Something's on my French Hollyhocks!

[stephanietx]

What is this and how do I get rid of it? Click pics to make larger.

Top of leaf:


Underneath side of leaf:


Thank you!
Stephanie

[Dirt Doctor]

Good shots. Top looks like virus and the bottom looks more like a fungal disease. I wish the Plant Wash was on the market. In the meantime spray hydrogen peroxide 3% straight from the bottle from the grocery store and let us knows if it works.

[stephanietx]

Thanks for the reply. Will try it and let you know how it works!

Stephanie

[stephanietx]

I've tried several applications of the peroxide to no avail. It only comes back worse than before! Last night I cut off the most severly affected leaves, which was almost half of them!

I'll be calling to order the Plant Wash today and will give that a go when it arrives.

I'm wondering if it's some kind of rust or something like that. There are definitely spores on the underside of the leaves. Also, I'm wondering if it's related to the wet weather we had recently.

Stephanie

[sandih]

Do you have mulch under them? If not, I'm wondering if you're getting a lot of soil splashing up on the leaves from the rain which can really aggravate a fungal disease problem.

[stephanietx]

Yes, they are very well mulched with a native cedar mulch. This problem actually started very late in the season last year. I'm completely perplexed. :?

Stephanie

[sandih]

I'm thinking it is HH Rust.

http://forums2.gardenweb.com/forums/load/organic/msg0614523120474.html

Check this out:

The various stages of rust development produces different types of spores. Some rusts produce up to five different spore forms. Some of these spores parasitize one host while other spore stages infect and parasitize different (alternate) hosts. The teliospore (sexual stage) is the overwintering stage, which creates a structure producing spores the following spring to begin the infection anew.

found in the link below..


http://www.coopext.colostate.edu/TRA/PLANTS/index.html#http://www.coopext.colostate.edu/TRA/PLANTS/holyrust.html

[sandih]

By the way, I just went to Yahoo and typed in "diseases on French Hollyhocks" and came up with tons of sites about Rust. Apparently a big problem with HH.

[stephanietx]

Sandi, thank you so much! You have been so helpful! We didn't have any problems with our HH until very late in the season last year. I attributed it to the hot, dry weather. When it came back this year, I knew I had a problem. I really love these flowers and get lots of comments on it from the neighbors.

Have dusted with cornmeal and will try the milk when I get back from vacation.

Stephanie

[sandih]

be sure you read both links. I would spray it with a fungicide. Remove all the affected leaves.

[stephanietx]

What fungicide would you recommend? Of course, it's raining today which doesn't help matters at all!

Stephanie

[sandih]

No I really don't. I would do an internet search on organic fungicides.

[khwoz]

The home page lists all the info that you are needing. Click the link below & check out the info.

http://www.dirtdoctor.com/view_question.php?id=204