Sheffield daisy foliage discoloration - Ask Extension
My small bed of Sheffield Daisies has ugly yellow markings this year. Could you suggest a reason?
The plants are in shade. Thanks.
Knowledgebase
Sheffield daisy foliage discoloration #871449
Asked June 04, 2024, 6:57 AM EDT
My small bed of Sheffield Daisies has ugly yellow markings this year. Could you suggest a reason?
The plants are in shade. Thanks.
Montgomery County Maryland
Expert Response
These symptoms suggest a serious fungal disease called Chrysanthemum White Rust (not the same kind of rust that affects certain trees). Can you share more close-up images, including the leaf undersides? We're looking for key features of fungal spores that would help to confirm this diagnosis.
While shade isn't much of a direct factor in this case (though it can prolong leaf wetness after rain, which will indirectly increase the risk of any infection), shade will affect the vigor and blooming potential of the plant, since mums are sun-loving perennials.
It sounds like you have had this plant for at least a year since it seems like the discoloration is new...did you buy it relatively recently from a local nursery or a mail-order nursery, or did you recently add new mums to the garden that appear to be symptomless so far?
Miri
While shade isn't much of a direct factor in this case (though it can prolong leaf wetness after rain, which will indirectly increase the risk of any infection), shade will affect the vigor and blooming potential of the plant, since mums are sun-loving perennials.
It sounds like you have had this plant for at least a year since it seems like the discoloration is new...did you buy it relatively recently from a local nursery or a mail-order nursery, or did you recently add new mums to the garden that appear to be symptomless so far?
Miri
Thanks for your reply. I have had this bed for more than five years, but this is the first year I have seen this problem. These are plants that have been in place for a lng time. Right now the discoloration is in part of the bed, but not on all the foliage. Attached are close up pics of the front and back of a leaf. Thanks. Maureen
Hello Maureen,
Thank you for the additional information and photos. We do suspect Chrysanthemum White Rust is responsible for the infection, and consulted with the Maryland Department of Agriculture to get their opinion, since this is a disease they monitor in Maryland. They are interested in getting in touch with you (using the email you put onto this submission form, which we can share with our contact) and they will probably ask you to send them samples for lab testing to confirm if this is that particular pathogen. They will provide instructions for taking and sending samples if that is the case.
Miri
Thank you for the additional information and photos. We do suspect Chrysanthemum White Rust is responsible for the infection, and consulted with the Maryland Department of Agriculture to get their opinion, since this is a disease they monitor in Maryland. They are interested in getting in touch with you (using the email you put onto this submission form, which we can share with our contact) and they will probably ask you to send them samples for lab testing to confirm if this is that particular pathogen. They will provide instructions for taking and sending samples if that is the case.
Miri
Thanks. Much appreciated. After I send them samples do I cut it back, dig it up, spray it with something? Maureen
On Jun 6, 2024, at 1:33 PM, Ask Extension <<personal data hidden>> wrote:
You're welcome.
We'll let the MDA guide you about what to do after sending in samples for testing. Use of a fungicide will not cure the condition, nor will cutting back the foliage. The MDA might recommend that all symptomatic plants be destroyed, but there may be a specific procedure to doing this if they suspect the white rust infection so it doesn't spread. Plus, in case they need to re-test new samples for any reason, they might not want the original plants removed just yet until a test result is available. Since we don't know exactly what they will suggest, we defer to the MDA's pending communication with you.
Miri
We'll let the MDA guide you about what to do after sending in samples for testing. Use of a fungicide will not cure the condition, nor will cutting back the foliage. The MDA might recommend that all symptomatic plants be destroyed, but there may be a specific procedure to doing this if they suspect the white rust infection so it doesn't spread. Plus, in case they need to re-test new samples for any reason, they might not want the original plants removed just yet until a test result is available. Since we don't know exactly what they will suggest, we defer to the MDA's pending communication with you.
Miri
