Mummy Berry - Post #9 (Shoot and flower cluster blight)

We want to share an important update regarding our High bush Monilinia monitoring. As we mentioned in our last blog post, all the mummy berries have dried up and cannot release ascospores. What we see now, are the symptoms of ascospores damage which were released earlier in the season.

In early maturity varieties, shoot blight symptoms such as drooping of affected shoots, followed by brownish purple discoloration of the upper sides of the midribs and lateral veins of affected leaves and flower cluster blight can be observed (Figure 1 and 2). The tufts of grayish conidia appear along the petioles, midribs of affected leaves, and on the infected peduncle or flower pedicels. These conidia that are forming on the diseased leaf shoots and flower clusters will now be spread further by bees, flies, and wind to open flowers where they will grow down the flower style and eventually form a mummy berry. 

Figure 1. Twig and flower blight. 

Figure 2. Twig and flower cluster blight.

• Most of mid and late maturity varieties are clean but a regular scouting of the fields is highly recommended to help plan for next years mummy berry management.
• Usually, fungicide sprays targeted to prevent these flower infections are not cost effective but can be practiced. The pruning of branches is not recommended but the easiest way to prevent further conidial spread would be to simply pick off diseased leaf shoots and flower clusters and drop them to the ground or collect them in a bag. This would limit the spread of conidia that are present now.  

Mummy Berry - Post #8 (infection period ended)

It was a bit of a weird start to the season, with a lot of cool temperatures, resulting in a slow progression in both the development of highbush blueberries and apothecia cups that result in infection of monilinia blight (mummy berry).  Farms should have put on 2-3 protectant sprays that would have protected the plants for the length of the infection period.

Most, if not all varieties should now be at or beyond F2 (Figure 1 and 2), and with the most recent stretch of dry conditions (25 May, 2020) there should be limited risk of monilinia blight infection periods.

Sajid is reporting from his monitoring that apothecia cups (the fruiting bodies that produce the infection spores) have dried up, eliminating the risk for infection (Figure 3).

 Figure 1. Floral bud development in early maturity variety.

Figure 2. Floral bud development in late maturity variety.

Figure 3. Dried apothecial cups of mummy berry. 

Stay tuned to the Berry Blog as we continue to monitor plant and pest development throughout the season. 

Mummy Berry 2020 - Post # 7

Over the past weekend we expected major progress in floral bud development. As you can see in Figure 1, temperatures from March 01 to May 19, 2020 are still tracking significantly behind the 5- and 10-year averages.

Figure 1. Heating degree day accumulations for plant (above 5°C) and insect (above 10°C) development from March 1st to May 19th for the past 17 seasons. Provided by Jeff Franklin (AAFC).

On Tuesday May 19th, Sajid confirmed that the early block of Duke he is monitoring now has 85-95% of floral buds are at F2 (bud scales have separated in the flower buds), as shown in Figure 2. Furthermore, the medium maturity variety has 60-70% of the floral buds at F2 stage (Figure 3). However, in the block of late variety, 35-50% buds are susceptible to Monilinia blight infection (Figure 4). 

Almost all apothecial cups have been matured (Figure 5) and they are drying up. If you already had sprayed once with the propiconazole, there is no need of additional spray at this point as the weather will be dry with no rain forecast for the next one week. If you have not sprayed in the last 7-10 days, it would be a good idea to apply a protectant spay to get you through. Please keep in mind that the propiconazoles (e.g. Pivot, Bumper, Tilt, Mission, Fitness, and Propi Super) with back action can only be sprayed a total of 2 times per season, so plan your sprays appropriately.

Figure 2. Early maturity variety, floral buds at F2 stage of development.

 Figure 3. Mid maturity variety, floral buds at F2 stage of development.

 Figure 4. Late maturity variety, floral buds at F2 stage of development.

Figure 5. Mature apothecial cups. 

To determine whether a planting has buds that have reached 40-50% F2, follow this protocol for floral bud evaluation:

In a field, block or variety (whatever area you would spray at one time) walk a zig zag (not only the edge) stopping a total of 5-10 times to count floral buds.  With each stop, count 10-15 floral buds on a stem and use that to guesstimate the floral bud stage on that plant.  Use your 5-10 plant guesstimates to determine the average floral bud stage of the field, block or variety.  Remember, you want to protect any planting that has 40% or higher of floral buds at F2 (Figure 1 above).

