per nursery (Gilliam et al., 1990; Evaluation of p-Hydroxyphenylpyruvate Mathers, 1999). Yet, control options Dioxygenase-inhibiting Herbicides for for mugwort are limited due in part to challenges presented by herbicide costs, Controlling Mugwort herbicide phytosafety across desirable crop commodities (including turfgrass 1,2,7 1,3,5 2,6 and ornamentals), and limited efficacy William E. Klingeman , Gregory R. Armel ,HenryP.Wilson , available herbicides may have on other Thomas E. Hines4,6,JoseJ.Vargas1, and Philip C. Flanagan1 key weed species. For example, ethyl N, N-di-n-propylthiolcarbamate applica- tion at 15 lb/acre has controlled mug- ADDITIONAL INDEX WORDS. Artemisia vulgaris, atrazine, bentazon, clopyralid, false wort in field nurseries, yet this rate is chrysanthemum, HPPD, mesotrione, PSII inhibitor, topramezone toohightosafelymanagemugwortin SUMMARY. Mugwort (Artemisia vulgaris) is a perennial invasive weed species that stands of field corn (Bing and Pridham, has infiltrated row crops, turfgrass, ornamentals, and various noncrop areas. 1963, 1964). Glyphosate is effective on Currently, multiple mimics of indole-3-acetic acid can provide control of this young mugwort plants but is less effec- species; however, these herbicides can damage certain sensitive ornamental plants. tive at controlling large mugwort plants When applied at reduced rates, the p-hydroxyphenylpyruvate dioxygenase (HPPD)- in later stages of growth (Ahrens, 1976; inhibiting herbicides mesotrione and topramezone have demonstrated some Bradley and Hagood, 2002a, 2002b). selectivity among certain ornamental plants. Field and greenhouse studies were initiated to evaluate whether these herbicides could control mugwort when applied Plant growth regulating herbicides that alone, or in mixtures with photosystem II (PSII)-inhibiting herbicides that often mimic indole-3-acetic acid, like 2,4- provide synergistic weed control. In the field, mesotrione controlled mugwort dichlorophenoxyacetic acid and clopyr- between 30% and 60% by 21 days after treatment when applied at 0.093 to 0.187 alid, have generally provided poor lb/acre. When the PSII-inhibiting herbicide atrazine was added, control increased mugwort control, even at high applica- to 78% and 79%. In the greenhouse, similar rates produced greater control in tion rates (Ahrens, 1976; Bingham, mugwort, and all mesotrione treatments limited mugwort regrowth by at least 95% 1965; Bradley and Hagood, 2002a, when compared with untreated control. When HPPD inhibitor rates were reduced 2002b; Day et al., 1997). Clopyralid further, the addition of the PSII inhibitors atrazine or bentazon was not sufficient at providing acceptable control of mugwort. can control mugwort and reduce regrowth the following year, yet clo- pyralid is relatively expensive, has lim- ugwort or false chrysanthe- crop plants (Barney and DiTommasso, ited efficacy against other commonly mum is an adaptable, non- 2003; Bradley and Hagood, 2002a, encountered weed species, and is chal- Mnative perennial plant that is 2002b; Holm et al., 1997; Rogerson lenged by limited crop safety across a management challenge to commer- and Bingham, 1964; Uva et al., 1997). a diverse assemblage of ornamental cial agronomic and ornamental crop In nursery fields, rhizomes are abundant plant species (Bradley and Hagood, production worldwide (Barney and in the upper 4 inches of soil (Pridham, 2002a, 2002b; Bradley et al., 2000; DiTommasso, 2003; Henderson and 1963; Rogerson and Bingham, 1964). Day et al., 1997; Koepke-Hill et al., Weller, 1985; Holm et al., 1997; Uva Tillage will exacerbate localized 2011). Still, the broad utility of clopyr- et al., 1997). In the eastern United mugwort infestation because rhi- alid (StingerÒ and TranslineÒ;Dow States, mugwort has expanded be- zome sections 2-cm long reproduce AgroSciences, Indianapolis, IN) across yond ornamental nurseries into turf, well when grown in pine bark, sand, corn, sugarbeet (Beta vulgaris), pasture pastures, and cropping systems includ- and soil substrates (Guncan, 1982; and rangeland, Christmas tree, orna- ing corn (Zea mays), cotton (Gossypium Klingeman et al., 2004; Rogerson mental plant, and fruit and vegetable hirsutum), and soybean (Glycine max) et al., 1972). crop production systems makes this (Bradley and Hagood, 2002a, 2002b; Postemergence (POST) control herbicide a practical choice for selective Yelverton et al., 2012). of weeds in nursery operations re- control of mugwort. Mugwort reproduction and dis- mains a particularly attractive option Mesotrione and topramezone persal is achieved primarily by transport for both field-grown and container impede carotenoid biosynthesis by of rhizome pieces on contaminated cul- production systems due, in part, to inhibiting the enzyme p-HPPD (Norris tivation equipment and within soil and need to reduce labor costs incurred et al., 1998). Mesotrione is registered soilless substrates around the roots of for hand-weeding in addition to the for preemergence (PRE) and POST current practice of making about applications in corn and turfgrass 1Plant Sciences Department, The University of Ten- three annual herbicide applications (BASF, 2013; Mitchell et al., 2001; nessee Institute of Agriculture, Knoxville, TN 37996 2Professor 3Assistant Professor Units 4Research Associate To convert U.S. to SI, To convert SI to U.S., 5Current address: BASF Corporation, Research Tri- multiply by U.S unit SI unit multiply by angle Park, NC 27709. 0.3048 ft m 3.2808 6Current address: Eastern Shore Agricultural Research 9.3540 gal/acre LÁha–1 0.1069 and Extension Center, Virginia Tech, Painter, VA 2.54 inch(es) cm 0.3937 23420. 1.1209 lb/acre kgÁha–1 0.8922 7Corresponding author. E-mail: [email protected]. 6.8948 psi kPa 0.1450
• August 2014 24(4) 433 RESEARCH REPORTS
Syngenta Crop Protection, 2011, (Weigela florida), spiraea (Spiraea ja- All treatments contained 1% (v/v) crop 2012) and provides effective POST ponica), arborvitae (Thuja plicata), oil concentrate [COC (Agridex; Hel- control against many annual broad- herbaceous daylily (Hemerocallis), ena Chemical, Memphis, TN)] and leaf weeds and certain grass species hosta (Hosta), autumn fern (Dryopteris 2.5% (v/v) urea ammonium nitrate (Armel et al., 2003, 2009; Beckett erythrosora), and pachysandra (Pachy- (UAN) solution. Experimental plots and Taylor, 2000; Sutton et al., sandra terminalis) (Cutulle et al., were8.3ftwideby20ftlongandwere 1999). Topramezone is also regis- 2013b). arranged in a randomized complete tered for POST weed control in corn Few selective weed control op- block (RCB) design with three repli- and turfgrass (e.g., Amvac, 2007; tions are available for mugwort con- cates. Mugwort control was assessed BASF, 2013). Apparent as foliar pho- trol, and it generally is not adequately visually at 7, 14, and 21 d after treat- tobleaching, topramezone reduces controlled with single applications or ment (DAT) using a 0% to 100% scale, total chlorophyll, b-carotene, lutein, reduced rates of POST herbicides where 0% represented no mugwort and other xanthophyll cycle pig- (Bradley and Hagood 2002a, 2002b). control and 100% represented com- ments in susceptible grassy and It follows that synergistic mixtures of plete mugwort necrosis. Following broadleaf weeds, including common reduced rates of HPPD and PSII in- a land manager decision to mow ex- bermudagrass (Cynodon dactylon), hibitors could optimize weed control perimental field plots in advance of hybrid bermudagrass (C. dactylon · and increase herbicide tolerance to right-of-way remediation efforts, field C. transvaalensis), and annual blue- turfgrass and ornamental crops (Cutulle trials were ended before regrowth data grass (Poa annua) (BASF, 2013; et al., 2013b). Therefore, objectives of could be taken. An alternative site with Brosnan et al., 2011; Elmore et al., this research were to evaluate low rates sufficient contiguous mugwort infesta- 2011, 2013). of the HPPD herbicide mesotrione and tion could not be found to repeat and In limited tests with ornamental to assess control efficacy of mesotrione extend the field trial component. plants, some HPPD herbicides have combined with known synergist like the GREENHOUSE EXPERIMENTS. provided acceptable ornamental tol- PSII inhibitor atrazine for enhanced Greenhouse experiments in Virginia erance at rates that provide some level activity on mugwort compared against were initiated in 2001 to evaluate of weed control (Armel et al., 2009; the standard