I was away last week and while I was, I had a comment on my post called “Why Is My Black Lace Wilting?” The very perceptive commenter named Kim had noticed the same thing in her Black Lace and had cut it open and found small yellow worms. When she called her garden center, they recommended a systemic insecticide. She chose to remove her plant instead.
From the time I got her comment until the time I actually got to examine my Black Lace it’s been almost 2 weeks–and I was quite pleasantly surprised to see how well it had recovered from its wilting. Nevertheless, I went down, cut off a branch that still showed some residual evidence of wilt, and started probing (and by the way, there were still some lovely red aphids on it this time!)
I found this evidence of a borer tunnel–and many like it. I never actually saw any borers, but they may be long gone, based on the recovery I am witnessing in the shrub.
Once I cut open the stem in several places, this is what I saw.
This is borer damage in an apparently otherwise healthy stem. There is clear evidence of an insect residing in the stem at one point, but no damage to the stem or the leaves that were on it, and no wilt on the branch (because I wanted to show the close-up of the insect home, I didn’t show the leaves so you’ll have to take my word for that).
This, on the other hand, is a stem that had been damaged and was showing some wilting. The inside shows some evidence of frass, or chewing debris left behind by an insect.
So that’s all I can tell you about my experience with the Black Lace stem borers since they appear to have left my plants. I will be more alert for them next season and I thank Kim for sharing her experience so we can all learn from them!