from the soil.
The Response of Fumitory to Various Herbicides
Authors: Jeffery Larry S. , Nalewaja John D.
Published: June 2019

Ioxynil (4-hydroxy-3,5-diiodobenzonitrile) and 2-(2,4-dichlorophenoxy)propionic acid (dichlorprop) appeared effective for control of fumitory (Fumaria officinalis L.) of the 10 herbicides tested in 1963. In 1964 and 1965, both herbicides were further tested under field conditions, but fumitory control results were erratic. Fumitory plants which had been treated with dichlorprop, although not killed, did not produce seed. Experiments under controlled environmental conditions showed that susceptibility of fumitory to ioxynil and dichlorprop was affected by temperature and humidity. High temperature and humidity were necessary for both herbicides to completely kill the plants although dichlorprop injured fumitory under all the environments. Fumitory was more susceptible to dichlorprop applied at the early stages of growth and more susceptible to ioxynil applied at the later stages.
Seed Dormancy and Germination in Ecotypes of Johnsongrass
Authors: Taylorson R. B. , McWhorter C. G.
Published: June 2019

We studied germination of seeds of 44 morphologically distinct, vegetative ecotypes of johnsongrass (Sorghum halepense (L.) Pers.). Seeds of most ecotypes were highly dormant. Without low temperature pretreatment, best germination occurred with continuous fluorescent light, a KNO3 substratum, and an alternating 20 to 35 C temperature regime. Pretreatment of the seeds for 2 weeks at 10 C, followed by a temperature shift to 40 C for 2 hr was effective in breaking seed dormancy. Germination of each of 12 ecotypes, from harvests in each of 2 years, was markedly similar. Interpretation of the evidence suggests that seed dormancy is largely imposed by the relative degree of mechanical restriction afforded by the seed coat.
Effects of Ammonium Thiocyanate on Carbohydrate Metabolism in the Cotton Plant
Authors: Wu Yih-Fen , Basler Eddie
Published: June 2019

Some effects of ammonium thiocyanate (hereinafter referred to as NH4SCN) on the starch and reducing sugar content, amylase activity, photosynthetic O2release, Hill reaction, and glycine-14C incorporation into amino acids, organic acids, and sugar fractions in excised leaf and cotyledonary tissue of cotton (Gossypium hirsutumL., var. Acala 44) were determined. The starch content of leaf tissue floated on Hoaglands nutrient solution containing 2000 ppm NH4SCN decreased at 1 and 2 days treatment. The amylase activity of excised cotyledons was increased by 2000 and 5000 ppm NH4SCN and the reducing sugar of the same tissue was decreased. Photosynthesis of small leaf disks, as measured by O2exchange, was decreased and respiration was increased by 2000 ppm NH4SCN. Photosynthesis in isolated chloroplasts, as measured by the reduction of 2,6-dichlorophenolin dophenol in the Hill reaction, also was inhibited by NH4SCN at concentrations above 2000 ppm. Ammonium thiocyanate at 2000 ppm inhibited the conversion of glycine to sugars but had no effect on conversion of glycine to organic acids in leaf tissue.
Control of Johnsongrass on Drainage Ditchbanks in Sugarcane
Authors: Millhollon Rex W.
Published: June 2019

Several herbicides were applied to drainage ditchbanks in sugarcane (Saccharum officinarum L.) to control johnsongrass (Sorghum halepense (L.) Pers.) from rhizomes and seed. Five post-emergence applications of monosodium methanearsonate (MSMA) at 3.6 lb/A or 2,2-dichloropropionic acid (dalapon) at 7.4 lb/A controlled rhizome johnsongrass as effectively as 600 lb/A of sodium chlorate, the standard treatment. Johnsongrass seedlings infested ditchbanks 1 year after applying sodium chlorate. But preemergence treatments with mixtures of (2,3,6-trichlorophenyl)acetic acid (fenac), 5-bromo-3-sec-butyl-6-methyluracil (bromacil), or trichloroacetic acid (TCA) with MSMA, or postemergence applications of MSMA, dalapon, and sodium chlorate controlled these seedlings. Bermudagrass (Cynodon dactylon (L.) Pers.) rapidly vegetated ditchbanks treated with MSMA, but other herbicide treatments suppressed vegetation with desirable species to the point where erosion could become a problem.
Emergence of Medusahead and Other Grasses from Four Seeding Depths
Authors: Young James A. , Evans Raymond A. , Eckert Richard E.
Published: June 2019

Emergence of 23 medusahead (Taeniatherum asperum(Sim.) Nevski) selections from four seeding depths in two soils was investigated and compared with that of other grasses. Increased depth markedly reduced total emergence of medusahead and variability among selections. Selections of intermediate wheatgrass (Agropyron intermedium(Host) Beauv) and pubescent wheatgrass (Agropyron trichophorum(Link) Richt.) and downy brome (Bromus tectorumL.), among other grasses, greatly exceeded medusahead in emergence from all depths. Standard crested wheatgrass (Agropyron desertorum(Fisch. ex Link) Schult.) had less emergence than medusahead from all depths. The 3 and 4-inch planting depths exceeded the coleoptile length of medusahead. When medusahead emerged from these depths, the first true leaf was recurved and chlorotic.
Competition Between Flax and Wild Buckwheat
Authors: Gruenhagen R. D. , Nalewaja John D.
Published: June 2019

