2023 Updates and Seasonal Outlook for NS_ June 21_ Botrytis Blossom Blight and Spreading Dogbane Management

Botrytis Blossom Blight

 

We had many wet days starting at the beginning of June (June 1-7) when a majority of mainland fields were in mid to full blooms. Although temperatures were not very high (on average, it was around 10 c during those days), the duration of wetness was long enough for an infection to occur (see the severity rating table below). This year, we had a perfect condition for botrytis blight infection.

 

 

During those days, it was wet and windy which hampered growers to apply botrytis fungicides. We are starting to see symptoms of botrytis in crop fields in many regions/fields.

 

Here are some areas where I observed botrytis symptoms and received reports on botrytis infection, including Parrsboro (Kirkhill and Port Greville, but I am sure other fields in this area should have different levels of infection too), Oxford and Mt. Pleasant fields, Collingwood, Wentworth, Mt. Thom, and growers in Cape Breton also reported there was botrytis infection.

If you didn’t apply botrytis fungicides this year, I strongly suggest you check the fields. A lot of people put on Merivon towards the end of bloom which was helpful for late bloom patches but for early clones and fields, if you didn’t put on something during mid-bloom, you will likely see symptoms. I took some photos and I want to show all of them to you so you can see different angles and levels of infection from Botrytis.

Some key points about Botrytis Blossom Blight symptoms:

-       Only some flower clusters on a stem will be affected

-       Botrytis targets almost open and open flowers

-       As botrytis develops, you can see black hairs, some with gray tips. 

 

Please click on each photo to see a clear view of botrytis symptoms: 

 

 

 

 

 

 

 

Spreading Dogbane Management

 

If you are having trouble with spreading dogbane in your fields, this month towards the beginning of next month would be a good window to control them.

 

Crop fields: it would be hard and risky to apply chemicals to control dogbane in crop fields, so I recommend growers repeatedly cut above blueberry-canopy vegetation or simply cut them before harvest to make picking easier.

 

Sprout fields: when spreading dogbane reaches the early bud stage (see the photo below, when you start to see them produce green flower buds, that’s a good time). Currently, the industry standard to control this weed is still Dicamba. This is the active ingredient and the most common brands we are using now are Banvel (if you have leftovers from before) or Enginea (the product local stores carry now).

 

Rate and application recommendations:

Please spot spray spreading dogbane with Dicamba and be careful to not let chemicals run into blueberry plants.

 

3 mL of Banvel or Enginea per litre of water+ 2 mL of adjuvant (either activate plus or merge) per litre of water.

 

So, if you are mixing 5 L of water in your backpack sprayer, you would need 5 L of water+ 15 mL of the product+ and 10 mL of adjuvant.

 

Spreading dogbane in the early bud stage

 

Lastly, here is a photo of Cow Wheats in a crop field: 

Good Pollination Weather Ahead

The weather looks to be quite good for pollination over the next week or so.  High teens to low twenties in most areas.  This should allow for good pollination success as we are moving into full bloom in most areas! Note: this may mean we move through bloom quickly, as there doesn't appear to be any "cold" days that will slow down development.

From a Botrytis management standpoint, we are expecting rain over night tonight and then again over night on Thursday into Friday. With the relatively warm conditions and wet bloom, it does make sense to make an application in areas prone to the disease. Remember treatments should be applied prior to the infection period (wet period).

For most areas of Nova Scotia, a single application in early bloom should be sufficient to keep Botrytis pressure low through bloom.  In areas with traditionally high pressure for Botrytis, a second application may be warranted 7-10 days after the first application. Note: this 2nd application only needs to be made if wet conditions are persisting through bloom.

This is the last regular blight line update for 2019, but I will continue to update the blog and the phone line periodically as issues arise.

Sunny and warm, finally!!

There looks to be a warm sunny period from Friday through to Tuesday.  This should push flower development and pollination should start in many areas.

If you are considering a Botrytis control, some consideration should be given to making and application prior to the next wet period, which is likely through the day on Tuesday.  With the wet conditions we have had, it is likely botrytis pressure will be high in areas prone to this disease.

