Evaluation of Herbicides and Evaluation of Herbicides and Application Timings for LongApplication Timings for Long--term term

Control of Sericea LespedezaControl of Sericea Lespedeza

Kevin W. BradleyUniversity of Missouri

Sericea Lespedeza(Lespedeza cuneata L.)• Perennial legume native

to eastern Asia

• Introduced into the U. S. in the late 1890’s as a potential forage species and also planted for erosion control

• Declared a noxious weed in Kansas in 2000, spreading and becoming more problematic in many other states

Sericea Lespedeza

Prolific Seed Producer:Prolific Seed Producer: at least at least 1,000 seed per stem; ~600 lbs 1,000 seed per stem; ~600 lbs seed/A (Guernsey 1970; seed/A (Guernsey 1970; Ohlenbusch et al. 2001)Ohlenbusch et al. 2001)

Allelopathic:Allelopathic: Sericea lespedeza Sericea lespedeza residues reduced the germination, residues reduced the germination, emergence, and biomass of rye and tall emergence, and biomass of rye and tall fescue (Kalburtji and Mosjidis 1993) fescue (Kalburtji and Mosjidis 1993)

Current Management RecommendationsCurrent Management Recommendations

Triclopyr or triclopyrTriclopyr or triclopyr--containing herbicides containing herbicides applied in the applied in the vegetativevegetative stage, earlier in stage, earlier in the growing season (Junethe growing season (June--July)July)

Metsulfuron or metsulfuronMetsulfuron or metsulfuron--containing containing herbicides applied in the herbicides applied in the early bloomearly bloomstage, late in the summer/early fall (Auguststage, late in the summer/early fall (August--September)September)

Altom et al. 1992; Koger et al. 2002; Ohlenbusch et al. 2001Altom et al. 1992; Koger et al. 2002; Ohlenbusch et al. 2001

Objectives of this Research:Objectives of this Research:

To determine the effect of various To determine the effect of various herbicides and application timings herbicides and application timings on lateon late--season Sericea lespedeza season Sericea lespedeza control and density one year after control and density one year after the initial herbicide applications.the initial herbicide applications.

Active Ingredients Rate Trade Name Rate

--lbs/A-- --product/A--

Triclopyr + Fluroxypyr 0.28 + 0.09 Pasturegard 1.5 pts

Triclopyr + Fluroxypyr 0.38 + 0.13 Pasturegard 2.0 pts

Picloram + Fluroxypyr 0.30 + 0.24 Surmount 2.0 pts

Metsulfuron 0.02 Cimarron 0.4 oz

Triclopyr 0.75 Remedy 1.5 pts

Materials and Methods:Materials and Methods:Herbicide TreatmentsHerbicide Treatments

Materials and Methods:Materials and Methods:Dates of Application, Size and Density at TreatmentDates of Application, Size and Density at Treatment

Application Timing Date Height Density Date Height Density--Inches-- --- #/m2--- --Inches-- --- #/m2---

Vegetative Stage Early 28-May 22 44 6-Jun 17 66 Mid 17-Jun 29 24 29-Jun 35 96 Late 8-Jul 28 36 21-Jul 36 96

Bloom Stage Pre 25-Aug 38 38 31-Aug 34 78 Full 16-Sep 40 36 23-Sep 34 99

2004 Experiment 2005 Experiment

Influence of Selected Herbicides and Timings Influence of Selected Herbicides and Timings on Lateon Late--season Sericea Lespedeza Controlseason Sericea Lespedeza Control

Treatments Rate Early Mid Late Pre-bloom Full Bloomproduct / Acre

PastureGard 1.5 pts 99 a 99 a 93 a 94 a 55 bPastureGard 2 pts 100 a 99 a 99 a 93 a 86 aSurmount 2 pts 100 a 100 a 81 a 81 a 40 bcCimarron 0.4 oz 99 a 93 a 40 bc 29 cd 9 d

bMeans followed by the same letter are not significantly different, LSD = 0.05. LSD applies to all treatment by timing comparisons. Untreated controls not included in the analysis.

Vegetative Stage Applications Bloom Stage Applications

------------ % Late Season Sericea Lespedeza Control ------------

aAll treatments applied with a non-ionic surfactant at 0.25% v/v.

2004

2005 Treatments Rate Early Mid Late Pre-bloom Full Bloom

product / Acre

PastureGard 1.5 pts 99 a 99 a 99 a 83 e 93 abcPastureGard 2 pts 99 a 99 a 99 a 93 abc 97 abSurmount 2 pts 99 a 96 abc 99 a 91 bcd 90 cdeCimarron 0.4 oz 98 ab 92 bcd 85 de 38 f 32 fTriclopyr 1.5 pts 99 a 99 a 99 a 90 cde 96 abc

bMeans followed by the same letter are not significantly different, LSD = 0.05. LSD applies to all treatment by timing comparisons. Untreated controls not included in the analysis.

Vegetative Stage Applications Bloom Stage Applications

------------ % Late Season Sericea Lespedeza Control ------------

aAll treatments applied with a non-ionic surfactant at 0.25% v/v.

Influence of Selected Herbicides on Sericea Influence of Selected Herbicides on Sericea Lespedeza Density 1 Year After Treatment (YAT)Lespedeza Density 1 Year After Treatment (YAT)

Treatmentsa Rate 2004 2005product / Acre

PastureGard 1.5 pts 10 bc 35 bcPastureGard 2 pts 6 c 25 cSurmount 2 pts 14 b 44 bCimarron 0.4 oz 11 bc 27 cRemedy 1.5 pts ----- 27 cUntreated -------------- 42 a 93 a

Trial Year

bMeans within a column followed by the same letter are not significantly different, LSD = 0.05.

----Density 1 YAT (# plants/m2)----

aAll treatments applied with a non-ionic surfactant at 0.25% v/v.

Untreated 2 pts PastureGard mid-vegetative / mid- to late-June timing

1 YAT

Untreated 2 pts PastureGard pre-bloom/late August timing

1 YAT

Untreated 0.4 oz Cimarron mid-vegetative / mid- to late-June timing

1 YAT

Untreated 0.4 oz Cimarron pre-bloom / late August timing

1 YAT

Untreated 2 pts Surmount full-bloom / mid-September timing

1 YAT

ConclusionsConclusionsLongLong--term Sericea Lespedeza Controlterm Sericea Lespedeza Control

• Application timing does not appear to influence Sericea lespedeza control 1 YAT

• 1.5 pts PastureGard (62-76%), 2 pts PastureGard (73-86%), 0.4 oz Cimarron (71-74%), and 1.5 pts Remedy (71%) provided similar levels of Sericea lespedeza stem reduction 1 YAT

• 2 pts Surmount (53-67%)provided the lowest levels of Sericea lespedeza stem reduction 1 YAT