Temperatures dropped into the 30s F in many fields last night and below freezing in some, see table below.  These cold temperatures may damage flowers.  If you wish to see the temperatures for the weather station closest to your field, please go to the following website.  You can click on the graphs on the top to see air temperature (graphs for individual weather stations are not working) or you can download the data  for an individual weather station with the options on the top left of the page.

Weather Station data link

The last reports I had of new cups and pinheads was last Tuesday in Whiting/East Machias and most places reported no new pinheads or drying up cups later in the week through the barrens.  I think with the warm weather we have had after the weekend we are probably finished with mummy berry infection this year.

You will start to see disease symptoms of dead tissues with gray powdery spore masses on some of your leaves and flowers, but hopefully not much. Remember both flowers and leaves are killed with mummy berry.  The other major killer of flowers is Botrytis this time of year.  Botrytis is identifiable by its black “hairs” with gray spores at the tips of the hairs.

If you have any questions, please contact me. Seanna Annis  sannis@maine.edu or the blueberry hotline in Maine at 1-800-897-0757 Ext. 3. 

Washington County

Cups are probably dried up in most areas, except in later fields.  If you have a late field, your field may have experienced an infection period overnight. Please see table below.

Please let me know if you you still have cups. You can email me (Seanna Annis) at sannis@maine.edu or call me at the blueberry hotline 1-800-897-0757. 

If you applied fungicide about 7 days before the start of this infection period, your plants were protected during this infection period. 

If you have not applied fungicide and want to apply fungicide with some kickback activity, you have approximately 72 hours from the start of the infection period to do so.

Midcoast region, Knox, Waldo and York counties

None of the weather stations had temperatures below 32F last night.

Hancock and Washington Counties

Most weather stations did have temperatures below 32F last night.  Some fields  may have had flower damage from frost depending upon how open the flowers were and the cold hardiness of the clones. 

In late fields, there will also likely to be a  mummy berry infection period from Saturday to Sunday this weekend overnight. 

Botrytis

Time to start looking for Botrytis in your fields.  Botrytis kills almost open (pink stage)  and open flowers. There may be only a few flowers in a cluster or a few clusters of flowers on a stem that are infected.  The characteristic sign of the fungus is black hairs (often with gray spore masses at their tips) sticking out from the dead flowers. Please see pictures below.  You many need to use a magnifying glass to the see the hairs on the flowers.   Flowers will also die from mummy berry disease, but those dead flowers do not have any hairs and often die before they open.

Dead blueberry flowers killed by Botrytis showing characteristic black “hairs” with gray spores

Botrytis infection of flowers showing short “hairs”

Where Botrytis infection is found in a given year is highly variable and dependent upon local conditions in the field.  Botrytis can attack multiple plants and so levels of disease in a field depend on how much Botrytis is occurring on other plants in the field and surrounding it. In most fields,  the amount of disease varies every year.  Fields with very heavy damage in a crop field one crop cycle may have none or very little infection 2 years later. Whether this fungus is a problem can be detected by looking for Botrytis infection in early blooming clones from which the fungus can then be spread to other clones if there is enough wet weather.    I do not recommend protective fungicide sprays for Botrytis unless you are absolutely sure you have symptoms in your field and a lot of wet weather is forecast for your field during bloom.   Spraying fungicides during bloom should be avoided if at all possible.

Seanna Annis

Midcoast region, Knox, Waldo and York counties

All reports are the cups are dried up in this area. 

Hancock County

North Ellworth and Aurora did not have any cups.  There may still be cups in the  Franklin area.  If you have a late field, you may have experienced an infection period. 

Downeast

Cups are drying up in many mummy berry plots but active cups are still in some areas of the large barrens and are reported in Whiting/East Machias.  Infection periods  may have occurred in some areas overnight.  Hopefully the rain this weekend will be the last infection periods for most people. 

Please let me know if you you still have cups. You can email me (Seanna Annis) at sannis@maine.edu or call me at the blueberry hotline 1-800-897-0757. 

If you applied fungicide about 7 days before the start of this infection period, your plants were protected during this infection period. 

If you have not applied fungicide and want to apply fungicide with some kickback activity, you have approximately 72 hours from the start of the infection period to do so.

Midcoast region

Unless you have a really late field, the mummy berry cups are probably not active in your area.  If you have a late field, you may have experienced an infection period. 

Downeast

Infection periods  occurred in most areas from  Tuesday to Wednesday (today).  Reports are cups are drying up in many areas but I think they are still active in most fields.

Please let me know if you you still have cups. You can email me (Seanna Annis) at sannis@maine.edu or call me at the blueberry hotline 1-800-897-0757. 

If you applied fungicide about 7 days before the start of this infection period, your plants were protected during this infection period. 

If you have not applied fungicide and want to apply fungicide with some kickback activity, you have approximately 72 hours from the start of the infection period to do so.

Midcoast region

Cups are probably dying off.  If you have a late field, you may have experienced an infection period. 

Downeast

Infection periods  occurred in most areas last night and we are likely to have another today.

Please let me know if you you still have cups. You can email me (Seanna Annis) at sannis@maine.edu or call me at the blueberry hotline 1-800-897-0757. 

If you applied fungicide about 7 days before the start of this infection period, your plants were protected during this infection period. 

If you have not applied fungicide and want to apply fungicide with some kickback activity, you have approximately 72 hours from the start of the infection period to do so.

Midcoast region

On Friday we have reports that cups were dried up in Waldoboro, but still present in Hope and Appleton areas.  I suspect cups were active in areas over the weekend but are on their way out. There  were conditions in some fields for infection periods over the weekend.  Please see table below.

Downeast

We are still in the midst of mummy berry season and some fields had infection periods over the weekend. Please see table below.

Please let me know if you you still have cups. You can email me (Seanna Annis) at sannis@maine.edu or call me at the blueberry hotline 1-800-897-0757. 

If you applied fungicide about 7 days before one of these infection periods, your plants were protected during this infection period. 

If you have not applied fungicide and want to apply fungicide with some kickback activity, you have approximately 72 hours from the start of the infection period to do so.

Fungicides with some kickback activity include: Propimax, Bumper, Orbit, Tilt for example (containing propiconazole) or Indar (containing fenbuconazole).  Please see the 2018 Fungicide recommendations  and check with your buyer before applying any fungicides to your crop.

Midcoast region and Downeast

Many fields had infection periods overnight from Thursday, May 10th to Friday, May 11th.  In the midcoast, cups are still reported to be active in  Hope and Appleton and to have dried down in other areas.  I expect the cups to be finished by the end of the weekend.    Downeast we are still in the midst of mummy berry season with lots of active cups.  

Please let me know if you you still have cups. You can email me (Seanna Annis) at sannis@maine.edu or call me at the blueberry hotline 1-800-897-0757. 

If you applied fungicide after Thursday,  May 3rd (7 days), your plants were protected during this infection period. 

If you have not applied fungicide and want to apply fungicide with some kickback activity, you have approximately 72 hours from the start of the infection period to do so.  For this potential infection period on Thursday night, you would have until approximately  Sunday May 13th.   

Fungicides with some kickback activity include: Propimax, Bumper, Orbit, Tilt for example (containing propiconazole) or Indar (containing fenbuconazole).  Please see the 2018 Fungicide recommendations  and check with your buyer before applying any fungicides to your crop.