Just a reminder, the 2019 pest management guide is on the Perennia website.  Click on the link to take a peak https://www.perennia.ca/wp-content/uploads/2018/03/wild-blueberry2019.pdf

Always, check with your buyer to see what is allowable for their markets!!

Of note:  We are starting to see Monilinia symptoms showing up from infections that occurred 3+ weeks ago. The picture below is from a trial site in a field in Mt. Thom

Bloom time disease risk

We are slowly moving into bloom, but most fields have not reached 20% open flower yet.  If only a small amount of bloom is open, it is too early to make a Botrytis application.

Botrytis products, like Luna Tranquility, Switch etc. need to be applied prior to an infection. No registered products for this disease can be counted on for any post infection control.

The forecast is calling for significant rain on Wednesday night into Thursday.  If your fields are still in very early bloom at that point a control is not required.

Botrytis risk is highest in fields with constant dampness (ie. coastal fields, or areas with regular fog).  Also fields, or sections of fields, that are protected from wind, or early morning sun can have increased pressure.  Tall dense canopies also create environments for this disease to thrive.

If we get significant rain through mid bloom this will also create a situation for higher disease risk.  Keep an eye on bloom development and the weather.

The next update will be on Friday, June 7th in the late afternoon.

11th Monilinia Update for Nova Scotia

We saw our first open cups on May 3rd, from a naturally occurring population of mummy berries in central Cumberland county, not a monitoring site. So Monilinia has been leasing spores, in most areas of mainland Nova Scotia, for close to 4 weeks now.  Peak spore release has long since past in most regions with the exception of very late fields in Cape Breton. 

Controls for Monilinia from this point forward are unlikely to give you an economic return in most areas of Mainland Nova Scotia. Disease risk is decreasing.

Focus should now be turned to bloom time diseases like Botrytis.

As bloom progresses, I will update on Botrytis risk.

The next update will be on Tuesday, June 4th.

10th Monilinia update for Nova Scotia

This year, it is very hard to give general statements about plant development stage and susceptibility to Monilinia infection.  I am seeing delayed and uneven development across the province. Some fields in Cape Breton are just approaching 40% F2 while some fields in Central NS reached that stage 3 weeks ago. 

However, we are approaching the end of Monilinia season for much of the province, as infection risk is decreasing, particularly for typically early fields.  We received much less rain than forecasted today and the amounts forecasted for the rest of the week are quite low.  If the forecast holds and temperatures stay in the mid teens, much of the monilinia risk will be gone by the weekend in mainland Nova Scotia.

That being said, if you have fields, in small micro-climates, that are still in early fruit bud development stages, risk of monilinia infection could still be high for those areas.

I expect by next week we will be in early bloom, in many areas, and farms will need to consider controls for botrytis in areas prone to that disease.

The next update will be on Friday, May 31st.

Frost update

We had freezing temperatures again last night into this morning.  It wasn't as wide spread and we did not reach the duration or temperature minimums we saw on Monday morning.  If there is additional damage it should show up by mid morning and into the early afternoon today.

I looked at a good chunk of central Cumberland County yesterday and we are seeing significant damage throughout the region.

I did see some fields with open white flower, with pollinators active in the field. I also smelled blueberry bloom in a couple of fields which was encouraging.  However, some damage was still evident in these fields.

It is very difficult to determine the full extent of the damage at this point. I am still unsure if flowers that were pollinated before the frost event are still viable, in many of the fields I have looked at.  We should begin to see much of the impact over the next two weeks.

A decision to protect the crop against further disease, needs to be made on a field by field basis.  Growers need to be confident there is still a good yield potential before considering a treatment, to justify the cost of treatment and application.  I wish I could be more definitive but we are in uncharted territory. 

Frost Damage and Botrytis Risk?

Many areas are still in what would be mid bloom.  With the tissue damage caused by the frost on Sunday night and the wet weather over the last 24 hrs, it is likely that Botrytis risk is building, particularly in Botrytis prone fields.  Obviously the severity of damage that occurred on Sunday night and Monday morning is critical to determining whether a Botrytis treatment is cost effective.

