Cultural and Chemical Control of Ground Ivy (Glechoma Hederacea)
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HORTSCIENCE 39(5):1148–1152. 2004. had not been fertilized during the experiments or during the previous 2 years. The soil was a Chalmers silt loam (fi ne silty mixed mesic Cultural and Chemical Control of Typic Haplaquoll) with a 7.0 pH, 0.133 meq·g–1 CEC, 4.7% organic matter, 219 kg·ha–1 P, and Ground Ivy (Glechoma hederacea) 510 kg·ha–1 K. Plots were irrigated as needed to prevent drought stress and mowed three 1 Eric A. Kohler times per week at 6.4 cm with clippings re- Department of Agronomy, Purdue University, 915 W. State St., West Lafayette, turned. All herbicide treatments were applied –1 IN 47907-2054 in 374 L·ha water with a CO2-pressurized backpack sprayer using a three-nozzle (TeeJet Clark S. Throssell2 XR8002VS, Spraying Systems Co., Wheaton, Golf Course Superintendents Association of America, 1421 Research Park Ill.) boom at 207 kPa. Drive, Lawrence, KS 66049-3859 Nitrogen fertility study. Fertilizer treatments were applied to plots containing uniform stands Zachary J. Reicher3 of ground ivy beginning on 15 May 2000 and Department of Agronomy, Purdue University, 915 W. State St., West Lafayette, 14 May 2001. Average initial ground ivy cover was 32% in 2000 and 45% in 2001. Treatments IN 47907-2054 were a three by three factorial with three an- –1 Additional index words. nitrogen, preemergence herbicide, postemergence herbicide, nual nitrogen rates (98, 196, or 293 kg·ha ) kentucky bluegrass, Poa pratensis and three application schedules (heavy spring, heavy fall, or equal spring, summer, and fall), Abstract. Ground ivy is a common broadleaf weed that disrupts turf uniformity and is and an untreated control was included for diffi cult to control. The objective of this fi eld research was to evaluate cultural and chemi- comparison. Fertilizer and scheduled rates cal control of ground ivy. Increasing annual nitrogen fertilizer applications from 0 to 196 are given in Table 2. Fertilizer application and 293 kg·ha–1 reduced ground ivy cover by 24% and 32%, respectively. At 26 weeks dates were 15 May ±1, 25 July ±2, 18 Sept. after treatment, 1.1 kg·ha–1 isoxaben applied in May limited ground ivy spread by 34% ±2, 17 Oct. ±2, 15 Nov. ±2, 23 Mar. ±2, and compared to the control. Triclopyr, 2,4-D, or fl uroxypyr applied at the highest-labeled 23 Apr. ±1. On each application date, total rate in October provided superior ground ivy control by the following May. Combining nitrogen was applied as 50% (by N content) an annual fertility program of 196 kg·ha–1 nitrogen and an application of 1.1 kg·ha–1 urea (46N–0P–0K) (Shaw’s, Knox, Ind.) and isoxaben with or after an application of 2,4-D, fl uroxypyr, or triclopyr in the fall can 50% sulfur-coated urea (32N–0P–0K) (Shaw’s, maximize ground ivy control. Chemical names used: N-[3-(1-ethyl-1-methylpropyl)-5- Knox, Ind.). The experiment was a randomized isoxazolyl]-2,6-dimethoxybenzamide (isoxaben); [(3,5,6-trichloro-2-pyridinyl)oxy]acetic complete block design with three replications. acid (triclopyr); (2,4-dichlorophenoxy)acetic acid (2,4-D); [(4-amino-3,5-dichloro-6-fl uoro- While percent ground ivy cover was visually pyridyl)oxy]acetic acid (fl uroxypyr). estimated every 4 weeks for 1 year during each experiment, only data collected 12 months after Ground ivy (Glechoma hederacea L.) is a spring rather than fall when broadleaf weed initial treatment (MAIT) for each experiment creeping perennial weed in turf in the cooler control is often performed (Kohler, 2002). are presented. climates of northeastern and midwestern Ground ivy stolons creep beneath the turf Preemergence herbicide study. Three 10.2- United States (Mitich, 1994). During sum- canopy when colonizing new areas (Birch cm-diameter × 8-cm-deep plugs of ground mer and fall, populations rapidly increase in and Hutchings, 1994; Hutchings and Price, ivy were transplanted into plots on 14 May size through vegetative propagation of new 1999). Extensive rooting from these stolons 1999 and 10 May 2000. One week later, the ramets along stolons. Eventually the turf makes mechanical control diffi cult. Nitrogen following preemergence herbicides were ap- site is populated with patches of ground ivy, application (Dernoeden et al., 1993; Lowe et plied at the highest-labeled rate or at one-half resulting in a nonuniform turf stand. Once al., 2000), irrigation (Gaussoin and Branham, the highest-label rate for kentucky bluegrass established, controlling ground ivy is challeng- 1989; Jiang et al., 1998), and mowing (Brede, (Vencill, 2002): prodiamine (2,4-dinitro- ing for the lawn care industry. In a survey of 1992; Dernoeden et al., 1993) have been stud- N3,N3-dipropyl-6-(trifl uoromethyl)-1,3-ben- lawn care operators (LCOs) in Indiana, 49% ied to limit encroachment of weeds other than zenediamine) (Syngenta, Wilmington, Del.) of respondents reported poor or fair control ground