Dimethyl Tetrachloroterephthalate Research Articles

Sequential DCPA Treatments for Weed Control in Turfgrasses1

AbstractIn the southeastern USA, herbicides have not generally given consistent preemergence control of large crabgrass [Digitaria sanguinalis (L.) Scop.] and annual bluegrass (Poa annua L.). DCPA (dimethyl tetrachloroterephthalate) was applied as single and repeated treatments over a 3‐year period for large crabgrass control at Griffin and Blairsville, Georgia, and for annual bluegrass control at Griffin. The soil types were Cecil sandy loam (Typic Hapludult) or sandy clay loam at Griffin and Hatboro loam (Typic Fluvaquents) or sandy loam at Blairsville.None of the DCPA treatments controlled large crabgrass or annual bluegrass consistently at the, rates included in these studies. Treating plots with DCPA at 11.2 kg/ha in both March and June gave the greatest control in 2 of 3 years at each location. A significant multiple correlation between temperature prior to treatment and weed control ratings indicated that poor control of large crabgrass was related to germination of crabgrass prior to treatment. High temperatures that induced germination of crabgrass during 2 weeks prior to time of treatment resulted in less control than in years with lower temperatures. This emphasizes the need for early application of DCPA in Georgia.

Título en español.

Dos experimentos de campo se establecieron en las Subestaciones de Isabela y Fortuna, Puerto Rico para evaluar yerbicidas en el control químico de yerbajos en batatales. Los yerbicidas preemergentes se aplicaron mezclados con agua cubriendo toda el área 2 días después de sembrarse la variedad Miguela. A las 8 semanas de aplicados los tratamientos aún se notaba un control efectivo de los yerbajos con el uso de difenamida (N,N-dimetilo-2,2-difenilacetamida) solo, en combinación con Chloramben (3-amino-2,5- acido diclorobenzoico) o con DCPA (dimetilo-2,3,5 ,6-tetraclorotereftalato). No hubo síntomas visuales de daño al follaje como consecuencia de los yerbicidas. No hubo diferencias significativas entre los tratamientos de yerbicidas en cuanto a rendimiento de batatas por acre, entre las parcelas tratadas con yerbicidas y los obtenidos en las desyerbadas a mano.

Effects of Herbicides on Establishment of Centipedegrass1

AbstractThe control of weeds during the first growing season after centipedegrass [Eremochloa ophiuroides (Munro) Hack.] sprigging is a major problem for most homeowners. Field and greenhouse experiments were conducted on the effects of herbicides applied at different time intervals during the establishment of centipedegrass on weed control and rate of turfgrass cover. The soil type was either a Cecil sandy loam (member of the clayey, kaolinitic, thermic family of Typic Hapludult) or Cecil sandy clay loam.The survival of centipedegrass sprigs was as good with single applications of DCPA (dimethyl tetrachloroterephthalate) at 11.2 kg/ha, atrazine [2‐chloro‐4‐(ethylamino)‐6‐(isopropylamino‐s‐triazine], at 1.1 kg/ha, simazine [2‐chloro‐4,6‐bis(ethylamino)‐s‐triazine], at 1.1 and 2.2 kg/ha, and oxadiazon [2‐tert‐buty‐4‐(2,4‐dichloro‐5‐isopropoxyphenyl)‐Δ2‐1,3,4‐oxadiazolin‐5‐one], at 3.4 kg/ha, applied immediately after sprigging as in untreated plots. The turfgrass cover at the end of the growing season was as good or better in single treated plots as in multiple treated plots. Repeated applications of atrazine, simazine, and oxadiazon increased the control of large crabgrass [Digitaria sanguinalis (L.) Scop.] and goosegrass [Eleusine indica (L.) Gaertn.] when compared with the control in single treated plots. These results indicate that complete weed control is not necessary for optimum centipedegrass cover during the first season after sprigging.

