Anthurium no. 0586 "Vera Special"

First, a couple bits of unfinished business:

I e-mailed my local Iowa State Extension Office on July 29, asking about tests for dasheen mosaic virus (DsMV), as discussed in the comments to this post. They replied immediately, and recommended I ask the ISU Plant and Insect Diagnostic Clinic about it. So I sent the same e-mail to the ISUPIDC.

On August 20, I heard back from the ISUPIDC. The answer was: no, they do not test for DsMV, but they did know of a company that might, Agdia, Inc.

Agdia does in fact do DsMV testing, which is great, but they won't tell you on the website how much the testing costs. I assumed that that meant that it was an if you have to ask how much it costs, you can't afford it situation, but e-mailed Agdia to ask anyway, and got an autoreply "I will be out of the office until ______" message, because everything has to be fucking impossible today.¹

In the end, it's not going to happen: testing one sample is $67 at Agdia ($9 per additional.), which is more than I want to spend to answer this particular question. But if I change my mind later, I have somewhere to go. So thanks, ISUPIDC. I guess.

The other unfinished business is related to the ongoing thripstastrophe.² Ivynettle suggested in the comments on this post that I try getting parasitic mites to eat the thrips, that she had done so this year and had been pleased with the results.³

That didn't go very smoothly either, and is also expensive ($63.70, shipping included, for 50,000 mites.⁴), but it at least has the advantage of being something I haven't tried before. Imidacloprid doesn't seem to affect the thrips at all; white oil is cheap and somewhat effective, but also extremely messy, time-consuming, and the Anthuriums respond by dropping all their blooms, so I don't want to try that again unless I'm truly out of other options. Hand-picking is ludicrous, spraying with a non-imidacloprid insecticide (e.g. pyrethrin) is prohibitively expensive, giving up and living with the thrips is depressing,⁵ zero-tolerance for thrips infestation would end with all the seedlings in the garbage except one, and it would probably be a pink/pink. So this is something I can try. Even if it fails, as it almost surely will, doing something feels better than doing nothing.

With all that out of the way, then, let's talk about seedling 0586. The name assigned to her, "Vera Special," wound up being sort of a joke, because Vera is almost identical to 0580 "Marsha Marsha Marsha," and awfully similar to 0120 "Eliza Boutisecksis."

Which one is Vera?

It was this one! (L-R in the first photo: 0120 "Eliza Boutisecksis," 0580 "Marsha Marsha Marsha," 0586 "Vera Special."
It happens to be a look I'm really fond of, and even if it weren't, I see orange so rarely that I'd be inclined to keep and cherish it even if it were terrible. But it's not terrible! Hooray! The spathe is a decent size, and so far doesn't seem to want to flip backward. Add in the color, and I think that easily puts Vera into the top 25% of all seedlings.

The leaves are also basically identical to Marsha's, which makes sense because Marsha and Vera were both divided from 0115 "Erlene Adopter," and are either clones or siblings.⁶ Marsha, Adam, and Vera have another thing in common, which is that they have all done this at some point:

A weird 0586 leaf, by reflected (L) and transmitted (R) light.
Not all the leaves, or even most. Just a few per plant. In all three cases, it appeared basically overnight, I hadn't done anything any differently that I could remember, the leaves otherwise appear perfectly healthy, and it doesn't seem to be spreading or intensifying. I don't have any very satisfying theories about what's going on: it sort of resembles certain rare kinds of virus damage, and sort of resembles some kinds of fertilizer deficiency and mineral toxicity, but if it's fertilizer-related, then it's weird that of all the Anthuriums here, it's only affecting three very closely-related plants. I mean, they all get basically the same fertilizer, and I water heavily enough that anything toxic should all have been washed out of the soil long before the leaves changed colors. The coloration doesn't look much like most viruses I've seen, either. So I don't know what's going on.

The unaffected leaves are unremarkable. Nice when new, dull and kind of plain when older. Resistant to thrips damage, though, which is always nice.

Like her relatives, Vera suckers thickly, another strongly positive trait. It remains to be seen whether Vera will be like her relatives in being impossible to pollinate. I don't know how many blooms have appeared and withered without any pollination on 0120 "Eliza Boutisecksis," but, like, several. And I haven't had any luck with 0580 "Marsha Marsha Marsha" either. I suppose sexual reproduction doesn't seem as urgent when you can make so many suckers.

So overall? Vera's not perfect, but she's a keeper. No question about it.

-

¹ (I'm writing this on Friday August 21. It really was a pretty rough day, internetially speaking. Absolutely nothing worked the first time I tried it.)
² Not to be confused with the scalepocalypse, or the miteaclysm.
I'm pretty sure I haven't mentioned the miteaclysm before, so:
The Anthuriums in the living room, i.e., the parent varieties of most of my Anthurium seedlings, have developed some kind of mite problem, though the mites in question don't appear to be spider mites. Or at least they're not particularly inclined to spin webs. I suppose they could still be really lazy spider mites.

