Identify what is killing my hollyhock

Question: My client has the following question, "About a week and a half ago I noticed that the leaves on my hollyhock are turning brown. When I turned them over there is nothing moving but they are filled with raised spots. The spots start out a tan color and turn a darker brown. The flowers seem to be okay at this point, it's just on the leaves. What is damaging my plants and what can I do to get rid of whatever is killing them?

responder: Hello,   Replied June 30, 2024, 10:28 AM EDT
response: Hello Julie, I believe that the hollyhocks have a fungal disease known as RUST.  The lumpy spore appearing spots can be reddish or brown and contain the fungus.  There are many different types of rust and it is. one of the most common diseases affecting. hollyhocks. It typically attacks the lower leaves first and then moves up the plant. This article fro the Missouri Botanical Gardens is worth reading and gives a lot of info on how to treat and prevent the infestation. Below is some information from the University of Wisconsin which explains in detail better than I can.  How do I save a plant with hollyhock rust? Once symptoms of hollyhock rust appear, control can be difficult. If you observe the disease very early in its development, remove symptomatic leaves and dispose of them in your municipal garbage (where allowed) or by deep burying them. Consider follow-up fungicide treatments (although such treatments will be most effective when applied before any symptoms appear). If you decide to use fungicides for control, select products that are labeled for use on hollyhocks (or more generally on ornamental flowering plants) and contain the active ingredients chlorothalonil, mancozeb, myclobutanil, tebuconazole, or triticonazole. When making more than one application, DO NOT use the same active ingredient for all treatments. Instead, alternate the use of at least two active ingredients with different modes of action to help minimize problems with fungicide-resistant variants of the hollyhock rust fungus. Myclobutanil, tebuconazole and triticonazole have similar modes of action and should NOT be alternated with one another. Be sure to read and follow all label instructions of the fungicides that you select to ensure that you use products in the safest and most effective manner possible. How do I avoid problems with hollyhock rust in the future? Remove weedy mallow plants (especially common mallow) from your garden; they can serve as a source of P. malvacearum spores. Also, be sure to remove all hollyhock debris in the fall to eliminate another place where the fungus can overwinter. Weeds and plant debris can be disposed of as described above. DO NOT use seeds from infected plants and inspect new hollyhock plants for rust symptoms prior to purchase. Some hollyhock varieties are resistant to some, but not all, variants of P. malvacearum. Thus use of resistant varieties may not be a reliable method for control of hollyhock rust in all situations. Avoid planting hollyhocks densely to allow better air circulation that will promote more rapid drying of plants, as well as reduced humidity. Water and fertilize properly to promote optimal growth of your hollyhocks. DO NOT water with a sprinkler as this will wet leaves; use a soaker or drip hose that applies water directly to the soil. Fertilize only when needed based on a soil fertility test. https://www.missouribotanicalgarden.org/gardens-gardening/your-garden/help-for-the-home-gardener/advice-tips-resources/pests-and-problems/diseases/rusts/rust-of-hollyhock  I hope this helps THank you Kathleen

responder: The Question Asker Replied July 01, 2024, 9:45 AM EDT
response: The customer that requested I send in the question does not use email so I will print your response and links and forward it to her, so she has a reference number for this questions and a phone number to contact with follow up questions. Thank you!   Julie Eriksen Mason County Office Secretary Michigan State University Extension 3000 N. Stiles Rd Scottville, MI 49454   Office:<personal data hidden> Fax:<personal data hidden> <personal data hidden>   Michigan State University Extension programs and materials are open to all without regard to race, color, national origin, gender, gender identity, religion, age, height, weight, disability, political beliefs, sexual orientation, marital status, family status, or veteran status.   Michigan State University occupies the ancestral, traditional and contemporary lands of the Anishinaabeg – Three Fires Confederacy of Ojibwe, Odawa and Potawatomi peoples. The university resides on land ceded in the 1819 Treaty of Saginaw.   From: ask=<personal data hidden> <ask=<personal data hidden>> On Behalf Of Ask Extension Sent: Sunday, June 30, 2024 10:28 AM To: Eriksen, Julie <<personal data hidden>> Subject: Re: Identify what is killing my hollyhock (#0144521)