Renovation of Turfgrasses with Herbicides

Renovation of common bermudagrass [Cynodon dactylon(L.) Pers.] turf to either ‘Tifway’ or ‘Tifdwarf’ bermudagrasses, zoysia (Zoysia japonica Steud.xZoysia tenuifoliaWilld. ex Trin. ‘Emerald’) or centipedegrass [Eremochloa ophiuroides(Munro) Hack.] was undertaken with the aid of herbicides. Glyphosate [N-(phosphonomethyl)glycine] applied to common bermudagrass turf followed by treatments of MSMA (Monosodium methanearsonate) + 2,4-D[2,4-dichlorophenoxy)acetic acid] alone or in sequence with DCPA (dimethyl tetrachloroterephthalate) reduced the cover of common bermudagrass in renovated Tifway or Tifdwarf bermudagrass turf. Dalapon (2,2-dichloropropionic acid) applied alone or in sequence with DCPA, MSMA + 2,4-D, or DCPA + MSMA + 2,4-D also reduced coyer of common bermudagrass in some plantings. Paraquat (1,1′-dimethyl-4,4′-bipyridinium ion) and cacodylic acid (hydroxydimethylarsine oxide) did not reduce the cover of common bermudagrass in turf renovations. Slower growing Emerald zoysia and centipedegrass could not compete with the common bermudagrass that escaped the herbicide applications and renovation was unsuccessful.

Effect of Activated Charcoal on Herbicide Injury During Establishment of Centipedegrass1

AbstractControlling weeds with herbicides during the establishment of centipedegrass [Eremochloa ophiuroides (Munro) Hack.] often results in severe turfgrass injury. Experiments were conducted on Cecil sandy clay (Typic Hapludult) and Cecil sandy loam soils to determine if turfgrass sprigs dipped in activated charcoal before planting would protect the grass from herbicide injury when applied after planting for weed control.Dipping centipedegrass sprigs in activated charcoal improved early growth and appearance of the turfgrass when treated immediately after sprigging with herbicides for weed control. The rate of turfgrass growth (ground cover) during the first growing season was also improved in most instances by activated charcoal dip when treated with all herbicides except DCPA (dimethyl tetrachloroterephthalate). Activated charcoal treatment did not generally affect weed control during the establishment period. Therefore, when herbicides are used for weed control during establishment of centipedegrass, the rate of establishment was improved by activated charcoal treatments.

Herbicide Performance on Transplanted Annual Bedding Plants1

Abstract Alachlor (2-chloro-2′,6′-diethyl-N-(methoxymethyl)-acetanilide), diphenamid (N,N- dimethyl-2,2-diphenylacetamide) and napropamide (2-(α-naphthoxy)-N,N-diethylpropionamide) provided excellent broadleaf and grass weed control. Alachlor significantly injured the ‘St. John's Fire’ Salvai while diphenamid caused moderate injury to ‘Golden Torch’ Celosia. Both trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine) and DCPA (dimethyl tetra-chloroterephthalate) provided less than acceptable control of broadleaf weeds at the rates employed, but neither caused significant injury to any of the 15 cultivars of transplanted annual bedding plants used in this study.

