Mummy berry blight season winding down!

Apothecia cup samples were collected this morning in Kings County and only a few were still actively sporulatingsuggesting that the primary infection season for mummy berry disease is rapidly winding down in this area. With the warm, dry conditions forecast for today and Saturday it will likely be over completely this weekend and growers in the Annapolis Valley and southwest Nova can breathe easier with respect to this disease. If you are located to the east of the Annapolis Valley the season is progressively later, by as much as 1-2 weeks, and growers in these areas may wish to extend their protection sprays an appropriate period of time.

A final forecast will be prepared next week to review the number and severity of infection periods (as determined by the weather station at Tim Strong’s in Kings County).

Remember that this forecast is based on data collected from Tim Strong’s orchard on Brooklyn Street in Kings County and may not be applicable to your location. It is a guide only.  

Latest Mummy Berry Blight Alert

Two wet periods in the last 36 hrs have both been suitable for mummy berry blight infection!The details of these wet periods at the weather station in Kings County are as follows:

First event:         00:30 hrs May 5^th to 13:30 hrs May 5^th (13 hrs)

Second event:   19:45 hrs May 5^th to 08:00 hrs May 6^th and still running (>12.25 hrs)

 
If you have applied a suitable fungicide within the past 7-10 days you are likely protected. If not, you have within 72 hrs of the beginning of the wet period to apply a control with back-action capability to control any infections during these wet periods. This would mean that you have till 00:30 hrs Sunday May 8^thto apply one of these controls.
 

Registered fungicides with back-action control of mummy berry blight infections include Topas, Mission, and Funginex, although the latter cannot be applied if berries are to be exported to the US. Other newly registered fungicides such as Quash and Indar may have back-action control but have not been tested for this activity so it would be advisable to use Topas, Mission, or Funginex (if you are not exporting).  Refer to Perennia’s Highbush Blueberry Management Schedule at  http://www.perennia.ca/Pest%20Management%20Guides/Fruits/2016/Highbush_I&DGuide_2016.pdffor product formulations and read product labels carefully for product rates and application details.

 
Finally, remember that this forecast is based on data collected from Tim Strong’s orchard on Brooklyn Street in Kings County and may not be applicable to your location. It is a guide only. 

Mummy Berry Infection Alert!

This update is to report that there was a precipitation event on Monday evening and night that was a high risk for mummy berry infection!  If you had a spray on within a week to 10 days before this event you were likely protected.  If you did not, you can still protect your fields from the infection by application of a fungicide with back-action capability within 72 hours of the beginning of the event.  The beginning of the wetting period at the site on Brooklyn Street here in Kings County was recorded at 8 p.m. so growers in this area of Kings County would have until 8 p.m. on Thursday May 5^thto apply a control for back-action protection.

The weather forecast for Kings County is calling for 20-30 mm of rainfall Wednesday night and Thursday so a spray for back action control should be made today while an application window is available.  This spray will protect against the infection period Monday night as well as the one forecast for tonight and tomorrow.

Mummy Berry Forecast - April 29, 2016

Once again, primary infection for mummy berry disease in highbush blueberry requires three conditions to be met:

1. Inoculum presence - mature sporulating apothecia cups,
2. Susceptible bud development stage – bud scales separating in flower buds (F2 stage), and
3. Suitable weather conditions – long wet periods at relatively warm temperatures.

Also, it is not recommended to spray until 40-50% of buds of a given variety are at the F2 stage and there is no need to spray if you have no history of mummy berry disease on your farm.

Observations as of Thursday April 28^st:

• Mature apothecia cups are now present and actively sporulating so we have inoculum present at this time.

• The early variety ‘Bluetta’ had 70% of flower buds at the F2 development stage while the mid-season variety ‘Bluecrop’ was found to have 50% of its flower buds at the F2 stage. The late mid-season variety ‘Nelson’ was at 10% F2 while the late varieties ‘Jersey’ and ‘Burlington’ were at 0% F2. Surprisingly, the early variety ‘Duke’ was only found to be at 10% F2 but it appears most early and mid-season varieties are now at the ideal development stage for infection.

• A 15.5 hr long wet period from Saturday afternoon April 23^rd through to early Sunday morning April 24^th would have been sufficient for a high risk infection period but most (if not all) varieties would not have been at a susceptible bud stage and very little (if any) active spores were present at that time in Kings County; however, we can now say that we are now in the primary ‘mummy berry infection season’ and must either use a “fixed sprayed schedule” to protect bushes from infection or a ‘weather based spray program’ to control infections using controls that have “back-action” capability (eg. Topas).

Recommendations:

A ‘fixed spray schedule’ may be used to manage the disease whereby the first fungicide spray should be applied when 40-50% of the flower buds have reached the F2 stage (flower bud scales separating). One or more additional sprays may be required on a 7-10 day schedule. As such, most early and mid-season varieties would benefit from their first cover as soon as possiblewhile sprays to later season varieties may be delayed until their bud-development reaches the recommended 40-50% F2 stage.

 

Alternatively, a ‘weather based spray schedule’ may be employed. This strategy uses temperature and leaf wetness duration to determine if an infection period has occurred. If an infection period occurs and mature apothecia are present, and flower buds have reached the 40-50% F2, then the grower has up to 72 hours after the start of the wet period to apply Funginex, Mission, or Topas. An additional spray(s) may be required, depending on weather conditions, 7-10 days later. Identification of infection periods for back-action control will be communicated through this forecast in the coming weeks so please stay tuned and have your sprayers ready.