WBPANS circulated a factsheet via e-mail from Dr. David Percival yesterday which can help ID frost damage. Dr. Percival also circulated this factsheet at the twilight meetings last week. Here are some screen shots of that factsheet.  I will try and get the full factsheet posted later today.

If you are still seeing significant amount of white flowers in your field and bees are still active in the field, that is a good sign.  Protecting against further disease may be prudent in these fields.

Note: the weather forecast is for another frost event across the Maritimes tonight!

For many fields that have severe damage, it may not make sense to treat for Botrytis as too much of the crop has been lost.

For fields that have moderate damage, it would be worth your time to look closely at those fields, determine pollinator activity. Also cut open some flowers to see if the base of the flower (ovaries) are black. If the temperature was cold enough for long enough, the pollinated flowers could have been damaged as well.  This is what happened in 1996 when we had a major frost event near the end of bloom.

I will be looking at fields today and will report tomorrow.

If you have crop insurance and you think you have damage, please call the Nova Scotia Crop and Livestock Insurance Commission ASAP to report damage to your fields!!

Botrytis Update

Development is still variable across the province but we are moving into full bloom in many areas. 

Long, warm, wet periods are ideal for Botrytis infection.  Dense canopies that stay wet or have continual wet periods (daily fog) are very prone to this disease.  Over the last week or so we have had several frost or near frost events across the province.  If tissue is damaged by frost or another disease, like Monilinia, this can encourage Botrytis infection.

If you have a history of Botrytis infections, a control should be considered in early bloom (10-20% open flower) to protect the open flower and bloom that is not quite open but in the late pink bud stage.

Also but putting a control on at this time, the canopy is not fully closed and it is easier to get more of the product deeper into the canopy and protect more of the bloom further down the stem.

As always check with your buyer to see what products are allowable for their markets, and review the pest management guide to see what products are registered. 

http://www.perennia.ca/wp-content/uploads/2015/08/Wild-Blueberry-Pest-Guide-2018.pdf

http://www.perennia.ca/wp-content/uploads/2015/08/Wild-Blueberry-Fungicide-Chart-2018.pdf

10th Monilinia Update for Nova Scotia

With the exception of late ground in Cape Breton, the risk for new primary Monilinia infections has passed. If an infection has occurred over the last three weeks and the timing of the blight spray was off, you should be starting to see symptoms on the plants.

This is a picture from last year where you can see Monilinia infection on the flowers and the leaves.

We are rapidly moving into bloom, with many areas in central Nova Scotia at or above 20% open flower.  This is an ideal time to consider a first Botrytis spray, particularly if wet conditions are in the forecast. Not all fields in Nova Scotia have a history of significant Botrytis blight or other secondary crop year diseases like Septoria. However, you can find low levels of Botrytis in just about every field in Nova Scotia.  If weather conditions are wet and warm, it can lead to significant infections in any area of the province.

This will be the last Monilinia update for 2018, but I will continue to make updates for Botrytis Tuesday and Friday of next week and other updates throughout the summer.

9th Monilinia Update for Nova Scotia

Most fields in central Nova Scotia are beyond the risk of primary Monilinia infections at this point.

Any infections that have already occurred will start to show symptoms on the plants over the next week to three weeks depending on when controls were applied and when the infections occurred.

Cape Breton is still in the middle of infection risk as all sites reporting are beyond the 40-50% F2 threshold.

Skye Mt - 47% F2 (May 16th)
Borish - 77% F2 (May 18th)
MacLeod Settlement - 55% F2 (May 19th)
Keppoch - 50% F2 (May 20th)

These fields and other late fields that would have just reached this threshold within the last week and a half, would have experienced an infection period on Sunday.  The long warm wet period, combined with light frosts would have made the tissue susceptible to infection. The forecast is for more wet weather Wednesday, controls should be considered in these areas.

Many fields are starting to flower in central NS (Colchester, Cumberland and Pictou counties).  As fields approach early bloom controls for Botrytis should be considered, particularly in areas that are prone to this disease.

The next update will be late in the day on Friday May 25th.

Plant development and disease damage

Many fields are well along with regard to bloom (even though it has been fairly cold the last few days).

