Valdensinia leaf spot
Now is the time to look for Valdensinia leaf spot in your fields. The wet weather conditions we have had over the last month will have caused many cycles of spore production and infection if you have this fungus in your field. I have seen a new field with Valdensinia leaf spot in Ellsworth. Areas we have often found it are along the edges of roads, in wet areas in the field and areas that are shaded by trees along the field edges.
Do NOT scout your field when the plants or ground is wet. This may move infected leaves around your field.
Symptoms are large brown leaf spots that are rounded with dark margins compared to the inside of the lesion. On the underside of the lesion, you will see a dark spot with a hand lens, or sometimes the naked eye, which is the spore still attached to the leaf. Lower leaves, particularly in prune fields, will be falling off by now. Upper leaves, particularly in crop fields, may have many spots and may still be attached.
If you think you have Valdensinia leaf spot, please contact Seanna Annis at sannis@maine.edu or the blueberry hotline 800.897.0757 (in Maine only).