Becky for the link. The info is very helpful.

Gleni said:http://www.daylilyrust.org/survey_results.html

This url has link rot. Does anyone know what happened to these results?

Yes, there were technical difficulties with a new web host as far as I remember. I believe those survey results were incorporated into ATP's rust ratings, though, there's a note somewhere on here as to which studies/surveys were included. If you delete the last part of the url after the last / it will take you to my daylily rust info site because it's a "mirror" url that redirects to my site, but I had to remove the survey link from my site because the survey was no longer functioning and the survey's creator wasn't able to fix it. Hope this convoluted explanation makes sense!

Edited to add here are the notes for ATP's ratings, the survey in question appears to have been incorporated as the "circa 2003" note - I remember that in some of these results there was some consistency for some cultivars from garden to garden but some others were rated all over the place. I'm not entirely sure how this was reconciled into a single rating per cultivar:

http://garden.org/barn/notes/r...

IMHO susceptible ratings are more meaningful than resistant ratings, which is the main reason a cultivar's rating would not have been included in the survey results if there were less than 3 reports for it from different gardens.

It is like what they always say in positive-thinking lectures: "Is your cup 'half full' or is it 'half empty'?" Breeders are always going to say shows "resistance", not shows "susceptibility".

I wasn't thinking so much about breeder ratings but individual garden ratings. My thinking being that since the development and severity of rust depends entirely on environmental conditions (assuming the presence of spores and a susceptible plant) then if a cultivar doesn't get rust in an individual garden we do not know if it was not susceptible or whether the environmental conditions were not conducive. On the other hand if it does get rust then a single rating shows it is susceptible to at least some degree even if environmental conditions had an impact on the severity.

We found examples of that in the survey you mentioned - there were some cultivars with very inconsistent ratings from different gardens. There are even going to be places in an individual garden where the microclimate differs, so one may find a given cultivar appears to vary in susceptibility depending on where it is planted. So that's why to my mind a susceptible rating is more useful than a single resistance rating. Now if several people find a cultivar to be resistant in different gardens it would give me more confidence in that rating.

Of course we now know there are different races of daylily rust which further complicates matters since a cultivar may be less or more susceptible/resistant depending which variant of Puccinia hemerocallidis it encounters.

Someone correct me if I'm wrong but I believe ATP has two rust rating systems in the database. One is from the research articles listed in the explanatory article (the one that gives a numerical rating), and the other is open to amendment by individual ATP members. The latter means that someone can rate a plant as "shows susceptibilty" and then somone else can afterwards change it to "shows resistance".

Over in the soil and composting forum I mentioned watching some interesting videos(about soil biology) . In the videos Dr. Elaine Ingham says that if soil is not in balance diseases and insects can acquire access to plants, but that healthy balanced soil (biologically) will repeal insects and disease.
I tend to think of the environment as being "air" related, but I guess to a plant the soil is very much a main part of it's environment. So when I think of microclimate, I normally think of conditions present in the air, but maybe for a plant we should think about the "microclimate" in the soil.
If it is true that the soil microbes can make a plant immune to disease and insect attacks, then the
air borne spores and their temperature and moisture conditions etc. would be of little consequence if the plants could repeal them. Maybe there are pockets of micro organisms, near some plant roots that allow the plants to fend off rust while other plants are in pockets without such micro organisms?
In the videos she states that tomato verticillium, was completely avoided by having proper soil balance, and that pests because a non issue on the plants. She even went so far as to say that crop rotation would not be necessary because if the soil micro organisms were in balance there would be no nutrient deficiency, no pests and no plant diseases, therefore, no need to rotate crops. As a side note, she also states that all soils contain enough nutrients for healthy plant growth (no need for any additional nutrients once the biology is corrected).
So I am just wondering if other research and science actually supports the claims, and that daylily rust could be totally avoided along with slugs, thrips, etc. just by paying more attention to the soil than to the "environment" around the plant.
It sounds great and I love the ideas behind it, yet remain very doubtful.

