Effect of Herbicides on Weed Control and Sugarbeet (Beta vulgaris) Yield and Quality

Abstract

The “micro-rate” application, a POST combination of desmedipham plus phenmedipham at 0.045 + 0.045 kg ai/ha (desphen) or desmedipham plus phenmedipham plus ethofumesate (1:1: 1 ratio) (desphenetho) at 0.09 kg ai/ha plus triflusulfuron at 0.004 kg ai/ha plus clopyralid at 0.026 kg ae/ha plus 1.5% methylated seed oil received registration in 1998 and 2000 in North Dakota and Michigan, respectively. Herbicide rates are reduced by 80%, compared to standard-split applications, and growers typically apply the micro-rate three to five times to very small weeds that are 1 cm or less in height. In standard-split applications, growers make two sequential applications, the first when weeds are 1.5 cm tall and the sequential application usually 10 to 14 d later. Research was conducted in small plots and large grower plots in 2001 and 2002 to determine the effect of PRE herbicides on weed control and sugarbeet injury from micro-rates compared to standard-split POST herbicide applications. Sugarbeet populations were reduced in the cycloate treatment compared to all other PRE and the no-PRE treatment in 2001 and in the S-metolachlor compared to the ethofumesate treatment in 2002. Sugarbeet injury was 6% or less from POST-only treatments in 2001. Control of common lambsquarters and Amaranthus spp. by desphen and desphenetho treatments was similar. Sugarbeet injury in 2002 was 29 to 43% from POST-only treatments. The standard-split of desphenetho was more injurious than the standard-split of desphen. Common lambsquarters control was greater in both the standard-split and micro-rate of desphenetho compared to the standard-split of desphen in 2002. However, sugarbeet populations and recoverable white sucrose per hectare did not differ among POST herbicide treatments in either year. No herbicide program provided 100% control of all weeds in both years. In the seven large production fields, PRE herbicide treatments did not reduce sugarbeet populations or recoverable sucrose per hectare compared to the no-PRE control. Weed control from four POST micro-rate applications only was similar to weed control in instances in which PRE herbicides were applied prior to the POST micro-rate applications.

Control of annual broadleaf weeds by combinations of herbicides in sugar beet

“…Herbicides for control of dicots can only be used until the crop starts to develop true leaves and their efficacy decreases as the weeds grow (Strandberg et al, 2005). Often sugar beets are treated with post-emergence herbicides two or more times (Dale et al, 2006;Deveikyte, Seibutis, 2008 a;Smatana et al, 2008;Panjehkeh, Alamshahi, 2011). Herbicides are applied at the cotyledon growth stage at 5 to 14 day intervals (Konstantinović, Meseldžija, 2006;Odero et al, 2008;Kucharski, 2009;Domaradzki, 2011).…”

Weed Management in Glyphosate- and Glufosinate-Resistant Sugar Beet

“…The soil-applied herbicides included in this study have activity on Amaranthus species and common lambsquarters when enough soil moisture is present to make the herbicides available for uptake from the soil-water solution (Dale et al 2006). As a result, when rainfall occurred soon after application, the soil-applied herbicides were activated, weed emergence and growth were slowed, and the first POST herbicide applications in the soil-applied fb POST treatments were delayed by 3 to 7 d compared with the time of the first POST applications in the no-soil-applied herbicide treatments.…”

“…In the 1980s, growers continued to apply more POST herbicides, and in 1998 a new POST herbicide program called the microrate program was introduced in North Dakota and Minnesota (Dexter and Luecke 1998). Weed control with no PRE herbicide fb four POST microrate applications was similar to weed control with PRE herbicides fb the microrate program; however, crop injury from and the timing of multiple POST herbicide applications continued to be of concern (Dale et al 2006).…”

Selectivity of foramsulfuron + thiencarbazone‐methyl and classic herbicides in sensitive and non‐sensitive sugar beet genotypes

“…() for double the F + T dosage expected to be approved. In contrast, dosage‐dependent phytotoxicity of the classic herbicides was found in both genotypes, as has been demonstrated in several previous experiments (Bethlenfalvay & Norris, , ; Dale et al ., ; Hamouzová et al ., ). In these studies, higher phytotoxicity was associated with unfavourable weather conditions, such as low temperatures before applications, high radiation and high temperatures during applications, and moisture stress after applications, or overall cool and wet conditions during the application period.…”

“…If selectivity is too low, herbicide applications cause phytotoxicity to the crop. Particularly at early growth stages, sugar beet is susceptible to high dosages of herbicides (Dale et al ., ; Hamouzová et al ., ), and thus, herbicide applications require precise timing. Phytotoxicity can range from slight reversible symptoms, such as bleaching, to plant death all often linked to yield losses (Pfleiderer et al ., ).…”