Competition between wild buckwheat (Polygonum convolvulusL.) and flax (Linum usitatissimumL.) was studied in field experiments at various North Dakota locations and in a controlled environment chamber in relation to soil moisture, soil fertility, light, wild buckwheat density, flax seeding rate, and length of the competition period. In the field, flaxseed yield losses caused by competition were lowered by increasing the flax seeding rate and by early wild buckwheat removal. Fertilizer increased flaxseed yield losses at the high seeding rate and generally doubled wild buckwheat dry matter production. Flax dry matter was reduced by competition at the lower seeding rates. The field and controlled environment studies indicated that competition occurred mostly in the root zone. In the latter study, wild buckwheat was a better competitor than flax on a dry weight basis and the dry weights appeared to be related to nitrogen uptake. Wild buckwheat utilized water for growth more efficiently than flax.
Absorption and Translocation of 2,4-D by Wolftail (Carex Cherokeensis Schwein)
Authors: Burns Earl R. , Buchanan Gale A. , Hiltbold A. E.
Published: June 2019

Absorption and translocation of the sodium salt of radioactive (2,4-dichlorophenoxy)acetic acid (2,4-D-2-14C) by wolftail (Carex cherokeensis Schwein) plants grown from rhizomes were enhanced by high relative humidity but were not affected by dimethyl sulfoxide (hereinafter referred to as DMSO). Greatest accumulation of 2,4-D-2-14C translocated from the treated leaf occurred, in the meristematic tissue. DMSO increased the herbicidal activity of the triethanolamine salt of 2,4-D alone, but 2,4-D plus DMSO was no more effective than 2,4-D plus X-77. When both DMSO and X-77 were added to the 2,4-D solution, the treatments were no more effective than when either additive alone was included.
Dormancy of Wild Oat Seed Produced under Various Temperature and Moisture Conditions
Authors: Sexsmith J. J.
Published: June 2019

Four greenhouse trials were conducted to determine the effects of various growth temperatures and soil moistures on dormancy of primary seed of selected strains from two wild oat (Avena fatua L. ssp. fatua (L.) Thell.) varieties. Both higher temperature and lower level of moisture decreased dormancy, temperature having a greater effect than level of soil moisture. The dormancy difference between seed produced on plants grown at 15.6 to 18.3 C in soil with approximately 75% or from 100 to 75% available moisture and at 25.3 to 28.4 C in soil with approximately 25% or from 100 to 25% available moisture ranged between 31 and 100%, dormancy tests being conducted 10 or 14 days after seed maturity. The magnitude of the difference in seed dormancy caused by conditions of growth was affected by strain and variety of wild oat, and by age of seed.
Absorption and Translocation of Simazine in Parrotfeather
Authors: Sutton David L. , Bingham S. W.
Published: June 2019

Root applications of 2-chloro-4,6-bis(ethylamino)-s-triazine (simazine) at concentrations greater than 1.0 × 10-7M inhibited growth of parrotfeather (Myriophyllum brasilienseCamb.). Chromatographic analysis of exudate from detopped parrotfeather plants indicated that simazine was being tranlocated primarily as the intact molecule. A correlation coefficient of 0.985 was observed between the amount of simazine-14C removed from the treatment solution and transpiration during a 6-hr period. Absorption of simazine-14C by parrotfeather roots of intact plants was linear for the first 4 hr followed by a gradual decrease at the end of 6 hr. Simazine-14C at 1 and 2 hr after root applications was highest in the roots, intermediate in the lower part of the shoot, and lowest in the upper part of the shoot. After 192 hr, simazine-14C accumulated in the top of the shoot in a concentration higher than in the lower part of the shoot or the roots. A correlation coefficient of 0.988 was found between the amount of simazine-14C present in the tissue and the treatment concentration over a range of 1.2 × 10-6to 5.0 × 10-6M.
Effect of Stage of Growth of Field Bindweed on Absorption and Translocation of14C-Labeled 2,4-D and Picloram
Authors: Agbakoba Chuma S. O. , Goodin J. R.
Published: June 2019

The effect of stage of growth of field bindweed (Convolvulus arvensisL.) on absorption and translocation of14C-labeled 2,4-D and picloram was studied. Three stages of growth investigated weres-week old seedlings, and 7-week old and 16-week old vegetatively propagated plants. One middle leaf of each plant was treated with either14C-labeled (2,4-dichlorophenoxy)-acetic acid (2,4-D) or 4-amino-3,5,6-trichloropicolinic acid (picloram). Treated plants were harvested after 48 hr and assayed for radioactive14C. The percent of 2,4-D applied which was absorbed by seedlings was less than that absorbed by adult plants. Picloram absorption was not different in seedlings and 7-week old adult plants, but the 16-week old adult plants absorbed more picloram than either the 5-week old seedlings or 7-week old adult plants. More picloram than 2,4-D was absorbed at all stages of growth. Translocation of both 2,4-D and picloram was greater in seedlings than in older plants. No difference was found in amounts of 2,4-D and picloram translocated by adult field bindweed plants. More 2,4-D than picloram was translocated by seedlings.
Effect of Weeds on Harvesting Efficiency in Corn, Sorghum, and Soybeans
Authors: Burnside O. C. , Wicks G. A. , Warnes D. D. , Somerhalder B. R. , Weeks S. A.
Published: June 2019

Widely varying weed densities that had been desiccated by freezing did not reduce combine efficiency (gathering plus threshing losses) in harvesting corn (Zea mays L., var. Nebraska 508), sorghum [Sorghum bicolor (L.) Moench, var. RS 610], or soybeans (Glycine max L., var. Ford). Average combine gathering losses with corn, sorghum, and soybeans were 2, 7, and 16%, respectively. Average threshing losses with the combine were less than 1% with corn and sorghum and less than 3% with soybeans. The high gathering losses in this study were due partly to delayed combining to allow the weeds to be desiccated by freezing temperatures.
Phytotoxicity, Leachability, and Site of Uptake of 2-chloro-2′,6′-diethyl-N-(methoxymethyl) acetanilide
Authors: Eshel Y.
Published: June 2019

The toxicity, leachability, and site of uptake of the herbicide 2-chloro-2',6'-diethyl-N-(methoxymethyl) acetanilide (hereinafter referred to as CP 50144) were studied in different soils. Two inches of water leached most of the compound to a soil depth of 2 to 3 inches, when applied at rates of 1 and 2 kg/ha. The inherent toxicity of CP 50144 to cotton (Gossypium hirsutumL., var. Acala 4-42) was studied in culture solution. The herbicide was most toxic to cotton when the entire root system of the crop was exposed to soil treated with CP 50144; reduction of weight of seedlings was accompanied by severe inhibition of root growth. On the other hand, only a slight reduction in growth rate was noticed when only the shoot zone of cotton was exposed to the herbicide.
Hydrogen Bonding of Dalapon
Authors: Kemp T. R. , Stoltz L. P. , Herron J. W. , Smith W. T.
Published: June 2019

The hydrogen bonding of 2,2-dichloropropionic acid (dalapon) to N-methylacetamide (NMA) as a model protein was studied using infrared spectra. Changes in the spectra indicated that the dalapon carboxyl-OH, hydrogen bonds significantly to the model amide carbonyl.
Response of Weeds and Soybeans to Amiben and Naptalam Individually and in Mixtures with Dinoseb
Authors: Hauser Ellis W. , Marchant W. H.
Published: June 2019

On Tifton loamy sand, N-1-naphthylphthalamic acid (naptalam) controlled weeds much better, and injured soybeans [Glycine max (L.) Merr.] much less, when mixed with 2-sec-butyl-4,6-dinitrophenol (dinoseb) and applied as a delayed preemergence treatment, than when it was applied alone immediately after planting. Differences attributable to either timing of application or to mixing with dinoseb were not as marked for 3-amino-2,5-dichlorobenzoic acid (amiben) as for naptalam. Neither amiben, naptalam, nor mixtures of these two herbicides with dinoseb adversely affected germination, weight per seed, or total oil and protein content of the harvested soybean seed.
Dryland Sorghum Production and Weed Control with Minimum Tillage
Authors: Phillips W. M.
Published: June 2019

Herbicides applied shortly after wheat (Triticum aestivum L.) harvest combined with no tillage or with several minimum tillage treatments were compared with conventional tillage for weed control from wheat harvest 1 year through sorghum (Sorghum bicolor (L.) Moench) production the next year. Three lb/A of 2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine (atrazine) with no tillage did not completely control weeds, but over 4 years of sorghum grain yields on the atrazine-no tillage plots and on conventional tillage plots were not significantly different. One tillage either immediately before or immediately after application of 3 lb/A atrazine controlled essentially all weeds from wheat harvest until fall, but in some years grass weeds emerged in the spring. One pre-planting tillage or one cultivation after sorghum emergence reduced weed competition so that no additional weed control measures were needed. Sorghum yields from those plots were substantially above yields resulting from conventional tillage.
Some Quantitative Aspects of the Phytotoxicity of Monoterpenes
Authors: Asplund R. Owen
Published: June 2019

The phytotoxic monoterpenes, camphor, pulegone, and borneol, exhibit a marked synergistic action when used in combination. On a molar basis, these phytotoxic concentrations are enhanced from 40 to 100 times by using two compounds simultaneously. The toxicity of these compounds is about the same for radish (Raphanus sativus L.) and wheat (Triticum vulgare Vill.) but is less by an average of tenfold for oats (Avena sativa L.). When the compounds are used singly, they are from 3 to 12 times as effective in inhibiting root elongation as they are in inhibition of germination.
Bromacil Interactions in Plant Bioassay, Fungi Cultures, and Nitrification
Authors: Pancholy Sunil K. , Lynd J. Q.
Published: June 2019

Rates and magnitude for phytotoxic diminuation of 5-bromo-3-sec-butyl-6-methyluracil (bromacil) at 0.25, 0.5, and 1 ppm for oats (Avena sativa L.) and 1, 2, and 4 ppm for sorghum (Sorghum vulgare Pers.) plants were related to increased nitrogenous composition of organic and inorganic amendments with a Psammentic paleustalf, Eufaula sand. Soil isolates not inhibited by bromacil concentrations up to 2,000 ppm in defined broth media sans presynthesized growth factors included Aspergillus tamarii Kita, A. flavus Link ex Fries, A. oryzae (Ahlburg) Cohn, Penicillium funiculosum Thorn. P. brevicompactum Dierckx. Curvularia lunata (Wakker) Boedijn, Mucor pusillus Lindt, Trichoderma viride Persoon ex Fries, and Myrothecium verucaria Ditmar. A. niger van Tieghem was inhibited with bromacil levels less than 1500 ppm. This substituted uracil fungitoxicity was offset with increasing inorganic N levels to 500 ppm as NH4NO3 and/or 1,000 ppm of presynthesized growth factor additive as cyanocobalamin, yeast extract, and peptone. Bromacil levels to 100 ppm reduced nitrification temporarily for only 5 days in contrast to sustained inhibition of nitrification for 15 days by equivalent levels of 2-amino-4-chloro-6-methylpyrimidine (Toyo Koatsu AM).
Competition Between Kochia and Sugarbeets
Authors: Weatherspoon D. M. , Schweizer E. E.
Published: June 2019

In a 2-year study, kochia [Kochia scoparia (L.) Schrad.] competed with sugarbeets (Beta vulgaris L.) for various periods after emergence. Kochia then was removed and plants that emerged subsequently were controlled by hand-weeding. Yield of sugarbeet roots was reduced when kochia competed for more than 5 or 6 weeks. Kochia that competed with sugarbeets for the entire season reduced yields more than 95%. In another study, kochia was controlled by frequent hand-weeding for different periods after sugarbeet emergence. When kochia was controlled initially for 3 to 4 weeks, yield of sugarbeets was not reduced. Some kochia emerged following the 3 to 4 weeks of hand-weeding. However, competition from sugarbeets reduced the weight of this kochia at harvest by 59 and 92%.
Transformation of Solan in Soil
Authors: Bartha Richard
Published: June 2019

In laboratory studies, the herbicide 3'-chloro-2-methyl-p-valerotoluidide (solan) when applied to soil was transformed in part to 3,3'-dichloro-4,4'-dimethylazobenzene. The biochemically mediated transformation followed the pattern established previously for 3,4-dichloroaniline-based acylanilides, but the 3-chloro-4-methylaniline intermediate did not accumulate. Compared to 3,4-dichloroaniline-based acylanilides, solan yielded less azo residue and did not inhibit soil respiration, even if applied at 200 times the recommended field rate.
Plant Response to Herbicide Placement in Soil
Authors: Nishimoto Roy K. , Appleby Arnold P. , Furtick William R.
Published: June 2019

Greenhouse and growth chamber studies were conducted to investigate effects of herbicide placement in soil on toxicity to emerging seedlings. The use of a technique involving a plastic bag over the plants for 3 to 4 weeks to reduce soil moisture loss did not change the apparent site of 2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine (atrazine) uptake by green foxtail (Setaria viridis(L.) Beauv.) or oats (Avena sativaL.). Atrazine was more effective on oats through root exposure and more effective on green foxtail through shoot exposure when an untreated buffer zone around the seed was used. But in subsequent studies without the buffer zone, atrazine was most active when placed immediately below the seed of both oats and green foxtail. Proximity to the seed increased effectiveness of atrazine,S-ethyl dipropylthiocarbamate (EPTC), and 3-(3,4-dichlorophenyl)-1,1-dimethylurea (diuron). Also, a narrow concentrated layer of these three herbicides adjacent to the seed was more effective than a wider dilute layer above or below the seed. A diurnal fluctuating temperature regime with a low night temperature increased toxicity of EPTC to oats through root exposure, when compared to a constant temperature regime.
The Detection of Trifluralin Vapors in Air
Authors: Ketchersid M. L. , Bovey R. W. , Merkle M. G.
Published: June 2019

The volatilization of α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine (trifluralin) from a Miller clay and commercial sand was determined by analysis of air samples above the soils. The method requires no extraction of soil or traps and is sensitive to approximately 8 ppm of trifluralin in air. The loss of trifluralin was influenced more by soil moisture than by soil type. Data indicated that trifluralin vapors in air are photolytically degraded. Similar studies were conducted with 4-(methylsulfonyl)-2,6-dinitro-N,N-dipropylaniline (nitralin), but volatilization was so slow that detectable concentrations of this herbicide did not occur.
Movement and Persistence of Picloram in Pasture Soils of Nebraska
Authors: Scifres C. J. , Burnside O. C. , McCarty M. K.
Published: June 2019

More 4-amino-3,5,6-trichloropicolinic acid (picloram) was detected in soil samples by soybean (Glycine max(L.) Merr., var. Ford) bioassay when the herbicide was applied in the fall than when it was applied in the spring to several pasture types. Downward movement was greater in sandy loam than in silty clay loam. Dissipation of picloram was greatest in the upper 12 inches regardless of soil type. More picloram was detected in the 24 to 36-inch depth from plots treated 1, 2, or 3 years before sampling than in plots sampled the year of treatment. This indicated downward movement into the subsoil.
Tolerance of Cotton to Diuron, Fluometuron, Norea, and Prometryne
Authors: Eshel Y.
Published: June 2019

