Leaf mold (formerly Fulvia fulva) has been confirmed in field-grown tomatoes in Cape May County.
Leaf mold occasionally appears in high tunnel or greenhouse tomato production in New Jersey. However, under ideal conditions the disease will develop in field-grown crops. The fungus will cause infection under prolonged periods leaf wetness and when relative humidity remains above 85%. If relative humidity is below 85% the disease will not occur. The pathogen can survive (overwinter) as a saprophyte on crop debris or as sclerotia in the soil. Conidia (spores) of the fungus can also survive up to one year in the soil.Leaves of infected plants will develop pale-green or yellow spots that are distinct. A dense, olive-green to brown spore mass will develop on the undersides of infected leaves.
Management of leaf mold begins with recognizing early symptoms, applying preventative fungicides, and removing all infected plant material from the field, greenhouse, or high tunnel, and crop rotation. Protectant fungicides such as chlorothalonil used in weekly protectant spray programs will help control leaf mold. For organic growers, regular copper applications may help to suppress the disease.
Cultivars with resistance to leaf mold have been developed. A nice write up with more information on leaf mold and cultivars with resistance by Dr. Beth Gugino, vegetable pathologist at Penn State, can be found at Leaf Mold on Tomato: Host Resistance is a Management Option.