For those that haven't treated for Botrytis yet (later fields) it would be important to consider an application prior to the rainfall event on Friday.

We have been seeing a lot of Monilinia infection around, with some of it being quite severe, below is a picture from late last week that shows some of the damage.

Botrytis Update for Nova Scotia - May 30, 2017

It was certainly cold last night but I'm not sure we had a severe enough frost to do any amount of damage last night.   That being said, there could have been some pockets that did receive below zero temperatures.  Generally speaking temperatures need to be below -2 degrees C for an extended period of time to get significant damage to the flower.

Bloom is moving along nicely with good anticipated pollination weather for both today and tomorrow.  The weather forecast is calling for wet conditions Wednesday evening through Thursday. For those who have not treated for Botrytis yet, and are typically prone to botrytis infections, they should strongly consider making an application prior to the coming wet period.

If your bees are in the field, try to make the application when the bees are not flying (ie. in the evening or early morning) to minimize contact with pollinators.

I have yet to see any Botrytis symptoms showing up in the field, but we are still early in bloom.  I have seen a fair amount of Monilina infections, particularly on vegetative buds.

I will continue to make regular updates through the summer on this blog, but will make less regular updates on the blight line (662-4242) as we move through the summer.

Botrytis update for Nova Scotia - May 26th, 2017

So we are getting lots of rain today.  If you have a significant amount of open flower and you have a history of Botrytis you would have needed to apply a control before this wet period.  If you are still early, with <10% open flower, Botrytis infection risk should be low.

However, as we move into early next week and as flowers start to open, I expect Botrytis risk will be high if we get another wet period.  We have had lots of wet conditions that would have enable the disease to start cycling on other plants.

The important thing to remember, any product you are using should be applied before the wet period starts in order to prevent infection.  Most of the newer products ideally need a couple of hours to ensure they are into the leaf, before a rain fall.

I was looking at some fields this week and saw the first signs of Monilinia infection.

It was not very hard to find infection in this field.  It was an early field and to my knowledge had not been sprayed to manage Monilina. When the sun comes out on Saturday afternoon or on Sunday, you should start seeing more and more symptoms if your crop wasn't adequately protected.

Reminder: The WBPANS Twilight meetings are next week

May 29 - Joe Slack's Receiving Shed in Debert - 5:00 pm

May 30 - John Cameron's Receiving Shed in East River St. Mary's - 5:00 pm

June 1st - Art Sargent's Receiving Shed in Parrsboro - 5:00 pm

  

10th Monilina Update for Nova Scotia - May 24th, 2017

The risk for new Monilinia infections has past for most of Nova Scotia.  If there are very late fields in Cape Breton that have not been treated some consideration should be given to making an application before the rain on Friday.  Although there could be some late infections on some late fields in mainland Nova Scotia, the risk of significant crop loss is now very low.

Most of Nova Scotia is moving rapidly into bloom and consideration should now be given to protecting against Botrytis infections.  If you are 20 to 30% open flower or beyond, and your field has a history of Botrytis infections, a treatment should be applied before the rainfall event forecasted for Friday.

Botrytis controls can be expensive so it is important to consider what your yield potential is before an application is made.

Refer to the Wild Blueberry Pest Management Guide 2017 for product options

http://www.perennia.ca/wp-content/uploads/2015/08/Wild-Blueberry-Pest-Guide-2017.pdf

As always, check with your processors to see which products are allowable for their markets.

Botrytis protection

We are in a stretch of pretty good pollination weather, however it looks like we will get some wet weather towards the end of the weekend and into next week.  If you are in Botrytis prone areas or you are concerned about this disease, an application before this next wet period would be worth considering.

We are starting to see the impacts of herbicide applications from this spring and last fall. The photo below was from a November 27th application of Kerb to control fescue. I applied it with a 2 metre CO2 sprayer.  You can see the "control plot" in the centre of the screen that didn't receive any product.

 

13 Monilina Blightline Update

The risk for Monilinia infection has past for all areas of Nova Scotia, except for late fields in Cape Breton and possibly the very late areas of Cumberland county.

