Deciduous Leaf curl Fungus Disease II

[Bretts]

Been meaning to start a general thread about this disease and the trouble it has caused this season but always have trouble knowing where to start.
Guess a list of trees I know of being affected will be a good start.

Acer buergerianum (Trident Maple), Acer palmatum (japanese Maple), Acer ginnala (Amur Maple), Acer griseum (Paper bark Maple), Carpinus (hornbeam), Robinia, Fraxinus (Ash), Quercus (oak), Privet, Crataegus (hawthorn), Prunus, Ulmus.

Mela managed to get a pathology test done that found a fungus and recommended treatment with Yates BRAVO - active constituent "500g/litre chlorothalonil. It was a pity that a name was not given to the fungus but It's probably something like Anthracnose or Phyllosticta and Septoria a combination of any or something similar.
You can find information about these here.
https://www.utextension.utk.edu/publicat ... /SP546.pdf

Here is one on Anthracnose specifically
https://www.na.fs.fed.us/spfo/pubs/fidls ... idl-ae.htm
As always when a tree is affected by one condition it makes it easy game for other pests and disease so it can often be more than one issue.
It is always best to get a pathology test conducted but that is also never garenteed or often affordable for the hobbiest.

Here are a couple of threads that have lead to this point so far.
viewtopic.php?f=19&t=456
viewtopic.php?f=19&t=3198
There has also been some discussion on general care which as always with a pest or disease does influence the severity of the condition.
viewtopic.php?f=103&t=2682
Yet as you can see in this linked thread also full sized established healthy trees can also be affected. Also if it was just a matter of better care then why would the most accomplished Bonsai practitioners recommend Winter preventive treatment for Fungal disease and pest issues.
Although not often a killer on full sized trees although continued defoliation can kill even established full size trees. Bonsai as always are at more risk from their environment than ground grown trees. Yet it is not all bad news for Bonsai trees. Where full sized trees are usually not worth the effort of treating due to their size and it is often found easier just to replace them. Bonsai is much more manageable in care.

Watching this issue carefully in my own collection over the last 5 years and comparing it to other collections I have visited and discussing it with their owners as well as discussing it with some of the most experienced Bonsai practitioners available and general Horticulturalists as well I figure it is time to consolidate all this advise opinions and observations.
As their are many opinions on this I would like to leave the debates for the threads already about these issues and out of this thread to facilitate the consilidation of the information. I will be happy to join your discussions in the other threads about this but I will not debate these issues here.

[Bretts]

I was able to purchase BRAVO - active constituent "750g/litre chlorothalonil but had to purchase this in a 10 liter bottle from a farm center as it is not sold to the public in Australia.
See details here of the safety sheet and label for instructions.
http://www.syngenta.com.au/Start.aspx?P ... ctID=66608
Although it is available in NZ as Yates bravo in 500ml.
As the application rates are for spraying large crop areas at my and others best guess we worked this out at 2ml per litre of water dilution. Yates Bravo is weaker at 500g/litre chlorothalonil so their home dilution is 3ml per litre.
This bravo fungicide classed as a protectant. I am told it works by covering the fungus thus stopping new spores from being released. Treating an established fungus is not easy but I have found pretty decent results using the Bravo.
The biggest problem with Bravo is that it is one of the toxic chemicals we wish we did not have to use.
http://www.pesticide.org/chlorothalonil.pdf
One more point to add is that in all the information listed it recommends a fortnightly treatment. On the actual bottle under ornamental tree it suggests that in severe cases it may be used every 7 days. I have also read somewhere that it is better for a light frequent application than less heavy applications.

Seeing as it is stated that a fungal disease is never really cured and management will probably involve applications in Winter spring and possible more I don't fancy continuing to use this stuff.
I thought I might hit up Don Burke for some advice on treating this issue,I did ask him last year I believe and he was adamant that it was a pest that I could not see.
Anyway now that we know it is a fungal disease he has suggested a product called Yates Anti Rot Phosacid. I mentioned the Bravo and he said that although that would be recommended for this problem he did not like recommending that because of the toxicity. I think his words where you could put this stuff in the bath and bath in it .
As I was thinking I would love to have something to just saturate the yard with(considering that I have full grown trees in the yard with this fungus) This sounds much better than Bravo.
Also widely available at around $16 for 500ml I got my hands on a bottle today and will try it out ASAP.
http://www.burkesbackyard.com.au/2000/a ... t_phosacid
It is a systemic(spreads throughout the plant system) and works by inhibiting the growth of fungus and enhances the defence system of plants. Don stated that applying now before the tree goes dormant will ensure it is in the tree to help over Winter. It is worth noting that Don also made mention that the health of the tree is important and such things as adding lime (I guess this centres around getting conditions just right) might help.
You should be able to listen to a recording of said program here once they update it
http://www.2ue.com.au/burkesbackyard Saturady March 6th (now that is game because I haven't listened to myself yet )
It is not a Winter protectant though and the label states it should not be applied to a dormant ornamental. Lime sulfur may be the best for this but I have recently discovered that is also fairly toxic. Not sure how toxic but It was recently baned in California. Grant Bowies advice is very good. Cover yourself head to toe wear glasses and face mask even if spraying water.
OK There is still plenty more to document here but that will do for now. I will have to follow this up with some pictures to document what I have discussed so far. Might help with Google picture searches which I know is how other Bonsai practitioners have found their way to this site with this issue.

[Bretts]

First up lets look at some more pictures of what this disease can look like.

trident leaf curl.jpg

trident leaf curl (2).jpg

Trident leaf curl fungus.jpg

Trident leaf curl fungus 2.jpg

Also a Hawthorn that is severly affected

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In this last picture you can see this Hawthorn next to a healthy one.

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[Bretts]

Just heard Don Burke say this has been the worst season for Fungus in 20 years As I thought it had to be in a year that I had way too much to look after. This made it hard to keep trees separated manage watering and also caused some of my ground to become waterlogged.
With the shipping out of the dead and some re-aranging I have a slightly better arrangement and many of the affected trees are now on a tin sheet that drains the water away. There is also a wire mesh for the pots to sit on to encourage air flow and drainage.

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Usually there is a couple of tubs that collect the water to stop flooding.

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As you can see things are looking a little better than before.

[Bretts]

Although the Bravo is no miracle worker it has definitely helped. Watching carefully after spraying I saw improvement straight away.

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The next application was over two weeks later but I have since found that in severe cases application every 7 days is more appropriate.
I managed the third application within a week and there was continued improvement but then went away on holidays and had to squeeze all my trees under the pergola with an automatic watering system and rain forecast
On return home I found that they had not improved and may have regressed just a little. The plan I had from here was to move them under the veranda(can't be humid there ) but after another week I realised they where not drying out enough and needed to get them back out in the elements.
Came up with the above draining bench and they are continuing to improve in health.

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[Bretts]

I think I have mentioned already that It was suggested to me to defoliate the trees before treatment and I did experiment in this with the pesticide Confidor and also another fungicide called Triforine. I have found that defoliating the tree sent it backwards if not killing it. Looking at the pictures above of the Hawthorn you can see how the tree is trying in vein to get a leaf out that will actually make some energy. Once it is able to get some growth the fungus abates. We could consider that the tree is weak and that is the reason but what I have observed shows it is not as simple as that.
I did have the odd trident that got away and had what I call grown past the disease which has some thing that was being documented by other growers. Once a certain amount of growth occurs the disease seems to disappear.
On the second application of Bravo I decided to trim the growth of the trees back a little so I did not have all these wispy shoots that made application harder.
I found that this sent most of the trees back a little but they picked back up again pretty quick. But one trident in particular had grown past the disease some time before I had started treating with Bravo and I figured it had built up more strength than the others so felt safe cutting it back like the others but this left it with less leaves.
Although it was treated with bravo like the others it struggled to put any full sized leaves on like when this disease is at it's worst.
It is slowly improving but to me this concludes that we should be very careful in removing foliage when affected with this disease.
You can see this tree here

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A closer look at the leaves shows how I saw small deformed leaves struggle to form just because it was cut back and not that hard.

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It is starting to get back to normal leaves.

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More on this later including a Privet that didn't show any signs of disease until it was cut back

[Bretts]

I noticed a couple of curled deformed leaves on at least one of my English elms. Apparently I see fungus everywhere now according to my bonsai mates but that is one thing I have learnt this year. I and many others have seen deformed leaves on our trees and thought little of it. The only place that I have not found fungus this year is at Ray Nesci's I have bought little saplings at clearance sales that I knew had issues but expected my good care to see it right. We should not be so cavalier. These things can be serious given the right conditions and many of them are with the tree for good once they are there. It is understandable why the Japanese masters wear the white gloves.
I always thought that America and Europe had more issues than us but I recently heard that Australia is worse, for fungal disease at least.

