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Marssonina 2021
Posted by Michael Phillips
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Michael Phillips
Marssonina 2021
July 15, 2021 04:24AM Moderator
Registered: 10 years ago
Posts: 621
The conversation concerning leaf blotch is about to make a major comeback. I’m starting a new thread to direct immediate attention but please know this builds on an earlier thread entitled Marssonina 2019

I was in southeastern Vermont yesterday for a consultation, and then dropped by Scott Bolotin’s orchard on the way home. His trees are almost all yellowing, starting to drop leaves en masse, and no question it’s Marssonina Leaf Blotch. The similarity to Frog-Eye Leaf Spot on those leaves still with green hue gave me pause but there’s no escaping that yellow finale. What’s significant in this case is that the hundred varieties on Scott’s farm are mostly heirlooms on Antonovka rootstock planted some 30 years ago. Scott did no spraying whatsoever this season. His fruit is amazingly clean but it’s not going to have photosynthesis support to get to harvest. And next year’s fruit buds will certainly suffer as a result of nutrient flow shutting down.

This evening I’ve been sent pictures of a smattering of Marssonina found in a cider apple orchard in the western foothills of the Hudson Valley. This ten-acre planting is just down the road from “Angry Orchard” (accordingly I like to kid the brothers involved that their operation must be “Passive Aggressive Orchard”) and consists of 2nd and 3rd leaf trees, mostly on Geneva and Bud.9 rootstock, trained to trellis, just starting to bear. Management follows the core holistic program with trace minerals provided in tonic form (Mikronite from Agri-Dynamics). Sap analysis done at the end of the cell division phase revealed the typical need for more calcium, manganese, magnesium, and iron… but this supplementation was not underway in earlier sprays as sap levels looked righteous starting out. Cueva was applied on June 15 to the rows showing what looked like Frog-Eye spotting (with a curious red halo) despite that seeming so unlikely in young trees (and a bit late to have relevant impact). Now those leaves are turning yellow and blotchy, ergo, it’s Marssonina making inroads in this planting.

Let me end by pointing out two articles in previous issues of Community Orchardist. An overview of this up and coming fungal disease was provided in the Winter 2020 newsletter. A plausible means of addressing inoculum loading was then suggested by Lou Lego in the Winter 2021 newsletter. Time to zone in again, folks!

Lost Nation Orchard
Zone 4b in New Hampshire

Edited 2 time(s). Last edit at 07/15/2021 07:46PM by Michael Phillips.
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Mike Biltonen
Re: Marssonina 2021
July 15, 2021 07:29PM Registered: 10 years ago
Posts: 276
There’s lot of black rot going around and some varieties are obviously more susceptible than others to it. I am not surprised. It starts to get ugly when you CAR and yellowing (maybe Marsoninna , maybe not) starts to creep in. When visually IDing “Marsy” I look for the blotchiness and not just general yellowing. I have seen both this year and with all the rain I am not surprised. But general yellowing is not always Marsy. I am intrigued by Lou’s approach to spraying as well as his general approach of cleaning up leaves after each season (more for scab than Marsy). This year I have not yet seen much Marsy, though I expect that will change in the next few weeks. I have also seen some trees with apple mosaic virus that in the early stages could be confused as Marsy. Most of the growers I am working with are using a combo of Double Nickle/Cueva/Regalia/micros as well as other nutrition. Doesn’t work so well with CAR or scab, but other diseases including fireblight seem to be kept at bay. We’ll see over the next few weeks how the Marsy develops and maybe that helps as well too. What I am 100% sure of is that stopping any spray program too early in the season will result in extensive Marsy. And with this rain, like the cicadas in NJ, it could be biblical. Anyway, lets keep it\\the convo going.

Mike Biltonen, Know Your Roots
Zone 5b in New York
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Jay Kenney
Re: Marssonina 2021
July 28, 2021 02:36AM Registered: 4 years ago
Posts: 4
I’ve got what looks like Marssonina and am unfamiliar with it in apple trees. We see it out here in Colorado in Aspen, but not so much in apples. I’m reading this and the previous threads to see what if anything I can or should do but would appreciate any experienced eyes taking a look and seeing if you agree. Two of the pics in the folder look strikingly like marssonina, the third from a second graft, less so. Thoughts? And thanks in advance.

Here’s the link: Marsonnina

Wheat Ridge, CO, Zone 6a (2018)
Golden, CO, Zone 5b (2018)
Crawford, CO, Zone 6a (1905)
Lewis, CO, Zone 6a (2017)
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Michael Phillips
Re: Marssonina 2021
August 01, 2021 02:44PM Moderator
Registered: 10 years ago
Posts: 621
These young trees in pots have yellowing leaves, Jay, but it’s not Marssonina. Far more likely nitrogen is running short as the biology in that pot doesn’t have reserves to call upon. Irregular watering could be part of this situation. The infection lesions that resemble frog-eye leaf spot early on will coalesce into harder and browner blotches on apple. Perhaps that resembles how Marssonina plays out on aspen, perhaps not. Here I can watch the poplar trees but all appears green in far northern New England to date. We also have not had the deluge conditions growers a couple hundred miles south are experiencing where I first saw signs of blotch in downstate orchards this year.

Lost Nation Orchard
Zone 4b in New Hampshire
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Don Kretschmann
Re: Marssonina 2021
January 24, 2022 06:10AM Registered: 1 year ago
Posts: 11
Just for reference if needed, we have all scab resistant/immune varieties. 3 A total. Two blocks largely on M7–1985 and 1996, somewhat crowded as they’re 15-20′ tall, on 15’x15′ row spacing. 2007 and 2016 block are trelised on G11, G16, G-41 and a few M26 4’x15′ spacing. All have been grown with organic protocol since planting. We don’t thin to any degree, thus most varieties suffer biennielism to some degree.
Over the years we’ve not needed to much think about scab, since genetics was our defense. We’ve learned to live with a little fireblight after a bad fall hailstorm in the late ’90’s. Then about 4 years ago noticed a premature blotch and leaf drop noticeably in our very dependable Liberties. Since then, we’ve struggled to figure out what to do about Marssonina. Recommendations have centered around “a good scab program” which we’ve scrambled to find what other organic fruit growers have done. Defensively, these have revolved around sulfur and lime sulfur along with a sometime of copper. Proactively/offensively this has involved effective microorganisms, abetted by neem and karanja oils. (these proactive treatments we had used anyway previous to Marssonia)
So starting in 2020 in addition to our usual mineral nutrients, EM, oils, seaweed, and fish:
2020 we’d spayed a dormant copper (NuCop) in dormant, wet spring so every 2 wks 10# sulfur green tip thru bloom, then 2 qt. lime sulfur every 2 wks thru August. After bloom it was a pretty dry season overall, and somewhat the “off-year” following an odd freeze just after bloom. Crop yield was low-average.
2021 looked to be the year of all years! All varieties great bloom. Fair pollination (but gave me ideas if we could control the bees, maybe we could thin that way…??smiling smiley) Nucop dormant; 2 qt. lime sulfur at bloom; re-read LS labels and thought increasing to 2 gal/A at petal fall would be good timing. Subsequently did see some burn. Lesson learned. Don’t recall what I was thinking, but I missed several June LS spays before resuming July 5. Trees looked fantastic. Lots of fruit. Maybe I wasn’t looking for the first tell-tale signs. Was counting the bushels wondering how we’d pick them all. In August we began to see Marssonina set in. We’d picked lots of Pristines in late July early Aug. Lots of Redfrees. Stuggled to get all the Primas picked in August. Lots of good sized Liberties in early Sept. but they were without many leaves and brix was very low. Jonafrees generally much smaller than the abundant rainfall would have provided, and leaves missing or yellowed. By mid-late Sept the orchard looked like early spring–beautiful green grass, leafless trees. Most devastating for the November ripening Goldrush. Normal brix is 10-15+; this year 5-7. We left them on until early December hoping for a miracle. Some trees actually re-bloomed in late fall. Eerie.

