Guide For Tomatoes

T O M AT O E S
Disease Cycle
The fungus overwinters as sclerotia in soil and
on infected plant debris. The sclerotia give rise to
spore-producing bodies called apothecia in early spring.
Apothecia produce ascospores that serve as primary
inoculum for disease development. Ascospores are
disseminated via wind. The fungus can also enter
mature plants at the soil line. Mycelial growth spreads
between lush, overlapping plants, killing large circular
areas of infected plants within the field. Infected fruit
appears gray and rapidly breaks down in a watery rot.
The disease is generally monocyclic. However, disease
spread from plant to plant may occur via contact of
healthy plants with diseased plants or with the
fungus mycelium.
Conditions for Development
Cool, moist conditions with high humidity and free
moisture favor disease development. Long periods
of continuous wetness are necessary for ascospore
and plant tissue infection and lesion expansion.
Poor air circulation and moisture retention promote
disease development. White mold is more prevalent
in low-lying areas, in fields adjacent to heavily
wooded lots and in crops with lush vegetation.
W H I T E M O L D
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