This past week has pushed plant development very quickly.  Flowers are opening rapidly and should continue to do so throughout the weekend.  There are chances of showers through tonight but very little accumulation is expected.  There is a more significant rainfall expected on Monday and growers should consider protecting their bloom for botrytis.

Botrytis spores begin to develop on a wide range of other plant hosts and can move to the blueberry flower if conditions are right.  Wet and heavy ground, a dense canopy and a lot of bloom are all factors that can lead to higher infection risk.

As with most of the diseases we deal with, Botrytis needs warm and moist conditions to sporulate rapidly.  All of the products we have registered to control botrytis need to be applied before infection, therefore before a significant wet period.

Since we are moving rapidly into bloom it is best to avoid applications when bees are flying, applications in the evening or early morning are best.  You should also talk with your Beekeeper before making any application during bloom.

Botrytis, Frost and Pollination

We had some cool damp weather last week, up to and including Saturday.  Before this period, botrytis risk was low, but as we approach full bloom and with periodic wet periods approaching, protecting against Botrytis could be important.  (particularly if you have had a history of it in your fields).  Check the Wild Blueberry Pest Management Guide for allowable products ( WBB Pest Management Guide)

Remember if you have to spray, avoid contact with pollinators by spraying when it is cool or in the evening.  It's always a good idea to check with your beekeeper as well.

We had some light to moderate frost on Sunday and Monday mornings.  I haven't seen or heard of any damage.  The duration of the frost was generally short and temperatures did not appear to get low enough to cause any significant damage.

12th Monilinia Update for Nova Scotia

Monilinia infection risk is rapidly decreasing across the province.


Apothecial cups are drying up throughout most of central Nova Scotia.  I have one report of a viable cup, but this is in a late field on Glasgow mountain.  There will still be viable cups in late fields in the eastern parts of Mainland NS and Cape Breton.


We have had very sporadic, light rain over the past few days a very little rain is forecasted until Monday. It is unlikely there were any significant wet periods through the middle of this week for most regions.


If fields were treated this past weekend or early this week they are protected through the start of next week. For most areas of mainland NS this will cover you through the end of the Monilinia season.


If you did have a long wet period this week  in your area, it would have been an infection period, particularly in late fields and in the eastern part of the province. 


As we move into bloom, it is important to make plans to control Botrytis.  Botrytis thrives on warm wet conditions.  Our most commonly used controls (Switch and Pristine) need to be applied prior to infection.  Ideally one of these products need to be applied early in bloom (before 40% open flower) and before an extended rainfall event. This is needed to prevent flower loss to Botrytis.  Coastal and foggy areas may need a second application.  If the season is very wet throughout bloom, inland fields may need a second application as well. 


Talk to your beekeeper about which products you would like to use and for scheduling when the bees should be introduced.


I will be doing one last Monilinia update on Tuesday but will be continuing blog updates all summer.  Also, I will be keeping the blight phone line updated, starting in mid July as we start trapping for Spotted Wing Drosphila "SWD".  I will let growers know in what general areas we are catching the fly and when we are finding them.

11th Monilinia Update for Nova Scotia

All major growing areas in Nova Scotia are beyond or well beyond the 50% F2 stage of floral development, including Cape Breton.


We are still seeing mature, nearly mature cups in sites across central Nova Scotia.  Infection risk is still present in central and eastern regions of the province.


Many areas would have had an infection period either Sunday evening or Monday evening.  If Proline or propiconazole based products (Topas, Jade, Mission etc.) were put on just before these infection periods, the buds would have been protected.  If an application hasn't yet been applied, a propiconazole based product should be used in order to get the kick back control.


An application made on the weekend or early this week will provide protection for 7-10 days and that will get all fields through the monilinia season in Central Nova Scotia.  The exception to this would be extremely late areas (ie. Cape Breton etc.).


Of Note: Bloom is developing quickly in the western end of the Province. Growers should be considering botrytis management options in this region.  Botrytis controls should be applied before a major wet period and during early bloom.


Also: Sprout fields are developing quickly.  Velpar and Sinbar applications need to be made shortly, as the risk of plant damage increases as plants begin to emerge from the ground.


Check back on Friday for the next update