clopyralid. The second mugwort control using previously Elmore et al., 2013; Little et al., 2004; objective was to quantify the ability field-tested rates of mesotrione (0.093, Senesac and Tsontakis-Bradley, 2007; of reduced rates of multiple HPPD- 0.125, and 0.187 lb/acre), and the Stamps and Chandler, 2009). In- inhibiting herbicides, either alone or lowest mesotrione rate plus a low creased POST control of some peren- paired with the PSII-inhibiting herbi- atrazine rate (0.250 lb/acre), with nial weed species was achieved when cides atrazine or bentazon, to provide efficacy evaluated against the clopyr- HPPD-inhibiting herbicides, like mes- commercially acceptable mugwort con- alid herbicide standard. Five 1-inch- otrione, were combined with other trol for ornamental plant producers, long mugwort rhizomes were planted herbicides, especially those that inhibit whethergrowingincontainerorfield into 4-inch square pots (TO Plastics, PSII inhibitors (Bradley et al., 2000; systems. Virginia Beach, VA) filled with com- Kaastra et al., 2008). For example, mercial potting mix (Pro-Mix BX; POST mixtures of reduced rates of Materials and methods Premier Horticulture, Red Hill, PA). the PSII inhibitor atrazine plus meso- FIELD EXPERIMENTS. Mugwort As needed, plants were watered and trione has enhanced management of experiments were conducted on a fertilized with a 150 ppm nitrogen (N) larger and more difficult to control government right-of-way near Birds solution using 21N–2.2P–41.5K fertil- weed species, including nutsedge Nest, VA, in 2000. Treatments were izer (Excel All Purpose; Wetzel, Vir- (Cyperus sp.) and canada thistle (Cir- calculated as the active ingredient ginia Beach, VA) to facilitate maximum sium arvense)(Armeletal.,2005, equivalent from formulated products plant growth and vigor. In 2001, her- 2008, 2009; Beckett and Taylor, and included 0.093, 0.125, and 0.187 bicides were applied using a cabinet 2000; Johnson and Young, 1999, lb/acre of mesotrione (CallistoÒ;Syn- sprayer at 24 gal/acre with a pressure 2000, 2002; Johnson et al., 2002; genta Crop Protection, Greensboro, of 42 psi. A single even flow nozzle Kaastra et al., 2008; Mueller, 2000). NC) and mesotrione plus atrazine (8002; TeeJet Technologies) was Efforts to assess reduced rates of mes- (0.093 lb/acre plus 0.250 lb/acre) that placed 30 cm above the highest part otrione and topramezone in mixtures were compared with 0.500 lb/acre of the treated plants. All treatments with the PSII inhibitor bentazon, clopyralid (Stinger). Applications for contained 1% (v/v) COC (Agridex) which is one of the few PSII-inhibiting the first experimental run were made and 2.5% (v/v) UAN solution. Mug- herbicides registered for use in turf- on 25 July 2000 and repeated in time at wort control was rated visually at 7, 14, grass and ornamental production sys- an adjacent field site on 29 Aug. 2000. and28DAT.On28DAT,mugwort tems,revealedsomeweedcontrol Treatments were applied using a back- shoot heights were measured, and then efficacy yet induced moderate phyto- pack sprayer at 23.0 gal/acre with shoots were cut to the soil line, dried toxic injury to foliage and terminals of a pressure of 23 psi. Four flat fan and weighed. Mugwort regrowth was flowering dogwood (Cornus florida) nozzles (8003; TeeJet Technologies, quantified again via dry weight mea- and Knock Outä rose (Rosa sp. Wheaton, IL) spaced at 20-inch in- surements from additional shoots ex- ‘Radrazz’). Still, trials revealed accept- tervals. Applications were made to cisedon42DAT. able plant safety for treatments applied mugwort plants 0.8 to 9.1 inches tall. In 2008, a second series of to ornamental cultivars of woody jap- Soil type at this location was a Bojac greenhouse experiments were con- anese holly (Ilex crenata), burning sandy loam (coarse-loamy, mixed, ducted and repeated in time at the bush (Euonymus alatus), weigela semiactive, thermic Typic Hapludult). University of Tennessee campus in
