Disodium Methanearsonate Research Articles

Crabgrass Control and Dollar Spot Suppression in Creeping Bentgrass with DSMA

Research was conducted to evaluate crabgrass [Digitaria ischaemum (Schreb.) Muhl.] control, incidental dollar spot (incited by Lanzia and Moellerodiscus spp.) suppression, and turfgrass quality following sequential, low-level postemergence applications of DSMA to creeping bentgrass (Agrostis stolonifera var. palustris Farwell). DSMA was applied at 22 mg·m-2 at 7-day intervals for 15 consecutive weeks (DSMA-W) from May through Aug. 1986 and 1987 and for 10 consecutive weeks from June through Aug. 1988. DSMA also was applied in three split applications of 110 mg·m-2 every 10 days (DSMA-S) in June and July of each year. DCPA was applied in a single, preemergence application in May as a comparative standard for crabgrass control. Percent crabgrass in either DSMA-treated plot was 20% by 11 Sept., an infestation that was unacceptable for high-quality turf. Percent crabgrass infestation was 6% at all rating dates in 1987 or 1988 for DSMA-W and 11% at all dates in 1987 or 1988 for DSMA-S. DCPA significantly reduced percent crabgrass as compared to the nontreated control at all rating dates, but the percent crabgrass ratings tended to be higher than those for either DSMA treatment by the final rating dates of each year. The DSMA treatments significantly reduced dollar spot incidence in each year. Turfgrass discoloration was observed following the DSMA-S treatment in July 1987 as compared to the control, but the turf quality recovered by August. Turfgrass quality was higher for DSMA treatments than for either DCPA or the nontreated control due to season-long crabgrass control and disease suppression. Chemical names used: disodium methanearsonate (DSMA), dimethyl tetrachloroterephthalate (DCPA).

Characterization of arsenic metabolites in rice plant treated with DSMA (disodium methanearsonate)

Characterization of arsenic metabolites in rice plant treated with DSMA (disodium methanearsonate)

Relationships Between Phenylalanine Ammonia-Lyase Activity and Physiological Responses of Soybean (Glycine max) Seedlings to Herbicides

The effects of 16 herbicides from 14 different chemical classes on levels of soluble protein, hydroxyphenolics, anthocyanin, and chlorophyll were determined in light- and dark-grown soybean [Glycine max(L.) Merr. ‘Hill’] seedlings. Growth-reducing concentrations of the herbicides were supplied to 3-day-old dark-grown soybean seedlings in liquid culture. Soluble protein (per axis) was reduced by fluridone {1-methyl-3-phenyl-5-[3-(trifluoromethyl)phenyl]-4(1H)-pyridinone}, paraquat (1,1′-dimethyl-4,4′-bipyridinium ion), perfluidone {1,1,1-trifluoro-N-[2-methyl-4-(phenylsulfonyl)phenyl] methanesulfonamide}, and propanil (3′,4′-dichloropropionanilide) 24 or 48 h after treatment. In light-grown plants, soluble hydroxyphenolic compound levels were decreased on a per axis basis after 48 h by all chemical treatments except by atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine], the methyl ester of diclofop {2-[4-(2,4-dichlorophenoxy)phenoxy] propanoate}, DSMA (disodium methanearsonate), fluridone, MH (1,2-dihydro-3,6-pyridazinedione), nitralin [4-(methylsulfonyl)-2,6-dinitro-N,N-dipropylaniline], TCA (trichloroacetic acid), and 2,4-D [(2,4-dichlorophenoxy)acetic acid]. Total chlorophyll content in hypocotyls of these seedlings was decreased by fluridone, metribuzin [4-amino-6-tert-butyl-3-(methylthio)-as-triazin-5 (4H)-one], norflurazon [4-chloro-5-(methylamino)-2-(α,α,α-trifluoro-m-tolyl)-3 (2H)-pyridazinone], paraquat, and 2,4-D, but others had no significant effect. Anthocyanin accumulation in hypocotyls of 48-h light-grown seedlings was decreased by atrazine, fenuron (1,1-dimethyl-3-phenylurea), metribuzin, norflurazon, paraquat, propanil, and propham (isopropyl carbanilate). Phenylalanine ammonia-lyase (PAL) activity (previously reported work) was positively correlated with anthocyanin levels in tissues after treatment with these 16 herbicides, but not with glyphosate [N-(phosphonomethyl)glycine]. There was, however, no correlation between extractable PAL activity and chlorophyll, soluble hydroxyphenolic compounds, or soluble protein content. These results indicated that extracted PAL activities usually reflect relative in vivo activities and that PAL activity is limiting to phenylpropanoid synthesis in vivo.

