According to industry groups in Argentina, glyphosate is failing to control Johnsongrass in the northern region of the country.
Johnsongrass is a perennial grass native of Southern Eurasia. It reproduces from seeds and from thick scaly underground rhizomes and may reach a height of 1.5 meter tall. It was brought into Argentina as a forage and due to its excellent adaptation to the environment, it was transformed into a weed nationwide.
Private follow-up of the case began in 2004 after a grower from the Province of Salta submitted an inquiry to Monsanto on failure to control Johnsongrass using glyphosate. Monsanto has been investigating the case since that time. The studied area has nearly 63 km. from north to south and nearly 35 km. from east to west, taking Campichuelo as the south end and Tartagal as the north end. A preliminary assessment of the affected area determines a range from 7,000 to 10,000 hectares.
Trials were conducted, both field and greenhouse trials, confirming failure to control Johnsongrass using glyphosate at the label rate.