The phytotoxicity of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (diuron), 1,1-dimethyl-3-(α,α,α-trifluoro-m-tolyl)urea (fluometuron), 3-(hexahydro-4,7-,methanoindan-5-yl)-1,1-dimethylurea (norea), and 2,4-bis(isopropylamino)-6-(methylthio)-s-triazine (prometryne) to cotton (Gossypium hirsutumL., var. Acala 4-42) was compared. Warburg experiments indicated that fluometuron and norea inhibited photosynthesis in isolated leaf disks to a much smaller extent than did diuron and prometryne. When the plants were grown in solution culture, diuron and prometryne were much more phytotoxic to cotton than fluometuron and norea, whereas when grown in soil, prometryne was the least phytotoxic, followed by norea, fluometuron, and diuron. Results of experiments on root vs. shoot uptake showed that all four herbicides entered the cotton seedlings through the roots, and no injury occurred to cotton when the compounds were applied to the shoot zone only. Norea and fluometuron were much more leachable than prometryne and diuron. These results indicate that depth protection in the soil, in addition to translocation and metabolism, might account partially for the tolerance of cotton to preemergence application of the tested herbicides.
Some Chronic Effects of Diuron on Bluegills
Authors: McCraren Joseph P. , Cope Oliver B. , Eller Lafayette
Published: June 2019

Effects of sub-acute levels of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (diuron) on bluegill sunfish (Lepomis macrochirus Rafinesque) were assessed in a pond environment. Eight 0.1-A earthen ponds were each stocked with 300 bluegill fingerlings and treated once with diuron wettable powder at 0, 0.5, 1.5, and 3.0 ppmw, two ponds per treatment level. Dissolved oxygen was reduced severely in some pond waters 2 days following treatment and the low level persisted for 3 to 4 days. Gill lamellae were ruptured and hemorrhagic in 20% of the fish from the 3.0 ppmw ponds at 3 days post-treatment. Fish in a cage succumbed during this period in a 3.0 ppmw pond. No further bluegill mortality was observed in treated ponds 3 days after treatment. Hematocrit measurements of treated and control fish could not be correlated with treatment level. Best growth was exhibited by control fish and their progeny. Diuron residues were not detectable in treated pond waters after 28 days. Residues of diuron in treated-pond vegetation were detectable up to 95 days following treatment, whereas residues in mud were measured by gas chromatography 122 days after treatment. Invertebrate populations increased in all ponds with time, indicating little or no effect of the herbicide on their numbers. Good control of filamentous algae and vascular aquatic vegetation was demonstrated in the treated ponds.
Response of Turkey Oak to 2,4,5-T as a Function of Final Formulation Oil Content
Authors: Upchurch R. P. , Keaton J. A. , Coble H. D.
Published: June 2019

Shoots of naturally established specimens of turkey oak (Quercus laevis Walt.) 3 to 6 ft high were treated with 4 to 8 lb aehg of a commercial concentrate formulation of the butoxyethanol ester of (2,4,5-trichlorophenoxy)acetic acid (2,4,5-T) on or about May 1, June 1, July 1, August 1, and September 1. Foliar applications were made to the point of run-off and foliar-basal treatments were made first to the basal 8 inches of the main stem and then to the lower four-fifths of the remainder of the shoot. The objective was to assess the utility of number two diesel fuel as an additive for such treatments when the oil was used at rates of 0, 5, 10, and 20% in the final formulations. The experiment was repeated in 3 different years. Responses measured approximately 11, 14, and 23 months after initial treatment were percent control of original shoots, percent control of new shoots, shoot height, and number of live stems/plant. Foliar treatments without oil were progressively less effective as they were made later in the growing season. The addition of oil to foliar treatments provided more effective control of the original shoots and greater reduction in shoot heights, especially when the oil concentration was 20%. The foliar-basal method was notably ineffective in the absence of oil. Addition of oil to the foliar-basal treatments provided marked improvement in the original shoot, total shoot control index, shoot height, and stems/plant responses, especially at the 20% level of oil. Diesel fuel is useful as an additive for 2,4,5-T sprays to be applied to turkey oak, especially where treatment is to be made in the latter half of the growing season and in particular where the lower stems can be treated.
Degradation of Atrazine in Four Hawaiian Soils
Authors: Obien S. R. , Green R. E.
Published: June 2019

