Dimethyl Tetrachloroterephthalate Research Articles

Initial and Residual Herbicide Control of Crabgrass (Digitariaspp.) in Bermudagrass (Cynodon dactylon) Turf

Over 9 yr, bandane (polychlorodicyclopentadiene isomers) at 67 kg/ha, bensulide [O,O-diisopropyl phosphorodithioateS-ester withN-(2-mercaptoethyl)benzenesulfonamide] at 11 and 22 kg/ha, DCPA (dimethyl tetrachloroterephthalate) at 22 kg/ha, and terbutol (2,6-di-tert-butyl-p-tolyl methylcarbamate) at 22 kg/ha applied preemergence controlled 94 to 100% of large crabgrass [Digitaria sanguinalis(L.) Scop. # DIGSP] in a lawn of common bermudagrass [Cynodon dactylon(L.) Pers. # CYNDA]. Control from benefin (N-butyl-N-ethyl-α,α,α-trifluoro-2,6-dinitro-p-toluidine) at 5 kg/ha, DCPA at 11 kg/ha, simazine [2-chloro-4,6-bis(ethylamino)-s-triazine] at 5 kg/ha, and terbutol at 11 kg/ha was 90 to 99%. Bandane and bensulide persisted in soil to control large crabgrass a year after treatment.

Herbicides Applied to Dodder (Cuscutaspp.) after Attachment to Alfalfa (Medicago sativa)

When glyphosate [N-(phosphonomethyl)glycine] at 0.075 kg/ha, DCPA (dimethyl tetrachloroterephthalate) at 10 kg/ha, and H 26905 [O-ethyl-O-(3-methyl-6-nitrophenyl)-N-sec-butyl phosphorothioamidate] at 0.25 and 0.5 kg/ha were sprayed on foliage of alfalfa (Medicago sativaL. ‘Vernal’) on which field dodder (Cuscuta campestrisYunck.) and largeseed dodder (Cuscuta indecoraChoisy) were attached and growing vigorously, almost all visible dodder tissue was killed and alfalfa was not injured noticeably. Some dodder recovered from haustoria within the alfalfa stems and from remnants of twined tendrils, but devastation of the alfalfa by uncontrolled dodder was prevented. PP 009 (butyl 2-[4-(5-trifluoromethyl-2-pyridyloxy)phenoxy] propionate), BAS 9052 (2-[1-(ethoxyimino)butyl]-5-[2-(ethylthio)propyl]-3-hydroxy-2-cyclohexen-1-one) and RO 13-8895 (acetone-O-[D-2-[p-[(α,α,α-trifluoro-p-tolyl)-oxy] phenoxy] propionyl] oxime) at 0.25, 0.50, or 1.0 kg/ha did not control dodder.

Preemergence Herbicide Effects on Four Kentucky Bluegrass Cultivars1,2

Abstract Three preemergence herbicides [S-(0, 0-Diisopropyl phosphorodithioate) ester of N-(2-mercaptoethyl) benzenesulfonamide (bensulide) at 8.4 and 15.7 kg/ha, Dimethyl tetrachloroterephthalate (DCPA) at 11.8 and 16.8 kg/ha, and 2-tert-butyl-4-(2,4 dichloro-5-isopropoxyphenyl)-Δ2l,3,4-oxadiazolin-5-one (oxadiazon) at 2.2, 4.5, and 9 kg/ha] were applied to plugs of Kentucky bluegrass (Poa pratensis L. cvs. Baron, Enmundi, Newport, and Park) in the greenhouse. Bensulide and oxadiazon reduced root weight, but there were no cultivar differences. Cultivar differences in response to oxadiazon were observed for rhizome weight, rhizome length, and turfgrass quality, with ‘Newport’ and ‘Baron’ damaged more by oxadiazon than ‘Park’ and ‘Enmundi’. There were no cultivar differences in rhizome weight, rhizome length, and quality in response to bensulide or DCPA.

Kentucky Bluegrass Tolerance to Consecutive Preemergence Herbicide Treatments1

AbstractHerbicides are one of several management practices necessary to maintain good quality, weed‐free turf. To be acceptable, they must control weeds without causing turfgrass injury. An experiment was conducted on Congaree loam (Fluventic Dystrochrepts) in the mountain region of Georgia to determine the effects of consecutive annual herbicide treatments on six Kentucky bluegrass (Poa pratensis L.) cultivars.Standard rates of DCPA (dimethyl tetrachloroterephthalate), bensulide [O,O‐diisopropyl phosphorodithioate S‐ester with N‐(2‐mercaptoethyl) benzenesulfonamide], benefin (N‐butyl‐N‐ethyl‐a,a,a‐trifluoro‐2,6‐dinitro‐p‐toluidine), or oxadiazon [2‐tert‐butyl‐4‐(2,4‐dichloro‐5‐isopropoxyphenyl)−Δ2−1 ,3,4‐oxadiazolin‐5‐one] affected the quality and stand of Kentucky bluegrass cultivars very little. However, oxadiazon applied at the 3X rate reduced the quality of all cultivars in early spring and the stands of ‘Victa’, ‘Merion’, and ‘common’ in late summer when compared with bensulide. Benefin applied at the 3X rate reduced the quality of ‘Adelphi’, ‘Vantage’, Victa, and ‘Fylking’, but not stand when compared with the recommended benefin treatment. Neither napropamide [2‐(a‐naphthoxy)‐N,N‐diethylpropionamide] or prosulfalin {N‐[[4‐(dipropylamino)‐3,5‐dinitrophenyl]sulfonyl]‐S‐S‐dimethylsulfilimine} should be applied to Kentucky bluegrass cultivars because of severe injury.

Influence of Herbicide Rotation Treatments on Species Composition of Weeds in Turfgrass

DCPA (dimethyl tetrachloroterephthalate), bensulide [O,O-diisopropyl phosphorodithioateS-ester withN-(2-mercaptoethyl)benzenesulfonamide], and oxadiazon [2-tert-butyl-4(2,4-dichloro-5-isopropoxyphenyl)-Δ2-1,3,4-oxadiazolin-5-one] were applied to bermudagrass [Cynodon dactylon(L.) Pers. ‘Common′] as consecutive repeated annual treatments or in all possible sequence combinations for 3 yr to determine the effects on species composition of winter and summer annual weeds. Regardless of the rotation of treatments on winter weeds, oxadiazon increased the cover of common chickweed [Stellaria media(L.) Cyrillo], spur weed (Solivaspp.), and thymeleaf sandwort (Arenaria serpyllifoliaL.); bensulide increased the cover of corn speedwell (Veronica arvensisL.); and DCPA in most instances increased the cover of hop clover (Trifolium agrariumL.) and spur weed. When a herbicide controlled large crabgrass [Digitaria sanguinalis(L.) Scop.] or goosegrass (Eleusine indicaL. Gaertn.), the cover of weeds not controlled increased rapidly, with the exception of oxadiazon applied for 3 consecutive yr.

Weed Control in Cowpea (Vigna unguiculata) in the Humid Tropics

At least two weedings within the first 5 weeks after sowing are necessary to minimize yield reduction caused by weeds in cowpea [Vigna unguiculata(L.) Walp.]. During a 3-yr study, a preemergence application of metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide] at 2.0 to 3.0 kg/ha, DCPA (dimethyl tetrachloroterephthalate) at 10.0 kg/ha, or pendimethalin [N-(1-ethylpropyl)-3,4-dimethyl-2,6-dinitrobenzenamine] at 2.0 or 2.5 kg/ha controlled most annual grasses effectively. Itchgrass (Rottboellia exaltataL.) was controlled with pendimethalin at 2.5 kg/ha, but metolachlor had no effect on this weed. These herbicides caused no crop injury and cowpea grain yield was as good as in the handweeded and weed-free plots. Alachlor [2-chloro-2′, 6′-diethyl-N-(methoxymethyl) acetanilide] applied preemergence at 2.0 kg/ha was effective against annual weeds, but was phytotoxic to cowpea.

Combination of Herbicides for Winter and Summer Weed Control in Turf1

AbstractIt is usually necessary to apply herbicides to control both winter and summer weeds in bermudagrass [Cynodon dactylon (L.) Pers. ‘Common’] turf. A study was conducted on a Cecil (Typic Hapludult) loam or sandy clay loam at Griffin, Ga. to determine whether combinations of preemergence type herbicides for summer weeds and postemergence type herbicides for winter weeds would control both type weeds as effectively as when each herbicide was applied singly.Tank mixture of paraquat (l,l′‐dimethyl‐4,4′‐bipyridinium ion) at 0.3 kg/ha with preemergence herbicide treatments generally controlled a higher percentage of winter annual broadleaf weeds than when paraquat was applied alone at the same rate. In contrast, glyphosate [N(phosphonomethyl)glycine] mixtures were less effective than glyphosate alone. Control of corn speedwell (Veronica arvensis L.) was significantly improved from tank mixture of 2,4‐D [(2,4‐dichlorophenoxy)acetic acid] + mecoprop {2[(4‐chloro‐o‐tolyl)oxy]propionic acid} + dicamba (3,6‐dichloro‐o‐anisic acid) with preemergence treatments than with postemergence treatment alone. Bensulide [O‐O‐diisopropyl phosphorodithioate S‐ester with N‐(2‐mercaptoethyl)benzenesulfonamid] and prosulfalin {N‐[[4‐(dipropylamino)‐3,5‐dinitrophenyl]sulfonyl]‐S,S‐dimethylsulfilimine} controlled large crabgrass [Digitaria sanguinalis (L.) Scop.] as effectively when applied as tank mixtures with postemergence herbicide treatments as when applied alone. However, combination of DCPA (dimethyl tetrachloroterephthalate) with the same postemergence treatments reduced large crabgrass control in 1 or more years. Control of goosegrass [Eleusine indica (L.) Gaertn.] from tank mixtures of preemergence treatments with postemergence treatments was just as effective as with preemergence treatments alone.

Frequency of Herbicide Treatments for Summer and Winter Weed Control in Turfgrasses

Four herbicides were applied in the spring and fall over a 3-yr period to Kentucky bluegrass [Poa pratensis (L.) ‘Common′] in the Mountain Region and bermudagrass [Cynodon dactylon (L.) Pers. ‘Common′] in the Piedmont Region of Georgia at different frequencies of treatments for summer and winter weed control. Large crabgrass [Digitaria sanguinalis (L.) Scop.] was controlled throughout the 3-yr period from spring treatments of bensulide [O,O-diisopropyl phosphorodithioate S-ester with N-(2-mercaptoethyl)benzenesulfonamide] at 11.2 kg/ha and oxadiazon [2-tert-butyl-4-(2,4-dichloro-5-isopropoxyphenyl)-δ2-1,3,4-oxadiazolin-5-one] at 4.5 kg/ha in the first year followed by 5.6 kg/ha for bensulide and 2.3 kg/ha for oxadiazon the following 2 yr. To control large crabgrass with benefin (N- butyl-N-ethyl-α,α,α-trifluoro-2,6-dinitro-p-toluidine) it was necessary to apply 3.4 kg/ha for 2 consecutive yr before rates could be reduced to 1.7 kg/ha. Oxadiazon was the only herbicide that controlled goosegrass [Eleusine indica (L.) Gaertn.] completely. Control was excellent throughout the 3-yr period when oxadiazon was applied at full rate in the spring of the first year with no additional treatments during the following 2 yr. Optimum control of winter weeds was obtained throughout the 3-yr period when herbicides were applied at full rates for the spring and fall treatments the first year followed by one-half rates at similar dates the following 2 yr. Bensulide treatments increased cover of corn speedwell (Veronica arvensis L.) and hop clover (Trifolium agrarium L.); DCPA (dimethyl tetrachloroterephthalate) and benefin increased spur weed (Soliva spp.) and wild parsnip (Pastinaca sativa L.); and oxadiazon increased wild parsnip and thymeleaf sandwort (Arenaria serpyllifolia L.).

Post‐dormancy Growth of Bermudagrass as Influenced by Low Temperatures and Selected Preemergence Herbicides1

AbstractTurf managers in the upper south of the USA must often contend with slow recovery of bermudagrass (Cynodon sp.) following winter dormancy. It is, therefore, essential to identify factors which may contribute to reduced recovery from dormancy if bermudagrass is continued to be grown in this region. In this study, three experiments were conducted to determine the influence of the herbicides DCPA (dimethyl tetrachloroterephthalate), benefin (N‐butyl‐N‐ethyl‐α,α,α‐trifluoro‐2,6 dinitro‐ρ‐toluidine) and oxadiazon [2‐tert‐butyl‐4 (2,4‐dichloro‐5‐isopropoxyphenyl) ‐∆2−1,3,4‐oxadiazolin‐5‐one] on cold temperature tolerance and post‐dormancy growth of three bermudagrass cultivars, ‘Tifway,’ ‘Vamont,’ and ‘Midiron.’Two laboratory studies were designed to determine the influence of different rates of herbicides on the recovery of dormant bermudagrass that was subject to low temperatures. Herbicides were applied immediately before dormancy was initiated or prior to post‐dormancy growth. A field acclimated study was also conducted to ascertain the effects of herbicide application on post‐dormancy growth of two bermudagrass.From these experiments it was found that the preemergence herbicides DCPA, benefin, and oxadiazon reduce the cold temperature tolerance of Tifway bermudagrass. Post‐dormant root growth of Tifway bermudagrass was inhibited when new roots came into contact with a herbicide residue from an application prior to dormancy. The most severe root reduction occurred by applications of herbicides to dormant bermudagrass turf made after a laboratory freeze.Less phytotoxicity was obtained when low dosages of herbicides were applied to dormant Vamont bermudagrass that was not frozen. However, when herbicides were applied after Vamont bermudagrass was frozen, both low and high dosages produced similar results.Midiron and Vamont bermudagrass differed in their susceptibility to herbicide injury following freezing conditions. Vamont post‐dormancy recovery was decreased by the herbicides applied in this study, but Midiron was not.

Weed Control in Production of Okra in Trinidad1

AbstractWeed control is frequently a severe limiting factor in okra [Abelmoschus esculentus (L.) Moench] production in the Caribbean. The objective of this field investigation was to further evaluate the effectiveness of selected herbicide treatments to control weeds in okra and to determine their effects on the yield and quality of okra under rainfed conditions. The research was conducted for 3 consecutive years on River Estate loam, a fluventic eutropept, in Trinidad. Preplant herbicide treatments of benefin (N‐butyl‐N‐ethyl‐ά, ά, ά‐trifluoro‐2, 6‐dinitro‐p‐toluidine), butralin [4‐(1, 1‐dimethylethyl)‐N‐(1‐methylpropyl)‐2, 6‐dinitrobenzenamine], and trifluralin (ά, ά, ά‐trifluoro‐2, 6‐dinitro‐N, N‐dipropyl‐p‐toluidine) and preemergence herbicide treatments of benefin, butralin, DCPA (dimethyl tetrachloroterephthalate) + diphenamid (N, N‐dimethyl‐2, 2‐diphenyl‐acetamide), DCPA, diphenamid, nitrofen (2,4‐dichlorophenyl‐p‐nitrophenyl ether), and prometryn [2, 4‐bis (isopropylamino)‐6‐(methylthio)‐s‐triazine] were applied to ‘Dwarf Long Green Pod’ okra. All herbicide treatments controlled weeds during the first 28 days after treatment. At 42 days after treatment good weed control was obtained with prometryn, trifluralin, preplant benefin, and diphenamid; and acceptable weed control was obtained with preemergence benefin and DCPA. Preplant benefin and trifluralin, and premergence benefin, prometryn, and diphenamid gave fruit yields (i.e. weight and numbers) that were equivalent to those of the handweeded check and superior to those of the other treatments. None of the herbicide treatments significantly affected the grading quality, total carbohydrate, protein, fat, or moisture content of the okra fruit. Slight initial injury to okra plants was caused by prometryn, diphenamid, and DCPA + diphenamid. The DCPA alone caused some leaf distortion which later disappeared. With the exception of nitrofen, which reduced stands, no other symptoms of injury were observed. Results of this study indicate that preplant or preemergence herbicide treatments can be used effectively in okra production.

Combinations of MSMA with Preemergence Herbicides for Large Crabgrass (Digitaria sanguinalis) Control in Turf

Combinations of MSMA (monosodium methanearsonate) with bensulide [O,O-diisopropyl phosphorodithioateS-ester withN-(2-mercaptoethyl)benzenesulfonamide], DCPA (dimethyl tetrachloroterephthalate), or prosulfalin {N-[[4-(dipropylamino)-3,5-dinitrophenyl] sulfonyl]-S,S-dimethylsulfilimine} were applied at various dates of treatment to bermudagrass [Cynodon dactylon(L.) Pers.] and Kentucky bluegrass (Poa pratensisL.) in the spring for large crabgrass [Digitaria sanguinalis(L.) Scop.] control. Bensulide controlled a higher percentage of weeds than did DCPA, regardless of treatment dates. When treatments were delayed until late April in Griffin and mid May in Blairsville, Georgia, large crabgrass control was improved from combinations of MSMA with bensulide compared to bensulide alone. Combinations of MSMA with DCPA improved large crabgrass control when applied in March and April at Griffin and in May at Blairsville. Combinations of MSMA with either bensulide or DCPA performed equally well whether applied as a single tank-mix treatment or as separate applications on the same day. Large crabgrass control was not improved at any date from combinations of MSMA with prosulfalin when compared with prosulfalin alone.