ivy, but there are no reports of cultural at 1.7 or 0.9 kg·ha–1, dithiopyr (S,S-dimethyl of ground ivy and 40% reported nonuniform control of ground ivy. Both preemergence 2-(difluoromethyl)-4-(2-methylpropyl)-6- control (Table 1). Additionally, 86% indicated (Turgeon, 1996) and postemergence (Monaco (trifl uoromethyl)-3,5-pyridinedicarbothioate) repeated herbicide applications were neces- et al., 2002; Sterling and Hall, 1997) herbicides (Dow Agro Sciences, Indianapolis) at 0.6 or sary for successful ground ivy control, further have been used successfully for decades to 0.3 kg·ha–1, isoxaben (Dow AgroSciences, suggesting chemical control of ground ivy is control grassy or other broadleaf weeds, but Indianapolis) at 1.1 or 0.6 kg·ha–1, or pendi- challenging. Time, money, and effort spent on ground ivy control is challenging and incon- methalin (N-(1-ethylpropyl)-3,4-dimethyl- controlling ground ivy is considerable since sistent (Hatterman-Valenti et al., 1996). The 2,6-dinitrobenzenamine) (BASF, Research 31% of the LCO customers had ground ivy on objectives of this research were to evaluate Triangle Park, N.C.) at 3.3 or 1.7 kg·ha–1. their property. However, there has been little nitrogen fertility programming, preemergence Percent ground ivy cover was rated visually research focusing on ground ivy control using herbicides, and postemergence herbicides for at 6, 12, and 26 weeks after treatment (WAT). herbicides common to LCOs (Hatterman-Val- ground ivy control. Treatments were a 2 × 4 factorial with two rates enti et al., 1996). Furthermore, of those reports and four herbicides, and an untreated control that evaluated herbicides commonly used by Materials and Methods was included for comparison. The experiment LCOs (Czarnota et al., 2001; Olson and Hall, was a randomized complete block design with 1988; Vrabel, 1987), application was done in Conditions common to experiments. All three replications. experiments were conducted for 1 year at the Postemergence herbicide study. Ten postemergence herbicide combinations were Received for publication1 Apr. 2003. Accepted for W.H. Daniel Turfgrass Research Center in West publication 9 Sept. 2003. Lafayette, Ind. Experiments were repeated the sprayed at the highest-labeled rate or at one-half 1Graduate research assistant. following year on different but adjacent sites. the highest-labeled rate for kentucky bluegrass 2Director of research. Field plots (1.5 × 1.5 m) were located in full on plots containing dense, uniform stands of 3Associate professor; to whom reprint requests should sun in a low-maintenance stand of kentucky ground ivy on 30 Oct. 1999 and 15 Oct. 2000 be addressed; e-mail [email protected]. bluegrass (Poa pratensis L. ‘America’) that (Table 3) (Vencill, 2002). Average initial 1148 HORTSCIENCE VOL. 39(5) AUGUST 2004 Table 1. Questions and answers from a survey of Indiana lawn care operators in January 2000. N = 66. Question Answer 1) How many customers do you provide weed control service for? Range: 3–10,000 Mean: 847 Median: 160 2) Of this number, how many have ground ivy in their turf stand? Tange: 1–7500 Mean: 266 (31%) Median: 22 3) What chemicals do you use to control ground ivy? (percent of respondents) Triclopyr + clopyralid (20%) 2,4-D + triclopyr + clopyralid (18%) 2,4-D + MCPP + dicamba (18%) 2,4-D + clopyralid + dicamba (12%) 2,4-D + triclopyr (8%) 2,4-D + diclorprop + dicamba (8%) 2,4-D + diclorprop + MCPP (3%) 2,4-D + MCPP + dicamba + triclopyr + clopyralid (2%) 2,4-D (2%) Dicamba (2%) 2,4-D + dicamba (2%) Triclopyr (2%) Triclopyr + clopyralid + MCPA (2%) Miscellaneous (3%) 4) What time of the year do you usually apply herbicides for ground ivy control? Spring and fall = 52% fall = 18% Spring = 11% Spring and summer and fall = 6% Miscellaneous = 13% 5) Are repeat applications necessary? Yes = 86% No = 10% Miscellaneous = 4 % 6) How successful are the chemicals that you use for controlling ground ivy? Excellent = 11% Good = 38% Fair = 43% Poor = 6% Miscellaneous = 2% 7) Have you seen a fairly uniform response from the herbicides you use to control ground ivy? Yes = 56% No = 40% Miscellaneous = 4% ground ivy cover was 42% in 1999 and 76% reduced ground ivy cover compared to the to 196 kg·ha–1·year–1 reduced ground ivy cover in 2000. Ground ivy cover was rated visually unfertilized control. Therefore, nitrogen appli- 24%, which would be an acceptable nitrogen at 3, 6, and 30 WAT. Treatments were a 2 × 10 cation at any time of the year will help reduce rate for most home lawns. factorial with 2 rates and 10 herbicides, and an ground ivy cover. However, cool season turf Increasing nitrogen rates in turf reduces the untreated control was included for comparison. benefi ts most from fall-applied nitrogen, which cover of crabgrass (Digitaria spp.) (Dernoeden The experiment was a randomized complete results in better foliar color retention in the late et al., 1993; Johnson and Bowyer, 1982; Murray block design with three replications.