 Finally, please remember that the observations and recommendations above are derived from data collected in Kings County, Nova Scotia and may not be applicable to your location. Once again, if you are to the south and/or west of Tim’s location in Kings County you may well be ahead in development and if you are located to the east of the Valley you will generally be later. This forecast is to be used a guide only for mummy berry disease management in Nova Scotia.

 

Latest Mummy Berry Forecast

A quick reminder that primary infection of mummy berry disease in highbush blueberry requires three conditions to be met:

1. Inoculum presence – mature sporulating apothecia cups,
2. Susceptible bud development stage – bud scales separating in flower buds (F2 stage), and
3. Suitable weather conditions – long wet periods at relatively warm temperatures.

Also, it is not recommended to spray until 40-50% of buds of a given variety are at F2 stage and there is no need to spray if you have no history of mummy berry disease on your farm. For more information and pictures refer to “Management of Mummy Berry in Highbush Blueberry”.

                                                 Flower buds at F2 (bud scales separating)

Observations on Thursday April 21^st:

• Apothecia cups at the “pinhead” stage of development were found but were not actively sporulating and as such there is no inoculum at this time.
• Flower buds are not yet at the 40-50% F2 development stage recommended for spray application.The early variety ‘Bluetta’ had 15% of flower buds at the F2 development stage while Duke, Bluecrop, Nelson, Jersey, and Burlington had 0-4% flower buds at the F2 development stage.
• Showers and light rain is forecast for Saturday April 23^rdand Tuesday April 26^th.

Recommendations:

It is still too early to spray as of April 22^nd (at Tim’s farm), but we are getting close! There are immature apothecia cups present and buds of some early varieties are approaching the 40-50% F2 stage recommended for first spray. Suitable weather conditions for infection (long wet periods and mild temperatures) are possible within the coming week but most varieties will not be advanced enough to warrant protection. 

Note that several fungicides registered for mummy berry disease (eg. Topas) have what is referred to as “back-action” activity and can effectively control an infection if applied within 72 hours of the beginning of the infection period. For a complete list of registered products please refer to “Highbush Blueberry Insect and DiseaseManagement Schedule”.

Finally, please remember that the observations and recommendations above are derived from data collected in Kings County, Nova Scotia and may not be applicable to your location. Once again, if you are to the south and/or west of Tim’s location in Kings County you may well be ahead in development and if you are located to the east of the Valley you will generally be later. This forecast is to be used a guide only for mummy berry disease management in Nova Scotia. 

First Mummy Berry Forecast of 2016

Perennia will be delivering a mummy berry disease forecast for highbush blueberries again in 2016. Please keep in mind that Tim Strong is our co-operator on this project and recommendations will be based on weather data collected on his farm on Brooklyn Street, Kings County, Nova Scotia. It should be fairly accurate for other growers in Kings County but will be a guide only for growers west, south, and east of his location. Westerly and southerly locations are generally a little ahead of the Valley while more easterly locations become progressively later.

To review the disease, its symptoms, and life cycle, please examine the fact sheet on Perennia’s website titled “Management of Mummy Berry Disease in Highbush Blueberry”:

http://www.perennia.ca/Fact%20Sheets/Horticulture/Fruit/Highbush%20Blueberry/Management%20of%20Mummy%20Berry%20Disease%20in%20Highbush%20Blueberry.pdf 

The important thing to remember about the disease is that you need three things for infection to occur – inoculum, susceptible bud development stage, and suitable weather conditions. As of yet, we do nothave buds at the susceptible development stage and no apothecia cups (for inoculum) have been found. However, buds are expanding on early varieties and if mild conditions persist we could well be at susceptible development stages for some varieties over the next week. As such growers should have their sprayers ready to go.

For a review of the fungicides registered for use on this disease please take a look at Perennia’s Highbush Blueberry Insect and Disease Management Schedule found at http://www.perennia.ca/Pest%20Management%20Guides/Fruits/2016/Highbush_I&DGuide_2016.pdf

Mummy Berry Forecast

Prerequisites for Spray Decision:

1. Past history of Monilinia Blight on the farm.
2. Flower buds become susceptible to infection at the F2 stage (bud scales separating).
3. Once fields reach 40-50% F2 and beyond, a fungicide is required within 72 hrs of the start of an infection period. This application will provide 7-10 days protection.

Observations at Tim Strong’s farm as of April 22nd, 2011:

Early varieties are at 10% F2 stage; apothecia cups are just emerging and are at pinhead stage of development; extended wet period from 7 p.m. April 20th until 8:30 a.m. April 21st (13.5 hrs) with average temperature of 2 °C presented a very low risk condition for infection.

Recommendations:

Still too early to spray as of April 22nd (at Tim’s farm), but if conditions warm up (as forecast) buds and apothecia cups will develop quickly creating the plant and inoculum conditions suitable for infection. We are getting close and should have our sprayers ready to go for the coming week!

Refer to “Management of Mummy Berry in Highbush Blueberry” factsheet for pictures of F2 stage and temperature and wetness requirements for an infection period.
Refer to AgraPoint’s “Hishbush Blueberry Insect and Disease Management Schedule” for list of registered products for mummy berry (Monilinia) control in highbush blueberry.