Time of Day Effects on Peanut Herbicide Efficacy

Abstract

Recent research on the effects of time of d (TOD) when glufosinate is applied to cotton ( Gossypium hirsutum L.) and several protoporphyrinogen-inhibiting herbicides in soybean ( Glycine max L.) has growers concerned about potential TOD effects on peanut weed control. Consequently, research was conducted in 2015, 2016, and 2017 to determine if TOD influences the performance of peanut herbicides acifluorfen, bentazon, imazapic, lactofen, paraquat, and 2,4-DB. Both non- (bare-ground) and in-crop (peanut) studies were conducted. For non-crop, paraquat plus bentazon plus acifluorfen plus S-metolachlor, imazapic plus S-metolachlor plus 2,4-DB, and lactofen plus S-metolachlor plus 2,4-DB were applied to Palmer amaranth and a non-uniform mixture of annual grasses including Urochloa texana (Buckley), Dactyloctenium aegyptium (L.), Eleusine indica (L.), Digitaria spp. at 7:00, 12:00, 17:00, and 22:00 hr. For in-crop studies, two peanut weed control programs were used and herbicide programs were applied at the same TOD. Herbicides were paraquat plus acifluorfen plus bentazon plus S-metolachlor (EPOST) followed by imazapic plus S-metolachlor plus 2,4-DB, or lactofen plus S-metolachlor plus 2,4-DB (POST). For the non-crop studies, a significant interaction between TOD and herbicide program was observed for the 7 d after treatment (DAT) rating of Palmer amaranth control. Control was reduced with imazapic applied at 22:00 hr. At 14 DAT, there was no TOD effect and control was reduced with all imazapic treatments due to ALS resistance. There was no interaction between TOD and herbicide program for annual grass control. Annual grass control was unacceptable (<50%) with lactofen. For in-crop studies, there was no interaction between TOD or herbicide program. Peanut injury was lower at 7:00 hr and 22:00 hr when compared to other timings. Lactofen was more injurious to peanut than imazapic. Palmer amaranth control was not influenced by timing or herbicide program. A reduction in sicklepod control was observed at the 22:00 hr timing and with lactofen. While TOD influenced peanut injury and weed control, peanut yield was not affected.

Influence of time of day on dicamba and glyphosate efficacy

“…The diurnal effects of herbicide efficacy in this study suggest that midday applications of these herbicides will result in the greatest efficacy. Other studies have noted a similar trend, where applications occurring during midday result in greater weed control (Budd et al 2017;Carter and Prostko 2019;Mohr et al 2007;Montgomery et al 2017;Stopps et al 2013). These studies included several herbicides across MoAs but tended to have increased efficacy when applied under the high-light conditions at midday.…”

“…Yield data showed no differences between application TODs (Table 5)--a trend observed in peanut (Arachis hypogaea L.), soybean, and corn (Carter and Prostko 2019;Mohr et al 2007;Stewart et al 2009;Stopps et al 2013). The explanation for this finding is likely that although weed control was reduced during night applications, this reduction was insufficient to affect yield.…”

“…Diurnal leaf movement has been shown to affect spray droplet interception in some species such as sicklepod, and consequently would reduce herbicide absorption and efficacy (Norsworthy et al 1999). Furthermore, the TOD effect has been seen across several cropping systems, multiple MoAs indicating that most applications occurring during high-light midday applications tended to result in greater herbicide efficacy (Budd et al 2017;Carter and Prostko 2019;Mohr et al 2007;Montgomery et al 2017;Stewart et al 2009;Stopps et al 2013). Previous studies have indicated that additions of glyphosate to dicamba applications can improve control of glyphosate-resistant waterhemp (Amaranthus rudis J.D.…”

The Application Time-of-Day Effect for Trifloxysulfuron Against Velvetleaf as Affected by Nozzle Type

“…Previous studies have shown that the application of herbicides at different times of day can influence their activity. This is referred to as the application time-ofday effect reported for: aciflurofen (Carter and Prostko, 2019;Lee and Oliver, 1982), atrazine (Stewart et al, 2009), bentazon (Carter and Prostko, 2019;Doran and Andersen, 1976;Stopps et al, 2013 ), bromoxynil (Stewart et al, 2009), carfentrazone (Wersal et al, 2010), chlorimuron (Miller et al, 2003;Stopps et al, 2013), dicamba (Johnston et al, 2018;Montgomery et al, 2017;Stewart et al, 2009), diflufenzopyr (Stewart et al, 2009), diquat (Wersal et al, 2010), fluazifop (Fausey and Renner, 2001;Friesen and Wall, 1991), flumiclorac, fluthiacet (Fausey and Renner, 2001), fomesafen (Cieslik et al, 2014;Miller et al, 2003;Stopps et al, 2013), glufosinate (Martinson et al, 2002;Miller et al, 2003;Montgomery et al, 2017;Sellers et al, 2003;Stewart et al, 2009), glyphosate (Belbin et al, 2019;Martinson et al, 2002;Miller et al, 2003;Mohr et al, 2007;Norsworthy et al, 1999;Sellers et al, 2003;Stewart et al, 2009;Stopps et al, 2013;Waltz et al, 2004;), imazapic…”