Cooperative Extension: Maine Wild Blueberries

5.19.14 Mummy Berry Blight May NOT be Finished Yet

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Lincoln, Knox, Waldo Counties

Only dried up cups were found last week in these areas. There is a chance later fields farther north around Belfast area may still have had infection periods this last weekend.  I expect fields farther south were not affected.

Hancock and Washington Counties

Cup that would produce spores were found on Saturday, May 17 in Whiting area and numerous spore-producing cups were found on Monday, May 19 at Pea Ridge near Cherryfield. At other sites, the cups had dried up or were drying up on Friday, May 16 in the mummy berry plots.   I have seen this in other years where the cups are done in mummy berry plots but some mature cups can still be found in the field with some searching.  I expect cups can still found around in the barrens during this last weekend and I expect through the next few days.

Infection periods occurred from Friday, May 16 through Monday, May 19 (please see chart below) and are expected later this week.

Infection Periods and Fungicide Applications

In those areas where there was an infection period starting Friday, May 16 or the morning of Saturday, May 17, if you have applied fungicide on or after Saturday, May 9 your plants were protected  and  you have until the evening of Tuesday, May 20, in most areas to apply fungicides to kill any infection.

If you would be applying a second application of propiconazole, it would be a good idea to switch to a different fungicide with a different mode of action to help prevent resistance to propiconazole developing in your field (Please see the 2014 Maine Wild Blueberry Pesticide Chart, Fungicides (PDF)). Other fungicides should be applied as protectants and before infection periods occur.