Aminopyralid and Clopyralid Absorption and Translocation in Canada Thistle (Cirsium arvense)

Abstract

Aminopyralid is a new auxinic herbicide that provides Canada thistle control at lower use rates than clopyralid. Studies were conducted to determine if differences in absorption, translocation, or metabolism account for aminopyralid's greater biological activity. Radiolabeled aminopyralid and clopyralid were applied to individual leaves of rosette-stage Canada thistle plants. Nonionic surfactant was used for the absorption studies because it provided higher aminopyralid absorption than methylated seed oil or crop oil concentrate. Clopyralid was absorbed very rapidly, reaching 72% 24 h after treatment (HAT) and remaining near or above 80% during a 192-h time course. During the same time period, aminopyralid absorption increased from 34 to 60%. Clopyralid translocation out of the treated leaf was significantly higher than aminopyralid, 39% compared with 17%, respectively, 192 HAT. More of applied clopyralid translocated to aboveground tissue 192 HAT (27%) than to roots (12%), whereas aminopyralid translocation was similar in aboveground tissue (10%) and roots (7%) 192 HAT. Neither aminopyralid nor clopyralid was metabolized 192 HAT. Although aminopyralid is effective at lower use rates than clopyralid, clopyralid absorption and translocation were higher in Canada thistle. These results suggest that aminopyralid's chemical structure may provide for greater biological activity at the target site than clopyralid.

Dynamics of clopyralid herbicide during composting in small composting experiment units

“…18) The behavior of clopyralid in Canada thistle (Cirsium arvense) has been extensively investigated, and the uptake, absorption, translocation, accumulation, and foliar activity of clopyralid have been elucidated. [19][20][21] Not only broadleaf weeds but also broadleaf crops are affected at clopyralid concentrations of <10 ppb in soils and composts. 1,2) Therefore, the persistence of clopyralid in the environment can be problematic.…”

Absorption and Translocation of Aminocyclopyrachlor and Aminocyclopyrachlor-Methyl Ester in Canada Thistle (Cirsium arvense)

“…These herbicides are not labeled for use near water, or they have groundwater advisories that limit use in riparian environments (Bukun et al 2009). That situation recently changed with the introduction of a new herbicide, aminopyralid.…”

“…Understanding the behavior of these new molecules will provide valuable information about the advantages and disadvantages of each formulation and may help to explain differences in biological activity observed in the field (P. Westra, personal communication). Canada thistle was selected as the test species to make relative comparisons with previously published research evaluating clopyralid and aminopyralid absorption and translocation in the same species (Bukun et al 2009). …”

Levantamento de ocorrência, alternativas de manejo, mecanismos de resistência e herança genética do capim-amargoso (<i>Digitaria insularis</i>) resistente ao herbicida glyphosate

“…(2011) por Kniss, et.al. (2011) O uso de funções do tipo regressão assimptótica para descrição da absorção de herbicidas nas plantas é de comum prática para melhor visualização do comportamento do herbicida aplicado ao longo do tempo (BUKUN et al, 2009;DODDS et al, 2007;GRANGEOT;CHAUVEL;GAUVRIT, 2006 Tabela 4.7 -Parâmetros estimados pelo software R, utilizando o modelo proposto por Kniss, et.al. (2011) Tabela 4.8 -Parâmetros estimados pelo software R, utilizando o modelo proposto por Kniss, et.al.…”