Weed Control In Peanut Research Articles

A systematic review of chemical weed management in peanut (Arachis hypogaea) in the United States: challenges and opportunities

AbstractHerbicides are the primary tool for controlling weeds in peanut (Arachis hypogaea L.) and are crucial to sustainable peanut production in the United States. The literature on chemical weed management in peanut in the past 53 yr (1970 to 2022) in the United States was systematically reviewed to highlight the strengths and weaknesses of different herbicides and identify current research gaps in chemical weed management. Residual weed control in peanut is achieved mainly with dimethenamid-P, ethalfluralin, pendimethalin, and S-metolachlor. More recently, the use of the protoporphyrinogen oxidase inhibitor flumioxazin and acetolactate synthase inhibitors, such as diclosulam, for residual weed control in peanut has increased considerably. Postemergence broadleaf weed control in peanut is achieved mainly with acifluorfen, bentazon, diclosulam, imazapic, lactofen, paraquat, and 2,4-DB, while the graminicides clethodim and sethoxydim are the major postemergence grass weed control herbicides in peanut. Although several herbicides are available for weed control in peanut, no single herbicide can provide season-long weed control due to limited application timing, lack of extended residual activity, variability in weed control spectrum, and rotational restrictions. Therefore, effective weed management in peanut often requires herbicide mixtures and/or sequential application of preplant-incorporated, preemergence, and/or postemergence herbicides. However, the available literature showed a substantive range in herbicide efficacy due to variations in environmental conditions and flushes of weed germination across years and locations. Despite the relatively high efficacy of herbicides, the selection of herbicide-resistant weeds is another area of increasing concern. Future research should focus on developing new strategies for preventing or delaying the development of resistance and improving herbicide efficacy within the context of climate change and emerging constraints such as water shortages, rising temperatures, and increasing CO2 concentration.

Impact of Level of Nitrogen Fertilization and Critical Period for Weed Control in Peanut (Arachis hypogaea L.)

To avoid competing with economical plants, weed control must be implemented with a clean and appropriate strategy. Since the efficiency of leguminous crops in biological fixation of the atmospheric N2 is severely affected when grown under stressful conditions (the soil tested in this study was salt-affected; ECe = 8.99 dS m−1), an appropriate level of N fertilization should also be applied. Two field trials were performed in the 2018 and 2019 seasons to investigate the influences of soil-applied nitrogen (N) levels [48 (N1), 96 (N2), and 144 kg N ha−1 (N3)] and critical timing of weed removal (CTWR) on weed control efficiency, improving weed control, yield traits, and quality attributes in peanut (Arachis hypogaea L.). Each trial was conducted with three replicates and planned according to a split-plot in a completely randomized design. The results revealed that N levels had significant (p ≤ 0.01) variations for the dry weight of all weeds tested (narrow-leaved, broad-leaved, and total annual weeds), pods and seed weight and yields, N use efficiency, and oil and protein yields (t ha−1) in peanut in both seasons. N3 outperformed both N1 and N2 with respect to the above-mentioned traits, however, it decreased N use efficiency and seed oil content compared to N1 and N2, respectively. Dry weight of weeds and seed harvest index were significantly (p ≤ 0.01) increased, while seed oil and protein contents, N use efficiency, and yields of pods, seeds, and protein were decreased, with increased weed interference (with peanut plants) period in both seasons. In both seasons, the interaction effect of N × W (weed removal time) was significant (p ≤ 0.01) on the dry weight of weeds and peanut traits, including seed oil content, N use efficiency, and yields of pods, seeds, and protein, and their highest values were obtained with N3 × W6 (weed-free for the whole season). The CTWR had growing degree days (GDDs) of 221.4 and 189. These two GDDs each corresponded to 2 weeks after emergence (WAE) in both growing seasons. The critical weed-free period (CWFP) had GDDs of 1400 and 1380. These two GDDs corresponded to 9.5 and 10 WAE, respectively. The combination of CTWR and CWFP resulted in a critical period of weed control (CPWC) of 2–9.5 and 2–10 WAE in both growing seasons, respectively, for the peanut crop with an acceptable yield loss of 5%. A high positive (p ≤ 0.01) correlation was noted between oil yield and seed yield (r = 0.999 ** and 0.999 **). However, a high negative (p ≤ 0.01) correlation (r = −0.723 ** and −0.711 **) was found between dry total annual weeds and seed weight in the first and second seasons, respectively. The stepwise regression analysis revealed high significant participation of two traits (i.e., seed yield and oil content) and three traits (i.e., seed yield, oil content, and weight of seeds) in the variations in oil yield in the first and second seasons, respectively. These results recommend the use of N fertilization at a rate of 144 kg N ha−1 in conjunction with keeping the soil free of weeds throughout the season to maximize peanut productivity under saline (8.99 dS m−1) conditions.

Weed Management in Peanuts

Successful weed control in peanuts involves use of good management practices in all phases of peanut production. This 11-page document lists herbicide products registered for use in Florida peanut production, their mode of actions group, application rate per acre and per season, and reentry interval. It also discusses the performance of these herbicides on several weeds under Florida conditions. Written by J. A. Ferrell, G. E. MacDonald, and P. Devkota, and published by the UF/IFAS Agronomy Department, revised May 2020.

Peanut pod, seed, and oil yield for biofuel following conventional and organic production systems

Peanut (Arachis hypogaea L.) is a crop that can enter the human diet in various forms or be used as an alternative feedstock for livestock or industrial applications. Increased use of organic production systems and peanut's potential use as a biodiesel feedstock makes it increasingly necessary to develop organic methods in their production. Corn gluten meal (CGM) and vinegar are materials used in organic weed control. These were used alone, or in conjunction with cultivation, to evaluate their efficacy for weed control in peanut that had followed winter cover crops of red clover (Trifolium pratense L.) or wheat (Triticum vulgaris L.). Comparisons were made to conventional weed control (Dual®, S-metolachlor) and cultivation. Pod and oil yields and seed oil percentages were determined over 2 years in high oil cultivars Olin and Tam Runner. In 2009, cover crop, cultivar, and weed control treatments resulted in significant interactions impacting pod, seed oil yields, and seed oil percentages. Conventional weed control produced greater pod yields with clover (8220kgha−1) and wheat (7800kgha−1) cover crops, compared to all alternative weed control treatments. When averaged across cover crops, the conventional treatment produced greater seed oil yields (295.9Lha−1) and few differences in seed oil percentages. In 2010, the conventional weed control treatment produced superior seed oil yield and oil percentage for both cover crops and cultivars, and greater pod yields when the wheat cover crop was used for both cultivars; and Tam Runner with clover as a cover crop. Application of CGM and vinegar did not produce pod or oil yields at levels produced with conventional weed control, and/or reduced seed oil percentage. Further research should investigate additional alternative weed control systems that would increase weed control efficacy for organic peanut production systems.

Postemergence Weed Control in Peanut Using Reduced Rate or Combinations of Imazapic and Imazethapyr

Studies were conducted in different Texas peanut (Arachis hypogaea L.) production regions to evaluate POST applications of imazapic and imazethapyr at ½× (0.035 kg ai/ha) or 1× (0.07 kg ai/ha) of the manufacturers' suggested use rate and in combination with acifluorfen at 0.42 kg ai/ha, acifluorfen at 0.105 kg ai/ha plus bentazon at 0.05 kg ai/ha, or 2,4-DB at 0.28 kg ai/ha. Palmer amaranth (Amaranthus palmeri S. Wats) control was most consistent with imazapic or imazethapyr plus 2,4-DB. Imazapic in combination with 2,4-DB or acifluorfen plus bentazon controlled ivyleaf morningglory [Ipomoea hederacea (L.) Jacq] at least 75%. Smellmelon (Cucumis melo L. var. Dudaim Naud.) control was at least 95% with 1× imazapic. Imazapic at 1× in combination with acifluorfen controlled desert horse purslane (Trianthema portulacastrum L.) over 90%. No peanut stunting was noted at Yoakum with any treatment; however, at Lamesa, Lockett, and Quitaque peanut stunting was noted. Although 1× imazapic or imazethapyr provided slightly more consistent weed control than the ½× rate, peanut yield did not increase with higher rate. Therefore, growers may be able to reduce production costs with lower rates of imazapic or imazethapyr.

