May. 19, 2015
The Johnsongrass (Sorghum halepense
) was first detected to present weed resistance to glyphosate
in Targal, in the Salta province, northwest of Argentina, in 2005. In early 2015, it was also detected by researchers the resistance to graminicides (selective post-emergence grass herbicides), specifically to haloxyfop-R-methyl. Now, multiple resistance is confirmed in Johnson grass to these two active ingredients in the same biotype, a study carried out by the specialist Diego Ustarroz of Argentina's National Institute of Agricultural Technology (INTA) bring the result.
Ustarroz worked with bio-types coming from three different locations. Three samples showed multiple resistance to glyphosate and graminicides PFO group, especially haloxyfop-R-methyl, which was used in the experiment. Clethodim was also tested, finding no resistance to this graminicide widely used for weed control.
"The multiple resistance to glyphosate and graminicides limits significantly the management alternatives of this weed. Fortunately, so far, none of these bio-types have shown resistance to the DMI group, which clethodim belongs to, but even though this is a good new, it is not possible to know what is going to happen," adverted agronomist Martín Marzetti, manager at the Knowledge Network of the No-Tillage Farmers Association of Argentina.