Central coast California weather conditions in late 2017 and into early 2018 have resulted in possible stressed strawberry plants in some areas. Overall low rain levels through February 2018 may have contributed to buildup of salts in the root profile, causing leaf burn and less than optimal growth of the transplants (Photos 1 and 2). These foliar symptoms can be mistaken for the leaf blotch disease caused by the Zythia fungus. Leaf blotch symptoms consist of gray brown diseased patches on the leaf; such patches can occur anywhere on the leaf (Photo 3). The diseased blotches will also contain small structures (Photo 4) produced by the fungus; each of these fruiting bodies releases thousands of spores (Photo 5). In contrast, salt damage on strawberry shows up as tan to brown tissue that is always on the leaf margin, and there are no fungal fruiting bodies in the burned tissue (Photos 1 and 2). Due to the sparse rainfall through February, leaf blotch has not been detected yet this season.
PHOTO 1.
Buildup of salts results in abiotic damage to strawberry.
PHOTO 2.
Salt damage always causes marginal burn of strawberry leaves.
PHOTO 3.
The leaf blotch fungus causes gray brown patches on leaves.
PHOTO 4.
Leaf blotch patches will contain small, dark fruiting bodies.
PHOTO 5.
On the leaf, the Zythia fruiting bodies release thousands of spores.