(on the NOID red)
I'm not super worried about the mites, which I figure will probably go away once the days get shorter and colder. (This has happened in previous years.) The predatory mites are also alleged to go after spider mites, so hypothetically, the predatory mites could kill two birds with one stone although come on how are you ever going to kill two birds with one stone unless the birds are like lying on the ground with one of them resting its head directly on top of the second bird's head and they're both holding perfectly still? And even then, if the birds saw you walk up with a stone they're not going to keep sitting like that, they're going to fly away, right? I question the whole premise of the idiom, is what I'm saying. (And don't even get me started on "the more the merrier." I mean, some of the "more" might be assholes! How's that going to make anybody happy? And how are you supposed to transport eggs if you don't put them all in one basket? Two baskets? That's not efficient at all! Do you even know how much baskets cost these days?)
Anyway. The point is, it's possible that the predatory mites could solve all kinds of problems for me, though at this point my best-case imaginary scenario is that they slow down the thrips, a little. Expecting more than that seems like a recipe for disappointment.
³ As did another reader, by e-mail, some time ago, though if I remember right they didn't claim to have tried predatory mites personally; they were just suggesting it as an option.
⁴ I cannot imagine how much it must suck to be the employee who has to count out 50,000 individual mites to put in the bottles. No wonder they're expensive: that must take weeks. And what tiny tweezers they must have to use!
⁵ At least in the short run. In theory, I could maybe breed thrips-resistant seedlings, given enough time, but the thrips reproduce so much faster than the Anthuriums that I suspect the thrips could come up with new attacks more effectively than the Anthuriums could come up with new defenses.
⁶ Erlene herself has never bloomed, but offsets thickly and has similar foliage, like Vera and Marsha, so it wouldn't surprise me if all three plants were genetically identical. A fourth plant divided off of Erlene, 0581 "Adam All," has similar foliage and produced an orange bud once, but Adam sucked at follow-through and hasn't tried again. Wouldn't be surprised if he were a clone also, though.
Erlene/Vera/Marsha/Adam are from sibling group AG (seed parent 'Orange Hot;' sow date 12/7/11). 0120 "Eliza Boutisecksis" is from sibling group AH ("Orange Hot" and 12/17/11), which is close enough in sow date that it's entirely possible that Eliza is a half- or full sibling of the others, but she's probably not a clone of any of them.

Microphotography: Portulaca grandiflora

I'm unclear on the specifics of where and how, but the husband, knowing that I've been looking for a microscope for some time, somehow obtained a used one for me. Which is one example of how he's the best husband ever.

The catches -- and of course there are catches -- are:

1) Okay, I don't know the proper names for anything here, but I'm going to call that thing in the middle, with the four things sticking out from it, the microscope's "udder," because that's what it looks like. Each of those barrels on the udder has a different level of magnification (I don't know what levels of magnification, because I cannot decipher what the barrels say), only two of which appear to function.
2) It's a regular, old-school, 1960s-ish microscope, so it wasn't designed with digital photography in mind. If the camera lens is not exactly centered over the eyepiece, the camera doesn't register anything being there at all. Likewise if it isn't precisely the right height above the eyepiece. My hands shake way too much to get pictures by holding the camera in the right spot myself, and although we do have a tripod, the base of the microscope is just large enough to get in the way of the tripod's legs, so I can get within about a centimeter (0.4 in.) of the eyepiece, but then no further. Except! When I took the below pictures, I actually could get the tripod directly over the eyepiece. I just couldn't do it again a few days later when I moved the whole thing outside to try to get a better set of pictures in stronger light, and I don't know why, and the whole thing was very frustrating. Which leads us to the third problem, which is:
3) Even when I do manage to line the camera up, using the tripod, the amount of light coming through the eyepiece is small, so my camera uses long exposure times, which results in blurry pictures, even at its best.
4) And at its worst, the camera autofocus chooses to focus on the eyepiece itself, instead of the image in the eyepiece. Or it focuses on some part of the microscope outside the eyepiece, so I get a perfect shot of the top of the udder but the actual image I'm trying to capture is too fuzzy to make out.

So the point is that there are some problems with this, and you should, consequently, not expect to see a lot of these pictures until such time as I can figure out how to get better ones. And I would love some suggestions from other people, because I know there's got to be someone out there who's taken photographs through a microscope's eyepiece successfully.

Having said all of that, there have been some pretty cool moments with the microscope already, which I will hopefully be able to share with you someday. Portulaca grandiflora seeds, my only successful photos to date, turn out to be much more interesting than the gray, metallic dust they appear to be with the naked eye. For example, I had always imagined them as more or less spherical, since a lot of seeds are, but they turn out to have a specific, weird shape, somewhere between a comma and a nautilus:

At the higher magnification, they also have an unexpected texture, which is probably the coolest and most surprising thing I've seen in weeks. It didn't photograph well, of course:

The pattern is sort of approximately that of a bunch of tiny interlocked cogwheels, covering the whole surface of the seed. Which is even stranger in combination with the overall iridescent metallic gray color. (I now suspect that Portulaca grandiflora are robotic plants.)

I also tried for photos of the pollen, but that went even less well, and wasn't very interesting:

And those are the only actual pictures I'm able to provide to you at this point. Possible coming attractions, if I can figure out how to take the pictures:

A lot of leaves are hairier than I would have guessed. (Pedilanthus being the most surprising.) Though most leaves are disappointingly boring.

The serrated edges on Yucca guatemalensis are a lot less regular in shape and spacing than I expected.

Cryptanthus pollen is even more dull than Portulaca pollen: basically just irregular little white rounded things. At least Portulaca pollen has a color to it.

Ceropegia woodii flowers look exactly the way you would expect them to look, and brought to mind both "eyelashes" and "houseflies." Aeschynanthus speciosus flowers are boring and look just like they do with the naked eye, except bigger. Neofinetia roots didn't do much for me. (Think "styrofoam.") The Euphorbia fungus (yes, I still have Euphorbia fungus) looked exactly like I expected (sort of a creeping white net), and was dull.

Broadleaf plantain (Plantago major) really does have flowers (when you let it bloom), and the flowers are actually sort of pretty. I mean, if they were twenty times bigger, you'd grow the plant as an ornamental: there's a white, fluffy bottlebrush sort of stamen, with lots of white spherical pollen grains, and then the stigmas, or something I take to be the stigmas, are sort of shaped like white tulips with purple stripes down the center of each petal. (Plantago major is high on the list of stuff to get pictures of, whenever I figure out how to do that, but you can get some idea from the picture here at Wikimedia Commons. There must be some natural variation, though, because that's a darker, solid purple than what I was seeing.)

Another high-priority item: Anthurium spadices. It's a little easier for me to believe that those are flowers, now that I've seen them close-up. (I'd link to a photo, but I couldn't find one easily on Google image search.) It should probably be noted that they're still not pretty. At best, interesting.

Spider mites are every bit as horrifying as you'd think they would be, and they will continue to suck sap out of a leaf even after it's been removed from the plant. They also do this weird thing where they either shake their back legs like a dog getting a belly rub, or they rub their rearmost pair of legs together like a person trying to warm their hands. I only saw it do that once, and it was fast. I was so surprised and freaked out by there being, suddenly, movement, that I can't tell you exactly what it was. It also convinced me to throw the leaf in the trash more or less immediately afterward.

I think I've seen spider mite eggs now, though they weren't all the same color, so I'm not 100% on that. (They were all somewhere in the yellow or yellow-orange color range, but the darkness varied a lot, from pale yellow down to almost black.)

Some unknown white thing that was on our lettuce was one of the scariest things I've ever seen. It somehow managed to evoke deep-sea crabs, skeletons, spiders, and ghosts simultaneously, and I'm pretty sure seeing them come into focus in the microscope took a year off my life. The best match I found on-line for them was here, on a forum where they were identified as the shed exoskeletons of a molted aphid here. (The pictures at the link aren't magnified enough to be upsetting, FWIW.) So "skeleton" and "ghost" were actually pretty close. That also explains why they weren't moving.

So the point is, there's a lot of potential for interesting new posts, if only I can figure out how to get the pictures. It's going to take some experimentation, and I only have so much time, so if anybody has any relevant expertise, I'd sure appreciate hearing from you.

The Very Slow and Occasionally Sticky Inferno

So here's what's been going on.

Watering the plants has always been time-consuming and tedious, but it got worse in April. I've been watering almost everything in the house on a 14-day rotation. A lot of the plants would prefer more frequent checks than that, but 14 days is what I'm able to do, so they either live with getting watered every 14 days, or they die, or I make a special exception for them and check them every seven days. Previously, the special exception category was limited to about 10-15 plants on a small table in the plant room, but in April, I decided that about 500 plants in the basement also needed to be getting checked every 7 days, because a lot of them were seedlings or newish cuttings or plants that are just really drought-sensitive, and they wouldn't survive if I tried to keep them on the 14-day schedule.

What this has meant is that instead of checking about 1000-1050 plants every 14 days, I was suddenly checking about 1500-1600 plants every 14 days. So I took the most tedious and time-consuming part of the hobby and made it like 50% worse, basically.

And because of the extra work, I thought to myself at some point in May or June or probably both: I bet I'm never going to be lying on my deathbed thinking, "Gee, I wish I'd spent more time watering plants." And as I started mailing out plants to people I was selling to or trading with, I started fantasizing about how I could scale back the collection in a way that didn't involve outright killing anything, because that always makes me feel bad.

Open this in its own tab and you can even see its disgusting little legs.
And then the scaling back started to happen, in the most literal way possible: I started finding scale insects on the plants. One plant at the end of March. A handful at the beginning of May. And then at the end of June, the floodgates opened and I was finding scale everywhere:

1 Alpinia zerumbet variegata (plant room; 31 March; discarded)
3 Alworthia 'Black Gem' (basement; 1 May; discarded)
1 Aloe NOID (basement; 8 May; discarded)
1 Albuca bracteata (basement; 28 May; treated)
1 Strelitzia reginae (plant room; early June?; treated)
1 Aloe polyphylla (basement; 26 June; discarded)
1 Philodendron squamiferum (living room; 27 June; treated)
1 Agave desmettiana, variegated (basement; 28 June; discarded)
1 Agave titanota (basement; 2 July; treated)
1 Agave americana (basement; 2 July; treated)
2 Agave 'Blue Glow' (basement; 2 July; treated)
2 Agave lophantha (basement; 2 July; treated)
3 Aloe vera (basement; 3 July; discarded)
3 Gasteraloe x beguinii (basement; 3 July; discarded)
1 Aloe x 'Silver Ridge' (basement; 3 July; discarded)
13 Alworthia 'Black Gem' (basement; 3 July; discarded)
5 Hoya polyneura (basement; 9 July; discarded)
1 Philodendron hederaceum micans (basement; 11 July; discarded)
1 Philodendron erubescens 'Red Emerald' (basement; 11 July; treated)
4 Pereskia aculeata var. godseffiana (basement; 12 July; discarded)
1 Ficus benjamina 'Black Diamond' (basement; 12 July; treated)
1 Hippeastrum 'Red Lion' x ? (basement; 16 July; discarded)
1 Hippeastrum 'Red Lion' x ? (basement; 23 July; treated)

I think there were three separate infestations here, based on what plants were affected and when I noticed.

