Digitaria insularis: cross-resistance between ACCase inhibitors and multiple resistance to glyphosate

Abstract

Sourgrass (Digitaria insularis [L.] Mez ex Ekman) is a problematic weed with special attention to its damage and herbicide resistance in Brazil and Paraguay. Considering the complexity of management and failure in control approaches, the goal of the present study was to monitor and investigate herbicide resistance in D. insularis. Furthermore, we specifically analyze a case with multiple resistance in Paraguay. In this sense, studies were carried out for the development of dose-response curves. The results showed resistance of D. insularis to ACCase- and EPSPs-inhibiting herbicides in Paraguay, in which the resistance to ACCase inhibitors involves the chemical groups aryloxyphenoxypropionates and cyclohexanediones. This is probably the first case of resistance observed in the world. It is necessary to apply good practices in the set of integrated weed management. These practices should be accessed as quickly and effectively as possible, serving as a lesson for more proactive and less reactive actions in production systems.