Introduction

In 2023, the U.S. harvested approximately 35 million ha of field corn (Zea mays L.), 33 million ha of soybeans (Glycine max L.), 2.9 million ha of cotton (Gossypium hirsutum L.), 15 million ha of wheat (Triticum aestivum L.), and only 637,247 ha of peanut (Arachis hypogaea L.) (USDA-NASS 2024). Georgia, the nation’s top peanut-producing state, harvested 311,741 ha or 49% of the total U.S. peanut hectarage. Despite peanut being a valuable commodity for Georgia and the U.S., agri-chemicals are rarely developed for peanut production in contrast to the major agronomic crops.

Field crops, such as field corn and soybean, offer a competitive advantage to competing weeds due to their ability to quickly close the crop canopy and ability to shade the soil beneath (Ethridge et al., 2022; Jha et al., 2017). Because the growth habit and structure of peanut is low growing and is slow to shade the soil often allowing multiple flushes of weeds, peanut is considered a poor early-season competitor (Burke et al., 2007, Everman et al., 2008, Wilcut et al., 1994). Herbicides can be valuable tools maximizing peanut growth while minimizing the competitiveness of yield-limiting broadleaf and grass weeds such as Palmer amaranth (Amaranthus palmeri S. Wats.), Texas millet [Urochloa texana (Buckl.)], goosegrass (Eleusine indica L.), crabgrass spp. (Digitaria spp.), crowfootgrass (Dactyloctenium aegyptium L.), wild radish (Raphanus raphanistrum), Florida beggarweed [Desmodium tortuosum (Sw.) DC.], common cocklebur (Xanthium strumarium L.), Benghal dayflower (Commelina benghalensis L.), common ragweed (Ambrosia artemisiifolia L.), and sicklepod (Senna obtusifolia L.) (Buchanan et al., 1976; Burke et al., 2004; Burke et al., 2007; Cardina and Brecke, 1991; Everman et al., 2008; Grichar et al., 2004; Hauser et al., 1975; Norsworthy et al., 2010; Prostko et al., 2001).

Herbicide-resistant Palmer amaranth is the most prolific and second most difficult weed to manage in Georgia peanut production (Wychen, 2019). This finding was prior to Randell-Singleton et al., (2024) who documented a population of Palmer amaranth in Georgia with resistance to residual (soil) applications of WSSA Group 14 protoporphyrinogen oxidase (PPO) herbicides. This new resistance confirmation is additional to previous discoveries of resistance to WSSA/HRAC Group 9 (glyphosate), Group 2 (acetolactate synthase [ALS] inhibitors), and/or Group 5 (triazine) herbicides (Heap, 2024).

Flumioxazin, a WSSA/HRAC Group 14 PPO herbicide, is a key preemergence (PRE) herbicide that has been utilized in peanut production since 2001 and remains a critical component of a peanut weed management system (Basinger et al., 2021; Grichar et al., 2004; Wilcut et al., 2001). Flumioxazin is used on more than 60% of the U.S. peanut crop (USDA-NASS, 2024). Typically, growers do not experience yield loss associated with PRE applications of flumioxazin as peanut cultivars have excellent crop tolerance (Basinger et al., 2021; Grichar et al., 2004; Main et al., 2003; Wilcut et al., 2001). However, injury or stunting can occur early in the season under wet conditions, but research has shown this injury to be transient without impacting yields (Basinger et al. 2021; Wilcut et al. 2001). The recent discovery of PPO resistance to the residual activity of flumioxazin in Georgia has become a major concern for its future use in peanut especially when considering a single Palmer amaranth plant/row meter of peanut can reduce yields by 28% (Burke et al., 2007).

Weed management in peanut requires a dynamic systems approach utilizing a combination of herbicides (PRE + POST), and cultural production methods that promote vigorous crop growth reducing the competitiveness of problematic weeds (Buchanan et al. 1982; Burke et al., 2007; Everman et al. 2008). It is vital to evaluate herbicides, developed for use in other crops, for their potential use in peanut as herbicide-resistance and the lack of new herbicide chemistries are concerning.

