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

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.

Section: ------------------------------------------------------------supporting

confidence: 78%

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

Johnson¹,

Prostko²,

Davis³

2010

“…The non-AHAS imazapic-equivalent systems required two applications during the growing season, i.e., a PREapplied followed by the POST-applied treatment. This two-application requirement for adequate weed control has been demonstrated in previous research (Wehtje et al, 2000a).…”

Section: ----------------------------------------------------mentioning

confidence: 72%

Peanut Weed Control With and Without Acetolactate Synthase-inhibiting Herbicides1

Wehtje

Brecke

2004

Self Cite

Field studies were conducted in Florida and Alabama during 2001 and 2002 to compare weed control systems for peanut (Arachis hypogaea L.) that included only the herbicides registered on peanut that do not inhibit aceto hydroxyl acid synthase (AHAS). Three non-AHAS systems were identified that consistently preformed equivalent to imazapic, i.e., an AHAS-inhibiting herbicide that is very effective in peanut. These systems were either S-metolachlor plus flumioxazin, S-metolachlor plus S-dimethenamid, or S-metolachor plus norflurazon applied preemergence 'This research was supported by both the Alabama and Florida Agric. Exp. Sta.2Prof.(PRE), followed by paraquat plus bentazon plus 2,4-DB applied postemergence. Greenhouse studies established that tank mixtures of S-metolachlor plus flumioxazin and S-metolachor plus norflurazon applied PRE were synergistic with respect to yellow nuts edge (Cyperus esculentus L.) control. This synergism may contribute to the excellent performance of these Smetolachlor-containing tank mixtures in the field. Identification of systems which utilize herbicides with modes of action other than AHAS inhibition could offer rotational alternatives to delay the emergence of AHAS-resistant weed biotypes, or alternatives should such biotypes become problematic.

“…This can limit imazapic POST weed activity resulting in variable Florida beggarweed control which was observed in these and other trials . Paraquat plus bentazon plus 2,4-DB Florida beggarweed control was 55% or less across all experiments and has been previously noted (Wehtje et al, 2000a;2000b).…”

mentioning

confidence: 98%

“…Paraquat provides only early postemergence (EPOST) contact control (Grey et al, 2003), while chlorimuron provides contact and residual activity (Wehtje et al, 2000a). Peanut tolerance to paraquat was first noted in the late 1970s (Wehtje et al, 1986).…”

mentioning

confidence: 99%

“…Lack of early season Florida beggarweed control can lead to season-long interference that reduces yield (Grey and Bridges, 2005;Hauser et al, 1975;Cardina and Brecke, 1991;Wehtje et al, 2000a;2000b) and hinders crop harvest by interfering with digging and threshing Wehtje et al, 1999). Florida beggarweed consistently ranks as the most troublesome weed of peanut based on surveys for Alabama, Florida, and Georgia Elmore, 1989;Dowler, 1992Dowler, , 1998Prostko, 2001;Webster and MacDonald, 2001;Webster 2005).…”

mentioning

confidence: 99%

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Florida beggarweed (Desmodium tortuosum) management in peanut (Arachis hypogaea) with residual herbicides

Grey¹,

Prostko²,

Wehtje³

2009

Field experiments were conducted to evaluate the emergence and control of Florida beggarweed in peanut. Diclosulam preemergence (PRE), flumioxazin PRE, and imazapic postemergence (POST) were evaluated at three rates, along with paraquat plus bentazon plus 2,4-DB POST, and a nontreated control. These treatments were applied alone, or followed by chlorimuron applied late postemergence (LPOST). Variable Florida beggarweed control (16 to 90%) was observed when flumioxazin PRE, diclosulam PRE, paraquat plus bentazon plus 2,4-DB EPOST, or imazapic POST were applied alone. The pre-harvest population of Florida beggarweed was significantly reduced by the application of any residual herbicide (flumioxazin, diclosulam, or imazapic) alone at any rate either PRE or POST as compared to the nontreated control. Use of the contact treatment of paraquat plus bentazon plus 2,4-DB EPOST alone did not reduce Florida beggarweed populations as compared to the nontreated control. Adding chlorimuron LPOST to any treatment did not reduce Florida beggarweed populations, but provided suppression and reduced the biomass of existing plants. Consistent Florida beggarweed control (86 to 95%) was achieved with combinations of flumioxazin PRE at 105 g ha 21 , diclosulam PRE at 53 g ha 21 , and imazapic POST at 71 g ha 21 followed by chlorimuron LPOST at 9 g ha 21 . The benefit of chlorimuron LPOST was greatest when early season control was least.