Could these be scale bugs?
 

Hi all. A newbie and a first-time poster here.

I am having trouble identifying bugs I discovered in the humidity tray beneath my Phal. From what I was able to tell from searching online, they look a bit like a male and a female scale (or possibly mealybugs?).

Does anyone have an idea of what they are and how dangerous they are to orchids?

Sorry for the blurry pics but these suckers are tiny (~0.1") and not very photogenic.

St. Augustine Orchid Society - North Florida Orchid Growing is great reading material.

Welcome, atanasg!

They could be mealy bugs. When they get wet their cocoon sometimes falls off. How long since you repotted your Phal? If quite some time, it would be worth repotting into new medium, and examining the stem, crown and roots very closely.

Looks like mealies to me. Treating as soon as possible is essential and repeat in 10 days!


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The third photo looks like a mealybug.

First photo, the insect has wings, not a mealy or scale. Not sure what the second insect is.

Second and third pics are mealie bugs, immature crawler stage or young adult, and adult in the typical sticky powdery protection. The first appears to have wings, possibly a fungus gnat.

Wow, thank you all for responding! DeaC: thanks for the link!

Ok, mealybugs then. IIUC the treatment options I have are the same: a systemic insecticide (maybe some of the Bayer sprays with imidacloprid) or a IGR (looking at the Enstar AQ Insect Growth Regulator).

Does anyone have any experience with these? Which one would be gentler to the orchid?

Neem oil is out due to high temps (>85F) and alcohol+soap is out because the orchid is tiny and I can't reach everywhere (plus it already caused damage to one of the leaves as I tried it before).

What baffles me is that I can't seem to find any hint of these bugs on the orchid itself: I have been obsessing over it and scrutinizing everything with a magnifying glass but no visible bugs, no cottony white cover, no sticky residue. Is it possible that I am just not seeing the signs?

The closest I can think of matching this description is the powdery look of the roots during the last repotting (see pic). I took it to be a combination of the normal silvery substance that cover the roots plus some hairs sticking out seeking something to attach to. Am I misinterpreting?

As you can see, the phal is already stressed out having only four (soon three) not-so-great leaves and two (now three!) short roots left. It lost its older roots to rot during the repotting last week (estación seca: since you asked :) ). It seems to be recovering great so far and if it weren't for the infestation I would be fully confident that it would do well.

I don't have any experience fighting bugs though so now I am into an uncharted territory and worried about it again. Should I go for treatment right away or should I wait and give it more time to recover first?

For mealy bugs or scale on a small plant, during warm weather, I submerge the entire plant in a solution of a few drops of dish soap in a liter of water. Just enough soap to make a few bubbles on the surface when you agitate the water.

Soak overnight, about 10-12 hours. This normally kills all the bugs plus their eggs, and does not damage the plant. The dish soap is necessary to break the surface tension of the water and prevent the bugs from hanging on to a bubble of air, through which they might breathe.

Whoa, great find on the fungus gnat! I went by a drawing of a male scale bug in one of the St.Augustine Orchid Society's articles (argh, can't post links here!) but I see that the heads are different.

It seems like the gnats are the least of my problems now but I will see if I can get some sticky cards and check if any more of these buggers like to stick around (hah!)

If you have not already done so, you should thoroughly clean any affected plant and repot into a clean pot, new medium. Fungus gnats hang around in medium that has partially decomposed and needs replacing. Cleaning the plant and replacing the medium also eliminates many insect eggs that may be hanging around.

You can try the soap solution soak that estacion seca suggested. If bugs come back (you should watch carefully for this), the imidacloprid products work well. I am not familiar with the growth regulator product, but if you look on the St.Augustine OS site, there is a table that lists common pesticides that can be used on orchids. Maybe that product is on their list?

The orchid has been repotted 3 times in the past 3 months already (I said I was a newbie!). Would it be wise to do it yet again in this weakened state only a week after the last time?

Also, I suspect that I got these bugs from the sphagnum moss that started this series of repotting. If that's the case then I can't be sure that whatever new mix I get will be clean and I will have to treat it anyway. In all my previous repottings I've been using 1tsp/gal solution of Physan 20 to disinfect the mix.

estación seca: I like your suggestion since it bypasses the alcohol and I would like to try it. If it doesn't work I can always proceed with the heavy-duty stuff.

What kind of dish soap do you typically use? Reading up on this I see warnings against some types of soap, such as ones containing degreasers (don't all of them have degreasing action?).

Just to double check: when you say "submerge the entire plant", do you mean the leaves as well or just the pot? Do orchids like being submerged for that long?

If you have repotted that recently, no, I would not repot again.

But, if you re still getting fungus gnats, you are probably keeping it too wet. Let the bark get nearly dry before you water again.

As I said in the previous post, if the bugs come back after the soap solution, move on to using the imidacloprid.

I use soap sold here for washing dishes in the sink, by hand. I haven't seen that with degreaser. Probably the cheaper, simpler soap will work. You will only use a few drops. I submerge the entire plant; leaves, roots. If it is in a pot and does not otherwise need repotting, I will leave it in the pot and submerge the whole thing. Sometimes I need to hold the plant under the water with a weight.

@Orchid Whisperer: I just remembered that I saw all of these bugs before last week's repotting when I soaked both the new potting mix and the orchid in Physan 20. So while I don't think this did much for the mealybugs it must have taken care of the fungus gnats. The repotting was to remove root rot and scale way down on the sphagnum moss because of overwatering so you are spot on!

@estación seca: Alright, I've got a bottle of Seventh Generation liquid dish soap which seems to be advertised as USDA certified Biobased Product (95%), whatever that means. I am starting to finally see some microscopic white cottony stuff on the leaves so I guess that settles both the questions of the type of bug I am dealing with and the timeline I have to work with. I am going to give it a go tomorrow and will post an update.

One more thing: Do you wash the plant with plain water before you leave it to dry or do you let it dry with the soap in it?

I wash it sometimes. I don't think it matters. It depends on where I treated the plant. If I left it soaking overnight in the bathroom, I rinse it the next morning. If I bring the container of water into the growing room and soak there, I don't rinse.

I should add: If there are any visible dead bugs remaining after the soak, I use an old soft toothbrush to remove them gently.