my Canna look horrible, please help

bgaviator(7)July 22, 2014

New homeowner here, and I a ton of Canna growing on the south side of the house. I didn't even know what these plants were called when I first moved in, so I'm truly a newbie at them. They are starting to look terrible....they look chewed on, burned, shriveled, etc etc What is going on, what can I do?

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bgaviator(7)

canna pic 2

    Bookmark   July 22, 2014 at 3:50AM
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bgaviator(7)

canna pic 3

    Bookmark   July 22, 2014 at 3:51AM
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bossyvossy

Wow they do look bad,perhaps a virus? I don't think that is curable but before u completely give up, try whacking them to about 6" from the ground and see if new growth comes out healthy. If not, you prob need to yank out.

Mine get ugly by end of summer, I whack and they are beautiful again. I live in Houston area, don't know if u hv enough growing season for a 2nd growth. You could also spray with BT which treats for pests that eat canna, but from your pics, they don't look eaten up.

    Bookmark   July 22, 2014 at 6:59AM
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canna2grow

It would have been of great benefit to know; in what state do you live? Your cannas are definitely infected by the lesser canna leafroller and I do not see any visible virus issues. This leafroller issue has been cussed and discussed for years. If you will do a search for âÂÂleaf rollersâ in the search box you will find a multitude of suggested solutions; most of which do not provide adequate control or are simply ridiculous for the areas with major problems.

Having a basic understanding of the life cycle of this pest is important in its control. Your location has a major bearing on the risk for leafroller presence or its migration from the south and/or its ability to overwinter in your area.

Because the lesser canna leafroller larva lives in the tightly curled leaf, it can only be controlled by a systemic insecticide applied in a safe and timely manner.

Kent

    Bookmark   July 22, 2014 at 2:04PM
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bgaviator(7)

I live in northern Mississippi. I didn't move into this house until the end of May, and the dead canna debris from the previous years was all over the ground. I didn't cut it out and take it up, cause I didn't even know what it was at the time I had.

    Bookmark   July 22, 2014 at 8:39PM
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canna2grow

Living in Mississippi certainly explains the leafroller infestation. The dead canna debris left from last year may have provided refuge to overwinter the pest but your area certainly sees leafrollers most years.

If you choose, you can remove the most affected older stalks by cutting them off at the ground and leaving the younger emerging stalks least affected. Destroy the removed stalks/foliage. Treat the remaining plants with a good liquid systemic insecticide; consider Orthene (acephate). Applications may need to be applied every couple of weeks to get the pest under control. Unfortunately Bt will simply provide little or no control over the lesser canna leafroller. Please follow the label directions.

Your cannas can be rescued and will look much better if you choose to follow the above recommendation.

Kent

    Bookmark   July 22, 2014 at 11:20PM
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bossyvossy

thanks, canna2grow for your input. I didn't even know that there were two leaf rollers. Perhaps mine have fallen victim to the large lr, as my foliage looks chewed up but never with black/burnt out foliage as shown in the above pics. Or perhaps the infestation was severe, compounded by the fact there was no foliage cleanup in prev. year.

In any case, I now believe you have a pest problem not virus and pest problem is a much easier war to wage. Also, living in MS, you probably have a chance for a 2nd round of growth, so I would still recommend that you cut and remove foliage, use your product of choice per label instructions, and look forward to a pretty Fall show. Finally, you will have to keep a watchful eye on your cannas and the minute you see damage, go on the defensive. It is not a serious war, but definitely ongoing.

Here is a link that might be useful: two types of leaf rollers

    Bookmark   July 23, 2014 at 8:28AM
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bgaviator(7)

thanks everyone. Yeah I may just whack them down and see if anything grows the rest of this year. Probably easier to start from scratch. I'll make sure I do a fall/winter cleanup this year too.

    Bookmark   July 26, 2014 at 2:35AM
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professor_nick

We sprayed the folliage several times with "Seven" and the leafroller problem did not appear this year.

    Bookmark   September 23, 2014 at 10:39AM
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