Comparison of Six Cropping Systems for Yellow Nutsedge (Cyperus esculentus) Control

Six cropping/weed control systems were evaluated from 1978 to 1980 for the control of yellow nutsedge (Cyperus esculentusL.). Supplementing cultivation of cotton (Gossypium hirsutumL. ‘Acala SJ-2′) with either preplant applications of fluridone {1 - methyl - 3 - phenyl - 5 - [3 - (trifluoromethyl)phenyl] -4(1H-pyridinone} or two hoeings for 2 yr preceding cotton treated with DSMA (disodium methanearsonate) and MSMA (monosodium methanearsonate) reduced populations of viable yellow nutsedge tubers 98 to 99% within 3 yr. Dry- or wet - fallowing plus tillage after barley (Hordeum vulgareL. ‘Kombyne’), and double cropping potatoes (Solanum tuberosumL. ‘White Rose’) treated with EPTC (S-ethyl dipropylthiocarbamate) with soybeans [Glycine max(L.) Merr. ‘Williams’] treated with alachlor [2-chloro - 2′, 6’ - diethyl -N- (methoxymethyl)acetanilide] for 2 yr preceding cotton, reduced populations of tubers 98 to 99% within 3 yr. A similar reduction of tubers (97%) was obtained by double cropping potatoes with milo [Sorghum bicolor(L.) Moench. ‘NK- 265′] for 2 yr preceding cotton.

Uptake, Accumulation, and Translocation of Arsenical Compounds by Cotton

AbstractUptake, accumulation, and translocation of arsenic from different arsenical compounds were investigated in cotton plants (Gossypium hirsutum L. ‘SJ‐4’). Cotton plants grown in solution culture were exposed to arsenic trioxide (As2O3) from 0 to 8 µg As mL−1. Arsenic was readily taken up by the roots but was not translocated to the shoots. In contrast, when cacodylic acid (hydroxydimethylarsine oxide; (CH3)2As(O)OH) was applied in the range of 0–40 µg As mL−1, As was found not only in the roots but also in the leaves and reproductive structures. Plants treated with the herbicides MSMA (monosodium methanearsonate) and DSMA (disodium methanearsonate) also accumulated As in the roots and shoots. The defoliant, cacodylic acid, was applied as a foliar spray at the commercially recommendated rate of 1.4 kg/ha of cacodylic acid equivalents to cotton plants with green and mature bolls. Cottonseed from the treated bolls did not accumulae As above 2.6 µg As g−1, the tolerance limit. However, at higher application rates, the As concentrations increased in the cottonseed.Cotton plants grown in the greenhouse in Yolo clay loam (fine silty, mixed, nonacidic, thermic Typic Xerorthents) with a soil background level of 6 µg As g−1, were grown with cotton‐gin trash containing cacodylic acid at 0 to 53.5 µg As g−1 mixed into the soil. Analyzed plant samples contained < 0.05 µg As g−1 and did not accumulate or concentrate arsenic from the soil.

