Time to start scouting for Valdensinia leaf spot!

Valdensinia Leaf Spot - the "new" leaf spot.

Leaves infected with this fungus last year, will have over wintered on the ground. With the wet weather, Maine had from Thursday, June 3rd through Monday, June 6th, spores will be produced on leaves that were infected with this fungus last year and survived over the winter.

Leaf spots caused by the Valdensinia fungus may start appearing in your field in the next few weeks. PLEASE Scout your field for any areas of leaf drop or leaf spot.

You will see large (1/8 to 1/2”), often circular, light brown spots with dark margins on leaves. There may only be one or a few spots on leaves, and the lower leaves will be affected first.

Young lower leaves will be infected first and drop off while still green and with only a few spots.

Disease causes leaf drop starting after first infections anytime from May on and continues through August.

If you suspect Valdensinia leaf spot is in your field:

- Avoid diseased area, do NOT enter the field when it is wet

- Remove dead leaves from footwear, vehicles, equipment before leaving field (fungus can spread by moving infected leaves)

- Please send a sample to confirm disease and get information on control by contacting Seanna Annis or Dave Yarborough (Blueberry hotline: 1-800-897-0757)

- S. Annis also needs disease samples for DNA fingerprinting to determine how the fungus is spreading among fields

More info is available at the Blueberry Extension website

http://wildblueberries.maine.edu

Septoria leaf spot is a common disease found through out Maine

– It can be mistaken for Valdensinia leaf spot, but it has smaller, more numerous spots.

You will start to see very small (pin prick) spots in mid June which will grow bigger over the season. There will be many smaller, not circular spots with dark red/brown centers

Heavy infections can cause leaf drop mid July and later with dry conditions.