Gestione di popolazioni di Echinochloa crus-galli resistenti agli inibitori dell ALS in mais.

Several populations of Echinochloa crus-galli resistant to acetolactate synthase inhibitors have been identified in maize crop in Italy. Greenhouse experiments have demonstrated that these populations are resistant to all herbicides having this mode of action while they are susceptible to fluazifop-P-butyl, mesotrione + terbuthylazine and S-metolachlor. Field experiments have highlighted that these ALS-resistant populations can be easily controlled and managed with pre emergence treatments in non organic soils. On the other hand, the management is more difficult in organic soils where two applications of herbicide mixtures with three different active ingredients are required to control E. crus-galli. This situation can have an impact in the sustainability of maize cropping systems in the medium or long-term period. Therefore it is fundamental to mix and rotate both chemical products and agronomic practices to reduce this risk. This is the most efficient approach to limit the occurrence of herbicide-resistant populations and reduce their densities and spreading in the agroecosystem.