Effects of Herbicides on Growth and Extractable Phenylalanine Ammonia-Lyase Activity in Light- and Dark-Grown Soybean (Glycine max) Seedlings

Effects of 16 herbicides representing 14 herbicide classes on growth and extractable phenylalanine ammonia-lyase (PAL, EC 4.3.1.5) were examined in light- and dark-grown soybean [Glycine max(L.) Merr. ‘Hill’] seedlings. High purity (96 to 100%) herbicides were supplied via aqueous culture at various concentrations: 0.5 mM amitrole (3-amino-s-triazole), 0.1 mM atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine], 0.07 mM diclofop-methyl {methyl ester of 2-[4-(2,4-dichlorophenoxy)phenoxy] propanoicacid}, 0.5 mM DSMA (disodium methanearsonate), 0.2 mM fenuron (1,1-dimethyl-3-phenylurea), 0.05 mM fluridone {1-methyl-3-phenyl-[3-(trifluoromethyl)phenyl]-4(1H)-pyridinone}, 0.5 mM MH (1,2-dihydro-3,6-pyridazinedione), 0.5 mM metribuzin [4-amino-6-tert-butyl-3-(methylthio)-as-triazin-5(4H)-one], 1.8 μM nitralin [4-(methylsulfonyl)-2,6-dinitro-N,N-dipropylaniline], 0.5 mM norflurazon [4-chloro-5-(methylamino)-2-(α,α,α-trifluoro-m-tolyl)-3(2H)-pyridazinone], 0.05 mM paraquat (1,1′-dimethyl-4,4′-bipyridinium ion), 0.15 mM perfluidone {1,1,1-trifluoro-N-[2-methyl-4-(phenylsulfonyl)phenyl] methanesulfonamide}, 0.2 mM propanil (3′,4′-dichloropropionanilide), 0.1 mM propham (isopropyl carbanilate), 0.5 mM TCA (trichloroacetic acid), and 0.05 mM 2,4-D [(2,4-dichlorophenoxy)acetic acid]. Dark-grown soybean seedlings (3-day-old) were transferred to control solutions (2 mM CaSO4) or to herbicide solutions (in 2 mM CaSO4) and grown at 25 C in continuous white light (200 μE•m-2•s-1) or continuous darkness until harvested 24 or 48 h after transfer. After 48 h, growth (fresh weight, dry weight, elongation) was inhibited by most of the chemicals. Other signs of toxicity (necrosis, secondary root stunting, and root tip swelling) were noted for some treatments. Roots were most affected, although hypocotyls were generally not changed. Hypocotyl elongation was stimulated by atrazine, fluridone, and norflurazon after 48 h light. Extractable PAL activity from soybean axes was decreased by atrazine, fenuron, metribuzin, norflurazon, propanil, propham, and 2,4-D. Amitrole and paraquat were the only herbicides that increased extractable PAL activity. Other compounds tested had no effect on the enzyme. None of the herbicides significantly affected in vitro PAL activity.

Control and Competitiveness of Johnsongrass (Sorghum halepense) in Cotton (Gossypium hirsutum)

Four field experiments conducted over 3 yr indicated that cultivation alone failed to prevent johnsongrass [Sorghum halepense(L.) Pers.] from reaching densities that severely reduced yields of cotton (Gossypium hirsutumL. ‘Acala SJ-2’). Density of johnsongrass in plots cultivated four times and hoed weekly for 8 weeks after emergence was reduced to 1 shoot/m2at harvest compared to 74 shoots/m2for plots that were only cultivated. In addition to a 60% average yield loss of seed cotton, yield losses ranging from 40 to 76%, ginning losses were also greater from cultivated than from hand-weeded plots. Compared to cultivated plots, supplementing cultivation with two postemergence applications of 3.0 kg/ha of DSMA (disodium methanearsonate) increased the average yield of cotton by 20% and reduced perennial johnsongrass densities by 64% at harvest. Although yields were improved by applying DSMA, they averaged 40% less than those of hand-weeded plots. The temporary weed control obtained with DSMA was profitable in terms of the additional lint and seed obtained, but insufficient cotton was produced to pay expenses for producing the crop by any of the methods of weed control. High labor costs for hoeing prevented this treatment from being profitable.