Fluridone, formerly ELI-171, was originally developed for the aquatic weed control market and was introduced into the U.S. in 1986 under the trade name of Sonar® (Shaner 2014). Fluridone + fomesafen and fluridone + fluometuron pre-mixtures were registered for use in cotton in 2016 under the trade names of Brake® F16 and Brake® FX. Fluridone alone was labeled for use in cotton in 2017 under the trade name of Brake® (K. Briscoe, pers. commun.). Fluridone applied at rates above 450 g ai/ha has been documented to control pigweed spp. (Amaranthus hybridus L.), common purslane (Portulaca oleracea L.), Texas millet, junglerice [Echinochloa colonum (L.) Link] and seedling johnsongrass (Sorghum halepense L.) on Miller clay soils for up to 60 days after application (Banks and Merkle 1979). Fluridone, a WSSA Group 12 herbicide, inhibits phytoene desaturase and this inhibition that occurs in susceptible plants leads to bleaching, chlorosis, necrosis, and plant death (Waldrep and Taylor 1976). Fluridone, with its underutilized mode of action in agronomic crops, could be an important tool in a peanut weed-resistance management program if acceptable crop tolerance exists (Cahoon et al., 2015). Prior research indicates differential peanut cultivar response to other herbicides highlighting the need for research focusing on peanut cultivar response to fluridone (Jordan et al.,1998; McLean et al., 1994; Richburg et al. 1995; Wilcut et al. 2001). Additionally, little is understood regarding how fluridone would perform in a peanut weed management system.

Therefore, the objectives of this research were 1) to determine the effects of fluridone applied PRE on the growth and development of seven commercially available peanut cultivars and 2) to determine the effectiveness of fluridone as part of a peanut weed management system.

Materials and Methods

Peanut Cultivar Experiment 1

A field experiment was conducted each year from 2019 through 2021 (3 site-years) at the University of Georgia Ponder Research Farm in Ty Ty, Georgia (31.507654̊ N, -83.658395̊ W) to determine the effects of fluridone applied PRE on three peanut cultivars. The soil type was a Tifton sand with 92-94% sand, 4-6% silt, 2% clay, 0.62-0.93% organic matter, and a pH of 6.0. Treatments were arranged in a split-plot design with main-plots consisting of the cultivars [Georgia-06G (Branch 2007), Georgia-16HO (Branch 2017), and Georgia-18RU (Branch 2019)] and sub-plots consisting of four rates of fluridone including 0, 168, 336, or 673 g ai/ha, with all twelve treatments replicated four times.

Peanut cultivars were planted into conventionally tilled seedbeds using a vacuum planter (Monosem Precision Planters, 1001 Blake St., Edwardsville, KS) calibrated to deliver 18 peanut seed/m at a depth of 5 cm. Peanuts were planted in twin rows spaced 23 cm apart on a 91 cm center. Plots were 1.8 m (two sets of twin rows) wide and 7.6 m in length. Herbicide treatments were applied 1 day after planting (DAP) using a CO₂-pressurized backpack sprayer calibrated to deliver 140 L/ha at 5.3 km/hr. Immediately following herbicide applications, treatments were activated with 1.3 cm of overhead irrigation. Plots, including the non-treated control, were maintained weed-free throughout the season by applying pendimethalin [1066 g ai/ha] plus diclosulam [26 g ai/ha] over the entire experimental area PRE followed by hand-weeding when necessary. Production, irrigation, and pest management practices other than specific treatments were held constant over the entire experiment to optimize peanut growth and development (Monfort 2022).