Phytotoxicity of Herbicides to a Tifgreen Bermudagrass Green

A ‘tifgreen’ bermudagrass [Cynodon dactylon(L.) Pers.] golf-type green was treated with seven preemergence and one postemergence type herbicides at two rates each for three consecutive years to assess their phytotoxicity. A few herbicides were applied on a second, third, and fourth treatment date during the year with applications made in separate plots. Severe foliage injury occurred the first year with siduron [1-(2-methylcyclohexyl)-3-phenylurea] while moderate injury occurred with bromacil (5-bromo-3-sec-butyl-6-methyluracil) and DCPA (dimethyl tetrachloroterephthalate); and slight injury occurred with benefin (N-butyl-N-ethyl-α,α,α-trifluoro-2,6-dinitro-p-toluidine), bensulide [0,0-diisopropyl phosphorodithioateS-ester withN-(2-mercaptoethyl)benzenesulfonamide], and terbutol (2,6-di-tert-butyl-p-tolyl methylcarbamate). No injury was observed with bandane (polychlorodicyclopentadiene isomers) and tri-calcium arsenate. Injury to the bermudagrass in the second year following renewal treatments was severe with siduron and bromacil; moderate with benefin, bandane, DCPA, and terbutol; and slight with bensulide and tri-calcium arsenate. Injury in the third year following repeat applications was severe with siduron, terbutol, bandane, bromacil, benefin, and DCPA; slight to moderate with bensulide, and slight with tri-calcium arsenate. Injury observed the fourth year resulting from residues was moderate with bandane; slight with terbutol, benefin, bensulide, and DCPA; and none with siduron, bromacil, and tri-calcium arsenate.

Minimal Herbicide Treatments on the Establishment of Four Turfgrasses1

AbstractEstablishment of newly planted grasses for turf is influenced by weed competition. Since herbicides may reduce weed competition during the establishment period, an experiment was initiated to determine the effects of minimal vs. no herbicide treatment during the establishment of four turfgrass varieties and species. Herbicides as preemergence treatments were applied immediately after sprigging to centipedegrass [Eremochloa ophiuroides (Munro) Hacck.], ‘Emerald’ zoysia (Zoysia japonica × Zoysia tenuifolia Willd. ex Trin.), ‘Tifway’ and ‘Floraturf’ bermudagrasses (Cynodon sp.) in May and again the following March for experiments initiated in 1972 and 1973. The soil type was a Cecil sandy clay loam (Typic Hapludult). With the exception of Emerald zoysia, all turfgrasses grew well in untreated plots and competed successfully with the weeds after two growing seasons. Bensulide [0,0‐diisopropyl phosphorodithioate S‐ester with JV‐(2‐mercaptoethyl)benzenesulfonarnide] and terbutol (2‐ 6‐di‐tert‐butyl‐p‐tolyl methylcarbamate) generally caused more injury to the different turfgrasses than pronamide [3,5‐dichloro‐N‐(l,l‐dimethyl‐2‐propynyl)benzamide], DCPA (dimethyl tetrachloroterephthalate), or benefin (Nbutyl‐N V‐ethyl‐a,a,a‐trif luoro‐2,6‐dinitro‐p‐toluidine). Bensulide was the only herbicide that satisfactorily controlled grassy weeds during the first growing season both years.

Effects of Herbicide Treatments on the Establishment of ‘Tifway’ Bermudagrass

Selected herbicides were evaluated for control of large crabgrass [Digitaria sanguinalis(L.) Scop.] and goosegrass [Eleusine indica(L.) Gaertn.] in planted ‘Tifway’ bermudagrass (Cynodon sp.). The most effective treatment technique was sequential treatments of DCPA (dimethyl tetrachloroterephthalate) at planting followed with two applications of MSMA (monosodium methanearsonate) + 2,4-D [(2,4-dichlorophenoxy) acetic acid] which controlled 95% of the weeds and permitted bermudagrass to form a 96% ground cover in 22 weeks. Other treatments, listed in order of decreasing effectiveness were a single application of oxadiazon [2-tert-butyl-4-(2,4-dichloro-5-isopropoxyphenyl)-δ2-1,3,4-oxadiazolin-5-one], pronamide [3,5-dichloro-N-(1,1-dimethyl-2-propynyl)-benzamide] applied in two applications and MSMA + 2,4-D in two applications.

Herbicides for Establishing Kentucky Bluegrass Turf from Plugs1

AbstractThe use of herbicides for controlling weeds while establishing turf from seed has been limited by the intolerance of seedling turfgrass plants to many herbicides. However, the introduction of vegetative techniques tor establishing Kentucky bluegrass has presented new possibilites for successfully using herbicides in conjunction with turfgrass establishment. The purpose of this study was to determine whether the use of preemergence herbicides is feasible while establishing Kentucky bluegrass from plugs.Greenhouse studies were undertaken to evaluate the effects of preemergence herbicides on the growth of single‐plant cultures of ‘A‐20’ Kentucky bluegrass (Poa pratensis L.), All herbicides inhibited some aspect of growth as determined by measurements of roots, shoots, density, and rhizomes. In the field, however, only benefin (N‐butyl‐N‐ethyl‐ a,a,a‐trifluoro‐2,6‐dinitro‐p‐toluidine) and bensulide [O‐O‐diisopropyl phosphorodithioate S‐ester with N‐(2‐mercaptoethyl)benzene sulfonamide] reduced the lateral growth of ‘A‐20’ plugs while calcium arsenate and DCPA (dimethyl tetrachloroterephthalate) did not inhibit establishment of the turf compared to untreated plots. Where annual bluegrass (Poa annua L.) was seeded in conjunction with plugging the fastest Kentucky bluegrass establishment and best weed control were in plots treated with oxadiazon [2‐tert‐butyl‐4‐(2,4‐dichloro‐5‐isopropoxyphenyl)‐ Δ2‐l,3,4‐oxadiazolin‐5‐one]. Postemergence applications of endothall [7‐oxabicyclo(2,2,l)heptane‐2,4‐dicarboxylic acid] did not control annual weeds and reduced the amount of ‘A‐20’ in some plots due to its injurious effects on the plugs.

Dates of Herbicide Application for Weed Control in Bermudagrass

In field studies, herbicides were applied at various times to different plots during the summer and fall at two locations over a 3-year period to control winter weeds in nonoverseeded bermudagrass [Cynodon dactylon (L.) Pers.] turf. Annual bluegrass (Poa annua L.) control was higher at Griffin for all herbicide applications made in October when compared with herbicide applications made at the same rate in July, August, or September. At Lawrenceville, optimum annual bluegrass control was obtained when bensulide [O,O-diisopropyl phosphorodithioate S-ester with N-(2-mercaptoethyl) benzenesulfonamide] was applied in August, terbutol (2,6-di-tert-butyl-p-tolyl methylcarbamate) applied in either August or September, benefin (N-butyl-N-ethyl-α,α,α-trifluoro −2,6 dinitro-p-toluidine) applied in September, pronamide [3,5-dichloro-N-(1,1-dimethyl-2-propynyl) benzamide] applied in either September or October, and simazine [2-chloro-4,6-bis(ethylamino)-s-triazine] applied in October. DCPA (dimethyl tetrachloroterephthalate) did not control annual bluegrass satisfactorily at either location, regardless of dates of application. The control of several broadleaf weeds was generally higher when herbicides were applied in October at Griffin and when applied in September or October at Lawrenceville when compared with earlier treatments. Bensulide applied in October was the only herbicide that satisfactorily controlled parsley-piert (Alchemilla microcarpa Boissie Reuter).

Some Responses of Bluegrass to Herbicides and Temperature Variation

Growth-chamber studies were conducted to determine some effects of MSMA (monosodium methanearsonate) and DCPA (dimethyl tetrachloroterephthalate) treatments on ‘Pennstar’ and common Kentucky Bluegrass (Poa pratensis L.), grown at three different temperatures. Herbicide was applied at recommended rates at the beginning of regrowth following mowing. At sampling time, height and weight were recorded and some fresh tissue was frozen for chlorophyll analysis and the rest was oven-dried for amino acid analysis. Chlorophyll content of ‘Pennstar’ was significantly increased by MSMA. Common bluegrass grown at 18 C had significantly higher levels of free amino acids than did ‘Pennstar’ grown at the same temperature. At 27 C, asparagine and alanine were significantly higher in common bluegrass than in ‘Pennstar.’ MSMA had a more significant effect on all detected free amino acid concentrations except cysteine in ‘Pennstar’ than in common bluegrass. DCPA was more active than MSMA on common bluegrass; all amino acids were increased significantly by treatment.

Tolerance of Phalaris tuberosa L. and Festuca arundinacea Schreb. to Preemergence Herbicide Treatment1

The phytotoxic response of the cool‐season perennial forage grasses phalaris (Phalaris tuberosa L.) and tall rescue (Festuca arundinacea Schreb.) to several herbicides was evaluated in greenhouse and field tests. Phalaris was more tolerant than tall rescue to dimethyl tetrachloroterephthalate (DCPA) and 0,0‐diisopropyl phosphorodithioate S‐ester with N‐(2‐mercaptoethyl) benzenesulfonamide (bensulide). DCPA and bensulide treatments of at least 1.68 and 1.12 kg/ha in the greenhouse and 3.36 and 5.60 kg/ha in the field, respectively, did not cause measurable injury to phalaris. Phalaris and tall rescue tolerated up to 5.60 kg/ha of l‐(2‐methylcyclohexyl)‐3‐phenylurea (siduron). Goosegrass (Eleusine indica (L.) Gaertn.) was controlled with all siduron treatments, whereas siduron and 3,6‐dichloro‐o‐anisic acid (dicamba) gave the best control of several broadleaf weeds

Effects of DCPA on Seedling Infection by Root-Knot Nematode

Onion (Allium cepaL.) and bean (Phaseolus vulgarisL.) seedlings grown in soil treated with DCPA (dimethyl tetrachloroterephthalate) were less susceptible to northern root-knot nematode (Meloidogyne haplaChitwood) infection than seedlings grown in untreated soil. DCPA treatment of nematode larvae did not alter their pathogenicity. Resistance could be correlated with altered cell structure of the root epidermis, increased root exudate as evidenced by soil adherence, reduced fibrous root development, or both.

Effect of Benefin and DCPA on Overseeded Grasses Maintained as Putting Greens

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’].

Herbicides, Sprigging Rates, and Nitrogen Treatments for Establishment of Tifway Bermudagrass1

AbstractThis study was conducted to determine the best system for controlling weeds during the establishment of ‘Tifway’ bermudagrass (Cynodon sp.) without causing injury to the turfgrass. Sprigging rates did not significantly affect the turf ground cover after a 5 to 6‐month growing season. However, for a shorter growing season, the rate of establishment was increased with the higher rate (2.0 vs 0.5 or 1.0 m2/are) of sprigging. Nitrogen (490 g/are) applied at biweekly (eight applications) or monthly (four applications) intervals significantly increased turf ground cover and turf appearance as compared with turf not receiving N. Treatments of dimethyl tetrachloroterephthalate (DCPA) retarded early growth of Tifway bermudagrass. The plants had overcome this growth retardation by 11 weeks following sprigging. Postemergence treatments of monosodium methanearsonate + 2,4‐dichlorophenoxy acetic acid (MSMA + 2,4‐D) were nonphytotoxic to the turfgrass. Sequential treatments of DCPA followed with MSMA + 2,4‐D resulted in excellent season long weed control and the plots had 86% ground cover of turf at the end of the growing season. The turf ground cover was only 36% in plots not treated with any herbicide and 68% in plots treated with DCPA. Repeated postemergence treatments of MSMA + 2,4‐D resulted in good to excellent weed control and these plots had 91 to 96% turfgrass ground cover.

Effect of Gamma Radiation on the Bioactivity of Herbicides

Gamma radiation of 3 megarads was applied to undiluted commercial formulations and aqueous solutions of 3-(3,4 dichlorophenyl)-1,1-dimethylurea (diuron), 1,1-dimethyl-(3-a,a,a-trifluoro-m-tolyl)-urea fluometuron),N,N-dimethyl-2,2-diphenylacetamide (diphenamid), 2,4-bis (isopropylamino)-6-(methylthio)-s-triazine (prometryne), dimethyl tetrachloroterephthalate (DCPA),a,a,a-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine (trifluralin) and sodium chlorate. The effect of radiation on herbicidal activity was assessed with bioassays. Radiation did not affect the bioactivity of undiluted or 50% solutions of any of the tested herbicides but decreased appreciably the activity of 100-ppm solutions of fluometuron, diphenamid, and prometryne. Diluted 100 and 10-ppm solutions of trifluralin lost part of their activity during storage in plastic containers and, in addition, following irradiation. It was not clear whether the decrease in activity observed in the 100-ppm solution of diuron was due to irradiation or to storage. No reduction in bioactivity was produced following irradiation of 100 and 10-ppm solutions of DCPA or 1% and 10% solutions of sodium chlorate.

Herbicide Activity in Close-spaced, Pickling Cucumbers

The response of close-spaced, pickling cucumbers(Cucumis sativusL.) to preplant incorporation treatments ofO,O-diisopropyl phosphorodithioateS-ester withN-(2-mercaptoethyl)benzenesulfonamide (bensulide),N-butyl-N-ethyl α,α,α-trifluoro-2,6-dinitro-p-toluidine (benefin), and dimethyl tetrachloroterephthalate (DCPA) and preemergence applications of 4-(methylsulfonyl)-2,6-dinitro-N,N-dipropylaniline (nitralin) and the methyl ester of 3-amino-2,5-dichlorobenzoic acid (chloramben) has been evaluated over a 2-year period. DCPA and nitralin gave the best overall weed control, while benefin and the methyl ester of chloramben were less effective in controlling weeds. The poorest weed control performance was observed with bensulide. Nitralin, DCPA, benefin, and the methyl ester of chloramben caused crop injury if leaching rains followed application. Despite early herbicide injury, yields were usually not adversely affected.

Effects of DCPA on Tomato Hypocotyl Tissue

Dimethyl tetrachloroterephthalate (DCPA) caused localized swelling of the hypocotyl of tomato(Lycopersicon esculentumMill. ‘VF-99′). DCPA caused phloem and xylem parenchyma cells to become multinucleate and to develop into masses undifferentiated tissue within the stele of the tomato hypocotyl. Xylem procambium differentiated earlier than that of controls and matured into shortened and often disconnected elements. Xylem formed prior to treatment was often disrupted due to pressure from the dividing xylem parenchyma. Xylem parenchyma tended to break down resulting in the formation of air cavities within the stele. Cells in the stele of treated hypocotyls tended to stain more intensely with safranin than did the cells in the steles of untreated tomato hypocotyls indicating a difference in cell wall composition. Treated tissue had a higher concentration of total oxalates than did untreated tissue.

Effects of Continued use of Herbicides in Asparagus Plantings

The effects of repeated annual applications of nine herbicides on a planting of asparagus (Asparagus officinalis L. ‘Martha Washington’) were studied over a 7-year period. Weed competition during the cutting season seriously reduced yields. Large populations of common lambsquarters (Chenopodium album L.) developed where 3-amino-2,5-dichlorobenzoic acid (chloramben) and N,N-dimethyl-2,2-diphenylacetamide (diphenamid) were used. Large increases in redroot pigweed (Amaranthus retroflexus L.) occurred where dimethyl tetrachloroterephthalate (DCPA) was used. The fiber content of asparagus treated with 3-(p-chlorophenyl)-1,1-dimethylurea (monuron) and 3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea (linuron) increased during slow growing conditions. Spear emergence in the spring was delayed when 2,6-dichlorobenzonitrile (dichlobenil) was applied near bud break. There was no indication that continuous use of any of the herbicides studied resulted in a buildup in the soil or plants causing a deleterious effect upon the yield of asparagus.