Back to the English elm.
As Bravo is a protect and that stops the spores from being released I figured that although many of my trees where not showing great signs of distress it is very possible that they still have the fungus and enabling it to continue to infect the other trees so I Trimmed back much of my stock and sprayed everything with Bravo.
One of the possible reasons for an infection like this is spreading from infected pruning implements. Yet In observing my trees that are infected I have found the odd tree that was not yet touched by my pruner's and still had the issue. Still I was not taking chances and now carry a jar of metho with me when I am doing pruning on various trees.
I noticed as I had before that one of the branches that I had cut back on the English elm was coming out with the leaf curl. Only one branch for a few leaves and then it stopped and the growth returned to normal.
This can be seen here.

fun23.jpg

I have seen some seiju elms attacked by what seems to be this issue but that is in someone else's collection. I may have noticed a slight deformation of a few leaves on mine but that has long gone. All my other Elm species have not been affected in anyway I can tell.

[Bretts]

Looks like they are having issues with this overseas at the moment as well
http://ibonsaiclub.forumotion.com/bonsa ... -t3403.htm

[teejay]

I've got some shockers this year afflicted with something?? Just seedlings though.

Interestingly enough the older ones I've bare rooted, root pruned and repotted into a "free-er" mix have kicked the habit. The new growth is perfect and they're 100% healthy this year. It's those in old, wetter mix that are troubled.

[Mojo Moyogi]

I've got some shockers this year afflicted with something?? Just seedlings though.

Interestingly enough the older ones I've bare rooted, root pruned and repotted into a "free-er" mix have kicked the habit. The new growth is perfect and they're 100% healthy this year. It's those in old, wetter mix that are troubled.

Teejay, I had a few trees with this condition that cleared up last spring when repotted into better media. Maybe poor soil and or components/impeded drainage/overwatering/too frequent repotting/repotting out of season etc could be causing this and therefore would explain why many of us don't have this problem.

Cheers,
Mojo

[Bretts]

Hey Teejay
Sorry to hear you have come across this as well.
I have had a vast improvement this year so far but I am not out of the woods yet. From almost every Trident being affected to some degree last year it is down to about 10%. A group of trees from a Forrest now in a single nursey style pot. A mature single tree. A very nice tree that was given to me at the Tops by some one that has given up battling this affliction. One or two planted out in the ground. The same goes for the carpinus. I have trees that where affected last year looking excellent and the odd tree here or there that was excellent last year but a total mess this year. Then some that are still affected but new growth is looking promising.
The ones that don't show any signs so far have no constant. Some where treated with a good dose of lime sulfur over Winter some where not. Some where repotted and some where not, still in a very dense organic mix. Some are in the ground and some are not.
The only thing that makes sense at this time to me is a seasonal issue that made it worse last year, it is also possible that I just cleaned the yard better over Winter this year also. The breaking of the drought brang all soughts of nasties back to life on stressed trees which would have made the spore production rampant.
I don't think it is fair to say not many where affected by this. I found evidence of this affliction at almost every bonsai nursery and collection I visited last year. I also saw it all over the place on street trees around my town. It will be interesting to keep an eye on the street trees around this area to see how they go this year.
I am still being contacted by people and meeting others that are facing this issue in Eastern Australia.

Treating with bravo gave excellent results on the tridents but did not seem as affective on the hornbeams which I can only put down to the carpinus being a different species and aflicted by a different fungus. Although I have been treating the seedlings agian this year and they may be improving?
The one constant I have found is that immediate energy produced by the leaves is used to fight this affliction. This is often shown by trees that once they put on enough growth the condition improves.


Ray Nesci got a chance to have a first hand look at the tree that was given to me at the Tops weekend and could find no reason for the affliction. The only guess he could come up with was the affliction is systemic. Only time will tell

[cosmo123]

Hi Brett

I have a forest of 7 Tridents that were affected by this leaf curl last year. The tree budded normally and looked sensational for a month or two then went downhill real fast.

I have repotted into a more open mix this year. At repotting I noticed that the roots looked really healthy.

The forest has just started to come out with one tree appearing normal (mature leaves looking fine) but two other trees with the tiny curled leaves.

I tried to find Yates Phosacid in the green shed with no luck and according to previous posts Yates Bravo is not available here. You mentioned that you had previously used Confidor....how did this go in solving the problem.

Assistance appreciated...let me know if you want to see some pics

Cheers

Mike

[Bretts]

Hi Mike
Glad to hear you have had some improvement. I was some what surprised to find good root growth on the affected tridents as well this season when re potting. We are not the only ones to have noticed this either.
I used the confidor when I had no idea what I was fighting and also because this issue looks very similar to thrips. I had found some thrips on some tridents saplings growing wild in the yard last year and the confidor did get rid of them but was no help with this as I believe it is a fungus and I think confidor is only useful on sucking insects
When I stopped using bravo late last season and swapped to Phosacid the issue returned so I am not confident that is going to work but I have been told you can not over do that stuff and it is very very low toxic so maybe it is worth another try on a more frequent dosage I am pretty sure Bunnings will have it.
I have been thinking of trying Kocide Blue Extra Fungicide but am still not sure what effect this may have on deciduous trees in leaf. It may just be a seasonal thing but my privets have recovered well this spring after being sprayed with it.
The thing I try to remember is that these fungi are known to be very much species specific so it is very possible that although symptoms are very similar from species to species It may be that I am dealing with several different fungi affecting the different species. Still very much learning this but I am guessing that different fungicides will work better with different fungi.
I had never seen rust on any of my willows before last season and also found rust on several other species last Autumn in my yard trees.
Bravo has definatly shown to help with the Tridents but it is very toxic. I have returned to using it agian this season on those affected but I am very thankful the number affected has decreased alot as I now treat those trees on the front driveway believing this will protect the family from it as the residue last for 1 year in the soil. I am also covered head to toe with glasses and face mask.
I still have a few Litres left so I could sell you some if you want as long as you promise to be very careful with the stuff. PM me if you do want some.
Maybe some one can give us advice on trying Kocide blue Extra on deciduous trees in leaf or you could experiment with a small dose to less valuable trees as I will be soon. I would prefer you try that first as it is somewhat less toxic but please still take all precautions with it and cover from head to toe
Oh one more thing. I have found it is best to keep the tridents in as much sun as you feel comfortable with even though the leaves look burnt. I think that enables the tree to produce more energy to fight the fungus. I have all mine affected in full sun at the moment!
Good luck

[Bretts]

A member is asking about an issue that sounds similar to this so here is an update on how things are going.
I tried avoiding using Bravo last year as it is very toxic and started using Kocide extra Blue. I found several hornbeams (mostly my seedlings) seemed to be affected by curled leaves burnt on the edges. After treatment with kocide extra blue the new leaves came out unafected and they grew well for the rest of the year, infact the kocide blue extra seemed to work even better than the bravo on the hornbeam at least. I have found no ill affects of Kocide blue extra on deciduous in leaf. The Kocide extra blue did not work as well on the few tridents still affected but it did seems to help to some degree getting them through the year.

This season I gave all the trees a good dose of lime sulfur just before bud burst and it is only a few tridents that are now affected this year. I treated them with Bravo about a week ago. If I had of treated them with Bravo before/during bud burst then theoretical they would have leafed out with no issue. I guess I wanted to make sure it was still an issue so I waited a little long.

Here is a group of stock plants that where pretty heavily affected in the first year.

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It is now pretty hard to find any leaves on this tree affected but on close inspection I can find a few of the first leaves that came out are a little curled and burnt on the tip.

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This tree that I was looking after for the Orange club is the worst still affected. I gather that is because it was pretty weak when affected and is still to regain good vigor.

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Edit: what look lijke weeds are chives as I had heard chives help deter fungus so I had spread a few seeds around pots. Can't say it is doing any good
With the close up we can see the damage to the leaves before I sprayed with bravo and the new leaves that are coming out in better health after spaying with Bravo about a week ago.

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This is the tree that was given to me at Tops because the member was not keen on battling this issue anymore. This is the tree that got the pathology test and diagnosed as a fungus with Bravo recommended as the treatment.

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Again on the close up we can see the damaged leaves that emerged before treatment with bravo and the new growth after treatment that is healthy.

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I plan on using the bravo on a regular basis on these still affected at least through the spring so they are able to get thier vigor back and assess from there.

[Bretts]

Here are a few tridents unafected this year but recieving the same care.

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Excuse the weeds
I believe this trident now in the ground is the same one used as an example at the top of this thread.

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Here is the severly affected hawthorn shown above a couple of years ago. It was better last year and seems mostly unafected this year and I am hoping it will regain good vigor this year.

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I can't find a single affected leaf on my hornbeams this season so far.

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Over the last two years the street trees in my town have also become less afected.