434 • August 2014 24(4) Knoxville. For these trials, meso- applied to all data and Fisher’s least (numerator, denominator) = 5, 12; trione (CallistoÒ) was again tested significant difference test (P £ 0.05) P = 0.97 to 0.57]; thus data from for its efficacy on mugwort, both was used for mean separation using repeated trials were pooled for re- alone at a reduced rate (0.062 lb/ the general linear model procedure of ported analyses. Mesotrione alone acre) selected to assess phytosafety to SAS (version 9.3; SAS Institute, Cary, only provided 30% control of mug- ornamental plants, and also in com- NC). wort, regardless of rate, by 7 DAT. bination with atrazine (0.500 lb/ When 0.093 lb/acre mesotrione was acre) and bentazon (0.500 lb/acre). Results and discussion mixed with 0.250 lb/acre atrazine, Mugwort control achieved by these FIELD EXPERIMENTS. Mugwort rapid mugwort control was observed two combination herbicides alone responses to treatments applied in that exceeded 80%. Mugwort control was also assessed. Also in 2008, the field differed across time, thus improved through 28 DAT and all topramezone (ImpactÒ;Amvac,Los results from in-time repetitions could treatments achieved greater than 70% Angeles, CA) was included in tests as not be pooled. By 14 DAT, the low control of mugwort. Mesotrione rate a second HPPD-inhibiting herbicide rate of mesotrione plus atrazine treat- with atrazine provided 98% mugwort at a 0.010 lb/acre rate, both alone ment controlled 73% of the mugwort control, equivalent to clopyralid (Ta- and in combination with the same following the July applications. How- ble 2). Plant height and dry weight atrazine and bentazon rates used ever, this treatment achieved just 51% measurements among all treated mug- with mesotrione mixes. mugwort control following August wort plants still surviving at 28 DAT In 2008 greenhouse trials, five treatments on 14 DAT compared with were reduced compared with un- 1-inch-long mugwort rhizomes were the clopyralid treatment that was con- treated control plants (F =3.97to transplanted into 4-inch pots. The trolling 78% of mugwort. By 21 DAT 3.72; df = 4, 10; P £ 0.026 to £0.029). soilless potting substrate was replaced in both field trials, mugwort control Limited regrowth from treated mug- with a Sequatchie loam field soil with mesotrione plus atrazine and wort plants was also evident at 42 (Fine-loamy, siliceous, semiactive, clopyralid treatments was ‡79%. When DAT. Plants that received the lowest thermic humic Hapludult), with 6.2 applied alone, clopyralid controlled rate of mesotrione had recovered just soil pH and 2.1% organic matter mugwort 84% to 91% (Table 1). 5% of growth (as dry weight) demon- content mixed in a 3:1 ratio of soil GREENHOUSE EXPERIMENTS. Re- strated through comparison with un- to clay-based soil conditioner (Tur- sults from greenhouse trials repeated treated control plants (Table 2). face MVP; Turface Athletics, Buffalo in time in VA were consistent by Moderate mugwort control was Grove, IL), to facilitate water drain- treatment regardless of measured pa- achieved with mesotrione alone at re- age. Treatments were arranged in rameter [F = 0.16 to 0.79; df duced rates and also when combined a RCB design with four replicated blocks of pots. Each treatment also included methylated seed oil surfac- Table 1. Mugwort control following experimental treatments in Bird’s Nest, VA tant (Methylated Soybean Oil Plus; that were applied along a mugwort-infested roadside and repeated in time in Universal Crop Protection Alliance, 2000. All herbicide treatments included 1% (v/v) crop oil concentrate [COC (Agridex; Helena Chemical, Memphis, TN)] and 2.5% (v/v) urea ammonium Eagan, MN) at a rate of 1% (v/v). nitrate. Herbicide treatments were applied on 11 Apr. 2008 with a carbon dioxide Days after treatment (CO2)-pressurized backpack sprayer 71421 calibrated at 23 gal/acre. Visual rat- Treatment Rate (lb/acre)z Weed control (%)y ings of mugwort control were made 25 July 7, 14, and 28 DAT. Mugwort shoot Clopyralid 0.500 38 57 bx 91 a heights were measured 28 DAT; after Mesotrione 0.093 30 41 c 32 e these data were collected, shoots were Mesotrione 0.125 33 41 c 52 d cut to the soil line, dried, and Mesotrione 0.187 35 58 b 60 c weighed. Mugwort regrowth was Mesotrione + 0.093 quantified via dry weight measure- Atrazine 0.250 45 73 a 79 b ments from additional shoot excisions Untreated control 0 0 0 d 0 f taken 56 DAT. Herbicide rates tested in both 29 Aug. field and greenhouse trials represent Clopyralid 0.500 25 a 78 a 85 a the low labeled rate or reductions to Mesotrione 0.093 13 d 55 b 55 b the lowest labeled rated in pounds of Mesotrione 0.125 16 cd 46 b 48 b active ingredient per acre for topra- Mesotrione 0.187 18 bc 48 b 53 b mezone and mesotrione in corn and Mesotrione + 0.093 fine turf, with comparison with the Atrazine 0.250 22 ab 51 b 78 a labeled rates of atrazine, clopyralid, Untreated control — 0 e 0 c 0 c and bentazon. Arcsine square root z1 lb/acre = 1.1209 kgÁha–1. transformations were applied to sta- yControl was evaluated visually on a 0% (no control) to 100% (complete necrosis) scale relative to the untreated tistical analyses of visual weed control control. xWithin column means represent nontransformed data. Means followed by different letters are significantly data, and nontransformed data are different from untreated checks by Fisher’s least significant difference tests of arcsine-transformed values at P £ presented. Analysis of variance was 0.05.
• August 2014 24(4) 435 RESEARCH REPORTS with atrazine and clopyralid, yet these in time (F = 2.00 to 0.25; df = 8, 35; Conclusions application rates may still result in P = 0.08 to 0.98). Therefore, data from Currently, few POST herbicides unacceptable aesthetic injury when repeated trials were pooled for reported are labeled for mugwort control in trying to achieve POST control by analyses. Reduced mesotrione and top- ornamental crop systems and non- applications made over the top of ramezone rates, at 0.062 and 0.010 lb/ cropland areas. From this research, select ornamental plants (Cutulle acre, respectively, failed to provide ad- we conclude that moderate rates of et al., 2013a, 2013b; Hester et al., equate control of mugwort (<21%) by mesotrione (0.093 lb/acre) in mix- 2011; Little et al., 2004; Senesac and 28 DAT. Atrazine and bentazon her- tures with certain PSII-inhibiting Tsontakis-Bradley, 2007). bicides applied alone provided <24% herbicides can provide a viable field Mesotrione rates were also re- mugwort control. By 28 DAT, meso- management alternative for short- duced a further 30% and reassessed in trione plus atrazine offered the highest term, burn-down control of mugwort Tennessee greenhouse trials alone and levels of mugwort control, yet no treat- compared with clopyralid application. in combination with photosynthesis- ment surpassed 37% control (Table 3). However, the rate of mesotrione and inhibiting bentazon and atrazine her- Several treatments slowed mugwort the type of PSII-inhibiting herbicide bicides, to determine if ornamental regrowth between 28 and 56 DAT, needed severely limit the practicality of injury could be reduced. Results of with mugwort plants treated with mes- this use with some sensitive ornamen- Tennessee greenhouse experiments otrione plus atrazine achieving just 66% tal plant species. Mugwort regrowth were consistent across treatments for of the regrowth potential demonstrated by 56 DAT in the Tennessee green- all measured parameters when repeated by untreated control plants (Table 3). house trials suggest that field studies
Table 2. Mugwort control in 2001 Virginia greenhouse trials in which herbicide treatments were applied to container-grown mugwort plants in a soilless rooting substrate with experiments that were repeated in time. All herbicide treatments included 1% (v/v) crop oil concentrate (Agridex; Helena Chemical, Memphis, TN) and 2.5% (v/v) urea ammonium nitrate. Days after treatment 71428 Dry wt Ht (Percent Dry wt regrowth Treatment Rate (lb/acre)z Weed control (%)y (Percent of control) of control) (Percent of control) Clopyralid 0.500 62 bx 75 ab 99 a 25 abc 0 b 0 Mesotrione 0.093 28 c 42 c 72 c 36 a 19 a 5 Mesotrione 0.125 31 c 68 b 87 b 24 bc 5 b 1 Mesotrione 0.187 30 c 62 bc 88 b 28 ab 9 ab 2 Mesotrione + 0.093 Atrazine 0.250 83 a 89 a 98 a 16 c 2 b 0 Untreated control — 0 d 0 d 0 d — — — z1 lb/acre = 1.1209 kgÁha–1. yControl was evaluated visually on a 0% (no control) to 100% (complete necrosis) scale relative to the untreated control. xWithin column means represent nontransformed data. Means followed by different letters are significantly different from untreated checks by Fisher’s least significant difference tests of arcsine-transformed values at P £ 0.05.
Table 3. Mugwort control in 2008 Tennessee greenhouse trials in which herbicide treatments were applied to container- grown mugwort plants with experiments that were repeated in time. Mugwort was planted into a soil-based rooting mix that included 3:1 ratio of soil to clay-based soil conditioner (Turface MVP; Turface Athletics, Buffalo Grove, IL). Treatments were applied with a 1% rate (v/v) of methylated seed oil surfactant (Methylated Soybean Oil Plus; Universal Crop Protection Alliance, Eagan, MN). Days after treatment Dry wt Dry wt regrowth Treatment Rate (lb/acre)z 71428(Percent of control) (Percent of control) Atrazine 0.500 6 by 12 c 24 bc 66 c 96 ab Bentazon 0.500 14 ab 28 ab 18 cd 87 ab 99 a Mesotrione 0.062 11 ab 21 abc 21 cd 71 bc 106 a Topramezone 0.010 11 ab 14 bc 7 e 92 a 114 a Mesotrione + 0.062 atrazine 0.500 20 a 33 a 37 a 58 c 67 c Mesotrione + 0.062 bentazon 0.500 13 ab 27 ab 24 bc 74 bc 92 ab Topramezone + 0.010 atrazine 0.500 14 ab 23 abc 32 ab 64 c 74 bc Topramezone + 0.010 bentazon 0.500 13 ab 23 abc 14 d 88 ab 111 a Untreated control — 0 c 0 d 0 f — — zTreatments rates are expressed in pounds per acre; 1 lb/acre = 1.1209 kgÁha–1. yWithin column means represent nontransformed data. Means followed by different letters are significantly different from untreated checks by Fisher’s least significant difference tests of arcsine-transformed values at P £ 0.05.
436 • August 2014 24(4) with extended durations should be Beckett, T.H. and S.E. Taylor. 2000. Post- Elmore, M.T., J.T. Brosnan, G.K. Breeden, evaluated, in conjunction with re- emergence performance of mesotrione in and A.J. Patton. 2013. Mesotrione, top- peated applications. Regardless, other weed control programs. Proc. North Cen- ramezone, and amicarbazone combinations HPPD- and PSII-inhibiting herbi- tral Weed Sci. Soc. 55:81 (abstr.). for postemergence annual bluegrass (Poa cides should be evaluated for mug- annua) control. Weed Technol. 27:596– Bing, A. and A.M.S. Pridham. 1963. Field 603. wort control and then those mixtures trials for control of Artemisia vulgaris L. determined to be effective should be Proc. Northeastern Weed Control Conf. Elmore, M.T., J.T. Brosnan, D.A. Kopsell, studied further for tolerance among 17:202–203. and G.K. Breeden. 2011. Methods of multiple ornamental plant species. In assessing bermudagrass responses to Bing, A. and A.M.S. Pridham. 1964. The addition for container nursery produc- HPPD-inhibiting herbicides. Crop Sci. use of EPTC for control of Artemisia 51:2840–2845. tion systems, it may be advantageous to vulgaris L. Proc. Northeastern Weed assess benefits of multiple applications Control Conf. 18:242–244. Gilliam, C.H., W.J. Foster, J.L. Adrain, of reduced rate HPPD plus PSII in- and R.L. Shumack. 1990. A survey of hibitor mixtures that could achieve Bingham, S.W. 1965. Chemical control of weed control costs and strategies in con- mugwort control while offering better mugwort. Weeds 13:239–242. tainer production nurseries. J. Environ. Hort. 8:133–135. safety to ornamental plants (e.g., Bradley, K.W. and E.S. Hagood, Jr. Cutulle et al., 2013a) and other desir- 2002a. Evaluation of selected herbicides Guncan, A. 1982. Artemisia vulgaris: Its ablecropsnotgrowninfieldopera- and rates for long-term mugwort (Arte- biological control in tea and hazelnut tions. When applied sequentially, for misia vulgaris) control. Weed Technol. plantations in Turkey. Attaturk Univ. example, a mixture of topramezone 16:164–170. Proj. No. TOAG-276. plusthepyridineherbicidetriclopyr Bradley, K.W. and E.S. Hagood, Jr. Henderson, J.C. and S.C. Weller. 