Mummy berry infection period in Midcoast region April 25 to 26

April 27th, 2017 11:45 AM

Knox, Lincoln and Hancock counties

All grower reports early this week were that there were mummy berry cups in fields in these regions and the plants were far enough along or close to it for infection. The steady wet weather produced an infection event recorded at all of our weather stations in those regions (Waldoboro, West Rockport, Appleton and Searsport). The infection period started on Tuesday April 25 around 7 to 10pm and continued through to this morning, Thursday April 27th. I expect we will have another infection event with the wet weather predicted to start on Monday.

Hancock and Washington counties

I have reports of mummy berry pinheads and cups from Ellsworth, Eastbrook and through out the barrens as of early this week.  The consensus among most growers were the plants were not yet ready in most fields (not at 40% F2 flower buds). These are the percentage of flower cluster buds at F2 in the fields we have visited on April 25th; Sedgewick 27% , Aurora 22%, Eastbrook 25 to 36%, Deblois area very few F2, BBHF in Jonesboro 17% ).    If you have an early field you may have had an infection period over the last two days.   I expect we will have the first infection period in many fields with the wet weather predicted to start on Monday. 

Using Fungicide controls

If you have applied fungicides within the last  7 to 10 days (April 18 on) before Tuesday April 25th  your plants were protected during the infection period over April 25th to April 27th.  If you have not applied fungicides, you have until the evening of Friday April 28th, to apply fungicides (propiconazole or fenbuconazole) to kill any infection.  Please see the 2017 Fungicide recommendations  and the 2017 Fungicide chart . Other fungicides should be applied as protectants and before infection periods occur. 



Possible Mummy berry infection event in Midcoast

April 24th, 2017 10:04 AM

Waldo, Knox and Lincoln counties

As mentioned on Friday, some fields had suitable levels of F2 flower buds to see mummy berry infection over this weekend, but there were no cups reported in most fields. Only one field reported one cup.

If you have a very early field in the midcoast region and had more than 40% of your flower buds open you might have had an infection event this weekend.  I think it was early for most fields. With the wet weather we had this past weekend, and now warming temperatures, I expect we will have an infection period with the next rain storm predicted for later Tuesday through Wednesday of this week. 

If you have a mummy berry plot, please tell what it is doing and what stage your plants are now so I can give an accurate report for your area. Thank you, Seanna Annis

  Possible mummy berry infection periods  
Locations Friday April 21 start Saturday April 22 start Sunday April 23 start Mummy berry plot
Waldoboro none none 11am  ?
West Rockport 5:40pm 11am 8:20pm pinheads, one cup
Appleton 6:40pm none 11am pinheads

8:20pm on Friday through Sunday?  missing weather station reports

 no plot



Mummy berry season is starting for some fields

April 21st, 2017 2:28 PM

I have reports of mummy berry plots showing  pinheads in multiple fields in the Midcoast region (Liberty, Appleton, West Rockport), and in Ellsworth, Hancock and Jonesboro, Washington counties.  Pinheads are the stage before the cups appear.  We have one report of a single cup in West Rockport.  In fields we checked yesterday, plants in West Rockport  (Knox ) and Searsport (Waldo) had close to 40% of their flower buds at the F2 stage (crown stage).  

I think we are at the very beginning of the mummy berry season in the Midcoast counties.  You should count your flower buds to see what stage the plants in your field are.   Different parts of the field, depending upon the blueberry clones, landscape around the plants, and what direction the field is facing can have very different levels of development.    To get a good sample, collect 10 (or for a better estimate, 20) stems across your field from different clones.  You can make a quick guess of their development from looking at the top flower buds. The best method is to rate all of the flower buds and calculate the percentage of total flower buds that are at F2. Flower buds start to become susceptible at the F2 stage. 

The weather is supposed to be wet, but cold, tonight through to Saturday or Sunday in most blueberry areas.  The cold weather means a longer period of  leaf wetness would be required to cause an infection.    I think there is a low risk of infection in most areas.

If you have a mummy berry plot or check on your plants, please send me an email  ( or give me a call (207-581-2621) and let me know what stage your field is.  This information helps me determine when I should be considering an infection event may be happening in your area.

Seanna Annis

Blueberry stems showing flower buds at F1 stage, swollen but bud scales are still separating

Blueberry stems showing flower buds at F1 stage, swollen but bud scales are still separating

Blueberry stems showing flower buds at F2 (top) and F1 (bottom).

Blueberry stems showing flower buds at F2 (top) and F1 (bottom).

Blueberry flower buds showing F3 on top and F2 at lower buds, leaf buds at V2

Blueberry flower buds showing F3 on top and F2 at lower buds, leaf buds at V2


Mummy berry 2017 season is fast approaching

April 14th, 2017 6:07 PM

With the warm weather these last few days, mummy berry season will be starting soon.  Flower and leaf buds have started to swell in fields in the midcoast and downeast regions.   In the midcoast region,  we have seen a few clones with opened flower or leaf bud scales. 

We have our weather stations up in Waldoboro, Appleton and West Rockport and will be putting out more weather stations next week.  If you have a mummy berry plot, I would like to hear from you to see if anything is happening.  We have had no reports of mummy berry cups in any fields as of today.

Please take a look at your fields and see how your plants are developing.   To get a good idea of how your field is developing, take a random sample of 1 stem from 10 different clones across the field and see how far along the flower buds are.  The buds seen below are not yet susceptible to mummy berry.

Seanna Annis 

Blueberry swollen flower buds - notice bud scales are separating but no green tissue is exposed

Blueberry swollen flower buds
– notice bud scales are separating but no green tissue is exposed

Blueberry flower buds scales opening - notice green tissue exposed with opening bud scales

Blueberry flower buds scales opening
– notice green tissue exposed with opening bud scales

Climate Change and Blueberry Production

November 1st, 2016 11:42 AM

By Dr. Frank Drummond1,2, Seanna Annis1,2 and Hongchun Qu3
Climate Change and Blueberry Production (PDF)

Wild blueberry is well adapted to Maine’s climate (Drummond et al. 2009). However, commercial production of wild blueberry is restricted to the northern part of it current natural distribution (Maine, New Hampshire, Canadian maritime provinces, Michigan, and Quebec; Drummond et al. 2009), despite the fact that the major species comprising wild blueberry, Vaccinium angustifolium, can be found in the forest understory from North Carolina to northern Quebec and west to Minnesota and Manitoba (Vander Kloet 1988). However, changes in climate are already occurring in Maine. As climate continues to shift, more changes in the ecological interactions of this managed natural occurring food plant are bound to take place. We have developed a computer simulation model to investigate climate shifts in Maine wild blueberry.      

Climate Change and Blueberries Fig1

Figure 1. Aerial view of a wild blueberry field, red is blueberry (A), simulated blueberry field through spring (B [prebloom] – H [fruit stage]); patches represent individual plants (clones), green represents stems in bud stage, yellow: stems in flower, orange: stems with both flowers pollinated flowers, and red: stems with fruit.

Our computer simulation model has been developed and parameterized by data collected in the laboratory and in the field in Maine wild blueberry fields.  This model currently uses hourly weather conditions to simulate blueberry plant growth and development and the activity and foraging behavior of four different bee pollinator taxa (honey bees, bumble bees, digger bees, and leafcutting bees). The model also will incorporate the growth and development of mummy berry disease and its vectoring to flowers by bees. As bees visit flowers throughout the bloom season fruit set likelihoods are generated, mummy berry transmission will be estimated and yield (number of fruit and size) is calculated for each stem in the field. This model incorporates state of the art algorithms that allow simulation of a blueberry field across several scales of time (hrs, days, months) and scales of space (stems (sq. cm), clones (sq. m), and fields (sq. km).

We are currently validating the model for pollination based upon independent data collected between 2010-2016 . We are also conducting sensitivity analysis (ca. 2 million simulation runs) to identify parameters that affect fruit set and yield disproportionately. We will be adding validation of the mummy berry portion of the model with data gathered over the next few years. We have not yet added spotted wing drosophila to the model, but this should not be difficult since the foundation of the blueberry plant model has been completed. 

