What to do for crepe myrtle sooty mold?

curt33(z7MS)December 15, 2004

I had what I thought was sooty mold that formed late this past summer on one of my crepe myrtles, and was starting to spread to another one until fall arrived. It was a black substance that coated the leaves and trunks. The trees are small, and I am going to trim and shape them here in a few days for the desired shape I want them to grow into. Would right after this trimming be a good time to spray them for this mold? What should I use? Is dormant spray that I use on my peach trees ok?

Any and all non-condecending help will be greatly appreciated.

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Sooty mold is a result of aphids dropping honeydew on the leaves, which then provides the medium for sooty mold growth. Keep an eye on the underside of the leaves next spring/summer and spray with insecticidal soap to get rid of the aphids. Its of no use to spray now.

    Bookmark   December 16, 2004 at 8:06AM
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Are you sure it wasn't mildew? Crepes are notorious for mildew, especially in hot, humid days of late summer. You can thin the limbs by trimming from the center outward to develop an open space inside to allow air to circulate better and get more sunlight. Space the bushes so they are not crowded. Replace them with mildew resistant varieties. A lot of the newer varieties are mildew resitant.

    Bookmark   December 16, 2004 at 11:34PM
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rhizo_1 (North AL) zone 7

Black stuff on a crape myrtle is certainly black sooty mold. The mildew that these plants are prone to is powdery mildew, a white or gray disease of the leaves. Pterostyrax is correct that the black sooty mold is caused, most probably, by aphids (could be scale). However, I disagree that it is of no use to spray with dormant oil. Aphids overwinter as eggs in the nooks and crannies of our plants. Spraying with dormant oil is one of the BEST methods of suppressing a major outbreak come spring. I would spray three times during the winter and again in the spring just as the buds start to swell. Dormant oil applications are a very important part of IPM for Crape myrtles.

In the spring and summer keep your eyes out for aphids on the new growth and be prepared with the insecticidal soaps.

    Bookmark   December 30, 2004 at 10:21PM
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I think that pruning will help you as much as anything. Pruning also makes the Crepe Myrtle a lovely addition in the winter. Make sure that you get all of the lower branches and provide amost a "top heavy" look for these trees. You will love the look! With the added circulation of air, I think you will not have a problem. This took care of my problem.

    Bookmark   January 2, 2005 at 12:54PM
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tamivileine(z8b OS,MS, US)

sooty mold along with aphids.

I posted the query at the La/Miss forum, and got a response suggesting an organophosphate. Oh no, I'll let 'em get eaten, I'm right on the water...

But y'all are suggesting oils and soaps. So, can I get some advice regarding application and types?

thanks in advance

    Bookmark   August 2, 2005 at 2:17PM
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