Agronomic implications of diflufenzopyr application in peanut: transient physiological responses and sustained yield performance

Authors: Bucior, Erika; Sorensen, Ronald; McIntyre, Joseph; CARDOSO, AMANDA - North Carolina State University; TAGGART, MATTHEW - North Carolina State University; Lamb, Marshall

Submitted to: Journal of Crop Science and Biotechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/29/2025
Publication Date: 11/24/2025
Citation: Bucior, E.R., Sorensen, R.B., Mcintyre, J.S., Cardoso, A.A., Taggart, M.J., Lamb, M.C. 2025. Agronomic implications of diflufenzopyr application in peanut: transient physiological responses and sustained yield performance. Journal of Crop Science and Biotechnology. https://doi.org/10.1007/s12892-025-00320-4.
DOI: https://doi.org/10.1007/s12892-025-00320-4

Interpretive Summary: While herbicides are commonly used in agriculture to induce negative effects on unwanted herbaceous plants, many studies have found that application of sublethal doses of herbicides can enhance plant growth and induce varying physiological responses in a process called herbicide hormesis. Responses may include but are not limited to stimulation of shoot elongation, increase in aboveground biomass, altered protein content, and changes in photosynthetic habit. In peanut (Arachis hypogaea), an application of the herbicide Diflufenzopyr resulted in late season flower termination, inducing short-term determinate plant response resulting in less immature pods at harvest. Application of Diflufenzopyr did not cause dieback or permanent discoloration of leaves but did induce a temporary response of leaf rolling for about 4-5 days. Leaf rolling is a hydronastic mechanism that reduces light interception, transpiration, and leaf dehydration, playing a similar role as osmotic adjustment in maintaining internal plant water status and preventing water loss. Therefore, finding a sub lethal dose of Diflufenzopyr that acts as a stimulant to this hydronastic mechanism or illicit a temporary change in plant habit, could potentially result in a beneficial recovery in terms of plant water status, soil water status, and biomass allocation patterns. We found that in irrigated plots, application of Diflufenzopyr resulted in enhanced physiological functioning that maintained soil moisture, whereas in dryland plots the same application caused an inhibitory response and rapid decline of soil moisture. Application of this herbicide did not result in a straightforward strategy to limit plant transpiration and control soil moisture.

Technical Abstract: Low-dose applications of certain herbicides have been hypothesized to induce physiological responses that conserve water and reduce aflatoxin contamination risk in peanut (Arachis hypogaea L.). Motivated by reported leaf rolling following diflufenzopyr application, this study evaluated whether herbicide-induced stomatal closure and biomechanical changes could serve as a water-saving mechanism during late-season stress. Farm field, rainout shelter plot, and greenhouse experiments were conducted under irrigated and drought conditions to quantify the impacts of herbicide treatment on gas exchange, soil water potential, stem water potential, and leaf biomechanics. Herbicide application in well irrigated plots unexpectedly led to a short-term increase in transpiration, stomatal conductance, and photosynthesis without impacting plant physiological capacity or soil drying rate. However, herbicide application under drought conditions accelerated soil drying and promoted a more rapid physiological decline of plants in drier plots. However, stem water potential and leaf inclination data suggest only temporary disruption in stomatal regulation post-treatment, and after leaves had mechanically compensated to the stress by folding, physiological recovery was seen. Despite these physiological interruptions, responses were ultimately transient and not sustained more than a few days, and there was no significant yield or aflatoxin impacts measured in any treatments. These results revise the initial hypothesis of herbicide-induced water conservation by revealing a more complex, context-dependent interaction between plant water status herbicide response, and agronomic implications.