I have two Artemisia 'Powis Castle' plants, which have seemed to be doing really well in my front yard... except that yesterday I noticed they had both become badly infested with tiny reddish spidery looking things - I assume these are red spider mites, though they look bigger and darker in color than the internet pictures I could find when I Googled them. My first question is - I thought Artemisia were supposedly pretty much pest-free and in fact a pest repellant, in some cases? And second - any tips for getting rid of the things? I first sprayed with an (eco-friendly) insecticidal soap that said it works for mites. I waited a bit, then also used a high-power water spray to jet them off the leaves. If I keep doing this, should it be enough? Oddly, they don't seem at all interested in any of the other surrounding landscape plants, only the artemisia.
If you have pest mites they will cover the infested foliage with close, fine tent-like webbing when there are enough of them and the affected parts will become stippled (finely speckled yellow), eventually brown if severely infested. These mites are very small and can be hard to see without getting real close or using a lens. If you saw comparatively large and visible, bright red mites wandering around those were probably instead predator mites and should have been left alone.
Yikes, really? Didn't even know such a thing existed... though they were more of a dark brown-red than a true bright red. The incredible density of them (massed particularly at the very ends of each frond) made them seem like they must be pests... have no idea what they were feeding on, if they were good. And there was no webbing in sight, or visible leaf discoloration. Shoot, I hope they weren't the good ones! I'll try doing another google search.
I did some more searching, and I may have been completely mistaken - they may not be mites at all, but aphids. I thought that aphids were all green, like the ones I usually see, but I found some images of dark brownish/reddish ones, that look pretty dead on to what I saw - the visible legs made them seem spidery, but seems like all evidence is pointing away from mites. Though that still doesn't solve my confusion as to why a pest-repelling plant would be a prime attracter for aphids? Seems weird...
Yes, I was expecting you would find out they were aphids - the clustering near the tips sounds like those. There are many kinds of "pests", with few, if any plants being ironclad.
