Fungus

Question: What is the pink fuzzy fungus on the tip (flower buds) of the ninebark? This is not powdery mildew. What info do you have? How to treat? Is it systemic?

responder: An Ask Extension Expert Replied July 24, 2024, 7:55 PM EDT
response: Hi Elizabeth, Can you answer a few questions to help me diagnose your ninebark issue?  How old is this shrub?  How long has it been in its current location?  Are there other plants quite close to it?  How is it watered…and how often? Do you know which variety of Physocarpus this is? Can you possibly provide a clearer and closer image of one of the blooms? Physocarpus generally blooms in May/June. Is that when your plant bloomed? In other words, does your picture show blooms that are fading?   You stated there is no powdery mildew on the leaves. None at all?   Thank you for this additional information.

responder: The Question Asker Replied July 26, 2024, 10:55 AM EDT
response: The shrub is 15 years old. It has been in this location for 15 years. It is in a native plant MUNICIPAL garden. It is not watered. May have water from the lawn sprinkler. There are 7 or 8 ninebark in the 600' x 3'  garden. Last year one shrub (photos)was affected, now we see some of the others are showing this fungus. P. opulifolius I sent another question and included a close up photo. I have not seen any blooms so far. I need to check. We pruned rather later (April) than usual this year. They usually bloom mid summer.  The photos are from last year and were taken mid July. I will try to send them as attachments to this email. * We cut the main branches from the shrub in question in June. We left some short 2' sprouts. It is growning fairly well but the fungus is showing up again. Not powdery mildew.       On Wed, Jul 24, 2024 at 7:55 PM Ask Extension <<personal data hidden>> wrote:

responder: An Ask Extension Expert Replied July 26, 2024, 12:53 PM EDT
response: Thank you for your timely response. I have searched every avenue (as perhaps you have done), but I find no serious disease of Physocarpus other than powdery mildew. Other pests and diseases to which Ninebark is susceptible include fire blight, leaf spot, aphids and wilt. You didn't mention whether your affected shrub displayed witches'-broom, thickened shoots or blackened, curly leaves. Perhaps it's the lighting, but your second photo shows leaves that appear to be totally covered with the white conidia (spores) of powdery mildew. The pink "fuzz" on the blooms you referenced in your earlier message is puzzling and perhaps the disease appears differently on blooms than on leaves.  Here is some information from the May 1, 2021 Hort Science periodical:  "Ninebark is considered a hardy and persistent  ornamental shrub; however, it can be severely affected by powdery mildew caused by Podosphaera physocarpi. The fungus is highly specialized and forms a close association with ninebark, and a condition of high relative humidity but dry leaves favors the incidence of powdery mildew. The symptomatic plants exhibit witches’-broom with cream- to white-colored, thickened shoots, curly leaves, and patches of a white, powdery fungal colony growing on the surface of leaves, stems, flowers, and fruits."   Powdery mildew begins as white tips on the leaves. As it moves  through the plant, the leaves become black and crisp and the stems become black and curl. It occurs in the spring when there are cool nighttime temperatures and warm days and continues on through the summer.   Cultural practices that can contribute to it are: the plants may not be planted in the sun; there is poor air circulation either from being too closely planted or the shrubs are overgrown and  need to be thinned; the infected leaves and stems should be removed, raked from below the plant and discarded (the fungal spores live in the soil below the plant and can infect the plant the following spring).   Spraying with a fungicide will not "cure" the already-infected leaves/blooms, but it will help prevent the spread to healthy parts of the plant. Fungicides should be applied early in the spring or  when you see the first sign of the fungus. If you choose to do this, be sure to carefully read and follow all label directions.   Because you have so many of these shrubs and because all fungal diseases spread easily, and....because you are sure this is NOT powdery mildew...the best thing to do at this point for diagnosing and treating your Ninebark is to consult a certified arborist. He or she can examine your shrubs and make recommendations regarding their health, any needed judicial pruning, and whether or not (in his opinion) they should be removed. Hiring a certified arborist will ensure that you are getting a knowledgeable and qualified specialist. You can find a certified arborist in your area here:   http://www.treesaregood.org/   Click on "Find an Arborist" at the top of the page; then click on United States from the pull-down menu. Then enter your State and City. This should bring up a list of certified arborists nearest to you. Or you may be able to locate one under "Tree Services" in your local Yellow Pages.

responder: An Ask Extension Expert Replied July 29, 2024, 8:03 AM EDT
response: Hi Elizabeth, Here is another option for diagnosing the pink fuzz on your ninebark shrubs:   Another option is to send pictures and full descriptions to the MSU Plant and Pest Diagnostics lab on campus. Please email digital images prior to bringing or sending physical samples. Images can be sent to <personal data hidden>.   They may be able to ID your problem without seeing a sample. If they do request a sample, the link below tells you how to submit one.   https://www.canr.msu.edu/pestid/submit-samples/   Due to the coronavirus, the lab no longer accepts drop-off samples; they must be mailed. Give them as much information as you can possibly think of, i.e., when did this problem first begin, do you see insects, drooping shoots, cankers (oozing sores) on the trunk of the tree, etc.   Good luck!

responder: The Question Asker Replied July 29, 2024, 8:10 AM EDT
response: Thank you.  On Mon, Jul 29, 2024 at 8:03 AM Ask Extension <<personal data hidden>> wrote:

responder: An Ask Extension Expert Replied July 31, 2024, 12:37 PM EDT
response: Thank you, Erin! Sharon  On 07/31/2024 8:59 AM EDT Ask Extension <<personal data hidden>> wrote: