Benoit Marçais did a PhD (1992) on epidemiology of Phytophthora cinnamomi, a fungus causing oak canker.
He is now Research director on the epidemiology of fungal diseases affecting trees in forests and natural ecosystems.
Benoit studied the role of fungal pathogens on oak dieback (1996-2005). Then, he focused on determining the causes of forest disease emergence in relation with global change, in particular recent evolution in climate and invasion. He mainly works on the following pathosystems: Phytophthora alni, Chalara fraxinea, oak powdery mildew, Dothistroma needle blight and Diplodia shoot blight of pines.
He works in the research unit « Interactions arbres-microorganismes », a joint unit between INRA, Centre Grand-Est Nancy and University of Lorraine in France.
Notably, he contributed to Annals of Forest Science as an author with one article (Desprez-Loustau et al., 2006) being in the top 10 of the most highly cited articles of the journal and two other articles (Desprez-Loustau et al.,2016 and Marçais et al., 2012) in the top 10 of the most requested full-text articles in 2016.