Data collected included peanut density (stand) at 27 to 34 DAP, visual estimates of peanut injury (bleaching, necrosis, and stunting), plant height/width, and yield. Peanut plant density was obtained by counting the number of emerged plants from 1-row m of twin rows. Visual estimates of crop injury were obtained from 1, 3, 4, 5, 6, 8, and 10 weeks after application (WAA) using a subjective scale of 0 to 100 (0=no injury; 100=plant death). Plant height (cm) and width (cm) data were collected at 8 WAA by measuring 5 plants/plot. Plant heights/widths were recorded at 5 random but representative locations from each plot. Heights were measured from individual plants from the soil line to the top of the terminal leaflet, and plant width measurements were recorded from measurements of the lateral branches from the twin-row. Peanut yield data were obtained using commercial harvesting equipment with yields adjusted to 10% moisture. A complete summary of planting, inversion, and harvesting dates can be found in Table 1. Weather conditions, irrigation, and rainfall for the first 30 DAP are presented in Table 2.

Table 1

Planting, inversion, and harvest dates of fluridone peanut trials in Ty Ty, Georgia, 2019-2022.

Table 2

Weather comparison for fluridone cultivar experiment one during the first 30 days after planting (DAP) in Ty Ty, Georgia, 2019-2021.

Data for all parameters were analysed as a split-plot design and subjected to ANOVA using PROC GLIMMIX in SAS, version 9.4 (SAS Institute, Cary, NC). Peanut cultivar and fluridone rate were set as fixed effects. Replications within years and cultivars by replications within years were set as random effects. Peanut density, injury, plant height/width, and yield were set as the response variables. A fluridone rate-by-year interaction for 2019 prevented the pooling of data across all years. Thus, all data for 2019 were separated from that acquired during 2020 and 2021. Lack of year interactions allowed data to be pooled over the 2020 and 2021 experiments. All P-values for tests of differences between least-square means were compared and separated using the Tukey-Kramer method at P < 0.10.

Weed Control Experiment

Cultural production practices, location, and soil type for the weed control experiment were identical to those provided for the cultivar experiments. However, only one peanut cultivar [GA-16HO (Branch 2017)] was planted. Planting, herbicide application, inversion, and harvest dates are presented in Table 1.

Twelve herbicide treatments were arranged in a randomized complete block design with 3 to 4 replications. Fluridone at 126, 147, 168, 252, 294, and 336 g ai/ha was tank-mixed with pendimethalin at 1066 g ai/ha and applied PRE. Additionally, fluridone at 147 g ai/ha was applied with tank-mixtures of diclosulam, S-metolachlor, acetochlor, and/or dimethenamid-P. Fluridone treatments were directly compared to a standard recommended peanut PRE-tank-mix of flumioxazin + pendimethalin + diclosulam (1066 + 91 + 13 g ai/ha). All PRE-herbicide treatments were applied 1 DAP using a CO₂-pressurized backpack sprayer calibrated to deliver 140 L/ha at 5.3 km/hr. Immediately following herbicide applications, treatments were activated with 1.3 cm of overhead irrigation. All PRE treatments were followed with POST applications (27-31 DAP) of imazapic + 2,4-DB and either S-metolachlor, dimethenamid-P, or acetochlor. Two nontreated checks were also included for comparison. A complete list of treatment rates and combinations are presented in Table 3.

Table 3

Weed control programs, rates, and application timing for weed control experiment with fluridone in Ty Ty, Georgia, 2020-2022.

Data collection included visual estimates of peanut injury (stunting and bleaching), visual estimations of weed control, and yield. Visual estimates of crop injury were obtained from 2, 3, 5, 6, and 8 WAA using a subjective scale of 0 to 100 (0=no injury; 100=plant death). Weed control ratings were collected using a scale of 0 to 100 (0=no weed control; 100=weed free). Weed control ratings were collected on the same dates as injury evaluations with additional evaluations also occurring 9, 11, and 13 WAA. Peanut yield data were obtained using commercial harvesting equipment with yields adjusted to 10% moisture.

Data were subjected to ANOVA using PROC GLIMMIX in SAS, version 9.4 (SAS Institute, Cary, NC). Peanut injury, weed control, and yield were set as the response variables with replication within year included in the model as random factors. There was not a year-by-treatment interaction, thus data were pooled over years. All P-values for tests of differences between least-square means were compared and separated using the Tukey-Kramer method (P<0.1).

