Virginia Pepperweed (Lepidium virginicum L.) Control is Influenced by the Developmental Stage

Authors: Varanasi, Vijaya; BARARPOUR, TAGHI - Mississippi State University; Mubvumba, Partson; Fletcher, Reginald; Reddy, Krishna

Submitted to: Weed Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/25/2025
Publication Date: 8/27/2025
Citation: Varanasi, V.K., Bararpour, T., Mubvumba, P., Fletcher, R.S., Reddy, K.N. 2025. Virginia Pepperweed (Lepidium virginicum L.) Control is Influenced by the Developmental Stage. Weed Technology. 39(e89), 1–5. https://doi.org/10.1017/wet.2025.10035.
DOI: https://doi.org/10.1017/wet.2025.10035

Interpretive Summary: Virginia pepperweed is a winter weed in the mustard family found commonly in agricultural crops, roadsides, landscapes, and other undisturbed areas. Known for its peppery taste, V. pepperweed has emerged as a troublesome and problematic weed in major row crops of the Mississippi Delta. Recently, V. pepperweed control has become increasingly challenging beyond its early growth stages and due to its high seed production rates (~100,000 seed/plant). Therefore, there is a need to develop effective control measures that could check the spread of V. pepperweed in various crops. Greenhouse research was conducted at USDA-ARS, Stoneville, MS location in 2024 to evaluate the activity of various burndown herbicides labeled for V. pepperweed control in row crops. The herbicides tested at field rates were glyphosate, liberty, enlist, and gramoxone. Application of enlist resulted in 95 to 100% V. pepperweed control at all three growth stages. There was 40 to 50% control with glyphosate, 18 to 47% with liberty, and 0 to 71% with gramoxone. The study found that herbicide applications at the early growth stage resulted in maximum V. pepperweed control.

Technical Abstract: Native to North America, Virginia pepperweed is a winter annual weed in the mustard family (Brassicaceae) found commonly in agricultural crops, roadsides, landscapes, and other undisturbed areas. Known for its peppery taste, V. pepperweed has emerged as a troublesome and difficult-to-control weed in and around major row crops in the Mississippi Delta region. Recently, V. pepperweed management has become increasingly challenging due to its ability to survive control measures beyond its early rosette stage and high fecundity rates (~100,000 seed/plant). Therefore, there is a need to develop effective control measures that could check the spread of V. pepperweed in crop production systems. Greenhouse experiments were conducted in the 2024 season to evaluate the activity of various burndown herbicides labeled for V. pepperweed control in row crops. V. pepperweed seed was stratified, germinated in growth chamber, and seedlings transplanted in pots and kept in greenhouse. The herbicides tested at the 1x rate were glyphosate at 1,261 g ai ha-1, glufosinate at 672 g ai ha-1, 2,4-D at 1,065 g ai ha-1, and paraquat at 840 g ai ha-1, respectively. Herbicides were sprayed at three growth stages: early rosette, late rosette, and bolting. V. pepperweed control was evaluated at 1, 2, 3, and 4 weeks after herbicide applications (WAA). Shoot dry biomass data were collected at 4 WAA. 2,4-D application resulted in 95 to 100% V. pepperweed control at all three growth stages. Depending on the growth stage at which herbicides were applied, there was 40 to 50% control with glyphosate, 18 to 47% with glufosinate, 0 to 71% with paraquat, with zero percent biomass reduction at bolting stage. However, the highest dry biomass reduction (>80%) was observed with 2,4-D applications at early rosette stage. Herbicide applications at the early rosette stage resulted in maximum V. pepperweed control.