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Heritage rose leaves turning brown

Posted by RachaelLemmon 5 (My Page) on
Fri, Jun 20, 14 at 9:44

Im not sure if its disease or insect but i spray for both and see this on no other rose in my gardens. Its focosed in the bottom of the plant . Lots of buds and blooms with healthy leaves at the top. What is this?


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RE: Heritage rose leaves turning brown

  • Posted by hoovb z9 Southern CA (My Page) on
    Fri, Jun 20, 14 at 10:30

looks like spray damage. Did you spray when it was very hot?


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RE: Heritage rose leaves turning brown

Could be spray damage. Leaves in the back may have been skeletonized by rose slugs, but I can't say for sure as they are out of focus. Examine the undersides. But that could be spray damage too.

Generally, experienced rose gardeners do not spray for insects routinely. Watch for a problem, ID it exactly, and apply the remedy for that specific problem. People here will help.


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RE: Heritage rose leaves turning brown

The problem just started this week. I havent sprayed any of my beds since early may.. i usually do again when the JB start destoying my roses in summer. Never seen this before in any roses i have. These are on the lower inside of the bush, all the outer leaves are fine.. idk what to think.


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RE: Heritage rose leaves turning brown

To me, it looks like it suffered a heavy rose slug attack a few weeks ago, but the rose slugs were destroyed by visiting good predator bugs and the bush started pushing out good leaves with no damage (the ones on the "outside").

Check the backs of the damaged leaves and see if you can detect any tiny, teeny green "worms"--if so, they are the rose slugs and should be quished, or if you are squeamish, tossed into the yard. They probably won't find their way back. Since a few of the outer leaves also look like they may have some damage on them, it is likely at least a couple rose slugs are still hanging around.

If there are no rose slugs (and it only takes a couple to do a lot of damage), then your problem is already solved. In which case, you might spruce up the rose's appearance a bit by pulling off the most damages leaves, but if there is still some green on them, perhaps leave them since that means they are still producing food for the plant. But some of the damaged leaves could be removed.

Usually no spraying is needed. This only happens (sometimes) on some of my spring blooming roses. Between manual inspection procedures and, a week or two later, the arrival of the "good" predator bugs, the whole episode passes rather quickly (until next spring).

Kate


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RE: Heritage rose leaves turning brown

Rose slugs (actually sawfly larvae) while they are small graze on the underside of leaves, sometimes leaving the upper surface intact, so the injured area is translucent and white or tan. When they are larger, they chew holes between the veins all the way through the leaf.


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RE: Heritage rose leaves turning brown

Thank you kate! This is a young rose bush (3rd yr own root) , so its easy for me to see the inner parts . I decided to get out the gloves and really inspect my mature shrubs and i did find a similar damage on the very furthest inside canes, i would never had seen it if i didnt dig for it . I will take a look for these pests. Geneally here in upstate NY i struggle with blackspot early and the jap beetles late.. this is new to me. Thanks again!


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RE: Heritage rose leaves turning brown

There are strange small flys on the bush and holes in some of the leaves. Would they be the cause of this? I dont want to investigate it any further , now im seeing damage i hadnt noticed before :(


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RE: Heritage rose leaves turning brown

The lower right hand photo shows how these brown spots start very small and then they seem to grow and grow until the leaves are tan and brittle .


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RE: Heritage rose leaves turning brown

Are the brown parts lacy? If so it is rose slugs. Assuming yes, look on the underside. Do you find green worms on the lower surface of injured leaves? If no, the slugs have been wiped out by predators. If yes, and many of them, we can talk about control measures.

The larger non-lacy holes could be caused by rose slugs that have grown larger. Look on the underside! If yes, wipe them off.

Larger holes could also be caused by a stray caterpillar who may be hiding in the vicinity, or by a beetle now long gone, or by a leaf-cutter bee (but not a LCB in this case, they make round holes). Unless there is a lot of damage, you can ignore these. If you see a leaf sandwich with webbing, look inside for a caterpillar.


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RE: Heritage rose leaves turning brown

There are some perfectly round small holes in the leaves and some in the smaller buds .. The tan areas do have a lace appearance . Is there anything I can use to deter these insects? This particular rose doesn't get bayer product and such because it's very close to many of my nectar plants and also some lady bug favorites, so I try not to spray it for insects , just disease. I have milkweeds/ yarrow/ joe pye just beyond this bed and I'm very careful not to spray near my butterfly plants.


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RE: Heritage rose leaves turning brown

You have to look on the underside of the affected leaves to see if they are still there. Probably not.

Most of us have rose slugs every year. Wasps and other predators usually control them. Next spring, watch for the damage and wipe the tiny worms off the underside with your thumb. If you can't keep up with that, spray the affected areas with a spinosad product, reaching the underside of the leaves with thorough coverage.


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