The first plant, the Alpinia, was I think was a single isolated infestation: I don't know where the scale could have come from, since I hadn't brought anything new into that area, but the plant was stressed, so it's possible it had a low-grade infestation for a long time, and then it got a lot worse really fast when it got stressed.

Scale on the Alpinia.
The second infestation barely counts: somebody sent me a cutting in June that had some scale on it, but I found them pretty much immediately, and it wasn't very advanced, so I think that's not going to be a big deal either.

And then the third. I think it came in on an Aloe polyphylla I received in December as a gift, because the outbreaks have all been taking place on plants that had been grown near the plant in question at one point or another. This is the infestation that swept the basement, might still be sweeping it, and what's caused all the troubles.

It's now been a couple weeks since any new scale was spotted, so possibly the worst is over. For a while there, though, I'd have to throw out more plants every time I watered, and that was depressing as hell.

But did I let myself sink into despondency and depression? Hell, no! I took action! For a few plants that I suspected had been exposed, but which I couldn't find any scale on, I decided to get out there ahead of the infestation and spray neem oil on them, to stop the infestation before it became visible. Which sounds like a good idea, right?

Yes. Well. You know how the directions on neem oil say not to use it on plants that are in direct sun, or that will be exposed to sun within a few hours of application, and all that? They should probably also add fluorescent lights to that warning, because within 24 hours, I'd completely defoliated two small Euphorbia trigona cuttings, and produced a few bleached spots and several ominous dark brown blisters on my baby Agave victoriae-reginaes. The former have bounced back, but the latter look to be permanently disfigured:

Agave victoriae-reginae, neem damage.
Which was even more discouraging, not that I learned my lesson. I then sprayed a plant room Euphorbia milii and Pedilanthus tithymaloides with neem because there was some kind of fungus that had been growing on their leaves. The Euphorbia responded by dropping about 95% of its foliage, immediately. The Pedilanthus was less of a drama queen about it, and only lost about 30% of its leaves, over the space of a month. Either way, though.

Euphorbia milii, after neem oil treatment for fungus. It was technically a success, I suppose, in that I'm no longer even remotely concerned about the fungus. Probably what happens next here is that I take cuttings and start new plants, but I haven't tried that yet.
Also, some of the Agaves I treated with neem and stuck outside also bleached (no blistering, though); they'll probably come back inside again in the fall, because the scale is probably not a problem anymore, but it'll be sad regardless, since they looked better when they had scale but no sunburn: I didn't really have the time or means to try to ease them into the outdoor light, and we don't have much for shady spots.

So then I started sinking into despondency.

All this was happening on top of the usual plant attrition, too. Not saying I encourage it or anything, but it's normal for me to lose a plant here, a plant there, for various reasons over time, and this was an exceptionally good summer for that.

I finally had it with Crassula ovata 'Gollum' and threw the lot out, because they persisted in developing a stupid fungus (maybe the same fungus, maybe a different one; I have no idea) even though I told them not to, and I didn't have a way to make them stop if they weren't going to listen.

The Salvia elegans all dried out (even getting checked weekly, they still dried out!) and died, save for one, which had a round of spider mites and is only barely alive now.

The Aeschynanthus radicans all gave up due to underwatering.

I threw out most of the Gynura aurantiacas I had when became clear that nobody was ever going to want to buy one. This is something I should probably have learned last year, but I'm slow.

The Fatshedera x lizei got spider mites and was thrown out. In fairness, I should note that I'd been expecting that to happen for almost two years, so it should probably get some kind of posthumous medal.

One of the Hatioras ("Easter cactus") imploded, the way they do.

And so on.

It was basically like the plant collection had caught fire. A very slow, and occasionally sticky, inferno. Everything was sort of slowly falling apart: scale, drought, scorching, defoliation, 50% more watering to do, spider mites, and fungus. It also wasn't getting any better. I had no way to know what plants might go bad next. There wasn't much I could do about it. And when I tried to do something about it, I mostly just made things worse.

The upshot of all this being that for about two or three weeks, I basically hated my plants. I didn't want to think about them, talk about them, or take pictures of them, and I sure as hell didn't want to water them, because the surest way to find something horrible hiding in your plant collection is to pick them up and look at them. Which you have to do, in order to water the way I water. (I still did take care of them, of course, because I recognized that I'd probably like them again eventually, and that there was no point punishing the healthy plants upstairs for the scale infestations of the plants downstairs. I just hated doing so more than usual.)

Echinacea 'PowWow Wild Berry,' at the ex-job, with what I believe to be aster yellows disease. PATSP has an official celebratory flower (Gazanias), so it seems only appropriate that PATSP should have an official flower of depression (It's pretty amazing that I've gotten by without an official depression flower for four and a half years, honestly.), and this was kind of the best I could come up with. My apologies to any Echinacea fans in the audience.
It's now been a couple weeks since I've found a new scale infestation. (New mealybugs as of last Wednesday, alas, but the scale seems to have slowed down.) In the last couple weeks, the plant collection has done two big things which I am choosing to interpret as apologies too. I won't tell you what those are yet, but there should be posts about them in the relatively near future. So we're getting back to the point where I'm able to appreciate plants again, somewhat, but I'd still rather not spend a lot of time thinking about them.