The degradation of14C ring-labeled 2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine (atrazine) was studied in the laboratory with four Hawaiian soils selected for their wide range of organic matter contents (4 to 29%), pH values (4.4 to 6.3), and different mineralogies. Atrazine concentrations of 1, 5, 10, 50 and 100 ppmw in soils incubated at 30 C gave similar14C-recovery curves. Degradation was rapid in all four soils; atrazine recovery at 34 days (30 C) ranged from 15 to 30% of the quantity applied. Degradation was accelerated by a temperature increase from 30 to 50 C, suggesting a chemical rather than a biological process. The loss of atrazine from soils approached a first order reaction rate at 30 C, and deviated from this at 50 C. Hydroxyatrazine was the main degradation product with only a slight amount of an unidentified “Product B”. It was concluded that chemical degradation (hydrolysis) was the major pathway of atrazine loss in these soils. This process was more closely related to pH, i.e. faster on low pH soils, than with organic matter content or adsorption. The fraction of atrazine adsorbed on soil increased with the decrease in total atrazine caused by degradation. Extraction of soils with both water and methanol and subsequent analysis of extracts by thin-layer chromatography showed that some of the methanol-extractable atrazine was not readily desorbed by water. These results indicate that some of the residual atrazine extracted chemically may not be available for uptake by plants and would be relatively immobile in soil water.
Uptake, Translocation, and Fate of 2,4-D in Nightflowering Catchfly and Common Lambsquarters
Authors: Neidermyer Robert W. , Nalewaja John D.
Published: June 2019

The uptake, translocation, and fate of (2,4-dichlorophenoxy)acetic acid (2,4-D) were compared in nightflowering catchfly (Silene noctiflora L.) and common lambsquarters (Chenopodium album L.), resistant and susceptible species, respectively. Nightflowering catchfly leaf sections absorbed more 2,4-D from 5 × 10-4 M and 5 × 10-6 M 2,4-D solutions at pH 3.0 than did leaf sections of common lambsquarters. Intact plants of both species accumulated 2,4-D in the stems and leaves below the treated leaf. At 72 hr after treatment, nightflowering catchfly released 2,4-D through the roots into the nutrient solution while common lambsquarters continued to accumulate 2,4-D. Nightflowering catchfly metabolized 2,4-D and the metabolite was recovered in the roots 24 hr after treatment, whereas common lambsquarters did not metabolize 2,4-D.
Modes of Action of Pyridazinone Herbicides
Authors: Hilton J. L. , Scharen A. L. , St. John J. B. , Moreland D. E. , Norris K. H.
Published: June 2019

Four substituted pyridazinone compounds inhibited the Hill reaction and photosynthesis in barley (Hordeum vulgareL., var. Dayton C.I. 9517). These inhibitions appeared to account for the phytotoxicity of 5-amino-4-chloro-2-phenyl-3(2H)-pyridazinone (pyrazon). The pyridazinone chemicals were weaker inhibitors than 2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine (atrazine). Two substitutions onto the molecular structure of pyrazon result in a new experimental herbicide, 4-chloro-5-(dimethylamino)-2-(α,α,α-trifluoro-m-tolyl)-3(2H)-pyridazinone (hereinafter referred to as 6706), which retains the action mechanism of pyrazon but also has two additional biological properties. It is resistant to metabolic detoxication in plants, and it possesses a second mode of action involving interference with chloroplast development. The second action is like that expressed by 3-amino-s-triazole (amitrole) and by 3,4-dichlorobenzyl methylcarbamate (dichlormate). However, the new chemical is 100 to 1000 times more effective. The trifluoromethyl substitution on the phenyl ring and the dimethyl substitution on the amine are both required to give either of the two additional physiological properties. Analogs with only one of the two substitutions behave like pyrazon rather than like 6706.
Chemical versus Mechanical Fallow of Abandoned Croplands
Authors: Everson A. C. , Hyder D. N. , Gardner H. R. , Bement R. E.
Published: June 2019

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.
Life Cycles of Field Pennycress in the Subarctic as Influenced by Time of Seed Germination
Authors: Klebesadel L. J.
Published: June 2019

Field pennycress (Thlaspi arvense L.) was seeded in rows at approximately 10-day intervals from June 1 to August 30, 1963, and from July 12 to August 31, 1966, in subarctic, south-central Alaska (61.5° N.). Plants from June 20 and earlier seedings produced mature seed as summer annuals; those from seedings during the first 3 weeks of July produced elongated stems and green pods, while those from later seedings produced unelongated, basal rosettes. Seedlings that emerged during July or later were potential winter annuals. No study plants survived the 1963-64 winter. The 1966 plantings survived the 1966-67 winter as follows: July 12, 50%, July 20, 54%, August 1, 93%, and August 12, 23, and 31, 100%. Morphology, time of flowering, and seed pod production of plants surviving the winter also were influenced by planting date the previous growing season. To prevent field pennycress from producing seed as a summer annual, plants that emerge before the middle of July must be eradicated. Plants that emerge during July or later should be destroyed as seedlings or prior to seed production time the following year.
Herbicide Concentrations in Live Oak Treated with Mixtures of Picloram and 2,4,5-T
Authors: Baur J. R. , Bovey R. W. , Smith J. D.
Published: June 2019

