Glyphosate-resistant weeds of South American cropping systems: An overview.

- VILA-AIUB, M.M., VIDAL, R.; BALBI, M.C.; GUNDEL, P.E., TRUCCO, F. & C.M. GHERSA.

PEST MANAGEMENT SCIENCE

Willey InterScience

Año: 2007

1526-498X

Herbicide resistance in weeds is an evolutionary event which results of two combining factors: intense selection pressure and genetically diverse weed populations. In South America, orchard (Argentina, Brazil, Chile) and cereal-legume (Argentina, Brazil) production systems show a strong reliance on glyphosate use as a pre-plant and pre-emergence herbicide to control weed populations. This trend has been magnified in the last years given the massive adoption of no-till glyphosate-resistant soybean crops in Argentina mainly and Brazil, which allows the use of glyphosate as an in-crop herbicide. This agricultural technology facilitates the conditions to make these cropping systems ecologically vulnerable for evolution of glyphosate-resistant weeds. The first glyphosate-resistance cases include highly genetically diverse annual weeds (Lolium multiflorum, Coniza bonariensis, C. canadensis) after recurrent strong glyphosate selections in Chilean and Brazilian fruit productions. Recently, the appearance of glyphosate-resistant Sorghum halepense and Euphorbia heterophylla in Argentinean and Brazilian glyphosate-resistant soybean fields, respectively, are of major concern. The present review summarizes the current knowledge on the physiology, ecology and agronomy of all the mentioned glyphosate-resistant weeds.