Blue mould, Peronospora tabacina, is one of the most dangerous diseases for tobacco crops in Europe and particularly in France. Protection against this disease is systematic during the period of high risk as all registered crop protection agents are rather preventive.

Currently, the control of blue mould revolves around six active ingredients: Mancozeb + Dimethomorph, Acibenzolar-S-Methyl + Metalaxyl-M, Cyazofamid and Orange peel oil. The latter is the only active ingredient allowed in organic farming and is also a compound of biocontrol products. Almost all the conventional active substances are facing hurdles in the European procedure for the renewal of their reapproval due to their unfavourable toxicological and/or ecotoxicological profile, hence a need to look for new products to manage this disease.

In France, between 2009 and 2019, experiments against blue mould have been set up each year with several organic or biocontrol products in order to screen the most effective which are selected to go through the approval stage.

In 2009 and 2010, the products tested alone presented low efficacies. From 2011 onwards, an increase in efficacy was noticed as the rates of the treatments were increased and also because product associations were investigated. From 2016 onwards, trials have consistently shown good efficacy with biocontrol and organic products.

Today, despite a higher cost than current conventional registered solutions, it can be confirmed that new effective organic and biocontrol solutions exist to control blue mould and that these products have their place in an Integrated Pest Management.