Last Mummy Berry Forecast for 2013 – May 22

Good news…the primary season for mummy berry infection is over in Kings County! I collected apothecia cups this morning and verified that all spores had been ejected and they are no longer active and able to infect blueberry tissue. It was also very difficult to find cups at Tim Strong’s as most had already broken down and we were only able to find a few late cups.

As southwest Nova is usually slightly ahead of the Valley the season should also be over there. Central and eastern parts of the province tend to be a week to two weeks behind the Valley so primary infection may still be possible in these areas.

Good luck with your season and if any shoot strike symptoms (photo below) develop on your farm, please let me know.

Mummy Berry Forecast - May 13th, 2013

Hey Folks, I’m hoping everyone had a protectant on their blueberries over the weekend as there was a significant wet period with ideal conditions for primary mummy berry infection. If not, you may have time to protect them by “back-action” activity if you apply Topas or Mission this evening. I believe the forecast is for more rain tomorrow so an application this evening would also provide protection if another infection period is on the way. Keep in mind that our protectants provide 7-10 days control.

The primary season for mummy berry infection should be winding down this week in the Valley but until you hear me say "it’s over" continue to manage this disease.

J. Lewis

Mummy Berry Forecast – May 6th, 2013

I received a call today asking me why I hadn’t sent out a forecast in a while and plain and simple it is because there hasn’t been a need. Since my last forecast on April 25th there has been no rain and, as such, no infection periods for primary mummy berry infection. So in this case “no news is good news”!

However, we are in right in the middle of mummy berry infection season and if an infection period does occur, growers with a history of disease had better be protected or be prepared to apply a control with back-action immediately after the wet period. All varieties are currently at susceptible bud development stages and there is plenty of inoculum so all that is needed for infection is a sufficiently long wet period. Keep your eyes on the forecast and be prepared to act as suggested above if a significant rainfall is predicted.

I will be out of my office until Monday, the 13th and won’t be able to give my next forecast until then.

Mummy berry forecast – April 25, 2013

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.

On Monday this week I reported that there was no inoculum so there was no need to spray.

I can now report that as of Wednesday morning this week, numerous apothecia cups, mostly immature pinheads, were observed at Tim Strong’s farm in King’s County.  The majority would not have been mature enough to sporulate but will be maturing quickly under the warm conditions yesterday and today.

I can also report that early flowering varieties like Bluetta (40-50% F2 stage) are highly susceptible to infection as of yesterday evening, but that most other varieties including Duke (5%), Bluecrop (5%), Nelson (0%), Jersey (0%) and Burlington (0%) were not at a susceptible stage for infection at this time.

Finally, there were suitable weather conditions for infection on Tuesday evening through to Wednesday morning but there have not been suitable conditions since then.

What does all this mean?  Well, at worst there would have been a very small amount of inoculum present at the time of the infection period late Tuesday night through to Wednesday morning and only the earliest flowering varieties would have been susceptible to infection at that time in Kings County.  Growers have the opportunity to spray Topas, Mission, or Funginex within 72 hours of the start of an infection period (7 p.m., Tuesday the 23rd) which would mean that they would need to spray before 7 p.m. on Friday May 26th for “back-action” control of any infections.  In my opinion there would have been very little inoculum present during the infection period in question and it would be highly questionable if a back-action spray would be beneficial and would certainly not be warranted for most varieties that are not at susceptible bud development stage. However, these fungicides are also excellent protectants and if growers wish to make a spray on early flowering varieties for both back-action and protectant benefits for the next 7-10 days this may be beneficial.

Lastly, please keep my comments in the context of the conditions in Kings County.  If your blueberries are further developed than Tim’s in King’s County and/or you had a longer wet period you may well benefit from a back-action spray as discussed below.  Conversely, if you are behind in bud development a back-action spray would not be beneficial at all at this time.

The other take home message from this report is that we are essentially entering the mummy berry infection season and we have to be on guard for infection conditions over the next 3-4 weeks.  To review the combination of conditions (leaf wetness and temperature) required for infection you may find it beneficial to review the mummy berry management factsheet on Perennia’s website.

Mummy Berry Forecast – April 22, 2013

We finally started to get a little heat and buds are starting to open in early varieties so you are probably wondering if there is any risk of mummy berry infection right now.  The answer is no – not at this time!  Remember that you need three things for infection – inoculum, susceptible bud development stage, and suitable weather conditions.  I checked Tim Strong’s farm for apothecia cups this morning and we were not able to find any cups so there is no inoculum at this time and thus no need to spray.  I will be watching closely this week and will inform you when the first cups are observed.  Until then be prepared but save your Topas for another day!

Also, keep in mind that conditions at Tim’s site are most applicable to other Kings County growers but a guide only for growers located west, south and east of his location.  Growers in these areas should monitor their own on-site conditions for verification.

Mummy Berry Forecast – April 16th, 2013

I am delivering a mummy berry disease forecast again in 2013. Please keep in mind that Tim Strong is my co-operator on this project and recommendations will be based on weather data collected on his farm on Brooklyn Street here in Kings County. 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.

To review the disease, its symptoms and life cycle, please examine the factsheet 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. At this time we do not have inoculum or susceptible bud development stage so there is no need to spray for the disease yet. However, last year’s first pinheads were observed by April 10th so with a little warm weather conditions will advance rapidly. Timeliness of sprays is critical for the management of this disease so please have your sprayers ready to go on short notice.

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"