As a reminder, these recommendations are based on conditions observed in the Annapolis Valley, Nova Scotia and may not be applicable to your location. The decision to treat should be based on appropriate conditions observed on your farm and in particular fields/blocks. For detailed information please check out Perennia's Management of Mummy Berry Disease in Highbush Blueberry. 

A complete list of registered products can be found in Perennia's Highbush Blueberry Disease and Insect Management Guide.

Mummy Berry 2020 - Post # 6

Monilinia blight (mummy berry) infection period Saturday May 16 for highbush blueberry.

Rain started overnight last night (16 May 2020), when temperatures were just above 10 degrees C.  The temperatures have since dropped (approx 6 degrees C at 1 pm) but with over 12 hours of rain (100% leaf wetness), we have likely experienced infection periods in most regions of the Annapolis Valley.  

Temperature and wetness conditions required for Mummy Berry infection.

On Friday May 15^th, Sajid confirmed that the early block of Duke he is monitoring now has 81-85% of floral buds at F2 (bud scales have separated in the flower buds), as shown in Figure 1.  The medium maturity variety has 40% of the floral buds at F2 stage (Figure 2) while the block of late variety, only 15% buds are susceptible to Monilinia blight infection (Figure 3).

Figure 1. Floral buds at F2 stage of development.

 Figure 2. Mid maturity variety, floral buds at F2 stage of development.

Figure 3. Late maturity variety, floral buds at F2 stage of development.

If your planting has not reached 40-50% F2 (bud scales have separated in the flower buds), infection risk is limited.  For those of you with later varieties/blocks, particularly to the North of the Valley, your plants may not have reached F2 given the late season.

To determine whether a planting has buds that have reached 40-50% F2, follow this protocol for floral bud evaluation in Blog Post #5.  

If you have not protected against monilinia blight within the last 7-10 days I would suggest that you do so at your next opportunity. Keep in mind that the propiconazoles (e.g. Pivot, Bumper, Tilt, Mission, Fitness, and Propi Super) with back action can only be sprayed a total of 2 times per season, so plan your sprays appropriately.

As a reminder, these recommendations are based on conditions observed in the Annapolis Valley, Nova Scotia and may not be applicable to your location. The decision to treat should be based on appropriate conditions observed on your farm and in particular fields/blocks. For detailed information please check out Perennia's Management of Mummy Berry Disease in Highbush Blueberry. 

A complete list of registered products can be found in Perennia's Highbush Blueberry Disease and Insect Management Guide.

Mummy Berry 2020 - Post # 4

As discussed in the previous blog post, the season continues to chug along at a slow pace with buds slowly progressing. On Friday May 8th, Sajid confirmed that the early block of Duke he is monitoring now has 65-72% of floral buds are at F2 (bud scales have separated in the flower buds), as shown in Figure 1.  However, in the block of later varieties buds are swollen but not yet susceptible to monilinia blight infection.

Figure 1. Floral buds at F2 stage of development.

That said, mature apothecia cups (Figure 2) have been confirmed, meaning that if we do experience appropriate conditions (see previous blog post) an infection period is possible.  Given the cool temperatures we have been experiencing, we are projecting that the season will be prolonged.  I would encourage you to stretch out your sprays to 7-10 days and maintain a spray schedule that protects susceptible buds.  Keep in mind that the propiconazoles (e.g. Pivot, Bumper, Tilt, Mission, Fitness, and Propi Super) with back action can only be sprayed a total of 2 times per season, so plan your sprays appropriately.

 

Figure 2. Mature apothecia cups. To determine whether a planting has buds that have reached 40-50% F2, follow this protocol for floral bud evaluation:

In a field, block or variety (whatever area you would spray at one time) walk a zig zag (not only the edge) stopping a total of 5-10 times to count floral buds.  With each stop, count 10-15 floral buds on a stem and use that to guesstimate the floral bud stage on that plant.  Use your 5-10 plant guesstimates to determine the average floral bud stage of the field, block or variety.  Remember, you want to protect any planting that has 40% or higher of floral buds at F2 (Figure 1 above).

As a reminder, these recommendations are based on conditions observed in the Annapolis Valley, Nova Scotia and may not be applicable to your location. The decision to treat should be based on appropriate conditions observed on your farm and in particular fields/blocks. For detailed information please check out Perennia's Management of Mummy Berry Disease in Highbush Blueberry. 

A complete list of registered products can be found in Perennia's Highbush Blueberry Disease and Insect Management Guide.