Results and Discussion

Peanut Cultivar Experiment 1

Visual estimates of leaf bleaching and necrosis evaluations for 2019, presented in Table 4, were obtained at 3 WAA. A significant interaction between cultivar and fluridone rate was observed for bleaching (P=0.0005) and necrosis (P=0.0472). Foliar bleaching of 23 to 56% was observed with fluridone ranging from 168 to 673 g ai/ha with some cultivar differences. For example, GA-16HO exhibited more foliar bleaching than GA-06G and GA-18RU when fluridone was applied at 168 g ai/ha. For necrosis, the only difference observed between cultivars within comparable rates was with GA-16HO which exhibited greater foliar necrosis than GA-18RU at the 673 g ai/ha rate. In 2019, peanut cultivar stunting followed similar trends as noted with bleaching and chlorosis as GA-16HO was stunted more than GA-18RU when pooled over rates (Table 5). Fluridone at 168, 336, and 673 g ai/ha when averaged across cultivars, resulted in significant stunting of 11, 28, and 57%, respectively.

Table 4

Peanut cultivar and fluridone rate interaction effects on peanut injury (bleaching and necrosis), cultivar experiment 1, Ty Ty, Georgia, 2019.

Table 5

The influence of peanut cultivar and fluridone rate on peanut density, injury (bleaching, necrosis, stunting), and yield, cultivar experiment 1, Ty Ty, Georgia 2019-2021.

In 2020/2021, bleaching and necrosis data were obtained at 3 WAA, and stunting injury was obtained at 6 WAA (Table 5). Cultivar (P=0.0917) and fluridone rate (P<0.0001) main effects were significant. The cultivar GA-16HO exhibited greater foliar bleaching than GA-18RU when averaged across all fluridone rates (20% vs. 14%). Fluridone at 168, 336, and 673 g ai/ha, when averaged across cultivars, resulted in bleaching of 8%, 18%, and 39%, respectively, with each rate resulting in significantly more bleaching. Foliar necrosis was impacted by fluridone rate (P<0.0001) when averaged across cultivars. Fluridone rates at 336 and 673 g ai/ha resulted in 5 to 8% leaf necrosis and 6 to 22% stunting.

In 2019, there was no interaction between cultivar and fluridone for peanut density. (P=0.3568). However, the main effect of fluridone rate was significant (Table 5.) (P<0.0001). Peanut density was reduced across all cultivars when treated with 336 and 673 g ai/ha of fluridone. In 2020/2021 peanut density was influenced by cultivar and fluridone rate (Table 5). Peanut density main effects for cultivar were observed as follows: GA-16HO>GA-06G>GA-18RU, most likely due to seed quality (splits) issues. Differences in cultivar emergence can also be attributed to variations in management, harvesting, and storage/handling for each cultivar (W.S. Monfort, pers. commun. 2023). When averaged across cultivars, fluridone at 673 g ai/ha reduced final peanut density by 2 plants/1-row m (13%).

Stand loss differences in 2019 from the two highest rates of fluridone when compared to 2020/2021 can likely be attributed to environmental factors noted in Table 2. In 2019, on average over the course of 30 DAP, the metabolism of fluridone in peanut was decreased due to the extreme air and soil temperatures along with the increase of fluridone in an aqueous solution in the soil. Data reported by Ketring (1984) suggest air temperatures between 25 and 30 C are optimal for photosynthesis, vegetative growth, and development, whereas the temperature of 32C and 35C had significantly reduced leaf area, dry weight, and shortened stem length at 63 and 91 DAP in Spanish peanut cultivars. Temperature is directly proportional to vegetative and reproductive development in peanut, and increased temperatures can lead to reduced plant growth and metabolism (Boote 1982; Ketring 1984). Another contributing factor in 2019, could be that peanuts received 83% of total irrigation and rainfall within 14 DAP, allowing for increased root uptake of fluridone.

