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 sannis@maine.edu,   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.

Location

Estimated risk of Botrytis infection from May 23 to May 25

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

 14%

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.

Botrytis

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

 

Mummy berry infection period May 13 to May 14

May 14th, 2016 11:47 AM

Waldo, Lincoln, Knox counties

I am not sure if you are done yet or not.  We saw numerous spore producing mummy berry cups at the field in Hope (Appleton) on Wednesday May 11th.  I have no reports of cups from Liberty or other areas.  If you have a wet or slower field you may still have cups around for this infection period.

Hancock and Washington counties

I have reports of pinheads, immature and mature cups from across these areas on Monday May 9 and Tuesday May 10th and reports of new pinheads in East Machias area on Saturday May 14th.   I think there are still active cups in these areas.  With the warm weather the cups may be finishing up and hopefully will finish up next week.

Please report to me what your mummy berry plot is doing early next week.  I am hoping most things will be drying up.  Thank you, Seanna Annis  Contact info: sannis@maine.edu or the Blueberry Hotline 800-897-0757 (in Maine).

Infection period and Fungicide recommendations

We did have weather to cause an infection period in all monitored fields except Waldoboro area.    I suspect we may get another with the wet weather predicted for Sunday.

If you have applied fungicides within 7 to 10 days before an infection period, your plants are protected.  Some fungicides, such as propiconazole and fenbuconazole, have kickback activity which can kill off the fungus within about 72 hours after it gets in.  Most fungicides recommended for mummy berry have protectant properties and will protect your plants at least 7 days after application and depending upon the weather up to 10 to 14 days (check the label).

If you have applied fungicides after May 4th to May 7th (10 to 7 days before these current infection periods), your plants were probably protected.  If you have not applied fungicides and wish to, you have up to 72 hours after the infection period start to apply fungicides with kick back activity (fenbuconazole or propiconazole) to protect your plants.   If you are applying a second (or third) application of fungicide, it would be good to rotate to a fungicide with a different mode of action or at least a different chemical to avoid fungicide resistance developing in your field. 

 

Location

Infection period Fri. May 13 to Sat. May 14

Start of infection period on Friday

Waldoboro  none
West Rockport 3:20pm if cups present in your area
Hope (Appleton) 3:40pm
Searsport  6:2opm
Sedgewick  7:20pm
North Ellsworth 6pm
Eastbrook/Franklin  6:20pm
Aurora 7:20pm
Deblois  6:40pm
Columbia  8:40pm
Montegail  9:40pm
Jonesboro 8:15pm

East Machias

 8:40pm
Wesley  8:20pm
Love Lake 8:20pm

Mummy berry infection periods from Friday May 6 to Monday May 9

May 9th, 2016 10:10 AM

I had new reports on Friday of pinheads in some fields and dried up cups in other fields near by.  I suspect we are getting near the end, but I think we still have cups in most fields.  With this rainy weather we had over the weekend, many of our fields had 1 to 3 infection periods. All fields had an infection period from Saturday through Sunday (May 7 to 8).  Some fields had infection periods over Friday  night into Saturday (May 6 to 7)  and some along the coast from Sunday night into Monday (May 8 to 9).    Please see the table below for infection events in your area.  Some of our weather stations did not send the weather (due probably weather interference with the cellular signal) for a few time periods so some of the times are estimated from surrounding areas.

If you have applied fungicides within 7 to 10 days before an infection period, your plants are protected.  Some fungicides, such as propiconazole and fenbuconazole, have kickback activity which can kill off the fungus within about 72 hours after it gets in.  Most fungicides recommended for mummy berry have protectant properties and will protect your plants at least 7 days after application and depending upon the weather up to 10 days. 

If you have applied fungicides after April 26th to April 29th (10 to 7 days before these current infection periods), your plants were probably protected.  If you have not applied fungicides and wish to, you have up to 72 hours after the infection period start to apply fungicides with kick back activity (fenbuconazole or propiconazole) to protect your plants.   If you are applying a second (or third) application of fungicide, it would be good to rotate to a fungicide with a different mode of action or at least a different chemical to avoid fungicide resistance developing in your field. 

Please check your mummy berry plots at the beginning of this week and let me know what is happening since we are coming close to the end of the season.