Our hypotheses that we plan to initially test regarding climate change are:

  1. occurrence of wetter springs during bloom will result in:
    1. lower fruit set and the need for greater densities of honey bees due to less flight activity
    2. greater incidence of mummy berry disease AND a need to spray fungicide at more         frequent intervals
  2. occurrence of warmer springs during bloom will result in:
    1. higher activity of honey bees and digger bees and less activity of bumble bees during bloom AND shorter bloom periods…thus we predict similar or higher levels of fruit set in fields that import honey bees, but less fruit set in fields that are entirely pollinated by native bees, especially bumble bees.
  3. occurrence of hotter summers and milder winters will result in:
    1. earlier and higher rates of increase and damage rates in fruit due to the spotted wing drosophila.

Literature Cited

Drummond, F, J. Smagula, S. Annis and D. Yarborough. 2009. Organic Wild Blueberry Production. University of Maine Agricul. and Forestry Exper. Stn. Tech. Bull. 852: 43 pp.

Vander Kloet, S. P. 1988. The genus Vaccinium in North America. Publication 1828. Ottawa: Research Branch, Agriculture Canada. 201 p.

Authors affiliations

1 School of Biology and Ecology, University of Maine, Orono
2 Cooperative Extension, University of Maine, Orono
3 Division of Theoretical Research for Complex Systems, Key Laboratory of Industrial IOT and Networked Control (Chongqing University of Posts and Telecommunications), Ministry of Education, Chongqing 400065, China

Now is the time to put out Mummy Berry plots for 2017!

July 26th, 2016 3:58 PM

Now is the time to collect mummy berries to put out your own plot.  It is easy to set out plots and it will provide you valuable information in the spring on when the fungus is active in your field.  You will need to look at the plot in the spring about 2 times a week.

1. Collect about 60 to 150 mummy berries (20 to 50 for each mummy berry plot) from your crop field(s) near  harvest (or from the process line or winnow piles if you have them). The mummy berries will be whitish grey and smaller than the berries.   If you see a few mummies still on a plant, there are probably more underneath that plant.   Often clones produce different amount of mummy berries, so if there are no mummy berries in one spot, try another area in your field. Often there are more mummy berries at the edges of fields. As soon as possible after you have collected the mummy berries, put them out in the field you will be monitoring. Do not store them in the fridge or in a hot place before you put them out.  If you have to store them, the best way is in a paper bag in the shade or cool spot and to put them out as soon as you can. 
mummy berry
2.Find 3 good locations.    In next year’s crop field, choose 3 areas within your blueberry field. I suggest 3 areas because some years  one of our plots has not worked in a field.  Each area should be about 3” by 3” that is clear of stems but amongst the plants. Choose areas that look like they have damp soil most of the time AND will be easy for you to access next spring. These areas do not need to be widely spread around the field, 5 to 10 ft between each one will be fine. If you have different exposures, soil types or large shaded areas in your field you may want to place your mummy berry plots around your field to get the full range of when the mummy berries develop. The areas should not be on slopes where the mummy berries will be washed away, in hollows where they will be water-logged or in areas with lots of frost-heaves.
3. Place the mummies in the plots.  In each 3″ by 3″ area, clear off the leaf litter to one side and scrape off about 1/4” of hard packed soil and put aside. Place about 20 to 50 mummy berries on the surface of the soil and press the mummy berries firmly into the soil (with your fingers or step on them).  The mummy berries need to be buried in soil but not more than 1/4” deep at most.  Cover the mummy berries with a small amount of dirt (1/4”) on top and press them firmly down again. You should just have the mummy berries covered with soil. Replace the leaf litter over the mummy berries again.

50 mummy berries before being covered by soil; 3 inches

4. VERY IMPORTANT: Stake or flag the plots on either side so you can locate them in the spring.  Two stakes or flags makes it much easier to figure out where to look in the spring.