1985. successfully and safely removed com- 2002b. Influence of sequential herbicide Biology and control of Artemisia vulgaris. mon bermudagrass from desirable turf treatment, herbicide application timing, Proc. North Central Weed Control Conf. tall fescue [Lolium arundinaceum andmowingonmugwort(Artemisia vul- 40:100–101. (Brosnan and Breeden, 2013)]. garis) control. Weed Technol. 16:346–352. Hester, K., C.L. Palmer, and E. Vea. Bradley, K.W., P. Davis, S.R. King, and 2011. IR-4 Ornamental horticulture pro- Literature cited E.S. Hagood. 2000. Trumpetcreeper, gram mesotrione crop safety. 27 Mar. 2014. honeyvine milkweed, and hemp dogbane
• August 2014 24(4) 437 RESEARCH REPORTS substrates. J. Environ. Hort. 22:139– pds1 mutant with the gene encoding P and sulfentrazone to six wildflowers. 143. p-hydroxyphenylpyruvate dioxygenase. Proc. Southern Nursery Assn. Res. Conf. Plant Physiol. 117:1317–1323. 54:145–151. Koepke-Hill, R.M., G.R. Armel, W.E. Klingeman, M.A. Halcomb, J.J. Vargas, Pridham, A.M.S. 1963. Propagation of Sutton, P.B., G.A. Foxon, J.M. Beaud, J. and P.C. Flanagan. 2011. Mugwort con- Artemisia vulgaris from stem cuttings Anderdon, and R. Wichert. 1999. Inte- trol in an abandoned nursery using herbi- for herbicide test purposes. Proc. North- grated weed management systems for cides that mimic indole-3-acetic acid. eastern Weed Control Conf.17, p. maize using mesotrione, nicosulfuron, HortTechnology 21:558–562. 332(abstr.). and acetochlor. Proc. Brit. Crop Protec- tion Conf. 1:225–230. Little, D.A., R.J. Richardson, and B.H. Rogerson, A.B. and S.W. Bingham. 1964. Zandstra. 2004. Response of four orna- A growth study and seasonal characteris- Syngenta Crop Protection. 2011. Tenac- mental crops and selected weeds to mes- tics of Artemisia vulgaris L. Proc. South- ity herbicide label. Syngenta Crop Pro- otrione. Proc. North Central Weed Sci. ern Weed Sci. Soc. 17:360–363. tection, Inc., Greensboro, NC. Soc. 59:159 (abstr.). Rogerson, A.B., S.W. Bingham, C.L. Foy, Syngenta Crop Protection. 2012. Callisto Mathers, H. 1999. Weed control in con- and J.P. Sterrett. 1972. Influence of fenac herbicide label. Syngenta Crop Protec- tainer nurseries. Digger 43:36–37. on anatomy and carbohydrate reserves in tion, Inc., Greensboro, NC. Mitchell, G., D.W. Bartlett, T.E. Fraser, mugwort rhizomes. Weed Sci. 20:445– 449. Uva, R.H., J.C. Neal, and J.M. DiTomaso. T.R. Hawkes, D.C. Holt, J.K. Townson, 1997. Weeds of the northeast. Cornell and R.A. Wichert. 2001. Mesotrione: A Senesac, A.F. and I. Tsontakis-Bradley. Univ. Press, Ithaca, NY. new selective herbicide for use in maize. 2007. Phytotoxicity of spray and granular Pest Mgt. Sci. 57:120–128. mesotrione to ornamentals. 5 Nov. 2014. Yelverton,F.,B.R.Lassiter, G.G. Wilkerson, L. Warren, T. Gannon, J.H. Reynolds, and Mueller, T.C. 2000. ZA 1296: A new
438 • August 2014 24(4)