Annual Bluegrass Control Research Articles

Selective Control of Annual Bluegrass in Cool‐Season Turfs with Fenarimol and Chlorsulfuron

AbstractAnnual bluegrass (Poa annua L.) is a weed that presents turfgrass managers with serious problems upon infestation into desired turfgrass stands. This species can be managed as a turfgrass, but selective herbicides for its removal would be very useful in intensely managed turfs. In this study, fenarimol [3‐(2‐chlorophenyl)‐3‐(4‐chlorophenyl)‐5‐ pyrimidinemethanol] and Chlorsulfuron {2‐chloro‐N[(4‐methoxy‐6‐methyl‐1,3,5‐triazin‐2‐y1)‐aminocarbonyl]‐benzenesulfonamide} were tested in field and greenhouse trials over a 2‐yr period to determine their effectiveness as annual bluegrass (Poa annua L.) controls in both Kentucky bluegrass (Poa annua L.) and creeping bentgrass (Agrostis palustris Huds.) turfs. Fenarimol treatments in the field included rates of 0, 155, 306, 459, 612, and 765 g ha−1 applied eight times in 1984 until cumulative amounts of 1.2, 2.4, 3.7, 4.9, and 6.1 kg ha−1 were reached, and seven times in 1985 until cumulative amounts of 1.1,2.1,3.2,4.3, and 5.4 kg ha−1 were reached. In the greenhouse, fenarimol was applied at single application rates of 1.5, 3.0, 4.6, and 6.1 kg ha−1. Chlorsulfuron was applied in the field at single application rates of 18, 35, 70, 140, and 280 g ha−1 and in the greenhouse at single application rates of 70, 140, 210, and 280 g ha−1. Fenarimol was not effective in controlling annual bluegrass in the field or greenhouse and caused discoloration to the creeping bentgrass in the field at rates above 4.9 kg ha−1. Chlorsulfuron was effective in controlling all three annual bluegrass biotypes in the greenhouse and had no detrimental effects on creeping bentgrass or Kentucky bluegrass. In the field, Chlorsulfuron was effective in controlling annual bluegrass at one of the two testing sites.

Evaluation of Ethofumesate for Annual Bluegrass (Poa annua) and Turfgrass Tolerance

Field and greenhouse studies were conducted to evaluate annual bluegrass (Poa annuaL. # POAAN) control and phytotoxicity of ethofumesate [(±)-2-ethoxy-2,3-dihydro-3,3-dimethyl-5-benzofuranyl methanesulfonate] to selected warm- and cool-season turfgrass species. Annual bluegrass control in non-overseeded dormant hybrid bermudagrass [Cynodon dactylon(L.) Pers. XC. tranvaalensisBurtt-Davy Tifgreen’ # CYNDA] was 75% or greater with at least two ethofumesate applications at monthly intervals starting in December. Tifgreen bermudagrass spring growth was delayed with more than two applications of ethofumesate at 1.1 kg ai/ha, or when the second application was made after January. Under greenhouse conditions the growth of both Tifgreen and Tifdwarf bermudagrass was less when treated with ethofumesate. Stand and shoot growth of 29 cultivars of ryegrass (Loliumspp.), bluegrass (Poaspp.), bentgrass (Agrostisspp.), and red fescue (Festuca rubraL. # FESRU) were reduced by ethofumesate at 1.1 kg/ha as a preemergence or split (0.5 kg/ha preemergence + 0.5 kg/ha postemergence) application. Postemergence applications were less phytotoxic to cool-season turfgrasses than preemergence applications. Perennial ryegrass stands were generally not reduced by postemergence application of ethofumesate at 1.1 kg/ha. However, shoot growth of perennial ryegrass was reduced.

