JayDee
I have no mites on my Fargesia robusta clumpers but they are less prone to them. Boo-shoot gardens once sold a short booklet about bamboo that offers a specific cure for running bamboo but it amounts to destroying the village to save it. I’ve not done it but relate this since they don’t sell that booklet any more.
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In early spring, before the shoots begin, cut away all culms to ground level. Clear out all litter from around the plant–the mites live in the old leaves. Use fire to set the base of the stand burning, including any old leaves. Apply a nitrogen fertilizer and watch for the new growth, stripping any leaves that have mite splotches.
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Again, I’ve never tried this and obviously fire should be used with caution and a hose handy. I love black bamboo but the idea of a runner scares me. My clumper F. robusta is indeed robust–mine have topped out near 18 feet and a cat cannot pass between the culms. Good luck.