Mummy Berry 2020 - Post #3

Over the past weekend we expected some major development in bud but given the cool temperatures of late, we really have not seen things progress all that much.  To date, development is late and the cool weather has resulted in slow bud development.  As you can see in Figure 1, temperatures from 1 March to 4 May, 2020 are tracking significantly behind the 5- and 10-year averages.

Figure 1. Heating degree day accumulations for plant (above 5°C) and insect (above 10°C) development from March 1st to April 20 th for the past 17 seasons. Provided by Jeff Franklin (AAFC).

That said, with wet days and some mature apothecia cups confirmed, if you haven't applied a treatment in the last 7 days, it may be prudent to do so.  Please confirm bud stage in individual fields/blocks on your farm.  In advanced fields (40-50% or more at F2), there is risk of infection if all other conditions are present.  For the primary infection of monilinia to occur you need all three of these conditions to occur:

1. Inoculum present: history of monilinia blight and mature apothecia cups (Figure 2).
2. A susceptible host: vegetative buds are more than 6mm exposed green tissue and bud scales have separated (F2 stage) in the flower buds (Figure 3).
3. Ideal environmental conditions: wet periods with relatively warm temperatures (more explanation below).

 Figure 2. Mature apothecia cups.

Floral bud counts on Monday May 4, 2020 from the Annapolis Valley Nova Scotia: 

• Duke block: 50-65% of floral buds are susceptible to mummy berry infection (Figure 3)
• Second block of later varieties: Buds are swollen but not susceptible yet. 

Figure 3. Floral buds at F2 stage of development.

Based on the wetness period and different air temperatures, Paul Hildebrand and Rick Delbridge developed the Mummy Berry Forecast System in Nova Scotia (Table 1). By visually assessing when the floral bud scales have separated and leaf buds are more than 0.6 cm green, growers can determine when 40-50% bud break has occurred. If temperature and leaf wetness fall within the moderate to high infection range on the table, it is recommended that the grower apply a fungicide within 72 h from the start of the wet period.

     Table 1. Temperature and wetness conditions required for Mummy Berry infection.

Table 2 presents the susceptibility of common highbush blueberry cultivars to fruit infection by Mummy Berry (M. vaccinii-corymbosi). Susceptible (fruit infection incidence 30-50.9%), moderately resistant (fruit infection incidence 11-29.9%), and resistant (fruit infection incidence 0-10.9%) varieties. (Data from Stretch and Ehlenfeldt, U.S. Department of Agriculture).

Table 2. Highbush blueberry cultivar susceptibility to Mummy Berry

As a reminder, these recommendations are based on conditions observed in the Annapolis Valley, Nova Scotia and may not be applicable to your location. The decision to treat should be based on appropriate conditions observed on your farm and in particular fields/blocks. For detailed information please check out Perennia's Management of Mummy Berry Disease in Highbush Blueberry. 

A complete list of registered products can be found in Perennia's Highbush Blueberry Disease and Insect Management Guide.

Mummy Berry 2020 - Post #2

A quick update on Mummy Berry Development.

Floral bud counts on Friday May 1, 2020 from the Annapolis Valley Nova Scotia.

Duke block at 40 - 60% F2 bud development (Figure 1). 

Figure 1

Other varieties in the same field only at 25 - 36% F2 bud development and many are still immature (Figure 2).

Figure 2

A lot of apothecia are developing and some of the mature apothecia are releasing ascospores (Figures 3 and 4).

Figure 3

Figure 4

Given the anticipated rain and warmer weather expected this weekend, there is a risk of an infection for earlier fields and varieties.

In preparation for an infection period, make sure you have product on-hand.

Products with the active ingredient propiconozole (Pivot, Bumper, Tilt, Mission, Fitness, and Propi Super) can be applied after an infection event, providing up to 72 hour ‘back action’, in addition to being excellent protectants against future infections for 7-10 days after application. Quilt is listed as a preventative fungicide, but also displays systemic and curative properties.

A complete list of registered products can be found in Perennia's Highbush Blueberry Disease and Insect Management Guide.

As a reminder, these recommendations are based off conditions observed in the Annapolis Valley, Nova Scotia and may not be applicable to your location. Infection periods only occur when bud development has reached the F2 stage, monilinia spore cups are present, and temperature and moisture levels are ideal. The decision to spray should be based on these conditions being observed in your particular field. For detailed information please check out Perennia's Management of Mummy Berry Disease in Highbush Blueberry. 

