Standard cherry trees vs. SWD

[Oepfeli]

The general situation

As some of you may know my parents and I have some standard cherry trees on our farm. Most of these were planted and propagated by my grandparents, one tree even by my great-grandparents.
About 15 years ago my mother began planting fruit trees on the farm, including new cherry trees.
But the majority of the cherry trees are huge and old and majestic. Of these 13 old trees we only know the variety name of 1 tree.
About 4 of them are in bad shape and we wanted to cut them down anyway.
Most of these trees have not been pruned since 30 years, or not a all. So you can imagine them to be gigantic.

This ladder is about 8.5 m long = 27.88 feet. And this isn’t the biggest tree by far.

Fruiting Situation

As we are located at about 1100 m. above sea level we are in a marginal location for fruit production. We often get late frost or fog/rain in spring. Additionally we are on a south-facing slope which makes the trees bloom (too) early. All this to say we get a sizable crop about every third year and a full about every fifth.
If there are few cherries the birds get most of them since the trees are very big and you have to pick with a ladder. If there are many cherries we always picked as much as we could need and let the rest hang for the birds. Since many of the varieties are for making schnaps they are very sweet and they shriveled up to a kind of raisin. As late as September there were shriveled up cherries in the trees that were perfectly edible.

Fruiting Situation this year

This year 8 of the 13 old trees bore a full crop. An abundance of cherries. Over the course of 3 weeks we picked about 60 kilogram for fresh eating (about 15 are still in the fridge), froze about 30 kg and made 15 kg jam. All of this didn’t really make a dent into the mass of cherries. The trees were still packed.

SWD shows up

As you can imagine our cherry trees are a SWD paradise. From the beginning of cherry saison they have been here this year but if we found an afflicted cherry while eating we simply put it away and later doused them with boiling water. But in week 3 of our harvest they were suddenly everywhere.

The problem is, SWD only arrived in Switzerland in 2011 so we really had no precedent how fast the population would grow with such a big food source. I knew it in theory since I worked on a fruit farm but since they can spray and the trees are a manageable size it’s really not the same.

We decided to pick as many cherries as possible and destroy them. We picked about 200 kg in 2 days. We put them in buckets, doused them with boiling water, let them cool down and then threw them into the liquid manure pit. Problem is, in these 2 days we only cleaned 3.5 big and one smaller tree.
We don’t really have time for this.

Possible solutions:

This year I we can do nothing against them, but for going forward there are 2 main possibilites:

1. Cut down every cherry tree
2. Prune them down to manageable size if possible. Pick every last cherry and make schnaps with them. (We still have my grandfathers distillery and the permit)

Possibility 1 is simply unthinkable to me. These are my grandfathers trees. They are veterans of a different time, may be rare old varieties and are landscape defining. We can’t just do away with them.
At least I would want to propagate the good varieties on dwarf rootstock so they don’t die out and maybe one day we can find out what they are.

Possibility 2 is very much work. I don’t know if we will have the time to pick cherries during prime hay-making time.

For the moment we already took down the trees we picked to a more manageable size. We plan to cut down the 4 dying trees this winter. I bought SWD traps to put around other cultures that are susceptible like raspberries…
What we do will depend on how they react if there’s much less food next year. And it depends on how much they’ll procreate in the wild and at our neighbours (they all have big old cherry trees too).
If I have to be honest my hope is that the population collapses if there are much less cherries next year and that until the year after we have pruned the trees back to a sensible height.
Then I hope with good control (traps) we can stay somewhat ahead of them. I guess that’s much to optimistic. If any of you has any idea what to do in our situation (I’m aware what commercial growers do) please share.

For me, it’s not so bad to get a SWD-cherry pn the table now and then. I simply don’t want to breed them en masse in our trees.

Has anyone any luck with mass trapping?

[Drew51]

I only have a small backyard, but nothing I have done has stopped them. I culled all fruit that develops in SWD season. That worked, but any fruit that ripens in SWD is attacked. My cherry trees ripen before they get here.

[mroot]

Since your trying to preserve legacy trees I think your best course of action is this:

Propagate the trees on dwarf rootstock. I would graft each variety to multiple rootstocks to insure their survival if some of the new young trees die. The smaller trees will be easier to manage. When the new trees are well established cut the old trees down. I know this will be hard to do since they have been in your family for generations. I think the SWD is going to be a permanent problem and not go away. But I could be wrong and the new trees will take years to grow. So you will have some time to evaluate the situation and see if you can perhaps keep the old trees.

I don’t think mass trapping is going to work. I think you will need to spray an insecticide to control SWD. Most of the literature I see on SWD deals with raspberries and blackberries but even the organic growers of berries have spray programs to deal with the pest. Of course the organic growers use organic certified sprays like spinosad to control SWD instead of synthetic chemicals.

The current trees are huge and I don’t think it would be practical to spray them. I spray my cherry trees but my trees are all less than 5 meters in height with most less than 4 meters.

The other option would be to treat the old cherry trees as landscaping trees and no longer collect the fruit but that doesn’t deal with the SWD problem.

[Drew51]

@mroot

Of course the organic growers use organic certified sprays like spinosad to control SWD instead of synthetic chemicals.

Spinosyns occur in over 20 natural forms, and over 200 synthetic forms (spinosoids) have been produced in the lab. Not sure what they use or consider organic? Better look what you’re using.

[Oepfeli]

Thank you, @Drew51 and @mroot, for your thoughtful responses.
I think we’ll definitely propagate the trees as dwarfs. This year we could pick cherries for 3 weeks almost without SWD, so I think if the trees are smaller we can maybe evade SWD-season.
And I think we will prune down the rich-bearing trees and hope that the biggest ones don’t bear to much. But if they do and are a source of SWD they’ll have to go.
Concerning spraying: as of now we have never sprayed so there would be a considerable hurdle with getting equipment and a license. The old trees are of course imposible to spray.
While Spinosad (Audienz) has an emergency approval for organic farming right now in 2020 this may change.
Right now the focus in organic farming is on prevention with nets and they are researching mass trapping so maybe there will be something new there?
Anyway, I’ll update this thread next year with our results. Thank you!
Edit: the FIBL (swiss research station for organic farming) cites an italian study that allegedly shows that mass trapping is more successful than insecticides. No link though…

[mroot]

Well there is a thread on the forum about bagging entire trees including cherry trees. Some of the comments deal with using insect netting so it might be possible to keep the SWD out if the tree is small enough to net.

Here is the link:

Bagging entire trees, or dancing on the rain slick precipice of madness

To consolidate discussion of bagging entire trees, experiences/results, etc. I first attempted to bag some entire trees last year. This is my second year at this and I am no expert. Here is a little bit of my final review for my 2020 cherry bagging project on Juliet cherries. Bottom line… I feel like I had huge success. We had a couple days of solid rain right when I had originally planned to harvest and that resulted in some splitting and a little subsequent rot, but I lost probably only a …

Myself I bag apples to reduce the need to spray insecticides. But I don’t think bagging individual cherries would be practical. There is also research being done that involves using high tunnels to grow cherries that also might be an option. It might also help with avoiding frost damage to cherry blossoms.

As far as spraying, I don’t know what the laws of your country are when it comes to spraying fruit trees so I can’t offer advice on that. However, I can give some general advice. You may want to look at spraying Surround to protect the cherries from insects. Surround is a kaolin clay so it’s non toxic. That may be an option for you. Scott’s spray guide on the forum covers how and when to spray Surround.

The study about mass trapping is interesting. I hope it works but I am skeptical.

If you have dwarf cherry trees and keep them pruned spray equipment can be very modest. Many on the forum use backpack sprayers. I don’t even have that. I use a inexpensive 2 gallon (7.6 liter) pump up sprayer that cost about $10. It is the type usually used to spray weeds.

Dwarf trees are much much easier to harvest. I use a 2.4 meter ladder to harvest the high cherries and a smaller step ladder to harvest most of the cherries. So with small trees you can harvest all the crop and avoid leaving cherries for the birds and the SWD.

[Oepfeli]

Hey, I’ve been very busy, but thank you for your infos and suggestions. I’ll certainly report back!

[Oepfeli]

I have some news to share. As this year was truly horrible for fruit growing, we only got cherries on one tree, which of course were almost all eaten by birds. On the bright side this means that this year, there was no food source for the SWD. In fact, I have yet to see even one of the little devils. Meanwhile, we are one step closer to identifying our old cherry varieties. My mother is a member of Fructus, an Organization which concerns itself mainly with orcharding and old varieties of fruit. They have started offering a gene test for unknown fruit. As I understand it, they compare our sample against a database with “hundreds of varieties”,which makes me quite confident that at least some of our trees can be identified. While it is quite pricy, it is somewhat cheaper for members. We are testing 7 cherries, an unknown apple and our gage. Results should come in in December! I am beyond exited!

[mroot]

I am glad you have testing available to you. Who knows it’s even possible you may find you have varieties that aren’t in the database. Perhaps the old trees are something that is very rare. I hope the testing goes well.

[Oepfeli]

As I said our results should have arrived by December. As it is now June I called them and turns out that they sent an E-mail but we received none. The gentleman on the phone went looking in his records and turns out that all 9 trees were identified!
I am so exited!
The Cherries are all old Swiss varieties, but only one is virtually unknown.

We have:

• two Basler Langstieler (which means long-stemmed from Basel, a traditional Swiss cherry region)
• two Mischler
• one Baschimeiri (a cherry from Central Switzerland where I am from)
• One Heidegger
• One Helener, also known as Rote Rigi, which is a cherry from Central Switzerland, too.

Of these, the Heidegger is a table cherry that is sold by nurseries, but lesser known. Mischler, Baschimeiri and Basler Langstieler are the small dark Cherries for jelly, Schnaps and Preserves. These are seldom sold in Nurseries but not unknown. For example, they are mentioned in old pomological books.
The Helener on the other hand is unknown to me. While it is preserved in several federal collections, no nurseries are selling it right now. According to the federal Database 8 trees of this variety that were reported (In the 90ies, when the federal collection of old varieties began) and they were reported under several different names. Since 6 of the reports are from central Switzerland and 2 from the canton Bern, I believe that this is a variety from central Switzerland as well. So it seems that this variety was not widely planted. How my Grandfather got it, I can’t know, but propably not from a nursery.

[Oepfeli]

Edit: I have found a book from 1937, which describes the Helener as a variety of central Switzerland.
So it seems that with Mischler, Baschimeiri and Helener, my Grandparents planted traditional varieties from our region.
I am very relieved to hear that most varieties are still available in nurseries, because some of them are not the healthiest trees.

As for the Helener, I have one young graft of this tree already…

[Oepfeli]

The apple tree was a James Grieve, as my mother and I guessed.
The Gage is a Reine Claude dOullins.
Funny thing is, from both varieties we have already bought young trees before knowing what the old trees were. After trying the James Grieve fruit from our new apple tree we were almost sure that the old tree was a James Grieve as well, but it is nice to be sure.
And with the Gage it is very nice to be sure as well, because the old tree is dying and I have never grafted a plum successfully, so I am very glad that we already have a replacement.

[mroot]

It’s cool you got the testing results. Sounds like you have some interesting varieties.

[Oepfeli]

This year is again a year with an abundance of Cherries. Already the SWD are arriving, but we are less stressed about this than in 2020. This has several reasons:

• In 2020 we feared that the SWD would multiply in the Cherries and then attack the berries, the plums etc. This didn’t happen. While there were some SWD in the raspberries and strawberries, they never took over. Hope it stays like this…

• As I was picking this year I observed that the SWD-infested Cherries had many ants on them. While it could be that the ants eat the infested Cherries, it would be even better if they ate the SWD-larvae!

• As we got the naming results, I am filled with new love for these old trees and don’t dream of cutting them down.

[Oepfeli]

[Oepfeli]

The above photo was taken under the artificial kitchen light.
Under natural light the Mischler are much more red, while the Basler Langstieler are really that black.

Mischler Cherries under natural light.

[Oepfeli]

One of our newly identified cherries, the Helener, compared to the Spitzibühler Rote