@sooby
I have not been able to understand how the members ability to change "shows resistance" or "shows susceptibility" for each individual garden could possibly work. At first it seems that would only end up showing how the plant reacted in one garden(the last reported), so when viewed the rating might show the plant susceptible one day and resistant the next day (theoretically).
'Red Volunteer' a plant I specifically chose for rust resistance, has unfortunately shown rust in my garden. So I just now went and submitted a change from "rust resistant" to "rust susceptible"...the change has to be approved by a monitor! So an individual member like me would not be causing the rating to swing back and forth regularly, but it would be left up to the monitor to actually decide if the rating should be changed or not.
The criteria for the monitor approving or denying the change....I have no clue!

Two negative ways of looking at this...firstly if it is correct that diseases like rust, which need living tissue to survive (most plant pathogens do not), do better on or "prefer" healthy plants then that kind of counts against the idea if the notion is to make the plants healthier. In fact there was a paper published many years ago that found being stressed by thrips and other stresses reduced the incidence of rust on some plant species - I'd have to find the article again if anyone is interested (it didn't include daylily rust).

Secondly daylily rust, for a hundred years or so before it came to North America, evolved and happily infected wild daylilies in Asia, in that latter case presumably nature wasn't in balance there either

It is true that nutrient status can affect diseases like rusts, which are favoured by high nitrogen and discouraged by adequate potassium. It certainly also true that problems can be caused by indiscriminate inputs and over-fertilization.

There was a lot of discussion some years ago about aerobic compost tea suppressing diseases although we don't hear as much about it these days, perhaps because it wasn't, according to this article by Dr. Linda Chalker-Scott, supported by scientific testing:

http://puyallup.wsu.edu/wp-con...

I'm kind of doubtful that soil microorganisms would directly affect a foliar disease like rust, but there are other microorganisms called hyperparasites that attack rust on the leaves (in the absence of fungicides of course).

Interesting about the monitor for changing the susceptibilty or resistance in the database, I didn't know that. Even so there is another negative with an either/or definition like that because rust is not that straightforward in the sense that a resistant plant may still show some spots. So presumably someone might rate that either way?

Maybe a rating of "highly resistant" or "highly susceptible" would be a better rating method for ATP member gardeners.

Appreciate the input, apparently Dr. Ingham gives lots of speeches and seminars, and has gone into business promoting her ideas! I am just a bit baffled by the lack of support or nonsupport for her research and the theories she has presented.
I did just read this over in the rose forum, I found it interesting and somewhat related.
http://garden.org/thread/view_...

Probably more choices in case a cultivar is not highly either would be better, but the rating that shows would still be the last person's edit that was accepted by the monitor, so one person's experience. I suppose it may be that others don't change the rating because they agree with it in which case it's more than one opinion, but there's no way of knowing that. I wonder if there could be a way to indicate the history of any changes?

Yes, I've heard of Dr. Ingham before, her talks were discussed on the AHS Robin starting as long as fifteen years ago (just checked) but not in recent years as far as I recall.

One thing that I would recommend, and you probably already know this, is that if you want to try something don't treat all the plants at the same time. If you leave some untreated then it gives a better idea of whether the treatment made a difference.

According to this lengthy dissertation, the severity of a couple of rusts (not daylily) did not significantly differ between compost-amended and control plots. Rust tended to be worse on manure amended plots

https://www.ideals.illinois.ed...

In the summary the author concludes "Data from the field pointed to the fact that building up organic matter does not automatically guarantee disease suppression. Manure supplied more labile carbon and nitrogen, induced higher microbial activity and produced higher biomass, yet it promoted certain diseases, especially with biotrophic pathogens like rust......"

Very surprised to see my request to change the rating of 'Red Volunteer' was accepted by the monitor and the rating was actually changed to "shows susceptibility". True, in my garden it does show some susceptibility.

sooby said:Probably more choices in case a cultivar is not highly either would be better, but the rating that shows would still be the last person's edit that was accepted by the monitor, so one person's experience. I suppose it may be that others don't change the rating because they agree with it in which case it's more than one opinion, but there's no way of knowing that. I wonder if there could be a way to indicate the history of any changes?

Sue, you can find a record of changes to the cultivar database entry at the very bottom of the cultivar page in " View the history of this database entry". This record shows various proposals, who made them and the date/time submitted. To view the actual proposal you need to click the person who made it and then find the correct proposal under their Plant Database Contributions. Even then it can be difficult to see what was changed because the "View the proposal" doesn't show a a copy of the previous data entry before the change, only the proposed change and the now current data information. If there is a way to see what was there prior to the proposal being approved I haven't found it yet.

Thanks, Char. I checked it out and it gives "shows susceptibilty" for both the proposal and the "current original" for 'Red Volunteer', presumably because Larry's change was approved. If a change the other way is not allowed, i.e. from susceptible to resistant, then it's not so bad, but it would be much more useful if the database could show a history of multiple ratings from different people.

I almost feel bad about the change, but it is the way the system works! If 'Red Volunteer' does not show rust in my garden this spring, I will suggest it be shown as "Shows Resistance". It still shows the 1.1 resistance rating, so now it looks a bit odd to see it showing at the same time "Shows susceptibility" .But naturally that is how it would have to be if the rating in one garden is allowed to change the rating. Anyhow, I normally pull my selections up by using the rating numbers anyhow!
Then I narrow them done from there. I think now anyone who grows 'Red Volunteer" and finds that it "shows resistance" in their garden could submit a change.

As I mentioned above, I don't think it should be possible to change from susceptible to resistant. Apparent resistance cannot be determined from one observation in one garden but susceptible is susceptible (unless it was a plant with the wrong label) although the level of susceptibility can vary. I'm trying to figure out which study/ies gave it the numerical rating but it might take me a while to find it since it didn't come up on a simple search of my laptop files. The numerical rating of 1.1 implies it did show some rust in the study/studies that rating came from. It would be much better if the database could show multiple rust reports per cultivar rather than just last past the post.

Edit: Well in the U of Arkansas ratings it came out in both years as very resistant with a score of 1 (no pustules). Still haven't figured out where the .1 on ATP came from yet. Now the Arkansas study was over two years, 2001 and 2002. It's now known there is more than one race of daylily rust and it could be resistant to one but not another. I'll keep trying to find the .1!

Larry, I just checked the archives of the daylily rust email list and a poster there mentioned that 'Red Volunteer' was free of rust when planted in an area where there was not much rust but when planted near susceptible daylilies it would get it too, and not insignificantly. So it should really remain susceptible in the database.

I acquired Red Volunteer late August of this year. It looked great until the rust showed up in my garden beds in September. It promptly proved to me that it is rust susceptible. As far as a rating goes, I'd say probably a 3.0. I have others that were susceptible to rust but were more on the 5.0 scale, this one was not as bad as those. But ... yes! It is definitely rust susceptible.

I think the number ratings are confusing. Rust resistance ratings can go from 1.0 to 5.0. Rust Susceptible ratings can go from 1.0 to 5.0. At some point it would seem that the ratings overlap each other. Like a 2.5 - 3.0 rating. If a daylily has a 2.5 rust resistance rating ... it gets rust. If a rust susceptible daylily has a 2.5 rating .... it gets rust. So how do those numbers really help you?????

Sometimes I amaze myself! I knew how the rust rating system worked the rust resistant rating does not mean a plant does not get rust or even a noticeable amount of rust. But, somehow that knowledge temporarily slipped from my brain.
The rust ranking notes explain that the system is based on a 5 point rating, anything ranked 1-2.9(best I can tell ) should be ranked rust resistant. Anything 3-5 should be ranked rust susceptible. So being there are rankings of 1.1 etc. I would assume those are just showing incrementally larger areas of rust, so a 1.1 should still be very rust resistant. I would think even a 2 ranking would not be bad, but I would not want to risk too much on a 3 - 5 ranked plant in my garden. So it does not appear that the ease with which a plant contracts rust is the measure, but the degree to which it displays rust. So really I think my 'Red Volunteer' should still be ranked as rust resistant! Sorry about that...do the rest of you agree with my interpretation of the rankings?

Larry - I knew about the amount of rust, but the distinction between rust resistant and rust susceptible in the rating numbers is what I am not sure about. I have seen a rust "susceptible" rating of "2.5" for a number of daylilies: check the plant database

So what does that mean?

If I understand what you mean correctly isn't it because there are two different and separate systems in the database, Becky? There's the numerical rating which Chalyse (I think) calculated from various studies plus the AHS associated survey (now defunct), and then there's the ATP member input which is separate and confined to "shows susceptibility" or "shows resistance" and only reflects the opinion of one individual. So it's not surprising that the systems may disagree.