SWD Update from Frank Drummond – July 28, 2014

July 29th, 2014 7:08 AM

Last week we captured SWD in traps that were placed in Jonesboro. So far, SWD has been captured in a few fields in Coastal Maine, the Blue Hill area and in Jonesboro. SWD was also captured in Nova Scotia last week. Please deploy traps if you have not already done so and monitor them at least on a weekly basis. If you capture a male SWD, protect your crop with an insecticide. (see the SWD ID factsheet on the wild blueberry website:
http://umaine.edu/blueberries/factsheets/insects/spotted-wing-drosophila-identification-guide/)

SWD Detected in Parts of Southern and Downeast Maine

July 21st, 2014 8:52 AM
The spotted wing drosophila is starting to be detected in both southern and parts of downeast Maine. David Handley, who has been sampling highbush blueberry and raspberry fields has reported trap captures of spotted wing drosophila in Cape Elizabeth, Buxton, Turner and Wales. In wild blueberry fields MALE SWD have been captured in Blue Hill and Sedgewick. It is typical in the early season (from what we have observed in the first two years) that initial trap captures are quite spotty. Our recommendation is that if your crop is vulnerable (containing ripe fruit) and if you have NOT put traps out yet…you should put out traps as SOON as possible. Inspect the traps 2 times per week for males (spots on wings..see the wild blueberry factsheet on SWD Biology). IF a male is captured then it is time to protect the crop with an insecticide (see wild blueberry factsheet on insecticides suitable for SWD).

It is doubtful that any fruit has been attacked by SWD yet. We will be sampling the fruit in fields this week where SWD has been captured and let you know what we find.

SWD Management Recommendations Fact Sheet

July 21st, 2014 7:21 AM

Attached is a fact sheet for SWD management in Michigan Highbush bluberries (SWD Management for Michigan Blueberries_June 21 2014) , which is very informative and includes a table with rain steadfast properties of some of the SWD insecticides.

Here is the link to the the SWD Management for Michigan Blueberries  http://www.ipm.msu.edu/uploads/files/SWD/SWDManagementforMichiganBlueberries_-June212014.pdf

Some reports of Botrytis blossom blight and Frost – June 6

June 6th, 2014 6:51 PM

Botrytis with short hairsThere have been some reports of localized patchy frost damage the last week of May followed by Botrytis symptoms showing up this week.  Frost will make blossoms more susceptible to Botrytis infection.  I have heard this from growers in the Union area and around the Orland area.   In one field, we saw low levels of both frost and Botrytis infection on the blossoms.   One of the differences to previous years was the very short hairs of the Botrytis sticking out of the base of infected blossoms.  A hand lens will be needed to see this kind of Botrytis infection.   Please look at previous reports to see pictures of these different diseases. 

The rain over the last 2 days, Wednesday June 4 to Friday June 6th produced moderate to high risk of Botrytis infection across monitored blueberry areas.   Many growers are nearing the end of bloom, so there is little risk of further Botrytis infection that will impact the crop.  

Frost and Botrytis risk in some areas May 29th

May 29th, 2014 1:03 PM

Frost

In Northern Hancock at our Silsby Plains site and at our Deblois and Cherryfield weather station locations in Washington county, there were frost conditions overnight from Wed. May 28th to Thurs. May 29th.  Lee Beers is a PhD student studying cold tolerance in blueberries and his research has found conditions from 28 F to 24 F will cause some minor damage to flowers but temperatures below 24F will kill many flowers.  Temperatures at Cherryfield dipped to at least 26 F and at Deblois and Silsby Plains to dipped to 22 F for a number of hours.    All of the other weather station locations had temperatures above 30 F overnight.

Botrytis Risk

Two weather station locations, Dresden Mills and West Rockport reported weather conditions that produce a high risk of Botrytis infections, IF the fungus is present in a field.   This does not mean fields will get Botrytis, just that there is a risk of infection if the fungus is present.

Fields with mummy berry disease will also have killed blossoms, so please look at the symptoms to determine what has killed your blossoms.  Please take a look at previous blog posts or emails  for pictures and descriptions of the symptoms for Mummy berry blight, Botrytis blossom blight, and frost.

  Any questions please call Seanna Annis  1-800-897-0757 (Maine only), or email at sannis@maine.edu

Mon. May 26 – Mummy berry blight and Botrytis blossom blight

May 26th, 2014 5:04 PM

I think the mummy berry infection season is now over for 2014.  Any remaining cups would have dried up over the last few days, so there won’t be any spores to infect the plants.   I don’t think the wet weather we had this weekend or will have on Tuesday will be causing any infection periods for the mummy berry fungus.

You may be seeing symptoms of Mummy berry disease in your field  now and over the next week.    It is too late to spray fungicide at this time. Any symptoms you find are from infections that occurred at least 9 to 10 days ago.  The spores produced on the dead leaves and flowers will NOT cause new killing infections. These spores will infect healthy flowers and produce mummy berries. The number of mummy berries produced are typically too low to be concerned about trying to control this stage of the disease.

MUMMY BERRY SYMPTOMS

Symptoms of mummy berry disease are shown in the pictures below. This fungus does attack and kill both flowers and leaves.  Flowers are typically killed before they open.  The petiole (base of leaf) of leaves give a characteristic shepherd’s crook shape.  Powdery gray spores can be seen at the base of the leaves or flowers where they attach to the plant. Unless it is a very susceptible clone, you will only see isolated leaves and flowers with the disease.

Picture of mummy berry disease symptoms on leaves and flowers. gray powder is found at the base of dead flowers and leaves

FROST

Frost has been minimal this year but may occur in hollows or some more sensitive clones.  Frost tends to affect most of the flowers on a stem. You may also see just the green growing tip of the leaf dying off. Please see pictures below.

 

Picture of frost damage of blossoms, all flowers on a stem tend to be affected. On leaves, the youngest leaf in the center of the cluster have been killed. 

Botrytis blossom blight

You may see Botrytis blossom blight occurring in your field if you had some bloom last week.  The weather over this weekend only produced conditions for Botrytis infection at our North Ellsworth and East Machias/Whiting weather station locations.  Fields in these area are at risk of Botrytis infection, IF the fungus is in these fields.  You can scout for this disease in early blooming clones or dying tissue on weeds in the field.   The symptoms are dead, open, flowers with black hairs sticking out of them (see picture below). You will probably need a magnifying glass or hand lens to see the hairs.  

ONLY apply fungicides to control Botrytis blight IF 1) you have seen severe infection this year in early clones, this means more than one or two blossoms affected, and 2) you have had a severe problem with Botrytis blossom blight in previous years.

You will want to minimize any exposure of honey bees, bumble bees AND native pollinators to pesticides, including fungicides, during bloom.  Bumble bees and native pollinators will still be working pollinating your fields when poor conditions keep the honey bees in their hives.   The fungicides recommended for control of Botrytis blossom blight are considered non-toxic to honey bees BUT we do NOT know how native pollinators would react to these materials or how there may be subtle effects on honey bees and bumble bees. 

My recommendation is NOT to apply fungicides to control Botrytis blossom blight unless you are SURE you have it in your field.  In my experience  visiting many fields reported to have Botrytis blossom blight is that the dead blossoms have been due to Mummy berry disease in the majority of fields. 

If you do apply fungicides during bloom, apply them at LATE EVENING or at NIGHT to minimize the exposure of pollinators to these compounds.

Picture of Botrytis blossom blight showing black hairs coming off of dead flowers or leaves

 Any questions please call Seanna Annis  1-800-897-0757 (Maine only), or email at sannis@maine.edu

Thursday, May 22 Mummy berry disease and Botrytis blossom blight

May 22nd, 2014 11:42 AM

Hancock and Washington counties

Mummy Berry Disease

There was another infection period overnight for mummy berry disease at all fields with weather stations in Hancock and Washington counties.  Most cups will be dying off by now, but if you have a later or wetter field there is a chance you may have had infection period overnight.  Fungicide applications should protect your plants for about 7 to 10 days after application.   You have until about 3 days from the start of the latest infection to treat your plants to protect them. 

Botrytis Blossom blight
There were also conditions for a moderate to high risk of Botrytis infection around the weather stations at Sedgewick, North Ellsworth and Eastbrook/Waltham over  Tuesday, May 20th  and Wednesday, May 21st nights.   This does NOT mean these fields will get Botrytis blossom blight.  
 I suggest scouting for Botrytis blossom blight in early blooming clones  and dead weeds in those areas to look for the symptoms of the disease.  IF you find the symptoms, then your field may be at risk for Botrytis infection. 

 

Locations Mummy berry Infection  period starting Wednesday May 22nd 
Sedgewick 9:20am
North Ellsworth 11am
Eastbrook/Waltham 6:40pm
Deblois 9pm
Cherryfield 8:40pm
Jonesboro 8:15pm
Wesley  8:40pm
East Machias/Whiting 8pm

Any questions please call Seanna Annis  1-800-897-0757 (Maine only), or email at sannis@maine.edu

Mummy Berry Infection and Botrytis blossom blight Wed. May 21

May 21st, 2014 10:04 AM

Knox, Lincoln and Waldo counties

Botrytis blossom blight

This is the time of year to scout for Botrytis blossom blight on early blooming blueberry clones.  Look at dead open flowers, and any dead or dying tissue (leaves or flowers) you see on weeds near or in your fields.  The symptoms are dead, open, flowers with black hairs sticking out of them. You will probably need a magnifying glass or hand lens to see the hairs. Your flowers may also be killed by mummy berry disease, which will not have the black hairs sticking out of the dead tissue.    If you do have Botrytis in your field and are getting a lot of bloom, this wet weather over the next week may cause infections by this fungus.  It is only worthwhile to apply fungicides for Botrytis blossom blight if you are sure you have this disease in your field.  If you do not have this fungus in your field, no matter how much wet weather you get during bloom you will not get Botrytis disease.  Be careful to protect pollinators if you do have to spray for this disease, spray when pollinators are not in the field.

Mummy Berry Disease

Hancock and Washington counties

There were mature spore producing cups found in a few plots around the barrens on Tuesday.  Most locations the cups were drying up. I expect there are still a few cups around in the barrens and they will be finishing up this week.  If you have a later or wetter field there is a chance you may have had infection periods in the past few days. Infection periods occurred overnight on Mon. May 19th  and Tues. May 20th (please see chart below). Wet weather is expected to continue the end of this week.

Infection periods and fungicide applications

Your fungicide application should protect your plants for about 7 to 10 days.  With heavy rainfall, there may be a bit shorter protection than 10 days.   With the infection periods in the last 2 days, you have until about 3 days from the start of the infection to treat your plants to protect them.

If you would be applying a second application of propiconazole, it would be a good idea to switch to a different fungicide with a different mode of action to help prevent resistance to propiconazole developing in your field (Please see the 2014 fungicide chart).   Other fungicides should be applied as protectants and before infection periods occur.

 

Locations Infection  period starting Monday May 19th  Infection period starting Tuesday, May 20th
Dresden Mills likely none likely none
West Rockport likely none likely none
Appleton likely none likely none
Belfast  likely none likely none
Sedgewick 10am 3:40pm
North Ellsworth continued from Sun. May 18th 1:40pm
Eastbrook/Waltham 5:40pm 6:20pm
Deblois station down station down
Cherryfield 4:40pm 4pm
Jonesboro 3:45pm 7:45pm
Wesley  2:40pm 6:40pm
East Machias/Whiting 4pm 6pm

Mummy berry blight may not be finished yet: Monday May 19th

May 19th, 2014 5:42 PM

Lincoln, Knox, Waldo counties

Only dried up cups were found last week in these areas. There is a chance later fields farther north around Belfast area may still have had infection periods this last weekend.  I expect fields farther south were not affected.

Hancock and Washington counties

Cup that would produce spores were found on Sat. May 17 in Whiting area and numerous spore producing cups were found on Monday May 19th at Pea ridge near Cherryfield.   At other sites, the cups had dried up or were drying up on Friday, May 16th in the mummy berry plots.   I have seen this in other years where the cups are done in mummy berry plots but some mature cups can still be found in the field with some searching.  I expect cups can still found around in the barrens during this last weekend and I expect through the next few days.