Comparing the Risks and Benefits of Early Applications of Chlorimuron for Weed Control in Peanut

Abstract Chlorimuron is applied from 60 days after peanut (Arachis hypogaea L.) emergence (DAE) until 45 days prior to harvest to control Florida beggarweed [Desmodium tortuosum (Sw.) DC]. Research trials were conducted in Georgia from 2006 to 2008 to determine whether the benefits of controlling smaller weeds earlier in the season compensate for the potential risk of significant peanut injury from chlorimuron. Chlorimuron at 9 g ai/ha was applied at 21, 35, 49, 63, 77, and 91 DAE. Additionally, flumioxazin (105 g ai/ha) preemergence was included as a treated control, along with a nontreated control. Main plots were split into subplots; weed-free and weeds present. Flumioxazin controlled Florida beggarweed 82%. Chlorimuron controlled Florida beggarweed 38 to 67%, with applications 21 and 35 DAE more efficacious than later applications. With weeds present, peanut treated with chlorimuron at any application timing yielded less than peanut treated with flumioxazin. Weed-free peanut treated with chlorimuron at any application timing yielded less than peanut treated with flumioxazin. These data indicate that chlorimuron applied earlier than 60 DAE provided better Florida beggarweed control with greater peanut yield than when applied at the recommended time intervals. However, Florida beggarweed control and peanut yield from any of the chlorimuron treatments were consistently less than flumioxazin.

Critical Period of Weed Interference in Peanut

Field studies were conducted near Lewiston–Woodville and Rocky Mount, NC to evaluate the effects of mixed weed species on peanut yield. A combination of broadleaf and grass weeds were allowed to interfere with peanut for various intervals to determine both the critical timing of weed removal and the critical weed-free period. These periods were then combined to determine the critical period of weed control in peanut. The effects of various weedy intervals on peanut yield were also investigated. The predicted critical period of weed control, in the presence of a mixed population of weeds, was found to be from 3 to 8 wk after planting (WAP). Peanut yield decreased as weed interference intervals increased, demonstrating the need for weed control throughout much of the growing season in the presence of mixed weed populations.Nomenclature: Peanut, Arachis hypogaea L

The Effect of Cultivar on Critical Periods of Weed Control in Peanuts

Abstract Field experiments were conducted at Morro Agudo county, SP, Brazil, to determine the critical period of weed control in peanut. A different cultivar was planted for each experiment (runner...

Influence of Preplant Applications of 2,4-D, Dicamba, Tribenuron, and Tribenuron Plus Thifensulfuron on Peanut

Abstract Field trials were conducted in Georgia, North Carolina, and Texas to evaluate the effects of preplant applications of 2,4-D, dicamba, tribenuron, and tribenuron plus thifensulfuron on peanut yield. Herbicides were applied 30, 15, 7, or 0 d before planting (DBP) in conventional production systems in Georgia and Texas, and 28, 21, 14, 7, and 0 DBP in no- and strip-tillage systems in North Carolina. Amine and ester formulations of 2,4-D did not affect peanut yield at any time of application in any state. Dicamba reduced peanut yield when applied at 0 DBP in two of seven trials. Tribenuron did not affect peanut yield regardless of preplant interval. However, tribenuron plus thifensulfuron reduced yields when applied at 7 DBP in one of five trials. These data suggest that 2,4-D, tribenuron, and tribenuron plus thifensulfuron can be safely used for preplant weed control in peanut when applied 7 DBP. Dicamba should be applied a minimum of 15 DBP.