In comparison, 2020/2021 had optimal daily average air and soil temperatures during the first 30 DAP (Table 2). Despite rainfall and irrigation totals being greater in 2020/2021 for the first 30 DAP, emerging peanuts only received 39% and 28% of those totals during the first 2 weeks after planting, respectively (Table 2). These conditions could contribute to optimal fluridone metabolism, resulting in significantly less stand loss from the two highest rates of PRE-applied fluridone when comparing differences between years. While stand loss was significant for the highest rate of fluridone across all years, there was only a 13% reduction in density at the highest rate in 2020/2021, whereas in 2019, a 65% reduction in peanut density was observed with fluridone at 673 g ai/ha.

Plant heights or widths were not recorded in 2019. Plant height and width measurements from 2020/2021 are presented in Table 5. Peanut canopy height was influenced by herbicide rate (P=0.0001). Peanut canopy width was influenced by cultivar (P=0.0660) and herbicide rate (P<0.0001). Peanut plant height and width were reduced by 15% when subjected to the 673 g ai/ha rate, when averaged across cultivars. GA-16HO plant canopies were wider than GA-06G canopies at 10 WAA.

Peanut yield was reduced 18 and 54% by fluridone at 336 and 673 g ai/ha, respectively, during 2019 when pooled over cultivars (Table 5). When comparing cultivars, averaged over herbicide rates, no differences were observed. During 2020/2021, yield was influenced by both cultivar (P=0.0242) and fluridone rate (P=0.0149), but there was not a cultivar-by-herbicide interaction (Table 5). Following observations with injury and growth, fluridone influence on crop yield was less during the 2020/2021 seasons when compared to 2019 with only the highest rate of fluridone reducing yield (6%). Additionally, GA-18RU had higher yields than GA-06G and GA-16HO when averaged across all rates of fluridone. The yield loss associated with fluridone rates of 336 and 673 g ai/ha in this experiment, set the limitations on application rates for the second cultivar experiment.

Peanut Cultivar Experiment 2

Peanut density was not influenced by the interaction of cultivar and fluridone rate (P=0.4239). The main effect of fluridone rate did not influence final plant density (P=0.4660); however, the main effect of cultivar (P=0.0685) was significant (Table 6). FloRun331 density was reduced when compared to GA-20VHO but no other cultivar differences were observed (Table 7). Peanut emergence can be influenced by how seed is managed, stored, and handled prior to planting (W.S. Monfort, pers. commun. 2023).

Table 6

The influence of peanut cultivar and fluridone rate on peanut density, injury (bleaching, stunting), canopy height, and yield, cultivar experiment 2, Ty Ty, Georgia 2021/2022.

Table 7

Peanut injury, weed control, and yield in fluridone weed control experiment in Ty Ty, Georgia, 2020-2022.

Visual estimates of bleaching and stunting ratings for 2021/2022 are presented in Table 6. A significant interaction of herbicide rate was observed for both bleaching (P<0.0001) and stunting (P=0.0003). Fluridone at 252 g ai/ha resulted in 4% bleaching and stunting. No other visual injury was observed and the injury dissipated quickly as the season progressed.

Fluridone had no effect on peanut plant height. However, cultivar differences were observed with plant heights as follows: FloRun 331 = TifNV High O/L >AU NPL > GA-20VHO (Table 6). Plant width was not affected by either cultivar or fluridone rate (data not reported). This data supports peanut growth response to similar rates from cultivar experiment one.

Peanut yield in 2021/2022 was influenced by cultivar but not fluridone rate (Table 6). AU-NPL17 had 12 to 16% greater yields than the three other cultivars. In previous studies with older peanut cultivars, PRE applications of norflurazon, another WSSA Group 12 herbicide, did not influence yield (Mclean et al., 1994).