Recovery of (2,4,5-trichlorophenoxy)acetic acid (2,4,5-T), as the acid and ester, was significantly greater in live oak(Quercus virginianaMill.) tissues treated with mixtures of the 2-ethylhexyl ester of 2,4,5-T (2 lb/A)-.potassium salt or isooctyl ester of 4-amino-3,5,6-trichloropicolinic acid (picloram) (1/2, 1 and 2 lb/A) than in tissues treated with 2 lb/A 2,4,5-T ester alone. Recovery of 2,4,5-T as the ester was noted in the middle and lower-stem tissues. Between 90 and 99% of the herbicide recovered 1 month after treatment was gone 6 months after treatment. Evaluation of brush reduction 2 years after treatment indicated that mixtures of picloram salt and 2,4,5-T resulted in greater reduction of brush than mixtures of picloram ester and 2,4,5-T or 2,4,5-T alone.
Picloram Sensitivity and Nucleic Acids in Plants
Authors: Malhotra S. S. , Hanson J. B.
Published: June 2019

The changes in the nucleic acid metabolism were studied in plants susceptible and resistant to 4-amino-3,5,6-trichloropicolinic acid (picloram). The total RNA and DNA content of the tissue correlated inversely with the herbicide resistance; the resistant plants were low in nucleic acids, whereas sensitive plants were high. The increase in the nucleic acids of the sensitive species 24 hr after picloram treatment appeared to be associated with lower levels of ribonuclease and deoxyribonuclease. The inability of the resistant species to make more RNA may be associated with high levels of nucleases in the tissue.
Chemical Composition of Five Species ofNymphaeaceae
Authors: Riemer D. N. , Toth S. J.
Published: June 2019

Five species ofNymphaeaceae, representing four genera, were collected from various sites in New Jersey and their tissues analyzed for 12 elements. Three species were separated into leaf blades and petioles before the mineral analyses were made. Variations in the concentrations of many elements were noted between these two structures. Except for the petioles of these three species, the N content of the plants appeared to be sufficiently high so that no extra N would be required to prepare composts from them.
Factors Affecting Growth of Rooted Aquatic Plants in a Reservoir
Authors: Peltier W. H. , Welch E. B.
Published: June 2019

Water samples were taken from Pickwick Reservoir from 1965 through 1968 and the nitrogen and phosphorus content determined. The nitrogen and phosphorus content over a period of 3 years was not related to the year-to-year plant growth. Physical and climatic data were obtained from 1961 through 1968, and it was found that available light was controlled by the amount of rainfall and ensuing reservoir elevation during the critical plant growth period in April and May. Available light was correlated with the 2 years of severe infestations.
Behavior of Amiben and Dinoben Derivatives in Arkansas Soils
Authors: Talbert R. E. , Runyan R. L. , Baker H. R.
Published: June 2019

The influence of six Arkansas soils on the leaching characteristics of derivatives of 3-amino-2,5-dichlorobenzoic acid (amiben) and 3-nitro-2,5-dichlorobenzoic acid (hereinafter referred to as dinoben) in slotted soil columns was determined using large crabgrass [Digitaria sanguinalis(L.) Scop.] bioassay. The ammonium and aluminum salts of amiben and the sodium salt of dinoben were easily leached and leaching was not noticeably affected by soil type. The ammonium salt of amiben was not adsorbed, while the methyl ester of amiben was adsorbed by these soils. Adsorption was related to the clay and organic matter content of the soil. Methyl and butoxyethyl ester derivatives of amiben and dinoben resisted leaching in these soils and the amide of amiben was intermediate in leaching. The adsorption and leaching behavior of the ester derivatives of these compounds were complicated by their rapid hydrolysis in these soils. The hydrolyzed product behaved identically to the salt derivatives of the compounds in leaching, adsorption, and chromatographic properties. Hydrolysis of the methyl ester was inhibited by soil sterilization, dry soil, and temperatures below 20 C. In non-sterile, warm, moist soil, the half-life of the methyl ester of amiben was 28 hr. Four species ofBacilluswere capable of hydrolyzing the methyl ester of amiben in pure culture studies.
Combined Effect of Trifluralin and MSMA on Johnsongrass Control in Cotton
Authors: Kleifeld Y.
Published: June 2019

Preplanting application of α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine (trifluralin), reduced the number of monosodium methanearsonate (MSMA) applications needed for the control of johnsongrass (Sorghum halepense (L.) Pers.). The combined effect enabled weed control to be completed before cotton (Gossypium hirsutum L.) began to bloom, and hence without causing damage to the crop.
The Uptake of Picloram by Potato Tuber Tissue
Authors: Baur J. R. , Bovey R. W.
Published: June 2019

Pretreatment of potato (Solanum tuberosumL., var. Russet) tuber discs in pH 5.5 buffer significantly reduced uptake of picloram (10−3M). Tissue pretreated in buffer at 7 C subsequently absorbed more picloram than tissue pretreated at 25 C. Inclusion of cetyl trimethyl ammonium bromide (hereinafter referred to as CTAB) (2 × 10−4M) in the treating solution caused a significant increase in picloram uptake in tissues that were not pretreated in buffer. The reduction in uptake caused by buffer pretreatment was effectively reversed when CTAB was included in the treating solution. The results suggest that picloram uptake by potato tissue is related to the availability of the quaternary ammonium binding sites provided by membrane phosphatides.
Influence of Mowing and Spraying Dates on Herbicidal Control of Macartney Rose
Authors: Haas R. H. , Lehman S. K. , Morton H. L.
Published: June 2019