Fractionation of arsenous, arsenic, methanearsonate and dimethylarsinic acid by using strong-acid cation-exchange resin

Behavior of arsenous, arsenic, disodium methanearsonate (DSMA) and dimethylarsinic acid (DMAA) with a strong-acid cation-exchange resin was investigated. Dowex 50W×8 {(50100) mesh, hydrogen from} was used. A mixed solution, modified to pH 2, of these arsenicals was applied to the top of a short column (1.5cm×12cm) connected to a long column (1.9cm×118cm) and then eluted at a flow rate of (911)cm3cm-2h-1. The effluent was monitored for arsenic by using atomic absorption spectrophotometer equipped with graphite furnace atomizer. Arsenic, arsenous and DSMA were separately eluted with water in this order from the long column. DMAA held strongly on the short column was eluted with aqueous ammonia after the connection of the two columns was cut. Almost 100% of these arsenicals was recovered in the effluents. From an aqueous extract from a brown seaweed, Hizikia fusiforme, 4 arsenic peaks corresponding to the reference arsenic, arsenous, DSMA and DMAA were obtained by the method. This method is effectively applicable for studying chemical forms and metabolic fate of arsenic in marine organisms.

Chemical Distribution and Gaseous Evolution of Arsenic‐74 Added to Soils as DSMA‐74As

AbstractGaseous evolution of 74 As from a soil treated with arsenic‐74 labeled disodium methanearsonate (DSMA‐74 As) at 100 µg/g was a function of organic matter addition and moisture conditions. Loss of 74As was greatest from soils that received an exogenous carbon source and were maintained under wet conditions.Arsenic‐74 sorbed by soils of pH 4, 6, and 8 was fractionated by a differential dissolution procedure commonly used for phosphorus. Iron arsenate (soluble in 0.1N NaOH) was the most abundant form followed by aluminum arsenate (soluble in 0.5N NH4F). The soils generally contained more aluminum arsenate at pH 4 than at pH 6 or 8. Calcium arsenate fractions (soluble in 0.5N H2SO4) were usually higher at pH 6 and 8 than at pH 4. Water‐soluble forms and nonextractable forms were inversely proportional to each other.

Woollyleaf Bursage Control with Monosodium Methanearsonate and Tillage1

AbstractWoolyleaf bursage (Franseria tomentosa Gray) infests approximately 70,000 ha of cropland in Great Plains states. Since susceptibility of this weed to MSMA (monosodium methanearsonate) was observed, MSMA and DSMA (disodium methanearsonate) were investigated under several conditions for control of woollyleaf bursage. The most effective control occurred when MSMA was applied in mid to late May after all shoots had emerged in the spring. Experiments were conducted in playa lakebeds on Randall clay (Udic Pellusterts). Woollyleaf bursage was consistently more susceptible to MSMA than DSMA. Roots were killed to depths of 30 cm or more. Mold‐board plowing of infested areas delayed, rather than reduced, shoot emergence. In contrast, a disking operation allowed weed shoots to emerge earlier and more uniformly, which resulted in greater effectiveness of MSMA. Soil moisture and crop yields were increased when MSMA was applied to woollyleaf bursage before planting cotton (Gossypium hirsutum L.). One year after treatment with MSMA, woollyleaf bursage control was still evident and sudangrass [Sorghum sudanense Stapp (‘Piper’)] yields were increased in treated areas.

Over-the-top Applications of Herbicides in Cotton

Single and repeat applications of herbicides or herbicide combinations were made over-the-top of young cotton (Gossypium hirsutumL.). DMSA (disodium methanearsonate) and MSMA (monodosium methanearsonate) applied 4 or 8 weeks after emergence had less effect on cotton yield, boll components, and fiber properties than did applications made 12 weeks after emergence. Most single, over-the-top applications of DSMA, fluometuron [1,1-dimethyl-3-(α,α,α-trifluoro-m-tolyl)urea], or DSMA with fluometuron 4 weeks after emergence did not affect cotton yield, boll components, or fiber properties. One or two applications of diuron [3-(3,4-dichlorophenyl)-1,1-dimethylurea] or prometryn [2,4-bis(isopropylamino)-6-(methylthio)-s-triazine] alone, or with DSMA, reduced cotton yields. Applications of 1.1 and 2.2 kg/ha of fluometuron over-the-top of cotton 2 to 8 weeks after emergence did not affect cotton yields, boll components, or fiber properties.

