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Black Medic (Medicago lupulina) Emergence and Emergence Predictors within Florida Strawberry Fields

  • Shaun M. Sharpe (a1) and Nathan S. Boyd (a2)


Black medic (Medicago lupulina L.) infestations are a concern for Florida strawberry [Fragaria×ananassa (Weston) Duchense ex Rozier (pro sp.) [chiloensis×virginiana] producers. Current control techniques rely on hand weeding or clopyralid application. Coordinating POST control measures with emergence timing can reduce crop competition duration and increase control. The objective of this study was to evaluate M. lupulina emergence in response to burial depth and temperature and to model M. lupulina cumulative field emergence under subtropical Florida conditions using growing degree days (GDDs) as a predictor. Two studies were in controlled environments and looked at factors affecting emergence, burial depth, and temperature. A third experiment was a 2-yr emergence study conducted on four commercial strawberry fields in Hillsborough County, FL. Emergence was modeled as a function of accumulated standard and restricted daily GDD accounting, based on M. lupulina dormancy and germination. In Experiment 1, M. lupulina only emerged when seed was deposited on the surface. In Experiment 2, there was three-way interaction among temperature, burial depth, and measurement timing (P<0.0001). Medicago lupulina emerged from as deep as 2 cm at a temperature range between 15 and 25 C. Medicago lupulina field emergence was not consistent between years, although emergence was consistent across four sites in year 1, with 0 emergence in year 2. Dormancy and germination restrictions increased calibration and validation model fit and reduced GDD inflation, making models usable between years. Medicago lupulina primarily emerged during crop establishment, between mid-November and late-December, which corresponds to an ideal timing for control measures before the harvest period.


Corresponding author

Author for correspondence: Nathan S. Boyd, University of Florida, Gulf Coast Research and Education Center, 14625 Count Road 672, Wimauma, FL 33598. (Email:


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Anonymous (2011) Stinger® supplemental labeling for annual strawberry in Florida. Indianapolis IN: Dow AgroSciences LLC. 2 p
Boyd, NS Dittmar, PJ (2015) Impact of application time and clopyralid rate on strawberry growth and yield. Weed Technol 29:821826
Braul, AJ (2004) Recruitment Characteristics of Black Medic (Medicago lupulina L.) as a Self-Regenerating Cover Crop in a Continuous Grain Cropping System. Ph.D dissertation. Winnipeg, MB, Canada: University of Manitoba. 144 p
Clay, DV Andrews, L (1984) The tolerance of strawberries to clopyralid: effect of crop age, herbicide dose and application date. Asp Appl Biol 9:151158
Fernandez, GE (2001) Fall-applied rowcovers enhance yield in plasticulture strawberries. HortTechnology 11:440444
Figueroa, RA Doohan, DJ (2006) Selectivity and efficacy of clopyralid on strawberry (Fragaria × ananassa). Weed Technol 20:101103
Gast, KLB Pollard, JE (1991) Rowcovers enhance reproductive and vegetative yield components in strawberries. HortScience 26:14671469
Grundy, AC (2003) Predicting weed emergence: a review of approaches and future challenges. Weed Res 43:111
Hunnicutt, CJ, MacRae, AW, Dittmar, PJ, Noling, JW, Ferrell, JA, Alves, C Jacoby, TP (2013a) Annual strawberry response to clopyralid applied during fruiting. Weed Technol 27:573579
Hunnicutt, CJ, MacRae, AW Whitaker, VM (2013b) Response of four strawberry cultivars to clopyralid applied during fruiting stage. HortScience 23:301305
Martinson, K, Durgan, B, Forcella, F, Wiersma, J, Spokas, K Archer, D (2007) An emergence model for wild oat (Avena fatua). Weed Sci 55:584591
McMurray, GL, Monks, DW Leidy, RB (1996) Clopyralid use in strawberries (Fragaria × ananassa Duch.) grown on plastic mulch. Weed Sci 44:350354
Sharpe, SM (2017) Use of Clopyralid to Control Black Medic (Medicago lupulina) in Florida Strawberry (Fragaria xananassa) Production. Ph.D dissertation. Gainesville, FL: University of Florida. 131 p
Sharpe, SM, Boyd, NS Dittmar, PJ (2016) Clopyralid dose response for two black medic (Medicago lupulina) growth stages. Weed Technol 30:717724
Sharpe, SM, Boyd, NS, Dittmar, PJ, MacDonald, GE Darnell, RL (2018a) Clopyralid tolerance in strawberry and feasibility of early applications in Florida. Weed Sci 66:508515
Sharpe, SM, Boyd, NS, Dittmar, PJ, MacDonald, GE, Darnell, RL Ferrell, JA (2018b) Control recommendations for black medic (Medicago lupulina) based on growth and development in competition with strawberry. Weed Sci 66:226233
Sharpe, SM, Boyd, NS, Dittmar, PJ, MacDonald, GE, Darnell, RL Ferrell, JA (2018c) Spray penetration into a strawberry canopy as affected by canopy structure, nozzle type, and application volume. Weed Technol 32:8084
Sidhu, SS (1971) Some Aspects of the Ecology of Black Medick. Ph.D dissertation. London, ON, Canada: University of Western Ontario. 357 p
Sidhu, SS Cavers, PB (1977) Maturity-dormancy relationships in attached and detached seeds of Medicago lupulina L. (black medick). Bot Gaz 138:174182
Singh, A, Syndor, A, Deka, BC, Singh, RK Patel, RK (2012) The effect of microclimate inside low tunnels on off-season production of strawberry (Fragaria xananassa Duch.). Sci Hortic 144:3641
Taylor, GB (1981) Effect of constant temperature treatments followed by fluctuating temperatures on the softening of hard seeds of Trifolium subterraneum L. Aust J Plant Physiol 8:547558
[USDA] U.S. Department of Agriculture (2016) Soil Survey Staff, Natural Resources Conservation Service, Web Soil Survey. Accessed: March 30, 2017
Uzun, F Aydin, I (2004) Improving germination rate of Medicago and Trifolium species. Asian J Plant Sci 3:714717
Van Assche, JA, Debucquoy, KLA Rommens, WAF (2003) Seasonal cycles in the germination capacity of buried seeds of some Leguminosae (Fabaceae). New Phytol 158:315323
Van Assche, JA Vandelook, FEA (2010) Combinational dormancy in winter annual Fabaceae. Seed Sci Res 20:237242
Vleeshouwers, LM Kropff, MJ (2000) Modelling field emergence patterns in arable weeds. New Phytol 148:445457
Werle, R, Sandell, LD, Buhler, DD, Hartzler, RG Lindquist, JL (2014) Predicting emergence of 23 summer annual weed species. Weed Sci 62:267279
White, SN, Boyd, NS Van Acker, RC (2012) Growing degree-day models for predicting lowbush blueberry (Vaccinium angustifolium Ait.) ramet emergence, tip dieback, and flowering in Nova Scotia, Canada. HortScience 47:10141021
White, SN, Boyd, NS Van Acker, RC (2015) Temperature thresholds and growing-degree-day models for red sorrel (Rumex acetosella) ramet sprouting, emergence, and flowering in wild blueberry. Weed Sci 63:254263


Black Medic (Medicago lupulina) Emergence and Emergence Predictors within Florida Strawberry Fields

  • Shaun M. Sharpe (a1) and Nathan S. Boyd (a2)


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