Kentucky Bluegrass and Annual Bluegrass Responses to Ethofumesate

Abstract In a 1983 study, ethofumesate at 1.1, 2.2, and 3.3 kg°ha−1; bensulide at kg°ha−1; and an untreated control were compared for annual bluegrass [Poa annua var. annua (L.) Timm] control and injury to ‘Park’ and ‘Touchdown’ Kentucky bluegrass (Poa pratensis L.). Ethofumesate at 1.1 to 3.3 kg°ha−1 reduced verdure and clipping yields of both cultivars, but gave significant P. annua control. Bensulide at 13.6 kg°ha−1 caused no injury and had unsatisfactory P. annua control. In 1984 ethofumesate was applied to ‘Touchdown’ at 1.1 and 2.2 kg°ha−1 and in repeat treatments of 1.1 + 1.1 kg°ha−1 and 2.2 + 1.1 kg°ha−1 with a 30-day interval between treatments, and was compared to bensulide at 13.6 kg°ha−1 and an untreated control. Ethofumesate caused injury at 7 and 15 days after treatment (DAT), but only the repeat treatments had significant injury at 60 DAT. No injury was detectable at 260 DAT. Excellent annual bluegrass control was obtained at 2.2 kg°ha−1 and 2.2 + 1.1 kg°ha−1. Good annual bluegrass reduction was noted for the other treatments with exception of bensulide, which only reduced the pest population by 50%. Lateral spread of ‘Touchdown’ increased with ethofumesate treatment (when compared to the untreated control) due to reduced annual bluegrass competition. Chemical names used: (±)-2-ethoxy-2,3-dihydro-3.3-dimethyl-5-benzofuranyl methanesulfonate (ethofumesate); and O,O-bis(l-methylethyl)S-[2[(phenylsufonyl) aminojethyl] phosphorodithioate (bensulide).

Response to Vertical Mowing and Ethofumesate Treatments for Annual Bluegrass Control in Bermudagrass Turf1

AbstractAnnual bluegrass (Poa annua L.) is a major weed in bermudagrass (Cynodon spp.) golf greens overseeded with cool‐season grasses. Herbicides are often ineffective or may injure the overseeded grass. This study was initiated to determine the effects of sequential vertical mowing and ethofumesate [( ± )‐2‐ethoxy‐2,3‐dihydro‐3,3‐dimethyl‐ 5‐benzofuranyl methanesulfonate)] treatments on a bermudagrass green. Treatments were arranged as a split plot design with whole plots as vertical mowed treatments in a randomized complete block and subplots as ethofumesate treatments stripped across all whole plots with four replications. One‐half of each whole plot was overseeded with perennial ryegrass (Lolium perenne L.) in each of 2 yr. The bermudagrass was an established 'Tifway' Cynodon transvaalensisBurtt‐Davies ✕ C. dactylon (L.) Pers.] growing on a sandy loam (clayey, kaolinitic thermic Typic Hapludult). Vertical mowed treatments included: none, low (25% leaf removal), and high (60% leaf removal) intensity prior to overseeding and applying ethofumesate. Ethofumesate treatments were made at time of overseeding in October or delayed until bermudagrass was dormant in November. Herbicide treatments were also applied at the same time to nonoverseeded common bermudagrass [Cynodon dactylon (L.) Pers.] infested with annual bluegrass. October vertical mowing reduced bermudagrass quality the following spring. Quality was reduced with increased intensity. Vertical mowing and ethofumesate applied in October reduced quality in April and May more than either treatment alone. Transition from cool‐season to bermudagrass was generally slowest in the high‐intensity vertical mowed turf.

Effects of Repeated Applications of SAP on the Control of Annual Bluegrass of Penncross Bentgrass Putting Green Turf

Effects of Repeated Applications of SAP on the Control of Annual Bluegrass of Penncross Bentgrass Putting Green Turf

Studies on the control of annual bluegrass (Poa annua) in turf

Studies on the control of annual bluegrass (<I>Poa annua</I>) in turf

Control of Annual Bluegrass (Poa annua) in Overseeded Bermudagrass (Cynodonspp.) Golf Greens

Ethofumesate, [(+)-2-ethoxy-2,3-dihydro-3,3-dimethyl-5-benzofuranyl methanesulfonate] applied preemergence provided selective control of annual bluegrass (Poa annuaL.) in perennial ryegrass (Lolium perenneL.) overseeded on dormant bermudagrass [Cynodon dactylon(L.) Pers. XC. transvaalensisBurtt Davy ‘Tifdwarf’] golf greens. Control in excess of 95% was obtained with single applications at the 2.2 kg/ha rate in 2 of 3 yr, but multiple applications were required when ethofumesate was applied at 1.1 kg/ha or less. Ethofumesate caused temporary cessation of bermudagrass growth when applied in the fall. February applications slowed the spring transition to bermudagrass.