Summary and Conclusions

In 2019, peanut density was reduced 29% and 65% by 336 and 673 g ai/ha of fluridone resulting in an 18% and 54% reduction in yield. During 2020/2021, only fluridone at 673 g ai/ha resulted in a density reduction of 13% and a yield loss of 6%. Differing results by year were influenced by more stressful environmental conditions that occurred during 2019. Although cultivar response to fluridone was often similar, GA-16HO was consistently more sensitive to fluridone than GA-18RU. After concluding this first cultivar experiment, rates of fluridone were lowered for the second peanut cultivar experiment with a maximum fluridone rate of 252 g ai/ha. In the second cultivar experiment, the lack of foliar bleaching, necrosis, stunting, and effects on peanut yield supported the decision to consider the lower rates for potential labelling. For weed control, fluridone offers an alternative class of chemistry with a greater safety potential than current PRE chemistry. Additionally, when fluridone at 126 g ai/ha was applied in a PRE tank-mixture with acetochlor, diclosulam, dimethenamid-P, pendimethalin, S-metolachlor, and trifludimoxazin and followed with a timely standard POST herbicide program, control of Palmer amaranth, wild radish, and annual grasses were similar to current standard flumioxazin systems at seasons end. Other research has also shown that fluridone should not be a stand-alone treatment (Hill et al., 2016). Results from these studies suggest that fluridone will provide peanut growers with another viable option to control problematic weeds. In 2023, fluridone received a label for peanut with use rates ranging from 126 to 168 g ai/ha (Anonymous 2024).

This research could not have been conducted without the technical support of Charlie Hilton, Tim Richards, and Dewayne Dales. The contributions of A.S. Culpepper, W.S. Monfort, M.A. Abney, and C. J. Bryant were also greatly appreciated.

Literature Cited

Anonymous. Brake® herbicide product label. Carmel, IN, SePRO AgCorporation. 2024.

Banks, P.A., and M.G. Merkle. 1979. Field evaluations of the herbicidal effects of fluridone on two soils. Agron. J. 71:759-762.

Basinger, N.T., T.M. Randell, and E.P. Prostko. 2021. Peanut response to flumioxazin and S-metolachlor under high moisture conditions. Peanut Sci. 48:113-117.

Boote K.J. 1982. Growth stages of peanut (Arachis hypogaea L.). Peanut Sci. 9:35-40.

Branch W.D. 2021. Registration of ‘Georgia-20VHO’ peanut. Crop Sci. 43:1883-1884.

Branch W.D. 2019. Registration of ‘Georgia-18RU’ peanut. J. of Plant Reg. 13:326-329.

Branch W.D. 2017. Registration of ‘Georgia-16HO’ peanut. J. of Plant Reg. 11:231-234.

Branch W.D. 2007. Registration of ‘Georgia-06G’ peanut. J. of Plant Reg. 1(2):120.

Buchanan, G.A., E.W. Hauser, W.J. Ethredge, and S.R. Cecil. 1976. Competition of Florida beggarweed and sicklepod with peanuts. II. Effects of cultivation, weeds, and SADH. Weed Sci. 24:29-30.

Buchanan G.A., Murray D.S., and Hauser E.W.. 1982. Weeds and their control in peanuts. pp. 206-249. In Patee, H.E. & Young, C.T., eds. Peanut Sci. and Tech. Yoakum, Texas, American Peanut Research and Education Society.

Burke I.C., Price A.J., Wilcut J.W., Jordan D.L., Culpepper A.S., and Tredaway-Ducar J.. 2004. Annual grass control in peanut (Arachis hypogaea) with clethodim and imazapic. Weed Technol. 18:88-92.

Burke, I.C., M. Schroader, W.E. Thomas, and J.W. Wilcut. 2007. Palmer amaranth interference and seed production in peanut. Weed Technol. 21:367-371.

Cahoon, C.W., A.C. York, D.L. Jordan, R.W. Seagroves, W.J. Everman, and K.M. Jennings. 2015. Fluridone carryover to rotational crops following application to cotton. J. of Cotton Sci. 19:631-640.

Cardina, J., and B.J. Brecke. 1991. Florida beggarweed (Desmodium tortuosum) growth and development in peanuts (Arachis hypogaea). Weed Technol. 5:147-153.

Chen, C., K. Balkcom, A. Hagan, P. Dang, M. Lamb, and W. Mingli. 2017. Characteristics of a newly released runner-type peanut cultivar ‘AU-NPL 17’. National Peanut Laboratory. Pub. #342753.

