What’s this bug on my office plant?

An Adventure in Plant Biosecurity

I’ve noticed little tiny bugs on my favorite office plant, and decided to investigate (photo A).

My office plant is a small Monstera deliciosa (aka “swiss cheese plant”). Recently, I’ve noticed tiny little white things on the surface of the leaves and a couple of black specks. At first, I didn’t pay attention, but eventually I noticed that some of them were moving. Aha! Bugs! But what kind?

Time to practice some plant biosecurity! The bugs were too small to see any features with the naked eye. First, I took out my caliper measure them (photo B). The largest ones appeared to be about 1mm in length. I then tried taking an up-close picture with my phone camera (the phone camera is the poor-man’s microscope of the 21st century), but it wasn’t good enough (photo C). Hmmm... how to take a sample to bring to the lab microscope?

Eureka! Office tape! I wrapped a little tape on my finger (photo D) and then stuck a few little bugs (photo E), making sure to get both the white specks (presumably larva or nymphs) and black specks (adults, I assumed).

I looked at the stuck bugs under the microscope (photos F-J). It wasn’t easy to take microscope photos with my phone camera, but I managed to snap a few decent images. The bugs had feather-like wings (no membrane) and white markings on the underside of their thoraxes.

They appear to be some kind of thrip (order Thysanoptera), though I could only see one pair of wings and thrips usually have two pairs. Then again, by sticking them to tape from above, it’s hard to get a good look at the wings. I tried identifying it with the identification key at the CSIRO What Bug is That? website. Based on the observed number of antenna segments (5 segments), this thrip is likely in the family of Phlaeothripidae. I don’t have easy access to a genus or species level identification key for Phlaeothripidae, but at least I know enough to look-up pest treatment options. Unfortunately, there isn’t much I can do within the limits of office policy (my co-workers wouldn’t appreciate me releasing a bunch of ladybugs in the office).

Curiosity sated, I grabbed more office tape and used it to remove as many of the thrips as I could. Hopefully the plant will start looking a little healthier after a few days of sticky-tape treatment.