I decided to start TWO threads, because I inspected all my registered daylilies today and was surprised and also disappointed by those that did or did not have rust. I would love to hear from others as to which daylilies YOU have/had that had rust show up on the foliage. Many in the database don't mention the rust resistance, so I have no way of knowing which cultivars could harbor rust. My cultivars showing some (or a lot of rust) are the following :

Tet daylilies that showed rust:

Get Jiggy had rust which I would estimate to be a rust rating of 2.5 -3.5.

Marilyn Morss Johnson had rust. I'd estimate the rust amount to be 3.0-4.0. I was disappointed at this, as I love this plant. It is definitely rust susceptible!

Winter Rainbow also had rust. It is probably just as bad as Marilyn Morss Johnson with a possible 3.0-4.0 rating.

Mal show rust. I'd guess about a 3.0 rust rating.

Neon Rainbow probably has a 3.0 rust rating. I also noticed that it went from 3 fans down to 1 fan. Not sure what is up with that. It is a sev, so maybe that explains it?

Raspberry Beret - This one was a rust bucket this past Spring. But surprisingly, the rust rating I'd give it today would be a 2.0. This was unexpected as I was actually thinking of ditching that cultivar because I'd honestly say it was a 5.0 rust rating 6 months ago.

Dynasty Pink had a fair amount of rust, but the rust looked like it was dying. So I gave this one a 1.5 - 2.0 rust resistance rating.

Spiny Sea Urchin had quite a bit of rust. I'd rate it a 3.0.

Kipling I would rate a 2.5-3.0 for rust resistance. Disappointing to see at this time.

All Fired Up had quite a bit of rust too. I'd say a 2.5 -3.5 rust resistance rating.

Now for dips:

Planet Max - I was disappointed to see a fair amount of live rust on the foliage of this one. I'd rate it a 2.5-3.0 rust resistance rating.

Lillian's Thin Ice had some rust. I'd say a 2.5 rust resistance rating.

Beautiful Edging was another disappointment. I had read that it had a 1.4 rust resistance rating. Looking at the foliage today, I'd have to give it a 2.0-2.5 rating.

Persian Pattern had some rust. I'd say a 1.5 - 2.0 rust resistance rating.

Fol de rol had quite a bit of rust. I'd say a 3.0 - 3.5 rust resistance rating. With it's thin leaves, I was not expecting it to show that much rust. Disappointed to see the rust on this one!

I have 24 dips and 25 tet registered cultivars. Most I acquired because of their rust resistance. So 10 of the tets and 5 of the dips show more rust than I wanted to see on the foliage.

I am also going to also do a thread asking you to post your rust resistant cultivars. This list is of most interest to me. I hope you will consider adding your cultivar observations to these 2 threads. Thank you in advance!

I truly hope others will join in and list theirs, too. Since I garden organically, I really depend on reading about which cultivars tend to show rust and which ones prove to be highly rust resistant.

By the way, all of these cultivars are planted in a raised bed together, so they are exposed to the rust of their neighboring plants.

This is the other thread of my rust "resistant" cultivars: The thread "Which cultivars appear to exhibit rust resistance in your garden?" in Daylilies forum

'Bridgeton Entertainment' showed rust.

I had rust on the great majority of my plants this year. I think due to the fact that I brought so many new plants in.
There might have been a few that did not show rust I will have to see if I made any notes on that. I just mainly want to comment on how those plants look right now. Many of them had a small amount of rust, many had a moderate amount of rust, but in my opinion none of them had a severe case of rust. I was looking at them the other day (I fully intended to take pictures) and the recovery of the plants is fantastic. Almost all the rust laden leaves appear to be gone and green healthy foliage is now showing. They nearly all were looking so pretty...maybe there will be no freeze tonight and I can still get photos.
One thing I really noticed was that my last order of daylilies that was planted just a few weeks ago, showed no rust on any of the plants. So I am thinking fall planting in my area is a big bonus. The plants I planted during the heat of the summer sulked and for the most part came down with some degree of rust. The fall planted daylilies will have all Fall, Winter, and Early Spring (hopefully) to get established without the harmful effects of rust.
I think because we have had such a mild November (not even a first frost yet) that my plants have been given a chance to grow out of their rust stage and green up and look fresh as springtime plants. Last year by this time the foliage would have looked totally different due to very early frosts.
I will try to take a few photos tomorrow and come back an edit this by adding them.
Photos showing how green the foliage is looking in the garden today(11-24-2015):




Photo of one small bed:

Photo of a larger bed:

The foliage is not perfect, still some yellow leaves here and there, but very few from rust anywhere. I think the plants look great for this late in the season. It is so wet down there the water just squeezes up out of the ground when you walk. Still, the daylilies really seem to like it so far. Last year I was afraid they would all freeze and rot in that boggy ground, but it did not seem to bother them.
Of all the "rust resistant rated" daylilies I have, this year the one that showed the most rust was Tuscawilla Tigress. It was probably the first plant to show rust in the garden this year. It still is one of the worst looking as far as the foliage goes.

Larry - I seem to have had the opposite conclusion about the very last 4 daylilies that I acquired. They were from Maryott's. I received and planted all of them the end of September. I received: Marilyn Morss Johnson, Zoe Allegra, Get Jiggy, and Winter Rainbow. 3 out of the 4 now have quite a bit of rust on them, the other 1 has some rust but not a lot of rust.

Most all the daylilies in the raised bed were acquired this year. Most of them in the late summer or very early Fall.

Becky, I think if I had planted in September the new plants would have been enveloped in rust. That is about when they were looking their worst. But my last order was not planted until the middle of October, after the hot weather had abated a bit. That really worked out fantastic this year. I might not be able to do that every year, but I will be trying it again, I really enjoyed planting in the fall. I was really miserable planting in July, that I will hope to never do again.

That's disappointing to hear about all of the rust, especially on (as was mentioned on another thread) 'Marilyn Morss Johnson'. Some years ago I belonged to the "local" daylily club, where Marilyn was a member. She was a lovely lady, and I finally just got the plant this fall, to remember her by. I suppose I should expect to see it break out in rust not too long from now...

I really wish more hybridizers would work to incorporate some degree of rust resistance into their plants.

You know .... I looked at the pedigree of Neon Rainbow and saw "sdlg x Court Magician". Looking at the one known parent, Court Magician... it has a 4.0 susceptibility rating. So I should not have been surprised by the rust I am seeing on it's child. I liked it's pretty face, so decided to grow it anyway....

Even the rusty ones can be used in a hybridizing program if you cross it with cultivars that show strong rust resistance.

One of my favorite hybridizing plants is Dragonfly Dawn. I have seen rust on the 4 children I have. (I do NOT have DD, just had seeds from a cross with itself.) I love the pretty faces. It is not a rust bucket, but these children do show rust in at least the 2.5 to 3.5 range. So my intent is to cross them with some of my very strong rust resistant cultivars. I don't rule out the pretty faces, I have plans to just make children from them using one highly rust resistant parent.

If Dragonfly Dawn makes it through my winter, I will try and cross it with cultivars that have some rust resistance, if I can determine from the database which ones do, of course.

All of the plants that I got from Maryott's showed rust. I ordered BRIGHT IN THE NIGHT, MINERAL SPRINGS, and SAILING AT DAWN..they sent KAANAPALI COAST and SIGN LANGUAGE as bonus plants. I received the orders in July and pot planted them for a few weeks, then transplanted to a small bed in my back yard. The rust started with Mineral Springs and quickly spread to most of the cultivars in that particular bed.

Mineral Springs and Bright in the Night bloomed within a few weeks. I love love love the blooms on both, but it was disappointing to see rust show up, as I had never had it before. I'm hoping the winter freezing temps will rid my garden of the rust. I do plan to keep the cultivars to see how they do next spring , but they look awful right about now.

I'd read that rust often shows when daylilies are acquired from nurseries in the south not long after being sent and transplanted.

With Maryott's, I checked and quite of few of THEIR cultivars use some rust susceptible daylily in the pedigree. Which is one of the reasons I didn't buy one of theirs. I was tempted but knew what would happen growing them here in Florida. So that makes me wonder if because of that, they do grow quite a few daylilies that are prone to rust. For the rust to show up not long after receiving and transplanting, apparently whatever they treat them with to control the rust has worn off. So even with the chemical treatments they are doing, rust is alive and well at many southern daylily nurseries despite their rust treatment program.

