Current outlook and future research needs for harvest weed seed control in North American agronomic crops

Authors: LOVREET, S. SHERGILL - University Of Delaware; SCHWARTZ-LAZARO, LAUREN - Louisiana State University Agcenter; LEON, RAMON - North Carolina State University; ACKROYD, VICTORIA - University Of Maryland; FLESSNER, MICHAEL - Virginia Tech; BAGAVATHIANNAN, MUTHUKUMAR - Texas A&M University; EVERMAN, WESLEY - North Carolina State University; NORSWORTHY, JASON - University Of Arkansas; VAN GESSEL, MARK - University Of Delaware; Mirsky, Steven

Submitted to: Pest Management Science
Publication Type: Review Article
Publication Acceptance Date: 7/6/2020
Publication Date: 8/11/2020
Citation: Lovreet, S., Schwartz-Lazaro, L.M., Leon, R., Ackroyd, V.J., Flessner, M.L., Bagavathiannan, M., Everman, W., Norsworthy, J.K., Van Gessel, M.J., Mirsky, S.B. 2020. Current outlook and future research needs for harvest weed seed control in North American agronomic crops. Pest Management Science. 76:3887-3895.

Interpretive Summary: Many weeds in our cropping systems retain their seeds at crop maturity. During harvest, these weed seeds get collected by the combine and exit the machine in the chaff fraction that gets spread across the field. Harvest weed seed control (HWSC) targets weed seeds during the harvest operation by taking the chaff fraction and either destroying the seeds with an impact mill or banding the chaff and weed seeds in the field. These systems and techniques have been widely successful in Australia; our team has pioneered testing for US cropping systems. In this paper, we synthesize HWSC research efforts thus far in North America and where and how to best apply this approach including potential limitations. We critically review the HWSC technology and talk about concerns of weeds becoming resistant to HWSC, shifts in weed species composition, particularly with the diversity of weeds in North America. Currently the potential of HWSC vastly outweighs any drawbacks, necessitating further research. Grower participation for this kind of research is essential to drive greater adoption while identifying and correcting the limitations of HWSC. This review will be critical for agribusiness, researchers, and farmers in customizing HWSC to US cropping systems.

Technical Abstract: Harvest weed seed control (HWSC) comprises a set of tools and tactics that prevents the addition of new seeds to the weed soil seed bank, attenuating weed infestations and providing a method to combat the development and spread of herbicide-resistant weeds. Initial HWSC research efforts in North America are summarized and, combined with the vast area of crops suitable to HWSC, clearly indicate strong potential for this technology. But potential limitations exist that are not present in Australian cropping systems, where HWSC was developed. These include crop rotations with crops that are not currently amenable to HWSC (e.g., corn), high moisture at harvest, untimely harvest, and others. Concerns of weeds becoming resistant to HWSC (i.e., adapting) exist, as does shifts in weed species composition, particularly with the diversity of weeds in North America. Currently the potential of HWSC vastly outweighs any drawbacks, necessitating further research. Such expanded efforts should foremost include chaff lining and impact mill evaluation on commercial farms, as this will address potential limitations as well as economics. Growers must be integrated into large-scale, on-farm research efforts when possible to drive greater adoption while identifying and correcting the limitations of HWSC.