Resistence of Euphorbia Heterophylla L. to ALS-inhibiting herbicides in soybean

Authors

  • Gerson Augusto Gelmini USP; ESALQ; Depto. de Produção Vegetal
  • Ricardo Victória Filho USP; ESALQ; Depto. de Produção Vegetal
  • Maria do Carmo de Salvo Soares Novo IAC; Centro de Ecofisiologia e Biofísica
  • Márcio Luiz Adoryan USP; ESALQ; Depto. de Produção Vegetal

DOI:

https://doi.org/10.1590/S0103-90162005000500007

Keywords:

milkweed, cross-resistance, imidazolinone, sulfonylurea

Abstract

Herbicides are widely used in soybean for weed control, and the selection pressure attributed to the repeated use of herbicides with similar modes of action on the same site has caused selection for resistant biotypes within and among previously susceptible species, such as Euphorbia heterophylla L., in relation to ALS enzyme inhibitors, in the states of Paraná, Rio Grande do Sul, and São Paulo, Brazil. Seeds of E. heterophylla were collected to examine possible new cases of resistant populations and to test alternative herbicide treatments to manage these populations, in the Caarapó region, State of Mato Grosso do Sul, Brazil, in areas where plants of this species have survived continuous herbicide applications. The experiment was carried out under greenhouse conditions, where biotypes with a history of suspected resistance were compared with a known susceptible biotype. Several post-emergence herbicides were sprayed at zero, one, two, four, and eight times the recommended field application rates. Twenty days after application, plants were harvested, and control percentage and fresh weight were determined to establish dose-response curves, in the aim to obtain the resistance factor using CD50 and RD50 data. The chlorimuron-ethyl resistance factor values for the control percentage and fresh weight parameters were higher than 16.5 and 16.9, respectively, while imazethapyr showed resistance factors higher than 25.0 and 23.5, respectively. The resistant biotype showed different resistance levels to chlorimuron-ethyl and imazethapyr, showing cross-resistance to the sulfonylurea and imidazolinone groups. Nevertheless, this biotype was effectively controlled by fomesafen (250 g ha-1), lactofen (120 g ha-1), flumiclorac-pentyl (40 g ha-1), glufosinate-ammonium (150 g ha-1), and glyphosate (360 g ha-1).

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Published

2005-10-01

Issue

Section

Crop Science

How to Cite

Resistence of Euphorbia Heterophylla L. to ALS-inhibiting herbicides in soybean . (2005). Scientia Agricola, 62(5), 452-457. https://doi.org/10.1590/S0103-90162005000500007