Control of Photosystem II– and 4-Hydroxyphenylpyruvate Dioxygenase Inhibitor–Resistant Palmer Amaranth (Amaranthus palmeri) in Conventional Corn

Abstract

Palmer amaranth, a dioecious summer annual weed species, is the most troublesome weed in agronomic crop production systems in the United States. Palmer amaranth resistant to photosystem (PS) II- and 4-hydroxyphenylpyruvate dioxygenase (HPPD) inhibitors is of particular concern in south central Nebraska. The objectives of this study were to determine the effect of PRE followed by POST herbicide programs on PS II- and HPPD-inhibitor-resistant Palmer amaranth control, crop yield, and net economic return in conventional corn. A field study was conducted in 2014, 2015, and 2016 in a grower’s field infested with PS II- and HPPD-inhibitor-resistant Palmer amaranth near Shickley in Fillmore County, Nebraska. A contrast analysis suggested that mesotrione+S-metolachlor+atrazine applied PRE provided 83% Palmer amaranth control at 21 d after application compared to 78 and 72% control with pyroxasulfone+fluthiacet-ethyl+atrazine and saflufenacil+dimethenamid-P, respectively. Most of the PRE followed by POST herbicide programs provided ≥85% Palmer amaranth control. Based on contrast analysis, POST application of dicamba+diflufenzopyr provided 93% Palmer amaranth control compared to 87, 79, and 42% control with dicamba, dicamba+halosulfuron, and acetochlor, respectively, at 28 d after POST. All PRE followed by POST herbicide programs, aside from mesotrione+S-metolachlor+atrazine followed by acetochlor (2,530 to 7,809 kg ha−1), provided 9,550 to 10,500 kg ha−1corn yield compared with 2,713 to 6,110 kg ha−1from nontreated control. Similarly, PRE followed by POST herbicide programs, except for mesotrione+S-metolachlor+atrazine followed by acetochlor ($191 and $897 ha−1), provided similar net return of $427 to $707 ha−1and $1,127 to $1,727 ha−1in 2014 and 2015-16, respectively. It is concluded that herbicide programs based on multiple sites of action are available for control of PS II- and HPPD-inhibitor-resistant Palmer amaranth in conventional corn.

Weed control and response of yellow and white popcorn hybrids to herbicides

“…Similar Palmer amaranth control (95-100%) with acetochlor/atrazine has been reported in the literature (Janak & Grichar, 2016). Chahal et al (2018) reported 90% Palmer amaranth control and 82% biomass reduction 28 DA POST from saflufenacil/dimethamid-P fb diflufenzopyr/dicamba. Hauver, Chahal, Watteyne, and Jhala (2017) reported 93% control of Palmer amaranth with clopyralid/acetochlor/mesotrione.…”

“…Chahal et al. () reported 90% Palmer amaranth control and 82% biomass reduction 28 DA POST from saflufenacil/dimethamid‐P fb diflufenzopyr/dicamba. Hauver, Chahal, Watteyne, and Jhala () reported 93% control of Palmer amaranth with clopyralid/acetochlor/mesotrione.…”

Basis of Atrazine and Mesotrione Synergism for Controlling Atrazine‐ and HPPD Inhibitor‐Resistant Palmer Amaranth

“…Even though Palmer amaranth from Nebraska is resistant to atrazine and HPPD‐inhibiting herbicides applied alone, these herbicides can be tank mixed with different site of action herbicides for effective Palmer amaranth control (Chahal et al, 2018). However, it is important to adopt an integrated Palmer amaranth management approach that includes the use of a PRE herbicides followed by a POST herbicide program, rotation of herbicides with distinct sites of action, crop rotation, rotation of herbicide‐resistant cultivars, tillage, and harvest weed seed control methods to mitigate the evolution and spread of multiple herbicide‐resistant weeds including Palmer amaranth (Chahal et al, 2018; Ganie et al, 2017a).…”

Ciclo de vida y curvas en s aplicadas al cultivo de amaranto (Amaranthus spp.)

“…Esto, concuerda con investigaciones desarrolladas por centros de investigación argentinos, que evalúan la capacidad de resistencia a condiciones adversas de clima y suelo sobre las potencialidades alimentarias del amaranto y la resistencia a los efectos del cambio climático en condiciones de difícil adaptabilidad [41], [42].…”