Mummy Berry 2019 #1

From scouting performed Thursday April 25th, some blueberry varieties in the Annapolis Valley are approaching the F2 bud stage (bud scales are seperating in flower bud), and apothecia cups have began to develop but they are still immature (not releasing spores). So far there has not been a monilinia infection period, but if development continues at this rate there is potential for an infection period during the rain forecast for this Saturday. I will send out a blog post early next week to to confirm whether or not there was an infection period.

Apothecia cup from April 25,2019

Bud stage from April 25, 2019 

As a reminder though these observation are from the Annapolis Valley, Nova Scotia and may not be representative of 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. Scouting for monilinia cups, and monitoring plant development and conditions in your specific field is crucial to determining when infection periods occur. For more information on this disease, checkout 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.

Mummy Berry 2018 Post #6

Based on reports from our weather station in Lakeville, temperatures hovered between 11 and 12 degrees for most of the day on Thursday and we had approximately 9 hours of leaf wetness.  Using the monilinia blight infection model developed by Dr. Hildebrand (shown below), an infection period was indicated on Thursday.  

Observations from the Annapolis Valley show that most plants are past 40-50% F2 bud stage. Soil has also remained moist between precipitation periods, which aids the development of spore cups. 

Bud development in the Annapolis Valley

If fungicide was applied for the previous infection period, there might still be protection during this infection period, depending on the product used.  If you had not applied a fungicide before this most recent infection period, use a product with back action against monilinia to prevent infection. The choice to spray should ultimately be decided by field conditions, history of monilinia and in-field observations. As always, read the product label before applying fungicides or any other pesticides.

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.

Mummy Berry 2018 Post #5

The weather this past weekend resulted in a series of infection periods, with the last being Sunday evening into Monday morning.  We are currently in a stretch of warm dry weather, which if they are not there already, will likely push many sites beyond 40-50% of F2 - bud scales separating in flower buds.  With bud development moving along quickly, all growers should be looking at variety blocks/fields for fruit bud development.

The forecast for Thursday through the weekend looks like another series of wet period, which you should be prepared for and possibly make a decision for treatment based on the development stage of a variety block/field.

The next update will be at the end of the week.

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.

Mummy Berry Post 2018 - #1

Scouting early this week revealed that there are some varieties and locations in the Valley that are starting to see bud swelling and some F2 buds appearing.  That being said, please remember that every location and variety may be at a different development stage, requiring regular scouting of your own fields to verify their development stage.

 Image from this weeks scouting

Developing buds become ‘susceptible’ when about 5 mm of green tissue is exposed in vegetative buds and when bud scales are separating in flower buds (F2 stage).  The first fungicide spray should be applied when 40-50% of the flower buds have reached the F2 stage.  A second spray may be required 7-10 days later.

After that point you need to treat if there is an infection period.  Remember, the conditions necessary for primary infection include:
1. inoculum presence (history of monilinia blight in that field)
2. susceptible bud development stage (F2 stage), and
3. suitable weather conditions.

Infection periods are a combination of wetness duration and temperature.  The warmer the temperature, the shorter the wet period needs to be to cause an infection period. For more information on this disease, check out Management of Mummy Berry Disease in Highbush Blueberry

A list of products are available in the Highbush Blueberry Insect & Disease Management Schedule for NS 2017.

As we move into May and there is a significant infection period forecasted and fruit bud development is well advanced, a pre-infection application might be well advised.

Mummy Berry Forecast 2017 - #1

It is that time of year again and Perennia will be delivering a mummy berry disease forecast for highbush blueberries again in 2017.  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”.

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.

During scouting yesterday, a few varieties had buds that were just beginning to separate but for the most part, we do not have buds at the susceptible development stage.  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.  Have you sprayers ready!

Blue Gold at F1.

Scouting 20 April, 2017, Kings County.  Spartan at F1.

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.