Mugo Blight ID - Request Help with ID and treatment

[Kelly]

Greetings all,
My nursery purchased Mugo, repotted June 21st tree is developing a blight I think. Could any of you help me ID it and suggest treatments? Reviewing earlier pics - May - June I believe I can see this just starting but am new to pines so I thought it was a couple broken needles.

I think - after a google search - that the issue is either Dothistroma Needle Blight and/or Diplodia Tip Blight. Symptoms ... first I noticed a week ago or so that some needle tips were light yellow and one of this years buds had turned yellow/brown and died back. In the last couple days - I am starting to see a number of (e.g. 20-30) all over the tree of little brown bands on a needle with some actually bent, then the rest of the needle brown, assumed dead. I will post some pics ... some have double brown bands with a yellow band in between. One of the buds appears to have died back and the others showing the affected needles.

At first I thought that I had simply broken a few needles and removed them ... now it is spreading. My google search seems to indicate that this is a fungal infection and is treatable with a copper fungicide. I read that I must make sure that the soil be protected or it will kill the helpful fungus in the roots.

So - Do I have it right? Is this one blight or two?

Not sure where this came from ... I keep my few bonsai on a bench ... anything I can do to prevent this issue in the future?

Thanks in advance. I'm very new to pines and haven't had any kind of infections before.

 

[Paradox]

So - Do I have it right? Is this one blight or two?

Not sure where this came from ... I keep my few bonsai on a bench ... anything I can do to prevent this issue in the future?

It is possible that both are going on or some type of fungus. I suggest removing the effected tip and spraying the tree with a fungicide. Cover the soil with a plastic sheet to prevent it getting in the soil.

As for the prevention, there are some tips on the U.S. Dept of Agriculture Forest Service web sites about those two conditions. When you water, try toto keep the foliage dry. Wet conditions promote fungus.

 

[Bill S]

A variation of needle cast, I think.Fungicides help.

 

[Kelly]

Thanks and a couple questions for clarification ...

Thanks to you both for replying ... I have a couple questions ... I'm pretty new to pines and this is my first mugo.

I bought some "Bordo Copper Spray" (53% copper from Tribasic Copper Sulphate) and mixed up 1/2 a liter (16 ounces) and covered the base of the mugo and soil with plastic wrap and thoroughly sprayed the tree with it. Ontario, Canada has far less choices re pesticides/fungicides due to legislation passed a couple years ago. After drenching the tree branches, needles, buds with my mister / spray bottle - it left / dried to a bluish powder = good (I think). My internet research tells me to do it again in a couple weeks. Re-reading Vance Woods "notes" - he sprays with "Captan" in the fall.

Everything I read says that this fungus or fungi (found various names - types) affects many pines in the NE U.S and 17+ types of pines - it is worse in wet, damp areas and springs/summers and the spores are airborne and fall onto the tree(s) usually due to rain. The copper sulphate does not "cure" the tree but precludes the "next year's" needles / growth from being affected. I did prune the one bud as it appeared really affected/dead. I went through all the needles and snipped them 2-3 mm or 1/8th inch from the root or bud growing from the branch. I'm told this is purely for aesthetics and is not really doing anything re "cure".

Question1 - How long should I leave the plastic wrap on the base? I'm concerned that now that the upper tree is covered with bluish dust (on the needles/buds/needle bud roots); it will migrate down to the soil/roots with renewed watering and destroy the beneficial mycelium. (Tree was repotted into a pond basket 21 June or 6 weeks ago). I was thinking to water the tree a couple/few times with the plastic wrap still on to wash away most of the copper sulphate before removing the plastic wrap. Please comment.

Question 2 - I have tried to follow Vance's notes re watering mugo's ... "they like lots of water not not wet feet" ... The summer here (Ottawa, ON - 5b) has been cool, wet vs hot & dusty. I think I have overwatered it despite the pond basket and approx. 1/3 really free draining bonsai soil - the other 2/3rds is still nursery sand/clay that drains much more slowly - but - I couldn't remove more nursery sand per Vance's guidance on the repot. I am in transition then to convert the tree from nursery sand/clay to bonsai soil over a couple years; so it doesn't drain as well as I want. I use a moisture meter to test it - cheap plant probe and it usually shows "wet" if I water it everyday - therefore - for the last couple weeks I have been watering it every second day with misting on each day. All my reference books indicate that the best way to water is to "water from above" with a can or hose versus keeping the branches dry and watering "underneath". I use the probe to allow the tree to go from "wet" right after watering through moist to just touch the dry scale and then I water it fully. Depending on the local weather - that may mean a watering every 24 to even 48 hours. Given my fungi issues - I wonder if I have contributed to making it all too wet? Too much misting perhaps too!

Question 3 - How often with copper sulphate?? Most of refs (below) say early and then late spring ... all that was too late for me. Vance's notes say he uses Capstan in the spring/fall. So I plan on spraying again in a couple weeks, then in the fall to mimic Vance and I'm thinking next spring to get on the recommended schedule?? (paranoia?!)

How do others water their mugos? Use a meter? How does one deal with a less than ideal bonsai soil while in transition to a true, free draining soil? Water underneath now that the tree has the fungicide above?

Regret the long reply and more questions but I just want to learn all I can and not kill this tree. I have researched many threads on the site and my references yet find the specifics or details a bit lacking re watering - I am experimenting and watch closely but would welcome some the expert knowledge available by other members. It may seem awful basic to some yet all my refs indicate that proper watering in the proper soil may be the most important thing to learn re bonsai. We all live in different zones and have different species but ...

Thank you for your help / comments / concern. And thanks for reading my long a$$ post!!

Below find some of the internet sites I found re Dothistroma Needle Blight and Diplodia Tip Blight. Hopefully someone finds them helpful. I'm not a scientist but copper sulphate appears to work for the NEXT year's growth and the fungi are pretty persistent. If someone has expertise or other refs - please add them. I would hate to be a Xmas tree farmer ...

http://www.na.fs.fed.us/spfo/pubs/fidls/br_spot_pines/brown-spot.htm


http://learningstore.uwex.edu/assets/pdfs/A2620.pdf

http://www.ipm.iastate.edu/ipm/hortnews/2007/4-18/conifer.html

http://www.ipm.iastate.edu/ipm/hortnews/1994/6-24-1994/blight.html

http://www.ianrpubs.unl.edu/pages/publicationD.jsp?publicationId=1349

 

[Paradox]

Leave the plastic over the soil until the spray stops dripping off the tree. You dont need (or want) to leave the plastic on the soil for longer than that.

Watering on a timed schedule can cause alot of problems. If your soil isnt dry when the time is up, it can lead to overwatering.

For a good water meter, I leave a small 6 inch dowel stuck down into the pot. I pull that out of the soil every day and when it is mostly dry (except for the very bottom) I water. Some people use chop sticks. I found it easier to just buy some dowels from the hardware store and cut them down.

I would not wet the whole tree down when watering. I dont wet any of my pines when I water. I just water the soil. Yes I know trees get wet when it rains, but it doesnt rain as often as I water normally and too much moisture can lead to the problems you are seeing.

Right now you need to treat the issue at hand: the fungus. So treat the tree as per the instructions on the bottle. Many people do spray fungicide as a preventative in the spring and some also do in the fall (as you have read). It is up to you to decide what is best for you in your area/climate.

Vance is pretty much the resident expert on mugos. I have a few that I am learning on and have kept alive for a few years but I dont have anywhere close to his experience on them. I would follow his advice on mugo care.

 

[Kelly]

Paradox,
Copy all - makes sense. Tree is treated. I will amend the watering schedule and water mostly from underneath with an eye on requirement vs schedule. I will also modify the misting frequency. Thanks for your comments/tips. I guess with all the threads/rhetoric re the sensitivity of repotting, working mugos; I got a bit carried away. Local weather compounded the effects. I do have a couple junipers that are in true bonsai soil and "require" watering/mist everyday. They are thriving with no fungi and sit next to the mugo. Thanks again.

Wandering around the neighborhood with the dog and my new found knowledge re blights reveals many, many trees/shrubs affected ...

One more thing; according to refs provided, this tree had to have been infected last year prior to my purchase. I went to the nursery and they agreed it was a fungi and mentioned that "they have problems with the pines this year" - Lesson Learned is to carefully inspect a new purchase for signs of fungi and treat as required. The tree was purchased in May and I could have (I think) greatly reduced the damage this year with a more prompt treatment (per the directions and sprayed twice in May/June).

You get ripped off in the drive through ...

K

 

[Vance Wood]

Paradox,
Copy all - makes sense. Tree is treated. I will amend the watering schedule and water mostly from underneath with an eye on requirement vs schedule. I will also modify the misting frequency. Thanks for your comments/tips. I guess with all the threads/rhetoric re the sensitivity of repotting, working mugos; I got a bit carried away. Local weather compounded the effects. I do have a couple junipers that are in true bonsai soil and "require" watering/mist everyday. They are thriving with no fungi and sit next to the mugo. Thanks again.

Wandering around the neighborhood with the dog and my new found knowledge re blights reveals many, many trees/shrubs affected ...

One more thing; according to refs provided, this tree had to have been infected last year prior to my purchase. I went to the nursery and they agreed it was a fungi and mentioned that "they have problems with the pines this year" - Lesson Learned is to carefully inspect a new purchase for signs of fungi and treat as required. The tree was purchased in May and I could have (I think) greatly reduced the damage this year with a more prompt treatment (per the directions and sprayed twice in May/June).

You get ripped off in the drive through ...

K

There is nothing going on there that I have not seen from time to time and none of it has ever been serious. The propblem with the buds/shoots just opening up can and should be controled by removal, something you are probably going to do anyuway. The old needles that are doing wierd things are no problem either; simply clip them out. If you want to apply a propolaptic application of a fungicide you should be OK. I have found that Captan usually works really well.

As to water; don't flood the tree but water well including the foliage. As to regional problems; if you were to drive down I94 between the State Line and Roseville you will notice that very many pines growing along the highway are in decline. It could be that treating annually is a good idea.