Chitosans and grapevine trunk diseases: surprising results from laboratory and vineyard studies

The potential of chitosans to control grapevine trunk diseases (GTDs) has been studied in a public-private partnership. In vitro tests, vineyard efficacy trials and laboratory analyses were carried out to understand their mode of action. In vitro, low molecular weight (MW) chitosans, the most soluble, were often the most effective. In the vineyard, the most effective were those with a medium MW, in particular chitosan hydrochlorides which form a protective film. They could be used to dress wounds caused by pruning, re-trunking or curettage.