Effect of Pyridate Formulation and Adjuvants on Broadleaf Weed Control in Peanut (Arachis hypogaea)1

Field studies were conducted near Archer, FL, and Vienna, GA, in 1995 and 1996 to investigate the effects of pyridate formulation and adjuvants on broadleaf weed control in peanut (Arachis hypogaea). Pyridate formulations SAN 319H 450EC 361LZ, SAN 319H 450EC 216LZ, and SAN 319H 600EC 418LZ were evaluated at two rates, 1.07 and 2.14 kg/ha. Pyridate at 1.07 kg/ha plus 2,4-DB at 0.23 kg/ha were evaluated alone and with five adjuvants. The adjuvants included a crop oil concentrate, a nonionic surfactant, a nonionic surfactant with organosilicone blend, urea ammonium nitrate plus a nonionic surfactant, and chlorothalonil (a fungicide) plus a nonionic surfactant. No pyridate treatment injured peanut. Pyridate formulation did not affect broadleaf weed control. Increasing pyridate rate increased weed control and yield. Mixing 2,4-DB with pyridate generally enhanced sicklepod (Senna obtusifolia) and common cocklebur (Xanthium strumarium) control. Florida beggarweed (Desmodium tortuosum), smallflower morningglory (Jacquemontia tamnifolia), hairy indigo (Indigofera hirsuta), sicklepod, and common cocklebur control with pyridate was not enhanced by adjuvants. Adding chlorothalonil to pyridate plus 2,4-DB did not affect weed control or peanut injury.Nomenclature: 2,4-DB; chlorothalonil; tetrachloroisophthalonitrile; pyridate; common cocklebur, Xanthium strumarium #3 XANST; Florida beggarweed, Desmodium tortuosum # DEDTO; hairy indigo, Indigofera hirsuta # INDHI; peanut, Arachis hypogaea ‘Sunrunner’ and ‘GK-7’; sicklepod, Senna obtusifolia # CASOB; smallflower morningglory, Jacquemontia tamnifolia # IAQTA.Additional index words: SAN 319H 450EC 361LZ, SAN 319H 450EC 216LZ, SAN 319H 600EC 418LZ, crop oil concentrate, nonionic surfactant, organosilicone-nonionic surfactant blend, urea ammonium nitrate.Abbreviations: COC, crop oil concentrate; NIS, nonionic surfactant; NIS/OS, nonionic surfactant with organosilicone; POST, postemergence; WAT, weeks after treatment.

Evaluation of Tillage Implements for Stale Seedbed Tillage in Peanut(Arachis hypogaea)1

Abstract: Studies were conducted from 1995 to 1997 near Tifton, GA, to evaluate shallow tillage implements and tillage frequency for stale seedbed weed control in peanut. Tillage implements evaluated were a power tiller, disk harrow, field conditioner, and sweep cultivator. Plots for each implement were tilled once or twice prior to planting peanut. Results from midseason weed counts and peanut yield showed similar responses among implements and frequency of tillage. These results indicate no advantage of any shallow tillage implement for stale seedbed weed control, although peanut yields were generally greater in plots with tilled stale seedbeds than in the nontilled control. The implement of choice should be based on cost of operation and compatibility with the overall peanut production system. Nomenclature: Peanut, Arachis hypogaea L., ‘Georgia Runner’. Key index words: Cultural weed control, groundnut. Abbreviations: DAE, days after emergence; POST, postemergence; PRE, preemergence.

Performance and Economic Benefit of Herbicides Used for Broadleaf Weed Control in Peanut

Abstract Field experiments were conducted over two growing seasons (1995 and 1996) and at two locations (Jay, FL, and Headland, AL) to identify the most effective herbicide program for Florida beggarweed [Desmodium tortuosum (SW) D.C.] control in peanut (Arachis hypogaea L.). The most common herbicides used for Florida beggarweed control—including preemergence (PRE), early-postemergence (EPOST), mid-postemergence (MPOST) and late-postemergence (LPOST) applied treatments—were evaluated in a factorial treatment arrangement. All treatments had merit and could be assembled into programs that resulted in maximum weed control, crop yield, and net returns. However, at least two of the four treatment timings were required to reach this level. Four systems were consistently associated with the maximum statistical grouping for both yield and net returns, as well as acceptable Florida beggarweed control (> 81%). These systems were (a) paraquat + bentazon applied EPOST, followed by pyridate + 2,4-DB MPOST; (b) same as (a) only preceded by norflurazon applied PRE; (c) imazapic applied EPOST followed by pyridate + 2,4-DB MPOST; and (d) norflurazon applied PRE, followed by imazapic EPOST.

Diclosulam for Weed Control in Texas Peanut1

Abstract Field experiments were conducted in 1995 through 1997 in south and west Texas to evaluate diclosulam [N-(2,6-dichlorophenyl)-5-ethoxy-7-fluoro(1,2,4)-triazolo(1,5c)-pyrimidine-2-sulfonamide] for weed control in peanut. Diclosulam applied preplant incorporated at 0.01 kg ai/ha in combination with ethalfluralin at 0.84 kg ai/ha controlled Texas panicum, Palmer amaranth, morningglory species, and golden crownbeard at least 95% and devil's-claw 91%. When diclosulam rates were increased to 0.02 kg/ha, yellow and purple nutsedge were controlled at least 89 and 72%, respectively. Diclosulam applied postemergence (POST) provided erratic yellow nutsedge control.

Influence of Herbicides and Timing of Application on Broadleaf Weed Control in Peanut (Arachis hypogaea)

Field studies were conducted from 1992 through 1994 to evaluate application timing of seven postemergence (POST) broadleaf herbicides alone and in mixtures for control of eclipta and pitted morningglory. Imazethapyr and 2,4-DB did not control eclipta while AC 263,222 applied early postemergence (EPOST) at 0.07 kg/ha provided greater than 90% control in 2 of 3 yr. EPOST applications of bentazon, acifluorfen + bentazon, and pyridate controlled eclipta at least 92% all 3 yr. Lactofen applied EPOST at 0.28 kg/ha provided similar levels of eclipta control in 2 of 3 yr. Imazethapyr controlled pitted morningglory > 70% when applied EPOST. AC 263,222 controlled pitted morningglory a minimum of 83% when applied EPOST at 0.04 or 0.07 kg/ha. Pitted morningglory control was at least 85% with 2,4-DB applied alone or in a mixture with AC 263,222, acifluorfen, imazethapyr, lactofen, or pyridate. Effective weed control increased peanut yields up to 98% over the untreated check.

Flumioxazin for Weed Control in Texas Peanuts (Arachis hypogaea L.)1

Abstract Field experiments were conducted in 1991 and 1993 to evaluate flumioxazin alone and in various herbicide programs for weed control in peanut. Flumioxazin alone provided inconsistent control of annual grasses, while the addition of pendimethalin or trifluralin improved control considerably. Pitted morningglory (Ipomoea lacunosa L.) and ivyleaf morningglory [Ipomoea hederacea (L.) Jacq.] control was > 75% when flumioxazin was used alone. Flumioxazin caused early season peanut stunting with some recovery within 4 to 6 wk. Postemergence applications of imazethapyr or lactofen increased peanut stunting.

Weed Management in Peanut Using Stale Seedbed Techniques

Field studies were conducted from 1991 through 1993 to determine the effects of stale seedbed management practices on weed control in peanut. Main plots were four levels of stale seedbed management: deep till (23 cm) and plant the same day (standard system), deep till 6 wk early and shallow till (7.6 cm) at 2 wk intervals prior to planting, deep till 6 wk early and application of glyphosate (1.1 kg ai ha−1) 1 wk prior to planting, and deep till 6 wk early without additional treatment prior to planting. Sub-plots were three levels of weed management following peanut planting; intensive, basic, and cultivation alone. Stale seedbed management practices stimulated weed emergence when followed by other control measures prior to planting. Populations of Florida beggarweed, Texas panicum, and yellow nutsedge were lower when stale seedbeds were shallow tilled at 2 wk intervals prior to planting, resulting in greater peanut yields. Weeds on nontreated stale seedbeds were difficult to control once peanut was planted and reduced yields. Stale seedbed management practices generally had no effect on the quantity of foreign material contaminants originating from weeds, soil, or peanut plant in harvested peanut. These results indicate that shallow tillage on stale seedbeds can reduce weed populations prior to planting and increase peanut yields.

