Cooperative Extension: Maine Wild Blueberries

5.12.14 Mummy Berry Infections on May 12 and 13

Print

Knox, Lincoln, and Waldo Counties

I think we are getting close to the end of the infection periods in these areas.  There are a few drying up cups being reported but no new ones coming along.  There were infection periods overnight from Monday, May 12 to Tuesday, May 13 at our Appleton weather station, staring at 6:20 p.m. on Monday, May 12 and in Belfast on Monday, May 12 at 9:00 p.m.   There were infection periods reported farther south at our weather stations in West Rockport and Dresden Mills.

In those areas where there was an infection period, if you have applied fungicide on or after Monday, May 5 your plants were protected during the infection period over Monday night.  If you have not applied fungicides, you have until the evening of Thursday, May 15, depending upon the rain in your area,  in most areas to apply fungicides (propiconazole or fenbuconazole) 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.

Hancock and Washington Counties

There are still cups producing spores in the barrens.  Three of our weather stations reported borderline infection periods, which means the length of leaf wetness reported at the station was half hour short of what is required for an infection period. Since the length of rain events vary by location, some areas may have experienced an infection period from Sunday night to Monday.  We did not see any infection periods detected at Sedgwick, North Ellsworth, or Eastbrook/Waltham stations.

In those areas where there was an infection period, if you have applied fungicide on or after Sunday, May 4 your plants were protected during the infection period over Monday night.  If you have not applied fungicides, you have until the evening of Wednesday, May 14, depending upon the rain in your area,  in most areas to apply fungicides (propiconazole or fenbuconazole) 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.

I apologize for getting this information out so late. If you have any questions, please contact Seanna Annis at sannis@maine.edu.