Jan Carel Zadoks (born 6 February 1929) is a Dutch botanist and a professor emeritus of ecological plant pathology at Wageningen University & Research.

cum laude[1] from the same university in 1961 for his thesis Yellow rust on wheat, studies in epidemiology and physiologic specialization.

Zadoks developed what is arguably the world's first course on plant disease epidemiology with a wet lab and field practical.

He performed consultancy and evaluation missions for the United Nations Food and Agriculture Organization (FAO), CGIAR (Consultative Group for International Agriculture) and for Dutch, French and Swiss governmental institutions with a focus on crop loss, resistance, integrated pest management (IPM) and education.

One of Zadoks' conclusions is that the portrayal of Sinterklaas' blackface companion, Zwarte Piet, has undergone significant metamorphoses from 1960-2010.