Daramola, O.S., J.E. Iboyi, G.E. MacDonald, R.G. Kanissery, B.L. Tillman, H. Singh, and P. Devkota. 2024. A systematic review of chemical weed management in peanut (Arachis hypogaea) in the United States. Weed Sci. 72:5-29.

Eslami, S.V., G.S. Gill, B. Bellotti, and G. McDonald. 2006. Wild radish (Raphanus raphanistrum) interference in wheat. Weed Sci. 54:749-756.

Ethridge, S.R., A.M. Locke, W.J. Everman, D.L. Jordan, and R.G. Leon. 2022. Response of maize, cotton, and soybean to increase crop density in heterogeneous planting arrangements. Agron. 12:1238.

Everman, W.J., I.C. Burke, S.B. Clewis, W.E. Thomas, and J.W. Wilcut. 2008. Critical period of grass vs. broadleaf weed interference in peanut. Weed Technol. 22:68-73.

Grichar, W.J., B.A. Besler, and K.D. Brewer. 2004. Control of weeds in peanut (Arachis hypogaea) using flumioxazin. Peanut Sci. 31:17-21.

Hashem, A., D. Bowran, T. Piper, and H. Dhammu. 2001. Resistance of wild radish (Raphanus raphanistrum) to acetolactate synthase-inhibiting herbicides in the western Australia wheat belt. Weed Technol. 15:68-74.

Hauser, E.W., G.A. Buchanan, and W.J. Ethredge. 1975. Competition of Florida beggarweed and sicklepod with peanuts. I. Effects of periods of weed-free maintenance or weed competition. Weed Sci. 23:368-372.

Heap I. 2024. The International Herbicide-Resistant Weed Database. Online. Available www.weedscience.org.

Hill, Z.T., J.K. Norsworthy, L.T. Barber, and E. Gbur. 2016. Residual weed control in cotton with fluridone. J. Cotton Sci. 20:76-85.

Holbrook, C.C., P. Ozias-Akins, Y.E. Chu, A.K. Culbreath, C.K. Kvien, and T.B. Brenneman. 2017. Registration of ‘TifNV-High O/L’ peanut. J. of Plant Reg. 11:228-230.

Jha, P., V. Kumar, R.K. Godara, and B.S. Chauhan. 2017. Weed management using crop competition in the United States: A review. Crop Prot. 95:31-37.

Jordan, D.L., A.S. Culpepper, R.B. Batts, and A.C. York. 1998. Response of Virginia-type peanut to norflurazon. Peanut Sci. 25:4-7.

Jordan, D.L., S.H. Lancaster, J.E. Lanier, B.R. Lassiter, and P.D. Johnson. 2009. Weed management in peanut with herbicides containing imazapic and other pesticides. Weed Technol. 23:6-10.

Ketring, D.L. 1984. Temperature effects on vegetative and reproductive development of peanut. Crop Sci. 24:877-882.

Main, C.L., J.T. Ducar, E.B. Whitty, and G.E. Macdonald. 2003. Response of three runner-type peanut cultivars to flumioxazin. Weed Technol. 17:89-93.

McLean, H.S., J.S. Richburg III, J.W. Wilcut, A.C. Culbreath, W.D. Branch, and C.K. Kvien. 1994. Peanut cultivar response to norflurazon. Proc. South. Weed Sci. Soc.47:33 (abstr.).

Monfort, W.S. (editor). 2022. Peanut Production Field Guide. University of Georgia Extension Bulletin 1146. 179 pp. On-line at: https://extension.uga.edu/publications/ detail.html?number=B1146.

Monks, C.D., J.W. Wilcut, J.S. Richburg, J.H. Hatton, and M.G. Patterson. 1996. Effect of AC 263-222, imazethapyr, and nicosulfuron on weed control and imidazolinone-tolerant corn (Zea mays) yield. Weed Technol. 10:822-827.

Norsworthy, J.K., M.S. Malik, M.B. Riley, and W. Bridges Jr. 2010. Time of emergence affects survival and development of wild radish (Raphanus raphanistrum) in South Carolina. Weed Sci. 58:402-407.

Prostko E.P. 2024. Peanut Weed Control. pgs 217-236 In 2024 Commercial Edition of Georgia Pest Management Handbook, University of Georgia Extension, Special Bulletin 28, Vol. 1, online at: https://secure.caes.uga.edu/extension/publications/ files/pdf/SB%2028-24_2.PDF.

Prostko E.P., Johnson III W.C., and Mullinix, Jr B.G. 2001. Annual grass control with preplant incorporated and preemergence applications of ethalfluralin and pendimethalin in peanut (Arachis hypogaea). Weed Technol. 15:36-41.

Randell-Singleton, T., L.C. Hand, J.C. Vance, H.E. Wright-Smith, and A.S. Culpepper. 2024. Confirming resistance to PPO-inhibiting herbicdes applied preemergence and postemergence in a Georgia Palmer amaranth population. Weed Technol. 38:in-press.

Richburg III, J.S., J.W. Wilcut, A.K. Culbreath, and C.K. Kvien. 1995. Response of eight peanut (Arachis hypogaea L.) cultivars to the herbicide AC 263,222. Peanut Sci. 22:76-80.

Roncatto, E., A.A.M. Barroso, B.D.P. Novello, R. Goncalves, T. Jarek, and M. Young. 2022. Residual herbicides and cover crops interactions for soybean weed control. J. of Agric. Sci. 14:47-58.

Seale, J.W., T. Bararpour, J.A. Bond, J. Gore, B.R. Golden. 2020. Evaluation of preemergence and postemergence herbicide programs on weed control and weed seed suppression in Mississippi peanut. Agron. 10:1058.

Shaner D.L. 2014. Herbicide Handbook. 10th EditionWeed Sci. Soc. AmericaChampaign, ILpp. 513.

Taylor-Lovell, S., L.M. Wax, and G. Bollero. 2002. Preemergence flumioxazin and pendimethalin and postemergence herbicide systems for soybean (Glycine max). Weed Technol. 16:502-511.

Tillman, B.L. 2021. Registration of ‘FloRun ‘331’’ peanut. J. of Plant Reg. 15:294-299.

USDA-NASS. 2024. 2023 Agricultural Chemical Use Survey-Peanuts. On-line at: https://www.nass.usda.gov/Surveys/Guide_to_NASS_Surveys/Chemical_Use/2023_Barley_Oats_Peanuts_Soybeans/ChemHighlights-Peanuts-2023.pdf.

USDA-NASS. Crop Production – 2023 Summary. Released January 12, 2024. On-line at: https://downloads.usda.library.cornell.edu/usda-esmis/files/k3569432s/ ns065v292/8910md644/cropan24.pdf.

Waldrep, T.W., and H.M. Taylor. 1976. 1-methyl-3-phenyl-5[3-trifluoromethyl)phenyl]-4-(1H)-pyridine, a new herbicide. J. Agric. Food Chem. 24:1250-1251.

Wilcut J.W., York A.C., and Wehtje G.R.. 1994. The control and interaction of weeds in peanut (Arachis hypogaea). Rev. Weed Sci. 6:177-205.

Wilcut, J.W., J.S. Richburg III, and F.R. Walls Jr. 1999. Response of johnsongrass (Sorghum halepense) and imidazolinone-resistant corn (Zea mays) to AC 263-222. Weed Technol. 13:484-488.

Wilcut, J.W., S.D. Askew, W.A. Bailey, J.F. Spears, and T.G. Isleib. 2001. Virginia market-type peanut (Arachis hypogaea) cultivar tolerance and yield response to flumioxazin preemergence. Weed Technol. 15:137-140.

Wychen, V.L. 2019. 2019 Survey of the most common and troublesome weeds in broadleaf crops, fruits & vegetables in the United States and Canada. WSSA National Weed Survey Dataset. Available on-line at: https://wssa.net/wp-content/uploads/2019-Weed-Survey_broadleaf-crops.xlsx.