The blog, consequently, will be a bit up in the air for a while. I'm officially no longer on hiatus, but I'm probably not going to be posting very often, and I'll probably only be doing that when something exceptionally cool happens. And I'll keep going like that until . . . something changes and I start doing something else, I guess. Your guess is pretty much as good as mine right now.

Unpretty pictures: spider mites and scale

WCW told me once that if you want to, you can overwinter Hibiscus by letting them go dormant: you stick them somewhere cool, let all the leaves drop, and then only give them just enough water to get by until the spring. And then in the spring you put them outside and they leaf out quickly and then you go on.

It seemed like a sound enough idea, and WCW said she'd done it herself, but I wasn't quite ready to commit to it. I figured if I could keep them growing and flowering happily through the winter, then there was no reason not to, so I'd only let them defoliate if it turned out that I couldn't keep them growing happily.

So I stuck them in front of a small window in the basement, and waited to see what would happen.

For the most part, nothing happened. Some sporadic blooms at first, then they settled down and just sat there. I gave them full, thorough waterings when the soil got dry, but they didn't seem to be doing anything with it.

Then, beginning in maybe mid-December, specific branches would defoliate rapidly from time to time. Like, everything would be fine, and then suddenly all the leaves on one branch would go yellow and drop overnight, and the house would rattle as all the leaves hit the floor at once.

There didn't seem to be anything wrong with the plant otherwise: I saw a little webbing, but it looked like fairly coarse webbing, the kind that spiders make cobwebs from, and they were in the basement, where there are often spiders, so I didn't suspect spider mites at first. Plus I didn't actually see any mites, ever. But it kept happening, and I got kind of worried. Plus it sucks to get woke up in the middle of the night by the house rattling because your Hibiscus just had a massive defoliation.

Maybe I didn't want to let them go dormant after all. Maybe they were defoliating from lack of light, and if I just put them somewhere brighter, this would all stop.

So. They came out of the basement to the living room, and I gave them a spot on the floor near the big window. Plenty of light there. (Also a heat vent, but -- not a very big one! And it wasn't blowing directly at the plants!) Looked the plants over, didn't see any webs or any mites.

Imagine my surprise when a whole branch defoliated again, and, upon examination, turned out to be completely swarming with spider mites.

This is much more terrifying full-size. You can actually make out individual little legs on one of them. [shudder]
Then imagine my depression, frustration and rage. Next, imagine my inebriation, as I drank to try to forget about the mites.

(You're really very good at imagining my mental states! Good job!)

So. Both Hibiscus got a prolonged bath: dish soap, shower, more soap, more shower, and now they're back in the basement again. Where, to their credit, no branches have gone suddenly nude again. But still. Spider mites are despicable. In that I am completely able to despic them. I despic them so hard, y'all.

So that was a bummer. Then, a few days after the Hibiscus returned to the basement, I was watering the big purple Neoregelia when I noticed some spots on the leaves that rubbed off, when I tried to rub them off. Which is a bad sign.

Roundish green dots: part of the natural variegation. Roundish tan dots: scale. White crusty stuff toward the right side of the picture: mostly hard-water spots, I think. Though there could be some immature scale running around in there, I'd never know.
Further inspection revealed that I had scale. And they were everywhere. Leaf surfaces, leaf undersides, the inaccessible spaces at the base of leaves -- everything. It didn't appear to be too far gone, but it was still a surprisingly advanced infestation to be catching for the first time.

The long-term solution was to add imidacloprid granules to the soil. I don't know if this will necessarily help, but I had them already, and in theory they should work. Eventually. (I have yet to be particularly impressed with systemic pesticides, actually. This is maybe something we could discuss in the comments.)

The short-term solution was to get a wet paper towel or two, or ten, or fifty, and try to wipe off as many of the bastards as I could. The only problem with that is -- well, look up at the first Neoregelia picture again. See the spines all along the leaf margins? Yeah. They're actually kind of sharp. And pieces break off in your skin sometimes. So it's not that easy to get a hand down in there, never mind trying to do any serious leaf scrubbing once it's in.

So that was also a bad day. I haven't had any issues with scale in something like ten years. (I bought a Caryota mitis, fishtail palm, without noticing that it had a serious scale problem. I kept waking up to find the floor beneath it sticky, but somehow didn't put it together that there might be a bug problem for a really long time. When I did figure it out, the plant was thrown away.) I have little itchy cuts all over both hands, and down the back of my right arm, and this is something I'm going to have to do repeatedly for a while.

The slightly-raised tan circles are, again, scale. The small, white, elongated things scattered around them are probably baby scale. The babies are actually so small that I can't see them with my naked eye; I can only see them after taking a picture, uploading it to the computer, and looking closely at it.
For some plants, I'd just throw the thing out, rather than try to undertake an extermination program. I'm willing to try extermination in this case because the plant would be expensive to replace, I've already had it a long time, and the scale doesn't appear to have done much permanent damage to the plant yet. It has spread to one other plant, also a Neoregelia, but as far as I can find (and I looked pretty hard at everything in the vicinity) it's only the one, and the infestation on the second plant was very, very light. So I'm sort of optimistic that this can be dealt with in a way that permits me to keep the plant.

And it could always be worse. It's not mealybugs.

Still, though. Depressing.

List: Houseplants Which are Highly Prone to Spider Mites

There's no official or definitive list for this; spider mite susceptibility isn't something I've ever tried to quantify. That said, though, there are definitely some plants which are more likely to have mites when you buy them, or more likely to develop a raging case of mites once you get them home.

