Palmer amaranth (Amaranthus palmeri) interference and seed production in dry edible bean

Abstract

Although Palmer amaranth is currently not widespread in most dry edible bean−producing states in the United States, it is widespread in Western Nebraska, a major dry edible bean−producing region. There is currently a lack of research on management and biology of Palmer amaranth within dry edible bean production. The objective of this study was to quantify the impact of season−long Palmer amaranth interference on yield of dry edible bean and seed production of Palmer amaranth. A field study was conducted in Scottsbluff, NE in 2020 and 2021. Palmer amaranth interference at densities of 0, 0.2, 0.3, 0.5, 1, and 2 plants m−1 row of dry edible bean was evaluated. Palmer amaranth interference reduced dry edible bean yield by 77% at 2 Palmer amaranth plants m−1 row compared to the weed−free control; and a 5% yield−reduction threshold was estimated to occur at 0.02 Palmer amaranth plants m−1 row. Yield reduction occurred primarily through a reduction in the number of pods plant−1 as Palmer amaranth density increased. Palmer amaranth plants produced 91,000 to 376,000 seeds plant−1 depending on densities, and as much as 140,000 seeds m−2. Study results will help farmers and other stakeholders estimate Palmer amaranth interference within their fields, and may help justify the economic cost of incorporating additional Palmer amaranth management practices.

Comparison of residual activity of pre‐emergence herbicides for control and seed production of multiple herbicide‐resistant Palmer amaranth in food‐grade white corn

“…Miranda et al. (2022) concluded that the highest seed production of 376,000 seeds per plant was produced when 0.2 Palmer amaranth plants m −1 row of dry bean, and that this number decreased by 12%, 28%, 55%, and 75% when Palmer amaranth density increased to 0.3, 0.5, 1, and 2 plants m −1 row, respectively.…”

Effect of herbicide programs on control and seed production of multiple herbicide–resistant Palmer amaranth (Amaranthus palmeri) in corn resistant to 2,4-D/glufosinate/glyphosate

“…The highest Palmer amaranth seed production (1,077,650 seed m −2 ) resulted from glufosinate applied alone compared with the nontreated control (939,690 seed m −2 ) (Table 5). Miranda et al (2021) reported that Palmer amaranth seed production per plant decreased as Palmer amaranth density increased, and concluded that the highest seed production (376,000 seed plant −1 ) occurred at the lowest density of 0.2 plants m –1 row, and that it declined by 12%, 28%, 55%, and 75% when density increased to 0.3, 0.5, 1, and 2 plants m –1 row, respectively. Palmer amaranth density in this study was 43 to 149 plants m –2 in the nontreated control compared with 0 to 15, 6 to 30, and 0 to 8 plants m –2 in preemergence-only, early postemergence–only, and preemergence fb late postemergence herbicide programs, respectively (Table 4).…”

Control of acetolactate synthase-inhibiting herbicide-resistant Palmer amaranth (Amaranthus palmeri) with sequential applications of dimethenamid-Pin dry edible bean

“…Even when there were few yield differences among treatments containing an herbicide (Table 6), differences in Palmer amaranth biomass can relate to seed production. Previous studies reported a strong positive correlation between Palmer amaranth biomass and seed production, suggesting that as biomass increases, so does seed production (Mahoney et al 2021;Miranda et al 2022;Schwartz et al 2016;Spaunhorst et al 2018;Webster and Grey 2015). Liu et al (2021b) and Norsworthy et al (2016) concluded that lateemerging Palmer amaranth plants have negligible effects on crop yields; however, if those plants are left uncontrolled, even if they are small, they can set seeds into the soil and carry to future issues.…”

“…Palmer amaranth interference reduced corn, soybean, and peanut (Arachis hypogaea L.) yield by 91% at 8 plants m −1 row crop (Massinga et al 2001), 68% at 10 plants m −1 row crop (Klingaman and Oliver 1994), and 67% at 5.2 plants m −1 row crop (Burke et al 2007), respectively. Its interference in dry edible bean reduced yield by 77% at 2 plants m −1 row crop and a 5% yield reduction has been estimated to occur at only 4 plants 100 m −2 (Miranda et al 2022).…”