A New Approach to Weed Management to Mitigate Herbicide Resistance in Argentina

Abstract

The evolution of herbicide-resistant weeds is a major concern in the corn- and soybean-producing Pampas region of Argentina, where growers predominantly plant glyphosate-resistant crop varieties and depend heavily on glyphosate for weed control. Currently, 16 weed species in Argentina are resistant to one or more of three different herbicide mechanisms of action, and resistant weed populations continue to increase, posing a serious threat to agricultural production. Implementation of integrated weed management to address herbicide resistance faces significant barriers in Argentina, especially current land ownership and rental patterns in the Pampas. More than 60% of Pampas cropland is rented to tenants for periods that rarely exceed 1 yr, resulting in crop rotation being largely abandoned, and crop export taxes and quotas have further discouraged wheat and corn production in favor of continuous soybean production. In this paper we discuss ways to facilitate new approaches to weed management in Argentina, including legal and economic reforms and the formation of a national committee of stakeholders from public and private agricultural sectors.

The challenge of herbicide resistance around the world: a current summary

“…This includes developing diversified weed control recommendations for each growing region, education programs targeting farm consultants and farmers to communicate best management practices, and commercial programs consistent with science‐based weed management recommendations. In some cases, changes in national export policies and land lease arrangements, as well as the expansion of public research will be necessary to support greater diversification of cropping and improved resistance management …”

“…In some cases, changes in national export policies and land lease arrangements, as well as the expansion of public research will be necessary to support greater diversification of cropping and improved resistance management. 112 For the future, a general analysis of forthcoming technologies in soybeans shows that they are efficient and offer alternatives for controlling broadleaves (2,4-D, dicamba, glufosinate), but not grasses. Because no new herbicide SOA is likely to be introduced soon, one can speculate that grasses resistant to glyphosate will continue to be a primary problem for South American farmers.…”

Historical trends of the ecotoxicological pesticide risk from the main grain crops in Rolling Pampa (Argentina)

“…Bt-corn) as early as 1996 [56]. However, around the same period, herbicide resistance has been extensively documented in this productive area [57,58], which led to an increase in the use of herbicides [59]. This process was also enhanced by the relative increase in rotation of winter fallows without crop coverage due to the noticeable reduction of sown area with wheat and barley [60].…”

An ecological perspective on managing weeds during the great selection for herbicide resistance

“…Applying a diversified, but spatiotemporally invariant, suite of weed management tactics is insufficient to prevent any one weed species complex from getting too comfortable. Implementation of such dynamic management systems, however, will require concomitant adaptations in policy and market environments that enable producers to diversify their practices accordingly …”

“…Implementation of such dynamic management systems, however, will require concomitant adaptations in policy and market environments that enable producers to diversify their practices accordingly. 39,40 Integrated management approaches are already emerging that are successfully reducing weed populations, even ones with challenging levels of herbicide resistance, while reducing reliance upon herbicides. Control of Avena fatua in western Canada canola production has become increasingly expensive due to widespread herbicide resistance in this species.…”