Thick-leaved succulent plants and cacti tend not to have mite problems; spider mites don't seem to be able to pierce their thicker, waxier epidermises. Consequently, the plants most susceptible to mite attack have broad, thin leaves (like Musa or Dieffenbachia) instead of small, fleshy ones (like Crassula or Hoya). Certain families are apparently also a lot tastier than others; the Araliaceae, Marantaceae, and Apocynaceae seem to be particularly delicious.

(I realize that it would probably be a lot more useful to the reader to present a list of plants which are highly resistant to spider mites, as opposed to plants highly susceptible to them, but that's actually much tougher to do. Even if I've never seen a bad mite infestation on, say, an Aglaonema, I can't really be certain that they're that resistant. Maybe the Aglaonemas with whom I've personally been acquainted have just been really lucky, you know?)

Alocasia 'Frydek.' (also other Alocasia spp.)

Aspidistra elatior 'Milky Way.' (cast-iron plant)

Calathea roseo-picta, possibly cv. 'Rosy.' (also other Calathea spp.)

Chamaedorea elegans. (parlor palm)

Codiaeum variegatum 'Petra.' (croton) (also other Codiaeum variegatum cvv.)

Cordyline fruticosa 'Kiwi.' (ti plant) (also other Cordyline fruticosa cvv.)

Assorted Hedera helix (English ivy) cultivars.

Pachypodium lamerei (Madagascar palm).

Schefflera actinophylla (umbrella tree).

Strelitzia nicolai. (white bird of paradise)

Severity of infestations vary, enough that I really adore some of the above, and refuse to let others in my home. I consider Cordyline fruticosa worth the trouble, and both Pachypodium and Strelitzia are welcome, because they tend not to get out of control mite populations as rapidly as others on the list. Codiaeum variegatum, on the other hand, is a definite planta non grata here, mostly (though not entirely) because of its attractiveness to mites, as are Hedera helix, Calathea spp., and Alocasia spp. All four of those gave us ongoing, substantial problems where I used to work, to the point where I stopped bringing them in. (They've started ordering them again since I left, though, with predictable results.)

Am I missing anything? Let me know in the comments.

Not pictured:
Acorus spp. (sweet flag, Japanese rush)
Adenium obesum (desert rose)
Alternanthera spp. (including A. dentata 'Purple Knight')
Aspidistra elatior (cast-iron plant)
Breynia disticha cvv. (snow bush, snow on the mountain)
Brugmansia cvv. (angel's trumpet)
Chamaedorea seifrizii (bamboo palm)
Cissus rhombifolia (grape ivy)
Colocasia cvv. (elephant ears)
Datura cvv. (devil's trumpet)
Dieffenbachia spp. (dumb cane)
Dracaena marginata (Madagascar dragon tree)
Dracaena thalioides
Gardenia jasminoides (gardenia)
Hedera canariensis (Algerian ivy)
Heliconia psittacorum cvv.
Hibiscus rosa-sinensis (tropical hibiscus)
Impatiens spp. (impatiens)
Jasminum sambac (jasmine)
Maranta leuconeura cvv. (prayer plant, rabbit tracks)
Musa spp. / Ensete spp. (ornamental banana)
Plumeria cvv. (frangipani)
Polyscias balfouriana (balfour aralia)
Polyscias fruticosa (ming aralia)
Primula vulgaris (primrose)
Ravenea rivularis (majesty palm)
Schefflera arboricola (umbrella tree)
Schefflera elegantissima (also known as Dizygotheca elegantissima) (false aralia)
Stromanthe sanguinea cvv.

The War With the Spider Mites

I've mentioned before that there are only seven primary houseplant pests. In descending order of seriousness (in my admittedly subjective opinion), they are:

1. mealybugs,
2. scale,
3. whitefly,
4. spider mites,
5. aphids,
6. fungus gnats, and
7. thrips.

The first three on the list (mealybugs, scale and whitefly) can be very serious problems: they are very contagious, they multiply quickly, and they can cause a lot of damage. The last three (aphids, fungus gnats, and thrips) can be problems under certain circumstances, but indoors, you can either get rid of them pretty easily (aphids), they don't really cause much damage in the first place (fungus gnats¹), or you're unlikely to run into them (thrips).

Spider mites occupy that special middle rung, where they're very contagious and multiply quickly, and they can cause real damage, but at the same time they're not necessarily that big of a deal. The severity of a spider mite problem depends hugely on A) what plant is affected, and B) what the general growing conditions of the plant happen to be: change the plant or the conditions, and you have an entirely new ballgame.

Spider mites on a Ficus elastica.
So let's start with the basics. What is a spider mite?

Spider mites are not insects. What they are is arachnids, which means they're more related to spiders, daddy-longlegs and ticks than they are to flies and beetles. (Forgive the pedantry, but this sort of thing actually matters sometimes.²) And if you look at them closely (if you can look at them closely), this is actually pretty obvious, especially the resemblance to ticks. So there's that. Spider mites are all in the family Tetranychidae, and there are about 1600 species in the family, wikiposedly, though most of these are not abundant enough or hardy enough to pose a problem for cultivated plants.

The most common species of spider mite is Tetranychus urticae, usually called the two-spotted spider mite. It can be various colors,³ but most of the time when I've seen them, they've been red, beige, or brown. There are very, very few good pictures of them on-line, for the simple reason that they're very tiny, plus they move around, so it's difficult to get a good, well-focused shot, and if you do get a good shot, you're usually so close in to the plant that it's difficult to tell what parts of the picture are the mites and what parts are the plant. Though in cases where the background is all the same color, it's easier:

Spider mites on a Catharanthus roseus flower.
Fortunately, one doesn't need to see the mites themselves to know they're there. The usual first sign of an infestation is that the plant just starts to look kind of tired. The leaves in particular get a dusty or bronzed look to them, and close inspection of the leaves will probably show both a little actual dust and dirt, plus a bunch of very tiny yellow or gray spots, which are what give the dusty look. The spots are plant cells that have collapsed and died due to the spider mites' feeding. The mites pierce the cell walls with their mouthparts, suck out the liquid, and then move on when sated. The cells are unable to repair the damage, and consequently die, leaving a tiny gray or tan spot. Multiply times ten gazillion, and you have faded-looking leaves.

Mite damage to an Aspidistra elatior from work.
If you suspect spider mites from looking at the top of the leaves, looking underneath will generally confirm it. In very advanced cases, you'll see some webbing underneath, usually visible because it has "dirt" sticking to it. The "dirt" may be actual dirt that's been splashed up during watering of the plant, in which case it's no big deal, or it's mite droppings, which isn't a big deal either but it's kinda gross. Once you've seen both a few times, it's pretty easy to tell the difference. (As a rule, actual dirt will crumble and fall at the slightest touch, and embedded droppings will stick until you wipe them off with a finger.) Should also note that I know this mostly because I do basically all my watering at home and at work from overhead, which is a splashier process than using a watering can like a civilized person would, and leads to more dirt hanging from the undersides of leaves than you probably have on your plants.) In very very bad cases, especially if it's hot, you'll see the mites themselves running around.

Spider mites are, at least in theory, capable of living off of any plant, but in practice they're limited to those with fairly thin, easily-penetrated leaves, so your cacti and succulents are safe. Even among thin-leaved plants, they have some strong preferences for particular kinds.

It's impossible to come up with a comprehensive list of which plants are the bad ones for spider mites. That said, there are a handful of plants that I, customers, or people I know refuse to attempt anymore, because of spider mites, so I guess they're good candidates for the worst of the worst. Those unlucky few are:

Aspidistra elatior (cast-iron plant),⁴
Calathea spp., including Calathea ornata,
Codiaeum variegatum (croton),
Hedera helix (English ivy),
Schefflera actinophylla ,
Schefflera arboricola , and
Schefflera elegantissima (Dizygotheca elegantissima, false aralia).

I've got a list of other mite-prone plants. The list is long, and hard to make interesting, so I'll stick it in a footnote rather than ask everybody to read through it all.⁵


Ordinarily you'll find that mite problems are cyclical, recurring things, rather than a full-scale battle all year long. Mites have certain environmental conditions they prefer, and if you can make things less to their liking, they'll slow way down or even sometimes disappear entirely. This is the good news, if there is good news.

Mites prefer hot, dry conditions and stagnant air. Change a part of this equation, and you can accomplish a lot. If your home must be dry and stagnant, try cooling it down. If it must be hot and dry, at least get some air moving. That kind of thing. Another option, if you have a space available, is to move your plants outside for the summer: in a lot of areas, outdoors may be hot, but at least there will be humidity and air movement.

Most spider mite problems indoors start in the fall and last through the early spring, when homes are being heated, the humidity level is low, and moving plants outside isn't really an option. I had relatively good luck at home last winter using a humidifier (I still had mites, but it was a lot less of an issue than it had been the winter before.). Misting and pebble trays are better than nothing, though (in my opinion) not by much.

Another Catharanthus picture.
One can also try poison, of course. In the greenhouse at work, we spray miticides weekly, but for all the good it does us we could be spraying hopes and wishes; I think we're selecting for miticide-resistant mites, not keeping a pest population under control. And I have said so. And I am being roundly ignored.⁶ Last winter, we had a particularly bad plague sweep through the larger crotons (small ones were fine), most of which lived through it, but of course then they looked like crap, and they're only just now beginning to come back. Last fall, it was the banana (Musa) trees and the Alocasia 'Polly.' During the spring, it was some of the annuals (particularly Dahlia, Vinca, Angelonia, Nemesia, Alternanthera, Catharanthus roseus).⁷ At the moment we're pretty close to clear, though we've been preoccupied by the flood, too, so maybe there's a problem I'm just not yet aware of. I should probably check the bananas.

Spider mites are known for being able to develop resistance to miticides, so if you do elect to go with poison, my advice (which I do not, myself, follow, not that that makes it bad advice) would be to buy two or three types, containing different active ingredients, and use them in rotation. Using the same product repeatedly may still work: it's just that it's much harder for pests to adapt to multiple pesticides in rapid succession than it is for them to adapt to one: they have to hit a moving target, so to speak.

Other things to try, besides fans, humidifiers, poisons, and air conditioning, include moving affected plants (and any other plants, while you're at it) to the shower to water. It's not that watering from high overhead is any better than watering with a can, necessarily, but water droplets can dislodge the occasional mite, and every mite that gets knocked off is one more mite that isn't going to be laying eggs on your plant.⁸ Some insecticidal soaps also work on mites, though you're probably money ahead to skip the specially formulated "insecticidal" soaps and go with a solution of dishwashing liquid in water, or liquid hand soap in water. The insecticidal soap we sell at work is, if I read the label correctly, more or less repackaged, diluted liquid hand soap, i.e. potassium salts of fatty acids.

There are also oils one could try: we have a product at work that's formulated from cottonseed oil, clove oil, and garlic extract, that I've used sometimes at work. I'm not sure if it's all that effective, really - it wasn't terribly helpful with the bananas last summer - but it may also not have been used as regularly as directed. This sort of product seems to be intended to just annoy the mites into leaving: if they can't walk around or start new webs, because everything's covered in oil, I suppose they might eventually die off as a result, but it seems like it'd be hard to cover every available surface, and the oil does go away after a certain amount of time has passed.

Neem oil, on the other hand, has an actual poison in it, yet is safe to use in the house (more or less. I mean, don't go putting it on your salad or anything.). You still might not want to, as it has a weird smell: to me it smells sort of like peanut butter and garlic and socks. (Your perception may vary.) It has a chemical in it which disrupts the normal function of mites in a number of ways. I've only tried it once on a plant with mites, and the plant recovered (plus it was a Dizygotheca elegantissima, even), but I couldn't say that the neem was what won the battle.

So in conclusion: you are probably going to have spider mite problems sooner or later. (The saying was originally "death, taxes and spider mites.") One should be particularly vigilant with the plants that are known to be especially attractive to mites. If you find mites on a plant, it's not necessarily the end of the world: you have a lot of treatment options. The one thing you can't do is be complacent about watching for them or procrastinating on treatment if you see them, because infestations can flare up in very little time.

-

Photo credits: all my own.

Pre-emptive defense against charges of plagiarism: I just want to say for the record that this article has certain similarities to the corresponding article at Water Roots, including the assertion that some plants are more mite-prone than others and the metaphor of warfare. This is not because I plagiarized from said article; it's just that, you know, some plants really are more mite-prone than others, and the only metaphor that really works is warfare.

¹ I know, I know, fungus gnats killed your sycamore tree. Fine. Whatever. Bad fungus gnats.
² Among other things, mites not being insects is an indicator that the chemicals that will kill insects (like mealybugs, whiteflies, etc.) will not necessarily kill spider mites. It also, obviously, suggests that if you use a miticide in the greenhouse, you run a strong likelihood of killing any spiders, ticks, or daddy-longlegs that happen to be around too. It's hard to get sentimental about ticks, but how anybody could want the daddy-longlegs dead is beyond me.
³ According to the stuff I've found in the research for the post, the color of spider mites depends variously on what and how much they've been eating, the time of year, and the point of the life cycle a given individual happens to be in. Green, brown, tan, beige, translucent, red, red-brown, and probably others I can't think of right now are all options. The "two spots" in the common name may or may not be present.
⁴ I think under normal circumstances Aspidistra elatior is usually okay, because people don't usually bring lots of plants in and out of their home all the time. We have trouble with the ones at work because new plants are always being brought in, any one of which might have a mite or two on it, plus we always have a few lingering somewhere in the greenhouse, and the plants get rearranged a lot. So, however good a job we do at keeping the Aspidistras clean, inevitably there's going to be a new population springing up. It's been enough to put me off of buying one, though the A. lurida 'Milky Way' I had previously is still okay, knock wood. I do not know whether A. lurida is supposed to be better with respect to mites than A. elatior, but so far it does kind of look that way.
⁵ Other plants which are rumored to be exceptionally mite-prone, or which I've actually experienced having mites on: Anthurium andraeanum, Araucaria heterophylla, Aspidistra lurida 'Milky Way,' Caryota mitis, Chamaedorea elegans, Chamaedorea seifrizii, Citrus spp., Cissus rhombifolia, Cordyline fruticosa, Dieffenbachia spp., Dracaena marginata, Euphorbia pulcherrima, Ficus benjamina, Ficus elastica, Gardenia jasminoides, Maranta leuconeura erythroneura, Musa spp., Philodendron bipennifolium.
⁶ (Not that I'm bitter.)
⁷ Lest you think we're terrible people who are selling buggy plants to customers knowingly and on purpose: if I see mites on a plant, I'll say so to the customer and look for another plant of the same variety that's better, or suggest a different variety. I think this is generally the policy for everybody else, too. That said, during busy days, it's not always possible for an employee to inspect every plant that goes out the door, and different employees vary in their familiarity with pest problems, and mistakes do get made, so you should always always always do your own inspection too. Or at the very least you can ask the cashier to look when you're buying, if s/he doesn't do so spontaneously. I doubt that this matters a whole lot when it comes to annuals, because once people plant them outside and they've got some air movement, I think the spider mites generally go away anyway; it's only an issue because we have to keep some of them in the greenhouse, and the greenhouse gets very hot and dry sometimes:
Outdoor temperature: 85F/29C. Greenhouse temperature: 104F/40C. Greenhouse humidity: 60%. Heat index in greenhouse: 145F/63C.
Also, while I'm here: although Alternanthera is in the list of things we had trouble with in the greenhouse, spider mites don't seem to go for my Alternantheras at home any more than they do for the rest of my plants. Not sure how to explain this, but it's possible that the variety at work is just an extra-delicious one.
⁸ I've seen the claim made that spider mites are "born pregnant;" this is not the case. They lay eggs. The person making the claim was probably thinking of aphids, some of which are born pregnant. Not sure about thrips, but whiteflies, spider mites, scale, mealybugs, and fungus gnats all lay eggs.