Mummy Berry 2020 - Post #1

A few new changes you will notice...I have 2 new blogs, one of which is a blog dedicated to Highbush Monilinia blight monitoring (this one) and another general Berry Blog.  The other big change is the addition of Dr. Sajid Rehman to the Perennia team.  Sajid will be contributing regularly to this blog and many other Perennia publications.

For detailed information please check out Perennia's Management of Mummy Berry Disease in Highbush Blueberry.  A quick reminder that primary infection of mummy berry disease in highbush blueberry requires three conditions to be met:

1. Inoculum present: history of monilinia blight.
2. A susceptible host: vegetative buds have 5mm (V2 stage) of green tissue exposed and bud    scales have separated (F2 stage) in the flower buds.
3. Ideal environmental conditions: wet periods with relatively warm temperatures.

Sajid was in the field Monday morning and observed the following in an early block of Duke:

1. Mummy berries have started germination but there is no risk of infection yet as most of them are dry/dormant.
2. Some F2 floral buds were observed but had not yet reached 40%.
3. Weather has not been conducive to infection but with warm weather towards the end of the week/ weekend, things may move along, so we will recheck on Friday.

Floral bud development late April Annapolis Valley, NS

Development of stipe from pseudosclerotium.

Please keep in mind that regular monitoring is conducted on one farm in the Annapolis Valley, and recommendations will be based on weather data collected in Kings County, Nova Scotia.  It should be fairly accurate for other growers in Kings County but will be a guide only for growers to the west, south, and east. Westerly and southerly locations are generally a little ahead of the Valley while more easterly locations become progressively later.  Therefore, it is important that each grower checks their blocks to determine if their fields are susceptible to infection.

To do this, walk individual variety blocks in a "W" pattern and collect 30 stems randomly along that pattern.  Count the total number of floral buds and then the number that are F2 (5 mm of green tissue is exposed in vegetative buds and when bud scales are separating in flower buds) or beyond.

Divide # F2 buds by the total buds, and multiply by 100 = % of F2

Correct timing of the first spray is critically important for good control. Treatments should not be considered until greater than 40% of the buds are past the F2/V2 stage and there is no need to spray if you have no history of mummy berry disease on your farm. 

If you are below 40% it is too early to spray!

You should expect the next blog post on Friday or Saturday of this week.

Mummy Berry 2019 #9

From observations made Monday June 3 in the Annapolis Valley apothecia cups have dried up or are no longer producing spores. Because of this there is no longer any threat of primary monilinia infections, and this will be the last mummy berry post of the 2019 season.

Dried apothecia cup from June 3, 2019

Until next season, for more information on highbush blueberries, monilinia, and aprays please refer to Highbush Blueberry Insect and Disease Management Schedule 2019 and Management of Mummy Berry Disease in Highbush Blueberry.

Mummy Berry 2019 #8

As of this week the majority of apothecia cups have dried up or are otherwise unviable. Because of this the risk of primary monilinia infection has significantly diminished. There is a still a chance that infections could occur at this point, but it is very small and after this Saturday (June 1st) I think the risk will have completely dissipated. At this point it may not be necessary or economically viable to spray. I will put out another blog Monday to confirm the end of primary monilinia infection season.

Dried apothecia cups from May 29, 2019 

Mummy Berry 2019 #7

Since the last mummy berry post there have been three extended infection periods between Tuesday May 14-Wednesday May 15, Friday May 17-Saturday May 18, and Monday May 20-Tuesday May 21. From observations made Tuesday May 21 the majority of  blueberry varieties are past the F2 stage, and some varieties are beginning to approach pre-bloom. Viable apothecia cups are still present with the rain and lack of sun helping them persist, but decline is beginning to occur. If you applied a protective spray before or after the infection period Friday May 10 you should have had control through the week and most of the weekend. If you did not get on another protective spray before the infection period Monday May 20 you can still use a product with back action (Topas, Mission, etc) to achieve control within 72 hours of the infection period. If you have applied two back to back sprays of a group 3 fungicide (Topas, Mission, etc), then a non-group 3 fungicide such as Diplomat 5SC should be used for resistance management before applying an another group 3 fungicide. An ideal time to apply another spray would be Wednesday afternoon when the rains breaks temporarily as it appears there will be two more extended infection periods between Thursday May 23 and Sunday May 26.

As a reminder these recommendation are based off of observations made in the Annapolis Valley and may not be applicable to your region or field. The decision to spray should be based off of observations and weather conditions from your specific site. For more information on highbush blueberry production, mummy berry, and pesticides refer to Management of Mummy Berry Disease in Highbush Blueberry and Highbush Blueberry Management Schedule 2019.   

