Soybean Tolerance to Early Preplant Applications of 2,4-D Ester, 2,4-D Amine, and Dicamba

Abstract

Preplant applications of two 2,4-D formulations and dicamba were evaluated for injury to no-till soybean. Herbicides applied 28 or 21 d before planting (DBP) at 0.56 kg ae/ha for the 2,4-D formulations and 0.28 kg ae/ha for dicamba did not injure soybean. At 14 DBP soybean injury was lower (< 6%) with applications of 2,4-D than with dicamba (13% to 17%). Injury increased when herbicides were applied at 7 DBP with soybean injury from both 2,4-D (< 11%) and dicamba (< 38%). When the herbicides were applied at planting soybean injury was < 18% with the 2,4-D formulations and < 73% with dicamba. Soybean yields were unaffected by the injury from herbicides applied 21, 14, and 7 DBP. However, soybean yield was decreased to 870 kg/ha in 2005 when dicamba was applied at planting compared to the nontreated check (1,950 kg/ha)

Control of Glyphosate-Resistant Giant Ragweed (<i>Ambrosia trifida</i> L.) with 2,4-D Followed by Pre-Emergence or Post-Emergence Herbicides in Glyphosate-Resistant Soybean (<i>Glycine max</i> L.)

“…Plant-back restriction for soybean is 15 days for 2,4-D; therefore, it is important to apply 2,4-D as burndown at least 15 days before planting soybean to avoid injury. In an earlier study, soybean was injured 11% when 2,4-D was applied 7 days before planting [24]. Soybean cultivars with traits conferring resistance to pre-plant or POST applications of 2,4-D or dicamba are being developed and may be commercialized in the near future [30] [31].…”

“…Saflufenacil has also been premixed with imazethapyr for use in corn, soybean, and field pea (Pisum sativum L.) [23]. Because of the activity on broadleaf weeds, low cost, and a few number of weeds having evolved resistance, 2,4-D is an option for soybean growers as burndown treatment [24]. Therefore, burndown application of 2,4-D and saflufenacil plus imazethapyr should be evaluated for control of glyphosate-resistant giant ragweed.…”

Halauxifen-Methyl+Diclosulam: New Option to Control Conyza spp. Prior Soybean Sowing

“…However, in E1 (Assis Chateaubriand -PR) only treatments, the hand-weeded treatment and glyphosate + (halauxifen-methyl + diclosulam), in both doses, are statistically greater than the untreated check (Table 7), possibly because of lower plant density of Conyza spp. According to Braz et al (2017) the application of halauxifen-methyl + diclosulam does not interfere in soybean yield even when it is applied three days before sowing, thus showing the selectivity of this auxinic herbicide in soybean, similarly to the herbicide 2,4-D (ester and amine) and dicamba (Thompson et al, 2007). Thus, this herbicide becomes a great alternative for control of Conyza spp., and when it is applied 15 days before sowing, it does not interfere in soybean yield.…”

Herbicide Programs for Managing Troublesome Weeds Using New Soybean Technologies

“…This strategy prevents early-season competition between the weeds and the crop, thereby maximizing yield potential in a cropping situation. (Thompson et al, 2007;Anonymous, 2010). At the high rate, both 2,4-D (0.95 lb acid-equivalent acre -1 ) and dicamba (1.0 lb acid-equivalent acre -1 ) controlled I. lacunosa and S. spinosa ³79% 4 WAP.…”