Infection periods occurred from Friday May 16th through Monday May 19th (please see chart below) and are expected later this week.

Infection periods and fungicide applications

In those areas where there was an infection period starting Friday May 16th  or the morning of Saturday May 17th, if you have applied fungicide on or after Saturday May 9th your plants were protected  and  you have until the evening of  Tuesday May 20th,  in most areas to apply fungicides to kill any infection. 

If you would be applying a second application of propiconazole, it would be a good idea to switch to a different fungicide with a different mode of action to help prevent resistance to propiconazole developing in your field (Please see the 2014 fungicide chart).   Other fungicides should be applied as protectants and before infection periods occur.

Locations First Infection  period  Second Infection period  Mummy berry plot Mummy berry development
Dresden Mills likely none likely none No n/a
West Rockport likely none likely none Yes dried up cups
Appleton likely none likely none Yes dried up cups
Belfast  Fri. 8:40pm?  Sun. 7:40pm? no n/a
Sedgewick Sat. 10am Sun. 4:20pm no n/a
North Ellsworth Sat 10am Sun. 4:20pm Yes ?
Eastbrook/Waltham Sat. 11am Sun. 3:20pm Yes ?
Deblois station  down station down Yes Mon. cups
Cherryfield Sat. afternoon Sun. 3pm Yes Fri. dying cups
Jonesboro Sat. 12:30pm  continued from Sat. Yes Mon. dead  pinhead
Wesley  Fri. 9:20pm Sun. 12:40pm Yes Fri. dying cups
East Machias/Whiting Fri. 9:20pm  Sat. 12:40pm Yes Sat. cups

Mummy berry infections Wed. May 14 and Thurs. May 15

May 16th, 2014 10:25 AM

Knox, Lincoln, Waldo counties

Growers reported only finding dried up cups on Tuesday May 13th in their mummy berry plots.  I do not think the cups were done at that time in most fields since there is a range of when cups develop and I expect there were lingering cups around.  There were infection periods in some fields over Wednesday night into Thursday, please see the chart below.  I expect most cups will be done by Friday May 16th evening with this warm weather.   I don’t expect most areas to have infection periods occurring this weekend.  If you have a wet, late field you may still experience mummy berry infections this weekend.

Hancock and Washington counties

There were still active cups and some pinheads found in fields in the barrens on Tuesday.   Infection periods did occur in these areas over Thursday night.  I expect the cups will be around this weekend in these areas.   I expect the Blue Hill and  Ellsworth area will also be finishing up with cups this weekend. 

Infection periods and fungicide applications

In those areas where there was an infection period starting Wed. May 14th , if you have applied fungicide on or after Wed. May 7th your plants were protected  and  you have until the evening of  Saturday May 17th,  in most areas to apply fungicides to kill any infection. 

In those areas where there was an infection period starting Thursday May 15th , if you have applied fungicide on or after Thurs. May 8th your plants were protected  and  you have until the evening of  Sunday May 18th,  in most areas to apply fungicides to kill any infection.

If you would be applying a second application of propiconazole, it would be a good idea to switch to a different fungicide with a different mode of action to help prevent resistance to propiconazole developing in your field (Please see the 2014 fungicide chart).   Other fungicides should be applied as protectants and before infection periods occur.

 

Location 2014 Infeciton period start Wed May 14 Infection period start Thurs. May 15 Mummy berry plot Mummy berry development
Dresden Mills  9:40pm borderline 7:40pm No n/a
West Rockport 9pm 7:40pm Yes dried up cups
Appleton 7:40pm  7pm Yes dried up cups
Belfast  about 9pm  none no n/a
Sedgewick station  down (probably had infection period)  9:20pm no n/a
North Ellsworth 10:20pm  9pm Yes ?
Eastbrook/Waltham none 11pm borderline Yes cups
Deblois station  down station down Yes cups
Cherryfield none none Yes cups
Jonesboro none 7:30pm Yes cups/pinhead
Wesley  none 11:20pm borderline Yes cups
East Machias/Whiting none none Yes cups