Mummy Berry 2019 #6

From observations made on Monday May 13, 2019 some blueberry varieties have advanced past the F2 bud stage, and viable apothecia cups are still present. There is potential for an infection period during the rain forecast for Tuesday May 14, 2019 and Wednesday May 15, 2019. If you applied protective sprays for the infection period between Friday May 10 and Saturday May 11, you should still have protection during this next infection period. If you have not applied protection up to this point you can still achieve control by using a product with back-action capability (Topas, Mission, etc)  within 72 hours of the start of the infection period. 

Bud stage from May 13, 2019

Apothecia cups from May 13, 2019

As a reminder these recommendation are based off of observations made at a site in the Annapolis Valley, and may not be applicable to your specific field. The decision to spray should be based off scouting and observation made in your own field. Infection periods only occur when blueberries are at a susceptible bud stage, apothecia cups are present, and weather conditions are suitable. For more information on highbush blueberries, mummy berry disease, and fungicides please refer to Management of Mummy Berry Disease in Highbush Blueberry

Mummy Berry 2019 #5

There is a high likelihood of an infection period during the rain forecast for Friday May 10, 2019 and Saturday May 11, 2019. Rain is also forecast for the majority of next week, and could result in several infection periods. From observations made in the Annapolis Valley some blueberry varieties have reached the majority F2 bud stage, or are more advanced. Mature apothecia cups are also still present, and although some apothecia cups had started to dry up the forecasted wet conditions could slow this process.

Apothecia cups from May 9, 2019

Bud stage from May 9, 2019 

If you applied a protective spray for the infection period Tuesday May 7, 2019, you should still have control until early next week. If you did not apply a protective spray you should still be able to achieve control during the infection period this weekend by applying a spray before the rain on Friday May 10, 2019. If you are unable to get a spray on Friday you can still achieve control by applying a product with back-action capability (Topas, Mission, etc) if applied within 72 hours of the infections period. If you have already applied one of the back action products twice consecutively a non-group 3 fungicide should be used for resistance management. For more information on highbush blueberries, mummy berry disease, and fungicides please refer to Management of Mummy Berry Disease in Highbush Blueberry

As a reminder these recommendation are based off of observations made at a site in the Annapolis Valley, and may not be applicable to your specific field. The decision to spray should be based off scouting and observation made in your own field. Infection periods only occur when blueberries are at a susceptible bud stage, apothecia cups are present, and weather conditions are suitable. I will put out another update this coming Monday May 13, 2019.

Mummy Berry 2019 #3

From the rain forecast for this Saturday May 4th, 2019 it appears that we will have another monilinia infection period. From Observations made Thursday May 2nd in the Annapolis Valley, blueberries are still at or approaching the F2 bud stage. With the increasing temperatures over the weekend and next week, the percentage of susceptible F2 buds will quickly increase. Apothecia cups are also still present and sporulating. If you applied a spray for the previous infection period you may still have protection depending on when the application was made and the product used. If you have not applied a spray already, this Friday May 3rd would be an ideal time before the rain begins. I will put out a blog post early next week confirming whether or not there was an infection period.

As reminder the decision to spray should be based on scouting and observation made in your own field as development and weather can vary considerably between fields. For an infection period to occur blueberries have to be at a susceptible bud stage, apothecia cups have to be present, and weather conditions need to be suitable. For more information on blueberries, monilinia, or pesticides please refer to the Management of Mummy Berry Disease in Highbush Blueberry

 

Mummy Berry 2019 #2

For the primary infection of monilinia to occur you need three things:

1.       Inoculum present: history of monilinia blight.
2.        A susceptible host: vegetative buds have 5mm of green tissue exposed and bud           scales have separated (F2 stage) in the flower buds.
3.        Ideal environmental conditions: wet periods with relatively warm temperatures.

With that in mind it appears that we had our first infection period this past Saturday April 27, 2019.

Observations made Saturday April 27, 2019 from a blueberry field in the Annapolis Valley showed that mature apothecia cups are present (requirement #1), and buds are at the F2 stage (requirement #2). From weather data collected in the Annapolis Valley on Saturday April 27, 2019 there were 15 hours of leaf wetness, and an average temperatures of 7 degrees Celsius (requirement #3). Since all three requirements for infection were met, there was most like an infection period on Saturday April 27, 2019. 