We compared foliage sprays of (2,4-dichlorophenoxy)acetic acid (2,4-D) and 4-amino-3,5,6-trichloropicolinic acid (picloram) for control of Macartney rose (Rosa bracteata Wendl.) applied with ground equipment and airplane. Picloram at 0.5 lb/A was more effective than 2,4-D at 2 lb/A at all dates of application on mowed roses; however, time of application was important. Picloram was most effective in late April and early May, but 2,4-D was most effective in late May and early June. Combinations of picloram and 2,4-D were effective from late April to late June. If mowing is followed by foliage treatment of 2,4-D, the interval between mowing and spraying should be at least 1 year if mowing is done in the spring. The interval between mowing and spraying was not critical when picloram was applied not later than early May. Mowing in the summer reduced the effectiveness of subsequent 2,4-D and picloram treatments applied the following year. Aerial applications of 2,4-D and picloram on undisturbed Macartney rose plants in the fall were not as effective as spring applications; however, two successive fall applications of picloram at 1 lb/A resulted in control equivalent to that obtained with a single 2 lb/A application in spring.
Germination Characteristics of Three Species ofCruciferae
Authors: Young James A. , Evans Raymond A. , Gifford Richard O. , Eckert Richard E.
Published: June 2019

Germination of tumble mustard (Sisymbrium altissimumL.), tansy mustard (Descurainia pinnata(Walt.) Britton), and yellowflower pepperweed (Lepidium perfoliatumL.) is partially dependent on total degree hours of incubation (temperature above 0 C times the duration of incubation). This relation was similar under constant or alternating temperatures. Alternating temperature regimes with −20 C inhibited germination, and greatly depressed subsequent germination at optimum temperatures. Tansy mustard and yellowflower pepperweed have temperature-dependent after-ripening requirements. Germination of all three species responded similarly to osmotic stress. The relation between tumble mustard germination under osmotic or soil moisture stress is dependent on the texture of the soil substrate. A mucilaginous coating greatly aids the germination of yellowflower pepperweed seeds on the surface of media under low (0.05 to 0.2 bars) moisture tension. Germination of seeds of the three species recovered in soil samples from the field is radically different from that of freshly harvested material. The seeds acquire a dormancy which is broken irregularly under ideal conditions for germination.
Ultrastructural Changes of Tobacco Chloroplasts Induced by Pyriclor
Authors: Geronimo J. , Herr J. W.
Published: June 2019

Treatment of tobacco (Nicotiana tabacumL., var. NC-402) with 2,3,5-trichloro-4-pyridinol (pyriclor) leads to progressive disruption of chloroplast ultrastructure. Initial changes include the inception of a spherical form, swelling of the fret system, and commencement of loss of starch. More advanced changes include the complete disappearance of starch, further swelling and disorganization of the fret membrane system, followed by swelling and disruption of the membranes of the granal discs and rupture of the chloroplast envelope. The changes induced by pyriclor on chloroplast ultrastructure in tobacco are analagous to those caused by 2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine (atrazine) on kidney bean (Phaseolus vulgarisL.) and barnyardgrass (Echinochloa crusgalliL. Beauv.). The shape and size of mitochondria were not altered by treatment with the chemical; however, there appeared to be a significant increase in the number of mitochondria present when alterations in chloroplast structure could be seen. The appearance of visual symptoms of phytotoxicity (chlorosis) correlated with the onset of disruptive changes in chloroplast ultrastructure.
Diffusion of Three Chloros-Triazines in Soil
Authors: Lavy T. L.
Published: June 2019

Atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triaazine] diffused at a rate of 15.2 × 10−8sq cm/sec at 25 C which was faster than the diffusion rate of 2-chloro-4,6-bis(ethylamino)-s-triazine (simazine) and 2-chloro-4,6-bis(isopropylamino)-s-triazine (propazine) in the same soils. Diffusion rates were highly correlated with total surface area of the soil. Increasing soil moisture content, soil pH, and soil temperature resulted in greater diffusion rates. A relative indication of herbicide mobility may be obtained from some of the physical and chemical properties of the soils and herbicides involved; however, rate of diffusion appears to be governed by a combination of soil and herbicide properties.
Movement of Several Herbicides Through Excised Plant Tissue
Authors: Taylor T. D. , Warren G. F.
Published: June 2019

Uptake and movement of various herbicides and auxins by bean (Phaseolus vulgarisL.) petiole sections were studied. Isopropylm-chlorocarbanilate (chlorpropham) was the most mobile of the compunds studied, followed in order of decreasing mobility by: indole-3-acetic acid (IAA), 3-amino-s-triazole (amitrole), (2,4-dichlorophenoxy)acetic acid (2,4-D), 3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea (linuron), and 3-amino-2,5-dichlorobenzoic acid (amiben). Amiben immobilization may have been due to glucoside formation in the tissues. IAA was rapidly transported through basipetally but not acropetally oriented tissue. Tissue orientation had little effect on the movement of the other compounds. Mobility of the compounds studied, in general, appears to be a function of the amount of uncomplexed parent chemical. Retention is likely the result of conjugation with products in the cells or of physical binding in the cells.