Thank you, Seanna Annis  Contact info: sannis@maine.edu or the Blueberry Hotline 800-897-0757 (in Maine)

Location

Infection period Fri. May 6 to Sat. May 7

Start of infection period

Infection period Sat. May 7 to Sun. May 8

Start of infection period

 

Infection period Sun. May 8 to Mon. May 9

Start of infection period

 

Waldoboro  none none/borderline  no
West Rockport  none 5:40pm  no
Hope (Appleton)

 borderline

9:40pm

6pm  no
Searsport  none 7:20pm  no
Sedgewick  10pm 5:40pm  Sun. 3pm
North Ellsworth  ?borderline 7:20pm  rain continued from Sat.
Eastbrook/Franklin  11:20pm borderline 6pm  no
Aurora  8pm ~8:40pm  no
Deblois  none 6pm  no
Columbia  none 5:40pm  no
Montegail  none 6pm  no
Jonesboro  none Yes wet since Monday.  no

East Machias

 9pm

7pm

 Sun. noon
Wesley  none 6pm  no
Love Lake  none Wed. 9pm  no

Another mummy berry infection event night of May 5 to May 6

May 6th, 2016 1:39 PM

We had another mummy berry infection period in most areas where we have weather stations.  All locations EXCEPT Waldoboro and Searsport, had an infection period that started around Thursday May 5th and extended to Friday May 6th.  The infection period started on Thursday, May 5th between 5pm and 7pm in all locations. With this cool weather I expect the cups are hanging on through the weekend at least. 

If you have applied fungicides after April 26th to April 29th (10 to 7 days before this infection period), your plants were probably protected through this Thursday to Friday infection period.  If you have not applied fungicides, you have up to 72 hours after the infection period start, which is the evening of Sunday May 8th, to apply fungicides with kick back activity (fenbuconazole or propiconazole) to protect your plants.   If you are applying a second (or third) application of fungicide, it would be good to rotate to a fungicide with a different mode of action or at least a different chemical to avoid fungicide resistance developing in your field. 

Please let me know what your mummy berry plot is doing since we are coming close to the end of the season.

Thank you, Seanna Annis  Contact info: sannis@maine.edu or the Blueberry Hotline 800-897-0757 (in Maine)

Mummy berry infection period May 4th to May 5th

May 5th, 2016 2:27 PM

I have reports of cups still present in Appleton and Liberty and all through Downeast.  I suspect there are still mummy berry cups through out the area. I suspect the cups will last through to next week with the cool wet weather were are forecast to have this weekend.   We had another infection event in most monitored fields last night through today. Some of our weather stations did not send the weather (due probably weather interference with the cellular signal) for an hour or so near the end of the leaf wetness period.  These sites were very close to being long enough for an infection period.  I have marked these stations with a probably.

If you have applied fungicides after April 25th to April 28th (10 to 7 days before this infection period), your plants were probably protected through last night’s infection period.  If you have not applied fungicides, you have up to 72 hours after the infection period start, which is the evening of Saturday May 7th, to apply fungicides with kick back activity (fenbuconazole or propiconazole) to protect your plants.   If you are applying a second (or third) application of fungicide, it would be good to rotate to a fungicide with a different mode of action or at least a different chemical to avoid fungicide resistance developing in your field. 

Please let me know what your mummy berry plot is doing since we are coming close to the end of the season.

Thank you, Seanna Annis  Contact info: sannis@maine.edu or the Blueberry Hotline 800-897-0757 (in Maine)

Location

Infection period Wed. May 4 to Thurs. May5

Start of infection period

Waldoboro none
West Rockport Wed. 7:40pm
Hope (Appleton) Wed. 8p
Searsport Thurs. 5:20am, borderline
Sedgewick Wed. 7:40pm
North Ellsworth Wed. 8:20pm
Eastbrook/Franklin Wed. 9pm, probably yes
Aurora Wed. 8:20pm, probably yes
Deblois Wed. 9pm, probably yes
Columbia Wed 9:20pm
Montegail Wed. 9:20pm, probably yes
Jonesboro Yes wet since Monday.

East Machias

Wed. 7:40pm

Wesley Wed. 9pm
Love Lake Wed. 9pm