Enhancement of Herbicidal Weed Control in Sweet Potatoes (Ipomoea batatas) with Cultivation

Six herbicides were evaluated at two rates on sweet potatoes [Ipomoea batatas(L.) Lam. ‘Georgia Red’, ‘Georgia Jet’] with and without cultivation from 1972 through 1976. Cultivation with a ground-driven rotary hoe about 2 weeks later improved the control of late-season broadleaf weeds such as Florida beggarweed [Desmodium tortuosum(Sw.) DC] and showy crotalaria (Crotalaria spectabilisRoth.). Cultivation improved weed control where vernolate (S-propyl dipropylthiocarbamate), DCPA (dimethyl tetrachloroterephthalate), and napropamide [2-(α-naphthoxy)-N,N-diethylpropionamide] were applied. The improved weed control in cultivated treatments resulted in increased sweet potato yields in 1972 and 1973, which also were the years with the highest weed populations.

Response of Cucumber (Cucumis sativus) to Annual Weeds and Herbicides

Weed and cucumber (Cucumis sativusL. ‘Poinsett’) growth was studied where herbicides were soil-applied or applied to emerged weeds in the established crop. Cucumber yields were decreased at least 36% in 2 of 5 yr when weeds interfered for 4 weeks after emergence. Sequential applications of bensulide [O,O-diisopropyl phosphorodithioateS-ester withN-(2-mercaptoethyl)benzenesulfonamide] applied preplant and incorporated (PPI) + trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine) applied postemergence and incorporated (POI) were outstanding and controlled Japanese millet (Echinochloa crus-galliLink. var.frumentacea), Texas panicum (Panicum texanumBuckl.), Palmer amaranth (Amaranthus palmeriS. Wats.), and common purslane (Portulaca oleraceaL.) without affecting the growth or yield of cucumber. Compared with bensulide, the selectivity of soil-incorporated butralin [4-(1,1-dimethylethyl)-N-(1-methylpropyl)-2,6-dinitrobenzenamine] with cucumber was limited. Laboratory bioassays showed that under warm field soil conditions, PPI applications of 1.7 kg/ha of butralin persisted more than 2 months, but were dissipated after 4 months. Ethalfluralin [N-ethyl-N-(2-methyl-2-propenyl)-2,6-dinitro-4-(trifluoromethyl)benzenamine] reduced cucumber yields only when it was soil-incorporated to the crop-seed depth at planting. Applications to soil of bensulide + DCPA (dimethyl tetrachloroterephthalate) stunted cucumber plants, reduced leaf area, increased leaf thickness, and caused higher near-infrared (0.75 to 1.34 μm) leaf reflectance.

Goosegrass (Eleusine indica) Control during Bermudagrass (Cynodon dactylon) Establishment

Oxadiazon [2-tert-butyl-4-(2,4-dichloro-5-isopropoxyphenyl)-δ2-1,3,4-oxadiazolin-5-one] applied early enough for large crabgrass [Digitaria sanguinalis(L.) Scop.] control provided full season goosegrass [Eleusine indica(L.) Gaertn.] control during bermudagrass [Cynodon dactylon(L.) Pers. ‘Midiron’ and ‘Tufcoat’] establishment from sod strips. Prosulfalin {N-[[4-(dipropylamino)-3,5-dinitrophenyl]sulfonyl]-S,S-dimethylsulfilimine}, DCPA (dimethyl tetrachloroterephthalate), pendimethalin [N-(1-ethylpropyl)-3,4-dimethyl-2,6-dinitrobenzenamine] and bensulide [0,0-diisopropyl phosphorodithioateS-ester withN-(2-mercaptoethyl)benzenesulfonamide] gave full season goosegrass control in well-established Midiron bermudagrass, but not during the initial establishment period where open bare soil was present. Napropamide [2-(α-naphthoxy)-N,N-diethylpropionamide] provided long term residual control of goosegrass with some interference with rooting of bermudagrass from stolon nodes. Winter survival of Midiron bermudagrass was superior to Tufcoat bermudagrass. Controlling annual grasses permitted superior bermudagrass growth, and winter survival was improved tremendously. Postemergence goosegrass control was obtained with MSMA (monosodium methanearsonate) and methazole [2-(3,4-dichlorophenyl)-4-methyl-1,2,4-oxadiazolidine-3,5-dione] when repeated several times during the season. A mixture of MSMA and methazole was superior to either used alone. The rate of bermudagrass establishment was increased through the control of goosegrass with herbicides.

Effects of No-tillage and Herbicides on Carrot and Onion Seed Production1

Abstract Carrot roots (Daucus carota L.) and onion bulbs (Allium cepa L.) were planted in Kidman silt loam immediately after DCPA (dimethyl tetrachloroterephthalate), ethofumesate (2-ethoxy-2,3-dmydro-3,3-dimethyl-5-benzofuranol methanesulfonate), linuron (3-(3,4-dichlo-rophyenyl)-l-methoxy-l-methylurea), napropamide (2-(a-naphthoxy)N,N-diethylpropiona-mide), or trifluralin (a,a,a-trifluoro-2,6 dinitro-N,N-dipropyl-p-toluidine) had been soil incorporated. In a second experiment, carrot roots and onion bulbs were planted in a conventionally-prepared seed bed or among vigorously growing wheat plants (7 to 10 cm tall). DCPA, linuron, and oryzalin (3,5-dinitro-N4,N4-dipropylsulfanilamide) plus glyphosate (N-(phos-phonomethyl)glycine) were surface applied to these seedbeds after planting but prior to crop emergence. Methazole (2-(3,4-dichlorophenyl)-4-methyl-l,2,4-oxadiazolidine-3,5-dione) and nitrofen (2,4-dichlorophenyl-p-nitrophenyl ether) were applied postemergence. Chemical treatments significantly altered the seed yields within the no-tillage method. Carrots grown in the tilled plots exhibited no effect of chemical treatments on seed yield. Comparison of tillage methods indicated a highly significant reduction in carrot seed yield relative to the no-tillage plots. Those on the non-weeded control and no-tillage plots showed a highly significant reduction in seed yield. Many of the onion bulbs from male-fertile lines failed to develop seedstalks in the plots sprayed with linuron and napropamide and those that did were delayed in development. Linuron and ethofumesate reduced the numbers of onion flowers per umbel. Onions grown in the tilled plots exhibited no effect of chemical treatments on seed yield. Those on the non-weeded control and no-tillage plots showed a highly significant reduction in onion seed yield. Comparison of tillage methods indicated a highly significant reduction in onion seed yield relative to the no-tillage plots.

Root Growth of Southern Turf Cultivars as Affected by Herbicides

Root growth of three zoysia (Zoysiaspp. ‘Emerald’, ‘Meyer’, and ‘Matrella’) cultivars and four bermudagrasses [Cynodon dactylon(L.) Pers. ‘Tifway’, ‘Tifgreen’, ‘Tifdwarf’, and ‘Ormond’] was determined after several consecutive annual herbicide treatments. Napropamide [2-(α-naphthoxy)-N,N-diethylpropionamide] reduced the root growth of all zoysia and bermudagrass cultivars. Prosulfalin {N-[[4-(dipropylamino)-3,5-dinitrophenyl] sulfonyl]-S,S-dimethylsulfilimine} retarded root growth of Tifgreen and Tifdwarf bermudagrass when treated at any rate. Tifway and Ormond bermudagrass and zoysia cultivars were retarded at the 3X rate (10.2 kg/ha). Zoysia grass roots were not affected by oxadiazon [2-tert-butyl-4-(2,4-dichloro-5-isopropoxyphenyl)-δ2-1,3,4-oxadiazolin-5-one], bensulide [O,O-diisopropyl phosphorodithioateS-ester withN-(2-mercaptoethyl)benzenesulfonamide], or benefin (N-butyl-N-ethyl-α,α,α-trifluoro-2,6-dinitro-p-toluidine) treatments. DCPA (dimethyl tetrachloroterephthalate) and oxadiazon did not reduce root growth of bermudagrasses, except when Tifgreen was treated with oxadiazon at 3X rate (13.4 kg/ha).

Levels of DCPA, MTP, TPA, and Hexachlorobenzene in Radish Roots and Tops1

Abstract Residues of dimethyl-2,3,5,6-tetrachloroterephthalate (DCPA), monomethyl-2,3,5, 6-tetrachloroterephthalate (MTP), 2,3,5,6-tetrachloroterephthalic acid (TPA) and hexachlorobenzene (HCB) were determined in tops and roots of radish (Raphanus sativus L.) to which the herbicide had been applied as a soil treatment for preemergence control of weeds under commercial field conditions. Residues of these compounds in the radish roots were either negligible or less than the analytical method sensitivity (0.01 ppm for all compounds except HCB which was 0.001 ppm). Much more residues of DCPA were found in the radish tops ranging from about 2 to 13 ppm. Residues of the other compounds were higher in the tops, in all instances, than in the roots. Recoveries of all the chemicals in fortified controls ranged from 70 to 100%.

Influence of Thatch on Preemergence Herbicide Activity in Kentucky Bluegrass (Poa pratensis)Turf

The effects of five preemergence herbicides on turfgrass quality and control of crabgrass (Digitariaspp.) were measured to determine the influence of thatch on preemergence herbicide activity in Kentucky bluegrass (Poa pratensisL.) turf. Field applications of benefin (N-butyl-N-ethyl-α,α,α-trifluoro-2,6-dinitro-p-toluidine), oxadiazon [2-tert-butyl-4-(2,4-dichloro-5-isopropoxyphenyl)-Δ2-1,3,4-oxadiazolin -5-one], and prosulfalin {N-[[4-(dipropylamino)-3,5-dinitrophenyl] sulfonyl]-S,S-dimethylsulfilimine} to thatchy Kentucky bluegrass turf in spring caused injury that was apparent during periods of summer stress, while DCPA (dimethyl tetrachloroterephthalate) and bensulide [O,O-diisopropyl phosphorodithioateS-ester withN-(2-mercaptoethyl)benzenesulfonamide] caused little or no injury. The same treatments on thatch-free sites revealed that only prosulfalin was injurious. Adsorption of benefin, bensulide, and DCPA from solution was greater by thatch than by soil; however, the mobility of these herbicides in undisturbed thatch profiles was greater than measured in undisturbed surface soil from thatch-free sites. Thus, turfgrass injury from preemergence herbicides on thatchy sites is due to at least two factors: the greater mobility of preemergence herbicides in thatch than in soil; and the inherent susceptibility of Kentucky bluegrass to injury from preemergence herbicides that come into direct contact with roots and other absorbing organs.

Isolation and characterization of the herbicide dimethyl tetrachloroterephthalate by Gas Chromatograph-Mass Spectrometer-computer techniques

Isolation and characterization of the herbicide dimethyl tetrachloroterephthalate by Gas Chromatograph-Mass Spectrometer-computer techniques

Persistence and Movement of Ten Herbicides in Soil

Ten herbicides were each applied at two rates to Panache loam for 5 or 6 yr as soil-incorporated broadcast sprays directed to the base of cotton(Gossypium hirsutumL. ‘Acala SJ-1’) at last cultivation. Chemical determinations 6 months after annual treatment showed that trifluralin(a,a,a-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine), nitralin [4-(methylsulfonyl)-2,6-dinitro-N,N-dipropylaniline], benefin(N-butyl-N-ethyl-a,a,a-trifluoro-2,6-dinitro-p-toluidine), DCPA (dimethyl tetrachloroterephthalate), and prometryn [2,4-bis(isopropylamino)-6-(methylthio)-s-triazine] residues were essentially confined to the tilled zone of soil; whereas, bensulide [O,O-diisopropyl phosphorodithioateS-ester withN-(2-mercapteothyl)benzenesulfonamide], fluometuron [1,1-dimethyl-3-(a,a,a,-trifluoro-m-tolyl)urea], linuron [3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea], and diuron [3-(3,4-dichlorophenyl)-1,1-dimethylurea] residues were found below the tilled zone. At time of retreatment, annual residue determinations from the upper 15 cm of soil showed that nitralin and prometryn had dissipated completely and residues of the other herbicides and were notably reduced as compared to levels at cotton harvest. One year after final treatment herbicide residues below the tilled zone were essentially nondetectable, except for diuron, linuron, and fluometuron. There was no evidence of herbicide accumulation in soil with repeated applications.