We are looking for growers who are willing to check their mummy berry plots twice a week and report to me on the development of the mummy berry cups. We want to place our weather stations in fields with monitored mummy berry plots next year. Please let me know if you would be willing to put out a mummy berry plot and have a weather station in your field.

If you want to put out a plot and want some help setting it up, we can give you a hand.  Please contact Seanna Annis at 207-581-2621 or via email at,   if you need any help or have any questions. 


Botrytis risk May 23 to May 25

May 25th, 2016 12:35 PM

With the last bit of wet weather we have had from none to moderate risk of Botrytis infection, if it is already in your field.  You need to have the fungus present in your field in a number of clones before we get the wet weather conditions to get any spread of Botrytis.   We have found  the risk of Botrytis infection does NOT translate into actual Botrytis infection unless the fungus has already been found in the field.  

Please scout your fields for this disease before applying any fungicides to control it.    If you see symptoms of the disease (dead flowers WITH black “hairs” coming off of them) during mid bloom AND there is a chance of a lot of wet weather coming up, then a fungicide application may be needed.  Otherwise I do not recommend applying fungicide for this disease.  We have seen variable levels of Botrytis each year with no consistent pattern of it showing up in any field we have monitored.  If you do have a field that consistently does have Botrytis, I would be very interested in visiting it and using it for a fungicide trial if you are agreeable to that.

Seanna Annis

Questions marks in the chart below are due to estimates due to gaps with the weather stations.


Estimated risk of Botrytis infection from May 23 to May 25

Waldoboro  none
West Rockport 16%
Hope (Appleton) 7%
Searsport  none


North Ellsworth 16%
Eastbrook/Franklin  3%
Aurora 5.8%
Deblois 15%?
Columbia 30%
Montegail  none

East Machias

30% and 30% on May 23 to 24
Wesley 8%?
Love Lake 15%?

Wild Blueberry Spring Injury in 2016

May 24th, 2016 11:26 AM

There has been widespread reports on a new type of injury seen in wild blueberry fields this spring.  The plants have stopped developing, or have not developed at all in some fields, especially in the low areas of many fields.  Cold air flows like water and will accumulate in the low spots in your field.  We believe the injury was caused by the very warm weather we had in early April followed by 11 to 18 degree F temperatures recorded on April 28-30.  Normally wild blueberry would not be injured by these temperatures before bloom but with the early warm temperatures the plants lost their winter hardiness and water began to move back into the tissues.  The cold temperatures then froze the water and disrupted the tissues.  If you cut the flower buds on your plants you can see brown tissues that would have been the flowers.  This type of injury is usually seen with very cold winter temperature, but also can occur in the spring as it did this year.  Injury was also seen on peaches in New Jersey and apples in Maine as well.

Injured Plants

Injured plants in low area in back and non injured in bloom front.

Injured vs Non-Injured Plants

Injured vs non injured plants at bloom from low vs high area of same field.

Cold Injury

Cold injury to flowers in cut open bud. 

Mummy berry season is probably over, time to look for Botrytis

May 19th, 2016 9:09 PM

Mummy berry

I have only had reports of dried up pinheads and cups in the midcoast, and Hancock and Washington counties this week.   I think the cups are done in most locations.   Mummy berry season is probably over in most areas.


I have not heard any reports of Botrytis blossom blight this year so far.   Where Botrytis infection is found in a given year is highly variable and dependent upon local inoculum in the field.  In most fields, this 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 infection of early blooming clones from which the fungus can then be spread with wet weather to other clones.    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.

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

Botrytis blossom blight symptoms on flowers. Notice hairs sticking out of flowers.

Mummy berry infection from May 14 to May 15

May 16th, 2016 9:49 AM

There was an infection period in some fields from Saturday May 14th to Sunday May 15th.  Only our weather stations in Sedgewick (Sunday 1am start), Columbia (Sunday 12:20am start)  and East Machias (Sunday 2am start) detected long enough leaf wetness to cause an infection period.   All other field sites were too short a period to cause mummy berry infection.

We should be coming close to the end of mummy berry season.  Please let me know how you mummy berry plots are doing.

Thank you,

Seanna Annis