![]() Though experienced experts are confident that the insects probably won’t kill healthy trees, the condition seriously weakens plants and usually spoils the flowers. Of course, as Texas A&M horticulturist Greg Grant mused recently on my NPR program, with the naturally-dark foliage crape myrtles such as ‘Black Diamond’ being so trendy, “maybe scale-infested trees will be accepted as well…” Black Crapemyrtle (Lagerstroemia indica ‘Black Diamond’) But it’s temporary – because all the scale cannot be removed entirely from small twigs, they will simply come back the following year. The mold itself will flake off over the winter, or can be scrubbed off with a soft brush and soapy water, or can be washed off with a pressure sprayer using LOW pressure to avoid damaging thin bark. Infested trees completely covered with sooty mold Again, much worse than sooty mold from aphids. Crape Myrtle stem crusted with bark scaleĪ distinctive black “sooty mold” quickly develops on the drippings, which turns everything below the insects – leaves, limbs, trunks, other shrubs, garden furniture, even plastic flamingos and mulch – as dark as night. They can quickly cover entire trees in crusty masses, and as they suck sap they exude a sticky, plant sugary excrement, just like the stuff aphids and mites drip from undersides of leaves of crape myrtles, oaks, hackberries, gardenias, and other plants. The tiny legless white or grayish bugs hatch from eggs and crawl as nymphs onto twigs, branches, and trunks of crape myrtle trees, attach themselves, sorta like little plant ticks, and cover themselves with a spray-resistant waxy shell. Closeup of new infestation of crape myrtle bark scale ![]() Individual scale are just tiny things, not much bigger than fleck of ash, but they multiply and spread rapidly, overtaking trees in one or two seasons and rendering them basically unfit for landscapes. The invasive Asian insect called “crape myrtle bark scale” first showed up in the US around 2006 but has been spread far and wide, partly via infested trees being sent to garden centers, then to gardens, then from tree to tree. SPOILER: YOU’RE NOT GONNA LIKE ANY OF THIS This blog is about what the problem is, and what we can – or can’t – do about it. Architectural crape myrtle trunks with beautifully mottled barkīut just like whether to spell it “crape” or “crepe” or want to argue about pruning, they’re all moot points now, water under the bridge, as our beloved crape myrtles are being pushed out of the garden entirely by a new pest that is for all practical purposes uncontrollable. For more insight on this check this blog post out. ![]() I don’t even have a problem with their being pollarded, which in Japan is a form of topiary called “fist pruning” (what some folks call “crape murder”), especially when gardeners like me weave the trimmings into wattle fences. I even made the trek to South Carolina to hug the oldest crape myrtle in North America, planted in 1786 by André Michaux at Middleton Place near Charlesto (see last photo). In spite of their maybe being a tad overplanted, I love crape myrtles – the lilac of the South. ![]() “You’re not gonna like any of this.” Crape Myrtle flowers For more on aphid control as well as how to handle the associated issue of sooty mold, see our guide to common crepe myrtle problems.OUCH! Say “G’bye” to one of the South’s most cherished landscape trees. Occasionally aphids, a sap-sucking insect, attack plants but can be controlled through insecticides or a soap and water solution for a less harsh preventative. Steve Bender Common Pests & Plant Diseases Then next summer, spray the tree with a fungicide called Immunox, which can be found at most garden centers. Keep leaf spot from showing up next year by raking up all the fallen crepe myrtle leaves and throwing them out with the trash. The good news is that this leaf spot doesn't seem to really hurt an infected tree, even if it drops all of its leaves prematurely. And because the fungus spores are easily transmitted from tree to tree with the wind and more crepe myrtles are being planted every day, the problem will probably get worse. Unfortunately, while breeders have produced many crepe selections resistant to powdery mildew, they haven't given us many that resist this leaf spot. Mine have had the same problem in the past. If your crepe myrtle is dropping leaves, chances are your trees are infested with a fungus called Cercospora leaf spot.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |