Juniper health/disease

Hi all. I have battled with a handful of Junipers (Sargent Junipers specifically) where the foliage starts to become discoloured, pale and then light brown and eventually dies back. It usually start on the lower branches (tips of the foliage first) and slowly moves up the tree. This started in spring and continued through summer. Suspecting tip blight, I treated with Mancozeb as well as other fungicides. This did not help so I cut off all the infected foliage but the issue just kept occurring as if it were an incurable cancer… with some trees, I eventually cut off so much that there was not enough foliage to support the tree. Some experts suggested that it might be spider mite, but I found no sign of mites. Here are some pics.

I’ve checked the roots and can see no issue there. They are all planted in a mix of Akadama and Pumice. Below is another picture of a different type of foliage attack, not the same as the trees above. Again on Sargent Juniper.
Any ideas as to what this could be and possible treatment?

Here are some more pics taken this morning (mid winter)…all of these are Sargent Juniper that I grafted on to other Juniper species.

I’ve also sprayed with Lime Sulphur…it just keeps coming back. I’d hate to lose all of these trees.

I hope someone has an answer, having the same problem. Tried a copper spray with no success.

Hey Paul. could you add some close up pictures to compare?

At this point with the methods you have already tried i would suggest a systemic fungicide. It is absorbed by the plant and combats the fungal issue from within.
Not sure what is available to you but Bonide Infuse granular, or Cleary’s 3336 DG Lite are two suggestions.
You should look for the active ingredient Methyl Thiophonate. The concentration is usually 2.8 %.

Once again, thanks Frank for your advice!

Ha Mark if your going to use Cleary Liquid 3336F Systemic Fungicide. DON’T MIX IT with COPPER CONTAINING materials OR LIME SULFUR.
Daconil Fungicide Concentrate mix with Bondie Copper Fungicide works good together.
I usually add Ortho Malathion Insect spray in with my Fungicides.

Some of my friend like to use BAYER ADVANCED 3 in1 Insect, Disease and Mite control.

I suggest you look into “Nuke um” by: very expensive but very effective on everything troubling bonsai. Cleaned up a cyclimine mite problem on elms in one dose. And mostly used by Cannabis growers so it is non toxic.

I purchased a microscope (USB plug-in) today and had a closer look at some of the infected foliage. See pics… The white fuzz might however be the residue from prior spraying with Lime Sulphur…WIN_20190702_14_25_05_Pro WIN_20190702_14_41_11_Pro WIN_20190702_14_51_55_Pro WIN_20190702_14_21_54_Pro

I’ve also searched for a systemic fungicide containing Methyl Thiaphonate, without any luck. I’ll try Funginex by Efekto with active ingredient: Triforine. The package lists Black Spot, Rust and Powdery Mildew…not sure if this will have any effect though.

Looks like a tough problem. Because you’ve had trouble with multiple trees, I’d consider sending a sample to a lab, plant clinic, or department of plant pathology who can run plates and maybe help identify the problem. Not all fungicides apply to all pathogens and unnecessary applications can further stress the tree.

Also, it looks like it’s a problem in the roots rather than a foliar fungus as only discrete sections of foliage show damage. This makes me curious about the health of the roots, the character of the soil, and the fertilizer regimen as they all can contribute to the symptoms your trees are showing.

I see no signs of spider mite damage.

Thanks again Jonas, much appreciated! Most of these junipers have not been repotted for at least 5 years and are in “old style bonsai” soil including standard potting soil with river sand and grit.
Since grafting over with Sargent foliage two years ago, and removing all the old variety foliage, I’ve been waiting for the trees to become vigorous again before changing to the correct potting medium. Looks like I’m going to have a busy spring potting season…

I have used Phyton 27 successfully for red ring Pine needle blight where nothing else worked, and bacterial soft rot where 3336 and Agramicine was not effective. It is a systemic fungicide and bactericide. The Nuk um by Flying Scull I mentioned earlier is an insecticide, fungicide, miticide, and more. Looks to me like you have a fungal, bacterial or viral issue and maybe from weak roots. You may want to try Flying Scull Z7 to clean the roots and media of any chemical or sludge buildup.

Hi David
None of those brands are available here in South Africa. Here’s another product “VIRIKOP”.
Broad spectrum fungicide and bactericide. Active ingredient: Copper Oxychloride.

Would you suggest I try a soil drench with this? Or rather the “FUNGINEX” with active ingredient: Triforine?

I usually repot bonsai to help them regain their vigor as poor soil conditions are one of the most common causes of bonsai health problems. I’d wait until repotting season and bareroot up to 50% of the rootball. You’ll get an idea of how the roots are doing and give the tree a chance to recover if there’s bad soil in the core.

Thanks again Jonas, much appreciated!


I have no experience with the product VIRIKOP.

Phyton 27 is :

Its patented formula enables the active ingredient , copper sulfate pentahydrate, to be absorbed into the plant where it can move horizontally and up from the roots, killing pathogens that have attacked the internal system of the plant.

If you do have a weak root system issue a drench may not be absorbed through the roots and a spray would be more effective and faster.

Phyton 27 was originally developed for controlling bacterial rot in Poinsettia cuttings, now it is used for a lot of commercial ornamental crops. I think it is the absorption properties that make it so good. I have found no other systemic fungicide that works as well and it is very effective on bacterial rot as well. You might try contacting the MFG and see if it is available in Africa under a different name.

I have not found Funginex works well, on many of my pine fungal problems (red ring needle blight). It is ok for needle cast. Different copper salts work better on different fungal problems.

When I have root rot issues, I repot and use: It is the best root stimulator I have found. A small amount goes a long way. If I am repotting out of season I will soak the bare root ball in half the recommended dilution for 5 -10 minutes. For junipers I keep them on the dry side for a while.

Copper did not help me. lost most of my Juniper but what ever it is did not kill or harm the blue junipers. Maybe this will point to an answer for plant doctors .