I did not ask for a new bug. And if I had, I would have been asking for a new bug to replace the scale, not a new bug to add to the scale, much like Huey Lewis wanted a new drug to replace the problematic drugs he had previously tried, not because he wanted more variety in his drug use.1 And yet.
The problem is that I don't actually know what new bug I have, nor how to make it go away. So I'm asking y'all for thoughts.
It seems exclusively interested in Aglaonemas, and only two or three varieties of Aglaonema to boot.2
It looks basically like household dust. In fact, it looks so much like household dust that I've been assuming for quite a while that that's what it was.
The dust hypothesis didn't actually make that much sense, because it was only ever on certain specific leaves, and was sometimes accompanied by weird brown-orange discoloration at the leaf margins.
I don't know why the margins would be discolored, though, as the bugs seem pretty evenly distributed across the whole upper surface of the leaves.
There were also frequently sticky droplets of something or another. The droplets didn't alarm me terribly, because a lot of my Aglaonema varieties produce sticky droplets on the outside of the spathes when they produce flowers, and I first noticed the "dust" as the first affected plant was flowering. I'm still not 100% convinced that the droplets are related to the bugs, actually.
It doesn't seem to be particularly harming the plants, aside from the marginal discoloration, and the margin thing has really only been going on with 'Emerald Bay.'
So why do I think there's even a problem? Because I checked the leaves out with the microscope. As usual, getting decent photos with the microscope is nearly impossible, so forgive the quality, but you can see a couple mite-like things in the center of this photo, a relatively in-focus third one just above and barely to the right of those, and pieces of blurrier ones here and there around the periphery of the photo.
Which, it looks like an arthropod, not an insect: blurry though the picture is, it's pretty clear that they're holding four legs in front of the body, and either one or two pairs behind it. Plus there's that overall tick-/ mite-shape going on.
Obviously there are many, many species of mite, but the only ones I know of that make a habit of attacking houseplants are the two-spotted spider mite and the cyclamen mite, and I don't think these are either of those two species. Under the microscope, spider mites are 1) much larger, 2) yellowish and opaque, instead of translucent white, 3) inclined to stay mostly on the underside of leaves (these mites are almost 100% on the upper leaf surface), 4) detectable by the visible webbing they create, and 5) will move while you're looking at them under the microscope. I've never directly observed cyclamen mites under the microscope, but the pictures that come up in Google are of rounder, smoother creatures with stubbier legs. Cyclamen mites mostly look like white jellybeans, as far as I can tell, which these do not.
It's conceivable that I'm actually seeing the dead skins left after the mites molted.3 That's happened before, with the deep-sea crab/skeleton/spider/ghost things (probably actually aphids) I talk about at the end of this post, and would explain the translucent whiteness and lack of movement. I am also willing to entertain the possibility that my Aglaonemas are being haunted by the ghosts of deceased spider mites, because that likewise explains the translucent whiteness and makes about as much sense as anything else.
Of course I've Googled. There's plenty out there about spider mites and Aglaonemas, but nothing about any other kinds of mite.
So far, I've tried imidacloprid (when I was putting imidacloprid in all the plants), which definitely did not get rid of the infestation, and wiping the leaves with rubbing alcohol and a paper towel, which I did too recently to know about its effectiveness. (My guess: yeah, it'll probably work, but I'm going to have to do it several more times.)
So what about it? Anybody seen anything like this before? Have any suggestions for what I could do to find out what I've got, or how to make them go away? Suggestions for dealing with spider mite ghosts are especially welcome, since Google is as silent on the topic as you'd expect.
2 Almost all of it has been on 'Emerald Bay,' which is in my office. Also affected: 'Golden Bay,' 'Diamond Bay,' and 'Brilliant,' all of which are in the living room. 'Gold Dust,' which sits right next to 'Emerald Bay,' and has been for quite a while, doesn't seem to have the problem at all, though.
3 If you're into video of spider mites running around and molting -- and who among us isn't? -- check this out: