Weed communities of snap bean fields in the United States

Authors: PAVLOVIC, PAVLE - University Of Illinois; COLQUHOUN, JED - University Of Wisconsin; KORRES, NICHOLAS - Oak Ridge Institute For Science And Education (ORISE); LIU, RUI - Washington State University; LOWRY, CAROLYN - Pennsylvania State University; PEACHEY, ED - Oregon State University; SCOTT, BARBARA - University Of Delaware; SOSNOSKIE, LYNN - Cornell University; VANGESSEL, MARK - University Of Delaware; Williams, Martin

Submitted to: Weed Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/20/2024
Publication Date: 11/15/2024
Citation: Pavlovic, P., Colquhoun, J., Korres, N., Liu, R., Lowry, C., Peachey, E., Scott, B., Sosnoskie, L., Vangessel, M., Williams, M. 2024. Weed communities of snap bean fields in the United States. Weed Science. https://doi.org/10.1017/wsc.2024.76.
DOI: https://doi.org/10.1017/wsc.2024.76

Interpretive Summary: Snap bean is an important vegetable in the American diet and grown throughout the U.S. Weeds threaten snap bean production by reducing yield and contaminating harvested product with foreign material. In surveys of hundreds of snap bean fields from Delaware to Oregon, we found nearly all fields had weed escapes at the time of crop harvest, represented by >100 weed species. Certain species have been problematic for years (e.g. waterhemp), whereas other certain species appear to be emerging threats (hophornbeam copperleaf). This research serves as the first quantitative report on the weed communities escaping control in U.S. snap bean production. The research and development communities will now have a detailed understanding of the scope of weed problems in snap bean that can be used to improve weed management in the crop.

Technical Abstract: Weeds are one of the greatest challenges to snap bean production. Anecdotal observation posits certain species frequently escape the weed management system by the time of crop harvest, hereafter called residual weeds. The objectives of this work were to 1) quantify the residual weed community in snap bean grown for processing across the major growing regions in the U.S., and 2) investigate linkages between the density of residual weeds and their contributions to weed canopy cover. In surveys of 358 fields across the Northwest (NW), Midwest (MW), and Northeast (NE), residual weeds were observed in 95% of the fields. While a total of 109 species or species groups were identified, one to three species dominated the residual weed community of individual fields in most cases. It was not uncommon to have >10 weeds m-2 with a weed canopy covering >5% of the field’s surface area. Some of the most abundant and problematic species/groups escaping control included amaranth species (such as smooth pigweed (Amaranthus hybridus L.), Palmer amaranth (Amaranthus palmeri S. Watson), redroot pigweed (Amaranthus retroflexus L.), and waterhemp [Amaranthus tuberculatus (Moq.) J. D. Sauer]), common lambsquarters (Chenopodium album L.), large crabgrass [Digitaria sanguinalis (L.) Scop.], and ivyleaf morningglory (Ipomoea hederacea Jacq.). Emerging threats include hophornbeam copperleaf (Acalypha ostryifolia Riddell) in the MW and sharppoint fluvellin [Kickxia elatine (L.) Dumort.] in the NW. Beyond crop losses due to weed interference, the weed canopy at harvest poses a risk to contaminating snap bean products with foreign material. Random forest modeling predicts the residual weed canopy is dominated by common lambsquarters, large crabgrass, carpetweed (Mollugo verticillata L.), ivyleaf morningglory, amaranth species, and hophornbeam copperleaf. This is the first quantitative report on the weed community escaping control in U.S. snap bean production.