Utility of Clomazone for Annual Grass and Broadleaf Weed Control in Peanut (Arachis hypogaea)

Field experiments conducted in 1988 and 1989 evaluated clomazone alone and in a systems approach for weed control in peanut. Clomazone PPI at 0.8 kg ai/ha controlled common ragweed, prickly sida, spurred anoda, and tropic croton better than ethalfluralin and/or metolachlor applied PPI. POST application of acifluorfen plus bentazon was not needed to control these weeds when clomazone was used. Acifluorfen plus bentazon improved control of these weeds when clomazone was not used and generally were necessary to obtain peanut yields regardless of the soil-applied herbicides. Alachlor PRE did not improve clomazone control of any weed species evaluated. Fall panicum and large crabgrass control was similar with clomazone or clomazone plus ethalfluralin.

Use of F6285 for Weed Control in Peanut: Efficacy and Crop Injury1,2

Abstract Field studies in 1991 and 1992 at Tifton and Attapulgus, GA evaluated the weed control efficacy and crop safety of F6285 on peanut. Treated peanut were stunted by F6285 and had chlorotic leaflet margins. The degree and persistence of injury varied according to rate of F6285. The lowest rate of F6285 (0.14 kg ai ha-1) produced the aforementioned symptoms early in the season, but peanut recovered by late season with no yield effects (P≤0.05). F6285 at 0.28 and 0.42 kg ha-1 severely injured peanut and reduced yields. Preemergence and vegetative emergence applications of F6285 were equally injurious. F6285 effectively controlled yellow nutsedge at rates as low as 0.14 kg ha-1, but sicklepod was not controlled at rates up to 0.42 kg ha-1. F6285 controlled yellow nutsedge more effectively that standard treatments of metolachlor or imazethapyr, but crop injury from F6285 was greater (P≤0.05) than from other herbicides.

DPX-PE350 for Weed Control in Peanut (Arachis hypogaea L.)

Abstract Field experiments were conducted in 1991 and 1992 in Georgia to determine the efficacy of DPX-PE350 when applied either preplant incorporated (PPI), preemergence (PRE), and early postemergence (EPOST) at rates of 40, 80, or 120 g ae ha-1 for weed control in peanut. Species evaluated included coffee senna [Cassia occidentalis (L.)], Florida beggarweed [Desmodium tortuosum (Sw.) DC.], prickly sida (Sida spinosa L.), smallflower morningglory [Jacquemontia tamnifolia (L.) Griseb.], sicklepod (Cassia obtusifolia L.), and yellow nutsedge (Cyperus esculentus L.). Sicklepod was controlled better with either PPI or PRE applications than with EPOST. Coffee senna control was more consistent with DPX-PE350 applied EPOST. DPX-PE350 controlled prickly sida and smallflower morningglory regardless of application method and rate. DPX-PE350 did not control Florida beggarweed when soil applied. PPI applications were more injurious to peanut than PRE or EPOST applications. Peanut yields tended to decrease as DPX-PE350 rates increased.

Weed Control, Yield, and Net Returns Using Imazethapyr in Peanuts (Arachis hypogaeaL.)

Field experiments were conducted in 1988 and 1989 to evaluate imazethapyr for weed control in peanuts. Imazethapyr was applied PRE or POST at 3, 5, or 7 weeks after crop emergence (WAE) at 0.071 kg ai ha–1. Imazethapyr applied PRE controlled common lambsquarters 85%, prickly sida 92%, and a mixture of entireleaf, ivyleaf, pitted, and tall morningglory species 77%. Morningglory control was at least 91% with imazethapyr plus metolachlor PRE followed by imazethapyr plus 2,4–DB or imazethapyr plus acifluorfen at 3, 5, or 7 WAE. Yields from systems that included metolachlor plus imazethapyr PRE followed by imazethapyr plus acifluorfen, imazethapyr plus 2,4–DB, or acifluorfen plus 2,4–DB at 3 WAE were greater than yields from the handweeded check. All systems with imazethapyr plus metolachlor PRE followed by any POST treatment except imazethapyr plus acifluorfen 7 WAE provided net returns equivalent to the herbicide standard of metolachlor PRE and acifluorfen and bentazon plus 2,4–DB 3 WAE. All systems except imazethapyr PRE provided greater net returns than the handweeded weed–free check.