To be honest, that doesn't deter me all that much, it just makes me more determined to create some rust resistant hybrids from some of those pretty faces crossed with some highly rust resistant daylily cultivars. It's a challenge that is calling my name! But wouldn't it be nice to have some of these pretty faces already be rust resistant? I don't quite get why some southern hybridizers don't breed for rust resistance. Wouldn't that make sense? I am sure some do, but I have no idea which hybridizers.

Has anyone heard of a study of how consistent rust suseptability is in daylilies? Becky, you mentioned that Raspberry Beret was is different than it was 6 months ago. I'm going to start keeping notes on mine so I can compare them at different times of the year and from one year to the next.

Larry, did your plants that had had rust clear up by themselves or did you spray to help get rid of it?

Leslie - That did intrigue me about Raspberry Beret not being the rust bucket it was in the Spring. Could it have to do with the health of the plant? It was in a nursery pot, now it is planted in the raised bed. Could a happier, healthier plant be better able to fight against rust? I have to wonder ....

I have read though, that the healthier the foliage the worse the rust attack. Rust does like healthy leaves, which is what it thrives on.

Sure is confusing ....

Leslie, to answer your first question the only study I can think of that might address your question is Dr. Buck's on the responses of specific cultivars to different races of daylily rust. There was also another publication that rated cultivars at two different times of year, and I think in two different years - I'd have to check it again for the details if that's what you're asking. I believe that one was incorporated into the ATP ratings.

Rust will also vary depending on other factors like environment.

Since I have been adding a lot of Daylilies over the past few years have experienced rust just a.couple of times. Thank goodness live in a part on NC that gets cold enough to kill rust during the winter months. Didn't have any this summer.

@Lalambchop1
The cold winter of 2014 seemed to really deter the rust in my garden, and all through the spring and early summer rust was not a problem. Only later in the season ... almost after the season, the rust was able to get established.
The past two years I had a hit and miss type of rust spray program not sure it really did much good. This year I only sprayed one time and that was with a mixture of dish detergent and immunox(or daconil) can't remember for sure. At least in my mind that did a little good, only a few of the daylilies were showing rust at that time. As the weeks passed more and more of the plants became infected. But it was a very gradual thing and because of that I never did spray again. So the plants pretty much cleared themselves of the rust. When I walk through the garden I can still see some signs of rust, but those leaves seem to be dying off by themselves, and with this beautiful weather new green healthy leaves have been replacing them.
I want to comment on new plants brought in that show rust almost immediately. I am not sure that the new plants are bringing in the rust, or that those plants have no immunity to the rust that is present in their new surroundings. I have had several plants that during their first season showed rust, then they did not show rust after that to any major degree. Do they build up a tolerance? I don't know, did the weather conditions have to be just right for them to get rust? All I know is that I would not get rid of a daylily for at least a couple of seasons just because it showed rust, because I believe some of them might never get rust again, or at least not on a regular basis. I am not sure any plant has been checked to see if it consistently got rust for several years in a row, or did not get rust for several years in a row.

Larry - Yes, I thought about that too since my Raspberry Beret seemed to improve on it's rust resistance.

And you do have a point about the plants being healthy but became infected from their transplant into a garden bed that has some rust. The leaves are usually cut short when shipping. Those cut leaves are a point of entry for rust. So that would make sense that the immunity for many daylilies to fight rust is probably at it's all-time low during transplanting. So I absolutely agree that it would be wise to keep and grow any currently rust susceptible cultivars for a few growing seasons to see if their rust resistance improves. My guess is it might for some of them!

Becky, the cut leaves are not a point of entry for rust, rust gets into the leaves through the stomata. What can happen is that when a plant is cut back any loose spores can fall down between the leaves and cause an infection later. Also a plant that was infected before arrival may not show any pustules for a significant amount of time after receipt, whether it was treated with fungicides or not (and fungicides don't eradicate rust which is why we still have it).

It'll be difficult to separate the apparent variations from effects of environment on rust because the favourability of the environment for the fungus will vary during a year and from year to year, and even among plants in an individual garden in the same year. The balance of fertilizer or nutrients already naturally occurring can also make a difference and that's another variable. The same cultivar in one part of the garden may get rust while in another part it gets it less or more, simply because the environment differs enough to affect the ability of the fungus to infect. With plant fungal diseases it is all about the environment, e.g. how long the leaves stay wet at any one time, what is the temperature, what is the light intensity and so on. When the leaves don't stay wet for long enough there will not be any new spore germination, for example, just like a plant seed doesn't germinate until planted in moist medium at the right temperature.

