Ashlina Chin & Sally A. Miller
Leaf mold is caused by Passalora fulva. Because this pathogen is favored by high relative humidity and free moisture, it is a common problem in greenhouse and high tunnel tomatoes and uncommon in field tomatoes. Passalora fulva appears on the undersides of the foliage as an olive-green to brownish grey velvety growth, but can also cause pale green and chlorotic lesions visible on upper leaf surfaces. Eventually, the leaves drop and the plant dies. Fungicides can be used to help manage leaf mold on tomatoes, but using leaf mold resistant varieties, and increasing air circulation through pruning, increased row spacing, and/or opening vents is highly recommended. Sanitizing tools also aids in preventing the spread of disease caused by P. fulva.
Available Fact Sheets (pdf)
English: Leaf Mold
Passalora fulva, formerly Cladosporium fulvum and Fulvia fulva
High Tunnel Host Crops