Fixation of Arsenical Herbicides, Phosphate, and Arsenate in Alluvial Soils

AbstractThe sorption of arsenic (as arsenate), phosphate, DSMA (disodium methanearsonate) and the sodium salt of cacodylic acid (hydroxydimethylarsine oxide) by 16 Mississippi River alluvial flood plain soils was measured in a slurry experiment in which initial pH and solute molar solution concentrations for all four solutes were identical. Sorption of the two organoarsenical herbicides was strongly correlated with arsenate and phosphate sorption, and sorption of all four species was strongly correlated with clay and iron oxide contents of the soils. In 10−3 to 10−4M solution, the arsenicals are more strongly sorbed than phosphate with sorption increasing in the order P < cacodylate < arsenate ≃ methylarsonate.

Arsenical Herbicides for Removing Broomsedge from Forage Grasses

MSMA (monosodium methanearsonate) and DSMA (disodium methanearsonate) killed 27 to 90% of the broomsedge (Andropogon virginicusL.) plants when applied at 1.1 to 6.7 kg/ha in July. These rates did not reduce yields of smooth bromegrass (Bromus inermisLeyss.) or affect the density of Kentucky bluegrass (Poa pratensisL.) growing in association with the broomsedge.

Msma and Dsma for Removing Grass Weeds From Grass-Legume Seedlings

MSMA (monosodium methanearsonate) and DSMA (disodium methanearsonate) were applied to seedling orchardgrass (Dactylis glomerata L.) – alfalfa (Medicago sativa L. ‘WL-304′) and reed canarygrass (Phalaris arundinacea L. ‘Ioreed’)-birdsfoot trefoil (Lotus corniculatus L. ‘Dawn’) mixtures before grasses were beyond the three-leaf stage. MSMA and DSMA controlled foxtails (Setaria spp.), large crabgrass [Digitaria sanguinalis (L.) Scop.] and fall panicum (Panicum dichotomiflorum Michx.), but were not effective on barnyardgrass [Echinochloa crus-galli (L.) Beauv.]. The addition of 2,4-DB [4-(2,4-dichlorophenoxy)butyric acid] or bromoxynil (3,5-dibromo-4-hydroxybenzonitrile) to MSMA or DSMA increased broadleaf weed control over that obtained with MSMA or DSMA alone. The forage mixtures tolerated 2 to 3 kg/ha of MSMA or DSMA and increased in yield when weeds were controlled. Elemental arsenic found in the forage increased in forage as the rates of MSMA or DSMA increased. Eighty-six to 96% less arsenic was found in early-than in late-treated forage.

Response of Cotton and Weeds to Herbicides by Phytobland Oil or Surfactant

In field studies, surfactant and phytobland oil were compared as additives to herbicides and herbicide combinations for postemergence weed control in cotton (Gossypium hirsutumL. ‘Stoneville 7A’). Addition of phytobland oil to MSMA (monosodium methanearsonate) and MSMA + fluometuron [1,1-dimethyl-3-(α,α,α-trifluoro-m-tolyl)urea], dinoseb (2-sec-butyl-4,6-dinitrophenol), or norea [3-(hexadydro-4,7-methanoindan-5-yl)-1,1-dimethyl-urea] had no significant effect on weed control when applied as directed treatments to weeds in cotton 7 to 15 cm tall. In cotton 15 to 23 cm tall, addition of phytobland oil to MSMA + linuron [3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea] and MSMA + linuron + prometryne [2,4-bis(isopropylamino)-6-(methylthio)-s-triazine] increased weed control when compared to the same treatments with surfactant. MSMA + linuron + phytobland oil decreased cotton yields. Addition of phytobland oil to DSMA (disodium methanearsonate) and DSMA combinations had no effect on weed control when compared to the same treatments with surfactant. There were no differences in several paraffinic phytobland oils or surfactant when used as additives to MSMA + fluometuron for weed control in cotton 7 to 15 cm tall.