There's also the effect of environment on resistance genes, I'd have to look up the exact details again but where it's been investigated in some other rusts it was found that there was a temperature "switch" that turned on or turned off the genetic resistance capability depending if the air temperature was above or below that temperature point.

One thing someone mentioned in this thread or another is fall clean-up. Sorry I forget who and if I try and go back to find the post I'll lose what I just wrote. In areas where rust is borderline for survival, like USDA Zone 7, removing all the foliage in fall and not using a protective winter mulch should give the garden a better chance of being rust free the next year (unless new plants are brought in). The less foliage remaining green through the winter the better, but of course it still only takes one plant staying green to potentially carry rust through until the next year. That won't help you, though, Becky.

I have always thought that damaged leaves and especially cut leaves were a entry point for rust. I thought this paragraph was indicating that any entry point to the internal leaf structure would allow rust to enter.
"Germination produces a germ tube that grows on the surface of the leaf looking for access to the internal
plant tissue. It often gains access through natural openings such as stomata."
http://plantclinic.cornell.edu...

This diagram and explanation from my rust site may be of interest:

http://web.ncf.ca/ah748/diagra...

Quoting also from:
Brand A, Gow NA. Mechanisms of hypha orientation of fungi. Current Opinion in Microbiology. 2009;12(4):350-357. doi:10.1016/j.mib.2009.05.007.

"Uromyces and Puccinia species and many other plant pathogens gain access to the plant by forming appressoria over the guard cells of stoma. The germ tubes of these fungi exhibit contact sensing and orientation in relation to the topography of the epithelial substratum (thigmotropism). Initially, hyphae grow perpendicularly across the plane of axis of the epithelial cells — a strategy that is thought to aid the location of stoma, which in monocotyledons are often positioned in staggered rows. When the germ tube encounters a guard cell of a specific lip height, an appressorium is induced (thigmodifferentiation) [23]. Elegant experiments with chemically inert plastic replica surfaces demonstrated that these events are mediated entirely by the topography of the plant surface and not by any chemical gradients."

Years ago when I had some rust with which to experiment I did some leaf segment tests. The picture below shows a leaf segment that was exposed to daylily rust spores after being cut.



There are no pustules close to the cut surface. One could argue, I suppose, that I might not have exposed that part to spores but if you look at Figure 2, page 49 of this daylily rust research (incidentally also the one that first indicated dishwashing liquid had some benefit in rust control) there are no pustules near the cut surface as one would expect if that was a point of entry:
http://www.uoguelph.ca/%7Ethsi...

The cut surface would not have the topography that the germ tubes would be seeking so I can't see this as being a major infection point if it ever is at all.

Edited to add a quote specific to daylily rust:
".......germinating urediniospores produced germ tubes on the leaf surface within 24 hr. Each urediniospore formed one germ tube. Germ tubes stopped elongating at stomata, formed oblong appressoria that took the shape of the stomata, and often had a collapsed appearance. The infection peg, which originated from the appressorium, penetrated through the stomal opening and formed a spherical substomatal vesicle in the substomatal space from which intercellular hyphae were differentiated........."

This is from Li, YH, Windham MT, Trigiano RN , Fare DC. 2007. Microscopic and macroscopic studies of the development of Puccinia hemerocallidis in resistant and susceptible daylily cultivars. Am Phytopath Society.
Edited to correct broken link:
http://apsjournals.apsnet.org/...

Thank u Sue for that last post. I often rip off only as much of a leaf as has u-spores so the plant can have a bit more photosynthesis before I pull the bottom bit too. I once wondered if damaged/broken leaves succumbed more easily but saw no evidence in my observations.

I have noticed that some rusty leaves come away easily from right down at the corm. Wonder if that is an adaptive response also?? Others are stuck on like Super Glue.

Also I was long in 2 minds about ripping off leaves that have the brown resistance response markings. I look and if no u-spores are showing, I leave them until they have not much green.

Also I discovered another 2 small fans of CURLY ROSY POSY. They are spindly and have rust, so I will give them some TLC then do some experimentation. They have been stressed by growing in pretty much clay and stones and not been watered unless it rained.