All my canna lilies look sick

My cannas started looking a little sick back in early August, but I didn't give it much thought at the time. I thought they would outgrow the few scraggly looking individual plants. Since then, they've gone downhill really fast. I researched canna diseases, and I think it's a viral problem. I planted many new varieties this past spring, and they're all diseased. The problem has also spread to established cannas, including some I've been trying to get rid of for the past few years. I'm afraid it's either canna mosaic virus or canna yellow mottle virus. I've done some online research, and I've come across several websites that recommend digging them all up, burning them, and disposing of the ashes if they're infected with either virus. (I also planted cannas in my mother's perennial garden last spring 2009, and this year her cannas are similarly diseased - she lives about 3 miles away.) I'm posting a few pics, and would really appreciate some feedback. I'm hoping this is a fungal problem that I can treat with a copper based fungicide.

Another patch

yet another

Sorry, corrected view

Mine too .. like the brugmansia, 2 of my canna, chocolate cherry and journey's end have done poorly. I'm thinking its probably because of high temperatures and too much rain, because the bengal tiger, which is a water canna actually did the best, tho it was not as pretty this year as before.

This has been a very strange growing year.

Sorry yours are also doing poorly, madame X. I always look forward to their peak beauty this time of year. They were all healthy when I took this pic on 6/28/10. Back then I thought j. beetles were the only problem I had to worry about.

Your cannas look so beautiful in June. So did mine ! I had more problems with my Bengal Tigers. ??? I think you call the insect "leaf rollers". I'm sure there is a more scientific name but it is a very small worm/cat. that is inside the leaf. If you unroll the leaf you will see them. The trick is to find them early but my experience is the damage is done by the time you see them. Be sure you destroy those leaves when you cut them back or they will return next year. Sevin dust works if you can catch them in time.

Here is some leafroller info. Scroll down to "Lesser canna leafroller."


http://www.clemson.edu/extension/hgic/pests/plant_pests/flowers/hgic2104.html

This message was edited Sep 26, 2010 7:19 PM

Some of the unfurled leaves were damaged and slightly bent. I applied sevin dust to protect from j beetles from early june - late july, and the damage didn't show up until shortly afterwards. I thought cannas were bullet proof, but there's a lot of scary stuff online about viral diseases. I cut out most of the damaged leaves today, and I'm concerned that some of the rhizomes were dead and mushy beneath the soil surface. I also noticed insects at ground level that I associate with root rot. Plan to burn the canna leaves as soon as weather permits. I hope leaf rollers are the culprit - sure would hate to have to destroy all my cannas. Many leaves were filled with defoliated blotches that looked like something had been munching on them. Thanks, BSD!

Thanks for the helpful web link. I'm feeling more confident now that it's not a viral issue.

This message was edited Sep 26, 2010 7:35 PM

Actually if you know what to look for you can take some preventative action. The leaf rollers actually sew the leaf so it can't unfurl. When I see evidence of them I'll go around in the evening with a knife and cut the threads along with spritzing some insect killer in the unfurled leaves. If you're not adverse to chemicals, Bayer advanced works really well in controlling them .. you just apply it every 6 weeks.

Thanks, X. I'll try the Bayer Advanced because I have not had much success with the Sevin. I agree that it has to be more of a preventative plan than anything else. I did notice early this summer when we were having those 90 degree days, that there were small ? droppings at the junction of the leaf to the stalk. Pulling this back you could see what I thought were aphids. After this was when the leaf did not unfurl. The idea of cutting that seam sounds like it might do the trick.
I do not think that this efffects the roots because all of mine come back beautiful and look great untll about this time every year. So off with their heads this week and I will have a leaf burning- worm killing inferno going.
There is always next year !!!

All I can say about cannas is "water." Lots and lots of water. We've not had too much of that in the last month until today.

It doesn't affect the rhizome at all .. just unsightly. The trick is to catch it early and spritz a little insecticide in unfurled leaves whether or not they have been sewn together. I tell tale sign that trouble is on the way is noticing moths flying around them. They are the culprits that lay the eggs.

BordersandJacks, I agree with water. I watered mine more diligently this year and they still look ok.

Entlie

I'm still concerned about those areas with rotted rhizomes and insects. During droughts I've always provided supplemental water, and I've never had this problem. I just took a pic of my neighbor's cannas, and they look great compared to mine, although he never waters.

Thanks, madame X, next year I'll definitely check out the Bayers systemic product. Meanwhile, wherever I see insects at the base of the cannas, I'll be applying an insecticide. I have some cannas planted next to heliconias, their uppity relatives, which are lush and healthy. Next year, I'll be using all the preventive measures in this thread, but if the problem persists, I'm getting rid of them. The thought of battling j beetles for 2 full months, and then having to wage combat with leaf rollers, mites, etc. is too labor intensive for me. Hope the new cold hardy heliconias are truly cold hardy here in zone 8a.

I got rid of most of my canna last year and only kept three .. after this years performance I'm probably going to get rid of all of them .. too much work to keep them looking nice.

In my experience, unless a canna is deemed a water canna, too much water can cause rotting if the ground stays wet. My Chocolate Cherry is one that does not like wet feet.

I wonder how cannas perform so beautifully along I-95 medians. (They must be treated with a systemic!) The problem with my cannas is definitely leaf rollers. Just went out and unwrapped some of the many leaves sealed by web like structures, and they're filled with droppings. Still perplexed that they've infested every batch scattered all over my yard, but have left my neighbor's alone.

Do your cannas get good air flow? Take X's advise about the watering. Less is best.
The reason they are used for highway plants is they require little care.

Some do and some don't. I planted several new varieties, mostly dwarf, last spring, and many of them are now crowded/covered with overgrown mexican petunias, brugs, etc. (Surrounding shrubs and bananas also grew like crazy this season.) Airflow is definitely an issue for some, and this fall I will be moving and rearranging many plants. I also supplied lots of overhead water during drought and intense heat - probably not a good idea. But I also have leaf rollers infesting and disfiguring cannas in far flung areas of my yard that have good air flow and get little supplemental water. Seems that these leaf rollers had a population explosion in my yard (and my mother's yard a few miles away), but not my neighbor's. An obvious case of witchcraft.

Thanks BSD!

Sounds more like a case of nasty systemic poison to me. I had cannas that looked like that and I never regretted shovel pruning them. Life is too short to put up with ugly plants especially when there are so many beautiful ones I haven't grown yet. LOL

The Charleston Horticultural Society is holding their Fall Garden Tour this coming Sunday. Their tours are always worth the time and $; I get so many ideas for new plantings. This years tour is in the city so I suspect many of the gardens will be more formal than I like but I am certain I will see some new, to me, plants that I can't live without.

Charleston Horticultural Society
presents the

2010 FALL GARDEN TOUR
Gardens for Gardeners
Sunday, October 3rd, 12 - 4pm
RECEPTION IN PRIVATE GARDEN 3:30 - 5pm

Rain or Shine

A self guided tour of Private Gardens in Downtown Historic Charleston's
Mazyck Wraggborough Neighborhood

Reserve tickets online at www.charlestonhorticulturalsociety.org

CHS Members $25 - Non Members $45

Tickets, Tour Map and Program available at the
Charleston Visitor Center
375 Meeting Street
Charleston, SC

The private Chas garden tour sounds divine, ardesia. I'm interested in hearing about your new plant discoveries - hope some are cold hardy in my backyard.

My neighbor doesn't use systemics, unless 'systemics' is code for voodoo:)