Bud stage from April 29, 2019

Apothecia cup from April 29, 2019

If you did not apply a protective spray before the infection period, you can still achieve control of infections that have already occurred by application of a fungicide with back-action capability (Topas, Mission, etc) within 72 hours of the beginning of the event. For more information on sprays and monilinia please refer to Management of Mummy Berry Disease in Highbush Blueberry.

As a reminder though these recommendations are based off of conditions observed in the Annapolis Valley, Nova Scotia and may not be applicable to your location. Infection periods only occur when bud development has reached the F2 stage, monilinia spore cups are present, and temperature and moisture levels are ideal. The decision to spray should be based on these conditions being observed in your particular field. 

Mummy Berry 2018 Post #10

Based on scouting in the Annapolis Valley on Friday the majority of blueberry plants have begun to bloom, and apothecia cups have dried up and are no longer producing spores. As such, this will be the last mummy berry post of the 2018 season. 

This advisory, as with all previous recommendations are based on conditions observed in the Annapolis Valley. To ensure that you are no longer at risk of monilinia infection please continue to monitor fields, as there is considerable amount of variability across the province due to weather, varieties, plant development, etc...

Flower development from May 25,2018

Until next year, for more information on highbush blueberries, mummy berry, and sprays please refer to Highbush Blueberry Insect & Disease Management Schedule 2017 and  Management of Mummy Berry Disease in Highbush Blueberry.

Mummy Berry 2018 Post #9

Based on scouting performed in the Annapolis Valley, the majority of plantings/varieties are beyond the risk of primary Monilinia infections at this point.  

Many plantings are at the prebloom stage with flowers beginning to emerge, and based on our observations spore cups appear to be dried up.  Given the advanced bud stage and declining spore cups, Monilinia infection periods have or will soon be coming to an end. There will be a final blog post confirming that the risk Monilinia infection is sufficiently diminished or past at the end of this week.

Bud stage from May 22, 2018

Across most of Nova Scotia there was potential for infection on Sunday but it would be entirely site specific.  Those plantings that are still at the appropriate bud stage for infection would ahve been susceptible to Monilinia infection given the precipitation and average temperatures throughout the day Sunday.  It looks as though there is more rain in the forecast for Wednesday and Friday, so for those with plantings at later stages of development, you may want to consider a fungicide application.   

Before applying fungicides consider the in-field conditions, plant development, and history of Monilinia in the field as all these factor play a role in the occurrence of an infection period.  

For more information on highbush blueberries, mummy berry, and sprays please refer to Highbush Blueberry Insect & Disease Management Schedule 2017 and  Management of Mummy Berry Disease in Highbush Blueberry. 

Mummy Berry 2018 Post #8

From scouting done in the Annapolis Valley on May 18, 2018 buds are at the pre-bloom stage with some flowers beginning to emerge. It was also observed that spore cups are starting to dry up.  Although spore cups are starting to dry up there may still be a possibility of infection depending on field conditions, status of spore cups and plant development stage, so continue to monitor field conditions. 

Bud stage from May 18, 2018

The forecast for this weekend shows a possibility of precipitation, which could lead to an infection period. Monitor weather conditions in your area and consider applying fungicide if necessary. There will be another blog post early next week addressing the possible  infection period over the weekend. 

For more information on highbush blueberries, mummy berry, and sprays please refer to Highbush Blueberry Insect & Disease Management Schedule 2017 and  Management of Mummy Berry Disease in Highbush Blueberry.

Mummy Berry 2018 Post #7

Based on data collected from our weather station in Lakeville, Nova Scotia there was an infection period between Tuesday evening and Wednesday morning. Leaves remained wet for approximately 9 hours at an average temperature of 12 degrees. Below is an infection severity chart, which shows the risk of infection occuring at different temperatures and wetness durations. As temperature increases the wetness duration required for infection decreases, which increases the risk of infection.

If you were unable to get a spray on before the infection period, consider applying a fungicide with back action on monilinia within the next few days. The length of back action will be different depending on the fungicide so always read the label before application. These recommendations are based off of observations taken from the Annapolis Valley, and the decision to spray a field should be made based off of conditions and observations taken from that particular field.

There will be another blog later this week giving an update on bud stage and spore cup development. For more information on management of mummy berry in highbush blueberries please refer to Perennia's  Highbush Blueberry Insect & Disease Management Schedule 2017  and Management of Mummy Berry Disease in Highbush Blueberry.