Spoke with Lou Lego after reading his SARE research report. He said he isn’t too hopeful for his blocks of trees where it’s impossible to vacuum up Marssonina infected leaves. We are nearly surrounded by woods and infection from cherries and poplars is impossible. We’ve always done a final spray in November with EM, neem, and fish emulsion before leaf drop to promote breakdown. This season, we made a special effort by flail mowing in late November. After speaking with Lou in early Jan. I looked again at leaf litter and decided since I couldn’t vacuum and the weather was good, I’d mow with a lawnmower equipped with a mulching blade. That made a big difference in how much they were chopped up. Since it was physically impossible for this old guy to do the entire orchard, I re-flailed the 3/4 that hadn’t been mulch mowed.
Then got a bright idea that it would be good to spread a little compost on top to promote the breakdown. But how to do that easily? Struck me that we had granular organic fertilizers which have indeed been composted (though I certainly wouldn’t vouch for the quality). So a half hour trip on January frozen ground with the Vicon spreader seemed well worth the effort. With the subsequent 8″ snowfall, that should bind the litter and breakdown agents together well. Will report back on how that worked. If one can discern a difference.
All that said, I think there’s a lot more to go on a good strategy for Marssonina. Don’t know if missing some key June sprays was cause of bad Marssonina in 2021. Suspect it was only part of the story. I truly don’t like any of the elementals because it likely means much reduced biological activity. It would seem that outcompeting fungal pests for food supply would be a good stategy, but a question I’d pose is that since EM are primarily bacterial, is that the best competition we can muster? Wouldn’t there be other benign fungi interested in that same niche? And all things being equal, wouldn’t the allies likely reside locally in those same adjoining woodlots? Likely evolving? How could one nudge them toward our Edenic plantings?
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Brittany Kordick
Re: Marssonina 2021
January 24, 2022 05:19PM Registered: 4 years ago
Posts: 165
Thanks, Don, for the update from your orchard. I’m enjoying some welcome mental stimulation provided by the musing that we might be able to do better than EM-1 as far as competitive colonization against a pathogenic fungi like Marssonina. I’m afraid I don’t have anything to add to the conversation in this case, though, as our Marssonina experience hasn’t changed since my last post about it back in 2019 — happily, to date, Marssonina hasn’t been grievous enough in our orchard to specifically address, but prevention vs. control can be a razor’s edge, and given the increasing incidence of Marssonina all along the East coast, perhaps our priorities should change.

Every year the foliage of a few varieties throughout our orchard appear to be afflicted (we haven’t done any testing, but the defoliation timing and manner are consistent with Marssonina). It’s not always the same varieties, nor do affected varieties tend to be near each other, and we definitely seem to be faring far, far better than other local orchards and homeowner trees. It’s not unusual to see completely defoliated trees during the summer in our neck of the woods, and increasingly, customers are asking us what’s up with their own trees defoliating. I credit our holistic growing practices for the overall good state in our orchard, but can’t point to one aspect of this over any other . . . which is perhaps most encouraging! And yet our primary orchard issue remains pervasive fungal rots decimating any sellable fruit . . . hence my particular interest in more targeted competitive colonization against pathogenic fungi.

Your lime sulfur program made me gulp, as well, if mostly from a logistical standpoint, as I imagine you trying to keep up with re-populating EM-1 versus lime sulfur apps. We have a handful of peach trees that rarely have a speck of edible fruit due to brown rot, and a couple years ago, we decided to go heavy, heavy on a lime sulfur program to try and see if it was even possible to get a decent peach. I think it was something like every 10 days spray lime sulfur, wait a few days, spray holistic mix, kill off the bacteria with lime sulfur, put it back, etc, etc. We managed to stick to this schedule almost perfectly, but was exhausting and demoralizing to try and keep up with spraying our dozen or so trees . . . and we did not see ANY difference in the brown rot incidence in our peach trees. Now that we have a NEWA weather station, we can look more at pinpointing applications for things like this as most appropriate to infection windows . . . but we’re also grafting some ‘Indian Blood’ peaches this season to try and beat the brown rot with genetics.

Kordick Family Farm
Westfield, NC
Zone 7a

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MARSSONINA 2019

Marssonina 2019
Posted by Brian Caldwell
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Brian Caldwell
Marssonina 2019
January 18, 2020 03:43AM Registered: 10 years ago
Posts: 65
In central NYS, we are experiencing a new disease problem. It is called Marssonina blotch and is not really new; it has probably been around at low levels for many years. However, two very wet springs in a row have allowed it to become very noticeable. Wild trees and unsprayed ornamental crabapples were heavily defoliated by late summer. More to the point, some defoliation was also apparent in our organic orchard. We also saw Marssonina spots on fruit, evidently the first time this has been reported in NYS.

