Author(s)

Nicholas L. Hurdle, Timothy L. Grey, Cristiane Pilon, W. Scott Monfort, Donn G. Shilling

Department of Crop and Soil Sciences, University of Georgia, Tifton, GA, USA.

Diclosulam and flumioxazin applied preemergent (PRE) results in direct peanut exposure to these herbicides prior to seedling emergence. Flumioxazin has been reported to induce injury in adverse weather (i.e. cool-wet soil conditions) at crop emergence. Research at Ty Ty and Plains, Georgia evaluated the physiological effects of PRE herbicides to emerging peanut in 2018 and 2019. Peanut seed with variable germination and different planting dates were evaluated as additional factors. Peanut plant physiological measurements included electron transport (ETR), net assimilation rate (A_net), quantum yield of PSII (Φ_PSII), and stomatal conductance to water vapor (GSW). Data were obtained from V3 to R1 peanut growth stages using a LiCOR 6800, along with stand counts and plant width measures. In 2018, diclosulam reduced peanut ETR when measured across multiple growing degree days (GDD) after planting, compared to the nontreated control (NTC). Flumioxazin reduced peanut ETR compared to the NTC, at several sample timings for each planting date. In 2018 and 2019 at both locations, flumioxazin impacted A_net less than ETR, but was consistently similar to/or greater than the NTC. Peanut Φ_PSII responded similarly as A_net at each location and yr. GSW was variable in both years; however flumioxazin treated plants had higher GSW rates than other treated plants. Peanut stand counts, plant widths, and pod yields noted few differences compared to the physiological measures. Though some peanut plant physiological differences were noted when measured at varying GDD’s after planting with the different PRE treatments, planting date, and seed vigor, no specific trends were observed. Growers will often observe peanut injury from flumioxazin early in the season. However, it is transient and does not affect yield.

Diclosulam, Flumioxazin, Peanut, Arachis hypogaea L., Photosynthesis, Electron Transport

Hurdle, N. , Grey, T. , Pilon, C. , Monfort, W. and Shilling, D. (2020) Interaction of Seedling Germination, Planting Date, and Flumioxazin on Peanut Physiology under Irrigated Conditions. American Journal of Plant Sciences, 11, 2012-2030. doi: 10.4236/ajps.2020.1112142.