Beginner

Scientific Name
Passalora fulva

 

Identification

• Rarely seen in field tomatoes, but fairly common when the crop is grown under tunnels
• Pale green to yellowish spots develop on the upper leaf surface, starting with older leaves
• An olive-green to gray mold develops on the underside of the leaves, eventually covering most of the leaf
• Leaves wither, curl, and eventually drop
• The pathogen also infects stems, blossoms, fruit

Often Confused With
Powdery mildew

Period of Activity
The disease can be active between 4°C and 32°C, but prefers temperatures of 22-24°C. The disease requires leaf wetness and relative humidity over 85%.

Scouting Notes
Older leaves are affected first. Early symptoms are on the upper leaf surface.

Thresholds
None established.

Advanced

Scientific Name
Passalora fulva

Identification
Leaf mold is rarely seen in field tomatoes, but is fairly common when the crop is grown under tunnels.  Pale green to yellowish spots develop on the upper leaf surface, starting with older leaves. An olive-green to gray mold develops on the underside of the leaves. These symptoms eventually cover most of the leaf.  Leaves wither, curl, and eventually drop. The pathogen also infects stems, blossoms, and fruit.

Often Confused With
Powdery mildew

Biology
The fungal structures of this pathogen survive for at least a year without a living host. The fungus also survives on crop residue and in infected seed.

Period of Activity
The disease can be active between 4°C and 32°C, but prefers temperatures of 22-24°C. The disease requires leaf wetness and relative humidity over 85%.

Scouting Notes
Older leaves are affected first. Early symptoms are on the upper leaf surface.

Thresholds
None established.

Management Notes
High humidity and long periods of leaf wetness promote disease development under a wide range of temperatures. Maintain good air circulation in tunnels. Remove and destroy crop residue after harvest.