[extension.psu.edu]

The upshot of this is that our organic low spray scab program, based mostly on sprays of bicarbonate, Silmatrix, and Regalia, switching to sulfur from pink through bloom, does not control Marssonina very well. Straight sulfur programs have shown similar lack. In Europe, copper has been a bit more effective, but still not great.
The good news is that the fruit spots do not get much worse in storage. They are not “dry” like scab lesions, but they progress very slowly. So next year if we have them, we will grade mild cases as “utility” and not cider grade.
My hope is that if we have a drier spring this year, Marssonina will not be bad. We will probably add some Cueva copper into our spray program as well.

Hemlock Grove Farm
Zone 5 in New York
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Brittany Kordick
Re: Marssonina 2019
January 18, 2020 06:33PM Registered: 4 years ago
Posts: 165
In our rural area of NC, we see a lot of large apple “yard” trees — usually singular, older, larger trees that are not well maintained. While they never look that hot, during the summer months of 2019, we noticed that most of these were almost completely defoliated, which was unusual. We did not experience this defoliation in our orchard, but since we weren’t looking for it, can’t swear Marssonina wasn’t there in some respect. In September, our extension service put out a bulletin about Marssonina Leaf Blotch, dun, dun, DUN, and we suspect this is what was responsible for what we were seeing in those regional yard trees, most of which would not have had the benefit of any spray support whatsoever.

Here is a link to the NC State bulletin. No relevance to most of us as far as spray options, but does have very good pictures and info about the condition in general. Enjoy (and beware)!

[apples.ces.ncsu.edu]

Kordick Family Farm
Westfield, NC
Zone 7a
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Glenn Aldridge
Re: Marssonina 2019
February 06, 2020 03:33AM Registered: 6 years ago
Posts: 8
Wow

Thank you Brian and Brittany. Also thanks to NC State. I’m on Long Island, caretaking a small community orchard. I also had severe defoliation this past late summer/early fall. I had thought it was powdery mildew, but now I think it was Marssonina.. I had no idea until your posts… I have been considering using a (new to me) botanical fungicide called EcoSwing. Has anyone had any experience with this fungicide?

Glenn Aldridge
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Mike Biltonen
Re: Marssonina 2019
February 06, 2020 09:47PM Registered: 10 years ago
Posts: 276
Hi Glenn,
Apart from the fact that Ecoswing is not labeled for Marssonina, I plan on using it for Cedar Apple Rust and Scab in apples to a limited degree this year. I suspect – with no proof – that it will be mildly successful against Marssonina given that both scab and M are ascomycete fungal pathogens, albeit with different life cycle timings. Again, there is not any data I am aware of, but using it starting at tight cluster to mid-July for CAR and PM (on label) could yield some favorable data/observations.

Mike Biltonen, Know Your Roots
Zone 5b in New York
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Glenn Aldridge
Re: Marssonina 2019
February 06, 2020 11:08PM Registered: 6 years ago
Posts: 8
Thanks very much Mike!

Great to hear your advice. At this point, I’m deciding whether to use Cueva or Ecoswing. I’m starting to think I could do half and half so that we get some idea of what works. I’m still blown away that I had no idea that Marssonina was my problem – for the past several years! Thanks to this forum, and its generous contributors, I have been made aware.

Glenn Aldridge
Long Island – Zone 7
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Brittany Kordick
Re: Marssonina 2019
February 11, 2020 02:16AM Registered: 4 years ago
Posts: 165
I just got back from our annual “Winter Fruit School” for regional growers, and Marssonina was a hot topic, with several area growers (all conventional) reporting that they think may have experienced some damage last year. In a previous post, I stated that I didn’t think we experienced any Marssonina damage in 2019, but will have to amend that now. The back story: last June, we started noticing distinctive discoloration on select leaves from a handful of varieties in our orchard. I have a background in vegetable production, so am very familiar with mosaic viruses, and without knowing that there was an Apple Mosaic Virus, the damage looked very mosaic-like to me. We considered deficiencies, but really didn’t think there was evidence to support that . . . and visually, it looked like textbook Apple Mosaic Virus, though, since we grafted all of our trees ten years ago on what we believe to have been clean rootstock, and haven’t seen this before 2019, it did seem improbable that it was.

One lone extension agent from VA, when asked to id a leaf sample in person, without any preface from me of my theory, said, “You’re not going to like this, but I think this is Apple Mosaic Virus.” Afterwards, we pushed our NC extension service to help us definitively identify it and they were very dismissive (“It must have been one of those crazy organic sprays you all do that’s just burned the leaves”). We eventually got some samples tested and they came back negative for Apple Mosaic, though there were two other viruses in very minor evidence, but not on all the samples, so didn’t seem to be the source of the discoloration.

Well, today during the Marssonina slideshow, given, it so happened, by one of the extension agents who “assisted” us with our leaf discoloration quest last year, I was struck by one of the pictures — it looked very much like the late stages of what we originally thought was apple mosaic virus. I chatted with the extension agent afterwards, and now she thinks I may be right, that we were experiencing Marssonina in some respect last year. It wasn’t even on her radar until late summer, so never occurred to her at the time. But it makes sense from a timing standpoint, the fact that very few of our 150 heirloom varieties were affected (she stated that, so far, she has seen few heirloom varieties affected in general compared to the more mainstream varieties), and that we went on to lose about 50% of our leaves on affected trees.

Now for the good news: having boned up a little over the past few months, she advised growers to control Marssonina as they would apple scab for now. It has a similar life cycle; the bloom/early cover period is when trees are most vulnerable; the best way to control it is to get rid of that overwintered leaf litter. Of course, there were conventional sprays she recommended if growers want to go that route, but for the moment, they’re advising to just suck up some light leaf drop and trust that some of the conventional fungicides used for treatment of other diseases will take care of Marssonina, as well.

She mentioned that, while there is a chance that Marssonina could become the next Glomerella for Southern growers, particularly based on the rapid incident rate seemingly out of nowhere, they haven’t really seen it manifest on fruit down here yet, so they’re just keeping an eye on it and not aggressively treating for the moment. She reiterated that ‘Rome Beauty’ apples appear particularly susceptible. She stated that Marssonina looks a lot like Frog-Eye Leaf Spot starting out, but it shows up later (June-July down south).

I will try and dig out our photos of affected leaves from last year and post them here, with the caveat that I don’t know if they really are Marssonina, just a new hunch. Only three varieties were affected in our 10 acre orchard, and the blocks are nowhere near each other: ‘Baldwin,’ ‘Bramley,’ and ‘Ashmead’s Kernel.’
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Mike Biltonen
Re: Marssonina 2019
February 11, 2020 05:18AM Registered: 10 years ago
Posts: 276
Lots of interesting stuff here. Thanks for posting. I have to disagree though with the approach “treat it like scab.” It is the same fungal class – ascomycete – but the timing and life cycles are different. The infection period starts later and lasts longer – more like European scab. The time from infection to symptom is 45 days compared to 16 days (all estimated and can vary slightly). Also, since Marssonina has numerous forest species hosts – and scab only has a few – there are far more places where it can emanate than apple scab. We need to be aware that M can be infectious much later and far more problematic than scab. There are no fungicides currently labeled (of any type) for M – and not all scab fungicides appear to be more than peripherally effective on M as compared to scab. This is a new disease (relatively speaking) and I believe is way too simplistic to say “just treat it like scab.” The most important thing is to remember that it can come in from a number of forest species, so just keeping the inoculum low in your orchards is on a minor part of the overall program. I am personally, and for my growers, trying to maintain a robust beneficial fungal environment, keep all resistance pathways kicking at high gear, and use any allopathic treatments at a minimum, and only as needed. Trying new fungicides like Ecoswing, acidific clays, and variations on Bacillus spp. fungicides in concert is likely the best protective approach after CC and ISR.

Mike Biltonen, Know Your Roots
Zone 5b in New York
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Brian Caldwell
Re: Marssonina 2019
February 11, 2020 06:39PM Registered: 10 years ago
Posts: 65
I agree with Mike. I think we had a gap in our spray schedule focused on scab and sooty blotch that helped Marssonina get going–we applied no fungicides between 5/22 (end of primary scab) and 7/1 (start of biweekly SBFS sprays). M probably got a foothold then.
That said, our spray program definitely reduced M compared to unsprayed trees.
Brittany, Marssonina symptoms on our Baldwin trees looked very much like a mosaic to me too.
Mike, where can we get acidic clays and what is CC?

Hemlock Grove Farm
Zone 5 in New York