Topical Applications of DSMA and MSMA in Irrigated Cotton

Single topical applications of monosodium methanearsonate (MSMA) affected cotton (Gossypium hirsutumL.) growth more than did similar disodium methanearsonate (DSMA) applications. There was usually no difference in yield among rates and dates with single applications of DSMA. Single applications of MSMA at later dates and higher rates reduced yields. Repeated topical applications of MSMA reduced yields and affected boll weight, lint percentage, number of seed per boll, and fiber fineness as compared with these properties of cotton treated once with MSMA. Response of cotton to MSMA was related to the number of applications and rate of herbicide. Repeated applications of DSMA affected cotton yield, lint percentage, and number of seed per boll less than did MSMA.

Control of Nutsedge with Organic Arsenical Herbicides

Nonradioactive and14C-labeled arsenical herbicides were applied to foliage of purple nutsedge (Cyperus rotundusL.) and yellow nutsedge (Cyperus esculentusL.) grown under greenhouse and growth chamber conditions. Disodium methanearsonate (DSMA) controlled purple nutsedge better at 20 and 29 C than at 13 C. Monosodium methanearsonate (MSMA) was as effective in controlling this weed at 13 C as at 20 and 29 C. DSMA and MSMA provided 80% or greater control of yellow nutsedge grown at the three temperatures. When plants were treated with14C-DSMA and14C-MSMA, greater radioactivity was detected in yellow nutsedge than in purple nutsedge. The apparent differential herbicide penetration of purple and yellow nutsedge leaves is believed to have contributed substantially to the control of nutsedge observed in this study.

Cotton Response to Temperature and Organic Arsenicals

Nonradioactive and14C-organic arsenical herbicides were applied to foliage of young cotton (Gossypium hirsutumL., var. Acala SJ-1) at various temperatures. An application of 3.36 kg/ha of monosodium methanearsonate (MSMA), with and without 0.5% surfactant, severely injured plants exposed at 13 C. Similar injury resulted when plants were exposed and treated at 20 C with MSMA containing 0.5% surfactant. Applications of MSMA did not injure plants exposed at 31 C. Disodium methanearsonate (DSMA) was less injurious to cotton than MSMA. Only slight to moderate injury resulted when plants were exposed and treated at 13 C with 3.36 kg/ha of DSMA containing 0.5% surfactant. Applications at higher temperatures did not injure cotton. Cotyledons absorbed14C-methanearsonic acid (MAA) and14C-MSMA more readily than14C-DSMA. Contact injury from these herbicides was slight at 13 C but was pronounced at 20 and 29 C. Generally, translocation of herbicides into developing true leaves was slight. The exception resulted from applications of14C-MSMA to plants at 13 C when contact injury was negligible.

Vitality of Tubers of Yellow Nutsedge Treated by Arsenical Herbicides

We collected tubers from greenhouse-grown yellow nutsedge (Cyperus esculentusL.) control plants and plants foliarly-treated with 3.36 kg/ha of disodium methanearsonate (DSMA) or monosodium methanearsonate (MSMA). Where sufficient tubers were produced, they were separated into two classes, large and small. Some of the tubers were analyzed for elemental arsenic, and others were stored at 2 C and planted at various intervals. Vitality of tubers was noted in terms of sprouting and vegetative growth. Tubers collected from treated plants contained significantly more arsenic (4 to 33 ppm) than control tubers (1 ppm). Tubers collected from treated plants and planted without separation sprouted in significantly reduced numbers compared to control tubers. Small tubers contained a significantly higher concentration of arsenic (23 to 33 ppm) than large tubers (4 to 12 ppm). The treatments reduced the vitality of small tubers but had little or no effect on vitality of large tubers.

Directed Applications of Herbicides in Irrigated Cotton

Directed applications of low rates of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (diuron), disodium methanearsonate (DSMA), monosodium methanearsonate (MSMA), 1,1′-dimethyl-4,4′-bipyridinium salts (paraquat), and 2,4-bis(isopropylamino)-6-(methylthio)-s-triazine (prometryne) controlled annual weeds in irrigated cotton (Gossypium hirsutumL.). Although the first applications of most herbicides caused temporary, localized foliage chlorosis or burning, cotton yields, fiber properties, and boll components were not affected. Early applications of DSMA followed by diuron selectively controlled annual weeds. When a herbicide was applied before planting, fewer postemergence applications were needed for weed control.