The Orchid Pest That Is My Arch-Nemesis

I get along with orchids pretty well, but that doesn’t always mean caring for them is easy. Given the checklist of conditions an orchid grower should try to meet, it’s easy to overlook the challenge of pests. Luckily, most orchids aren’t as attractive to pests as many other plants are, but one pest in particular will happily suck the life out of an orchid: scale.

One of my first declarations of 2023 is one of war against the scale two of my orchids have been battling for months. It’s on, scale. 

There are over 1,000 species of scale in North America and over 8,000 species throughout the world, so it’s unlikely any plant collector will be able to avoiding the sap-sucking pest forever. Scale isn’t the most pernicious pest, but it’s one of the sneakiest. It masquerades as a benign (and usually brown) mark or small bump, often on the ridges or veins of leaves. Because scale doesn’t fly or create webbing, and because it often looks like a natural part of a plant, it can go undetected for a long time and can cause serious damage to plants.

Scale on plants.

The easiest way to detect scale is to look for and/or feel the leaves for the sticky honeydew they secrete. (Unlike soft scale, armored or hard scale does not produce this evidence.) This is how I realized my scale problem. Upon seeing a glistening, reflective substance on the surface of an orchid leaf, I got my rubbing alcohol and Q-tips and scraped away all the scale I could. 

Scale honeydew on my orchid’s leaf.

Things seemed fine for a couple weeks. This orchid is even spiking and preparing to bloom, so I figured it had to be doing well. But then I saw honeydew on a leaf again and found a couple of sneaky scales on the underside. Again I attacked them with rubbing alcohol. A couple weeks later, I visited family in Michigan over the holidays, and the scale used the opportunity to make another move.

Underside of a leaf on my orchid.

Scales are so sneaky that it’s tough to get them all. I’ve clearly missed some each time, so they’re continuing to reproduce and spread. I typically avoid using pesticides or insecticides on my orchids, especially if they’re budding, so I have a plan that escalates in pest-killing intensity and uses them only as a last resort. 

I’ll try one more round with Q-tips and rubbing alcohol under a bright light that allows me to see as much as possible. I’ll try to look in and clean the base of the plant, which has a lot of creases for scales to hide in. After that, I’ll try rubbing neem oil on the leaves, which suffocates the scale. If that still doesn’t work, I’ll try some Captain Jack’s Dead Bug Brew spray. Phalaenopsis orchid leaves are waxy and strong and stand up well to topical treatments. And if that still doesn’t work, I might consider a systemic, but that’s the orchid equivalent of DEFCON 1. 

I’m throwing down the gauntlet, scale. You picked the wrong orchid to mess with!

My orchid.