THE BIOLOGY OF CANADIAN WEEDS.: 37 Poa annua L.

A summary of biological information is provided on Poa annua L. (annual blue grass), which is common throughout the temperate regions of the world as a weed of cultivated and wasteground habitats. The distribution of distinct erect-annual and prostrate-perennial variants of the species is highly correlated with habitat type, with the latter predominating in closely mowed turf and the former in open fields, wasteground, etc. Poa annua is a serious weed in turfgrass. It is found on most soil types and exhibits a high tolerance to trampling, mowing and poorly aerated soils. The species, however, lacks tolerance of strongly acid soils, high pollution levels and extremes of temperature and moisture. The species is fully self-compatible and is predominantly selfing. Seed production and seed viability are generally high. Factors affecting seed germination are summarized; these include response to: temperature, moisture, O2 partial pressure, light, cultivation practises, fertilizers, pH and the environmental conditions under which the parent plant was grown. Selective herbicide control of established annual blue grass is difficult. Present postemergence herbicides include endothal and linuron. Differential herbicide response in P. annua has been recorded for endothal, metoxuron and atrazine.

Effectiveness of Herbicide Programs for Annual Bluegrass (Poa annua) Control in Bermudagrass (Cynodon dactylon)

Annual bluegrass (Poa annuaL.) growing in bermudagrass completes its life cycle in May and dies leaving open spaces in the turfgrass. This occurs at a time when summer annual weeds are germinating and these weeds fill the space formerly occupied by the annual bluegrass. As the summer annual weeds die in the fall, annual bluegrass germinates and fills the space formerly occupied by the summer annual weeds. To control annual bluegrass, it is important to control the summer annual grasses and manage the bermudagrass [Cynodon dactylon(L.) Pers.] to maintain a competitive groundcover especially during the peak germination period for the weeds. Herbicide programs over a three-year period were designed to control annual grasses with treatments in April for large crabgrass [Digitaria sanguinalis(L.) Scop.], in May or June for goosegrass [Eleusine indica(L.) Gaertn.] and in late August for annual bluegrass. Oxadiazon [2-tert-butyl-4-(2,4-dichloro-5-isopropoxyphenyl)-δ2-1,3,4-ozadiazolin-5-one] applied in August gave complete control of annual bluegrass. Although oxadiazon has a long residual life in the soil, annual bluegrass was poorly controlled with treatments made in June. Fall (August or September) applications of benefin [N-butyl-N-ethyl-α,α,α-trifluoro-2,6-dinitro-p-toluidine], prosulfalinN-[[4-(dipropylamino)-3,5-dinitrophenyl] sulfonyl]-S,S-dimethylsulfilimine and butralin [4-(1,1-dimethylethyl-N-(1-methylpropyl)-2,6-dinitrobenzenamine] provided adequate control of annual bluegrass with only a few exceptions during the three-year period. Bensulide [O,O-diisopropyl phosphorodithioateS-ester withN-(2-mercaptoethyl)benzenesulfonamide] gave variable control of annual bluegrass; however, this was improved in programs with oxadiazon which provide goosegrass control during summer. In these studies, DCPA [dimethyl tetrachloroterephthalate], even with three applications a year, gave very little control of annual bluegrass. When oxadiazon was used in rotation with DCPA, adequate control was obtained.

SELECTIVE CONTROL OF ANNUAL BLUEGRASS IN KENTUCKY BLUEGRASS TURF WITH LINURON

Optimum top growth of annual bluegrass (Pao annua L.) and Kentucky bluegrass (Poa pratensis L.) was obtained at 24/12 °C day/night temperature regime in controlled environment studies. The tolerance of seedling Kentucky bluegrass to linuron [3-(3,4-dichlorophenyl)-1)methylurea] appeared to be greatest at this temperature regime when photoperiods were 16 h in length. A granular formulation of linuron gave excellent control of annual bluegrass in Kentucky bluegrass turf at 6.7 kg/ha when applied postemergence. At this rate, all culitivars of Kentucky bluegrass tested, with the exception of Fylking, were tolerant to linuron as a granular formulation. After application of linuron at 3.4–6.7 kg/ha, phytotoxic residues remained in the soil at sufficient levels to injure seedling Kentucky bluegrass for up to 3 mo.

Effect of Tricalcium Arsenate Formulations on Control of Annual Bluegrass (Poa annua)

The influence of calcium arsenate (48% w/w tricalcium arsenate) rate, physical form, time of application, and phosphorus (P) rate on the growth of annual bluegrass (Poa annua L.) and Bray P1 extractable arsenic (As) were investigated. Both powder and granular formulations reduced clipping yields and enhanced extractable As levels. Higher initial soil As activity and significantly better control were obtained in one study when the powder formulation was used. Similar levels of control were achieved whether the As was applied prior to germination or to the mature turf. Soil P-levels did not influence the effectiveness of either As formulation.

Herbicides for Seasonal Weed Control in Turfgrasses1

AbstractCommercially available preemergence herbicides do not consistently control weeds in turfgrasses satisfactorily in the Southeast. New herbicide tests to determine if weed control could be improved were conducted on several soil types over a 3‐year period. Several herbicides were applied in early spring and evaluated for the control of large crabgrass (Digitaria sanguinalis L. Scop) in bermudagrasses [Cynodon dactylon (L.) Pers.] and Kentucky bluegrass (Poa pratensis L.) turf or they were applied in early fall and evaluated for the control of annual bluegrass (Poa annua L.) and other winter annuals in a bermudagrass turf. Soil types were Cecil sl and Cecil scl (Typic Hapludult), Appling loamy sand and Appling scl (Typic Hapludult), Madison scl (Typic Hapludult), Hatboro 1 (Typic Fluvaquents), and Davidson scl (Rhodic Paleudult). Oxadiazon [2‐tert‐butyl‐4‐(2,4‐dichloro‐5‐isopropoxyphenyl)‐ Δ2‐1,3,4‐oxadiazolin‐5‐one] applied in early spring at 4.5 kg/ha was better than with other herbicides tested for large crabgrass control. Oxadiazon was the only herbicide that consistently controlled large crabgrass at all locations. Parsley‐piert (Alchemilla microcorpa Boissier Reuter), a broadleaf winter annual not previously reported, was controlled satisfactorily when oxadiazon was applied preemergence in the fall. No other herbicide controlled parsley‐piert as well as oxadiazon.

Control of annual bluegrass

Control of annual bluegrass

Glyphosate for Weed Control in Dormant Bermudagrass

The control of winter annuals in dormant bermudagrass [Cynodon dactylon(L.) Pers. ‘Common’] has not been consistent with available herbicides. Experiments were conducted to evaluate rates and number of glyphosate [N-(phosphonomethyl)glycine] applications for control of winter annuals growing in dormant bermudagrass. Glyphosate applied as a single treatment at 0.6 kg/ha consistently controlled more parsley-piert (Alchemilla microcorpaBoissier Reuter), corn speedwell (Veronica arvensisL.), and henbit (Lamium amplexicauleL.) than paraquat (1,1′-dimethyl-4,4′-bipyridinium ion) or combination treatments 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). There was no difference between glyphosate and paraquat control of annual bluegrass (Poa annuaL.) and common chickweed [Stellaria media(L.) Cyrillo]. Glyphosate treatments did not injure the bermudagrass the following spring.

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).

Role of Endothall in the Control of Annual Bluegrass in Turf

Endothall (7-oxabicyclo[2.2.1]heptane-2,3-dicarboxylic acid) was evaluated for controlling annual bluegrass(Poa annuaL.) infestations in Kentucky bluegrass(Poa pratensisL.) and creeping bentgrass(Agrostis stoloniferaL.) turfs. Growth of annual bluegrass was selectively suppressed by three applications of 0.6 kg/ha of endothall, two or three applications of 1.1 and 2.2 kg/ha, and one application of 4.5 kg/ha made to the single plant sand cultures. Field treatments were variable and seasonably dependent. Endothall selectively killed annual bluegrass when applied to roots in sand culture at a concentration of 2.7 × 10−4molar. A granular formulation of endothall provided selective control of annual bluegrass in field and greenhouse studies. High watering frequency prior to application, low organic matter content of the underlying soil, and predominance of the annual biotype of annual bluegrass enhanced the selective action at the lowest rates of endothall application.

Annual Bluegrass Control in Overseeded Bermudagrass Putting Green Turf1

AbstractDCPA, bensulide, and diphenamid gave preemergence control of annual bluegrass in freshly tilled soil. Overseeding bermudagrass golf greens with cool season grasses reduced through competition the amount of annual bluegrass cover and provided a desirable putting surface. Annual ryegrass was more effective in this respect than red fescue. Bensulide and DCPA gave control of annual bluegrass and the rates required were partially offset by competing cool season grasses. The cool season grasses seeded one month after treatment were not affected by 5.6 kg/ha of bensulide whereas higher rates gave significant reductions in ground cover with cool season grasses. The margin of safety was not as great with diphenamid. Although bermudagrass growth was retarded in spring with the overseeded cool season grasses, the turf quality was maintained better with the transition from the overseeded grasses to bermudagrass than from the infested annual bluegrass to bermudagrass. Plant competition reduced the number of tillers and weight of annual bluegrass plants in the field and greenhouse studies.

Susceptibility of Annual Bluegrass and Turfgrasses to Bensulide and Three Uracil Herbicides

Golf putting greens were sprayed with N-(2-mercaptoethyl) benzenesulfonamide S-(O,O-diisopropyl phosphorodithioate) (bensulide). Creeping bentgrass (Agrostis palustris Huds.) and annual bluegrass (Poa annua L.) were observed for injury. Preemergence and postemergence treatments of 5-bromo-3-sec-butyl-6-methyluracil (bromacil), 5-chloro-3-tert-butyl-6-methyluracil (terbacil), and 5-bromo-3-tert-butyl-6-methyluracil (hereinafter referred to as DP 733) were applied to a prepared seedbed planted with Kentucky bluegrasses (Poa pratensis L., var. Merion and var. Newport) and annual bluegrass.Thirty lb/A of bensulide produced leaf discoloration and root length reduction of established annual bluegrass plants without injuring creeping bentgrass. Terbacil at 0.2 lb/A and bromacil at 0.4 lb/A gave highly selective control of annual bluegrass in Merion and Newport Kentucky bluegrasses when applied preemergence to the three grasses. Postemergence applications of these compounds produced moderate selective control of annual bluegrass.

Factors Affecting Poa annua L. Control

Complete control of annual bluegrass (Poa annua L.) at all levels of P and at both planting dates was obtained with a,a,a-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine (trifluralin) at 2 lb/A. For both planting dates, high levels of P reduced the effectiveness of both calcium arsenate (CaAs) and to a small degree dimethyl 2,3,5,6-tetrachloroterephthalate (DCPA). On a plant count basis, O-(2,4-dichlorophenyl)O-methyl isopropylphosphoramidothioate (DMPA) was more effective than N-(2-mercaptoethyl) benzenesulfonamide S-(O,O,-diisopropyl phosphorodithioate) (bensulide) for the control of annual bluegrass. In the field, injury to bentgrasses (Agrostis palustris Huds.) from preemergence herbicides generally was specific to one or two varieties. Washington bentgrass was severely injured from a 12-lb/A application of 1-(2-methylcyclohexyl)-3-phenylurea (siduron).

Preemergence Control of Annual Bluegrass (Poa annua L.)1

SynopsisDacthal at 10 pounds, betasan at 15 pounds, dipropalin at 6 pounds, trifluralin at 2 pounds, and enide at 4 pounds per acre significantly controlled annual bluegrass for periods of 9 to 12 weeks. Dacthal and betasan were completely nonphytotoxic to mature turf. It is possible under field conditions to achieve good preemergence control of annual bluegrass if applications of these preemergence herbicides are made to coincide with the germination periods of the seed.