The Return of the Miller Moth

Also, Soil Gnats, What's Your Deal?

It’s 2:00 and I have woken up in the middle of the night. I make the mistake of reaching for my phone. Even though I keep the brightness turned way down, the sudden wash of light hits my eyes, and then, from the darkness, something swoops into my face.

I scream. Then I apologize to Julio. Had I been rushed by the Mothman? One of those spiders from my recurring dreams?

No, dear reader, it was a Miller moth.

I lived in Colorado for years without experiencing the annual Miller moth migration in any meaningful way because we lived in a brick quad apartment that had few ways for a Miller moth to enter.

The first spring we lived in our house, we were shocked by the sudden proliferation of the moths, flying at our windows and doorways, getting trapped inside whenever we let the dog in or out, in or out. But, it was the first spring of the pandemic, and we were still howling at the moon at 8:00 each night, and everything was a little weird anyway.

Then, 2023 brought an unusually large Miller moth migration, and we took the time to learn about the moths coming in from vents and windows, finding holes in screens that we didn’t know existed.

If you are not from this area, you may have never heard of the Miller moth. The little, harmless, nocturnal pollinators spend their larval stage as army cutworms on the Eastern plains before migrating west to the cooler climate and flowering plants in the Rockies for the summer. A recent article in Denverite compared the Front Range to an Airbnb along the way. They could show up any day now for their annual pitstop.

Some people find Miller moths to be a nuisance. I am shocked by their abundance and how many find their way into the house, even when we are careful. But they are essential to the local ecosystem, providing meals for birds, bats, frogs, and reptiles, and pollinating plants along the path of their migration.

Their sudden arrival reminds me of the Biblical feeling some people attributed to witnessing the super brood of cicadas last summer. Local media outlets run stories explaining that there’s not much you can do to moth-proof and that there’s no good reason to kill the moths. Just leave them alone and turn off your porch light.

It makes me laugh, really. The moths disappear as suddenly as they arrive, moving on to the mountains. Why bother doing anything other than marvel at the hapless little things? How is fighting them worth your time?

Even still, when they fly around my bathroom light fixtures or divebomb my nightstand lamp, I wish they would migrate a little faster. I help them back outside when I can.

My mom and youngest sibling are visiting later this week. As they come from the East, I hope the Miller moths arrive too, so they get to experience this Colorado insect event that feels like it should be soundtracked by the Benny Hill Theme.

Photo by Thomas Elliott on Unsplash

Dealing with Soil Gnats

I do not feel so hospitable toward the soil gnats who have turned up in my houseplants again. These little critters, also called fungus gnats, are relatively harmless, but they are exponentially more annoying, especially as they procreate in my house instead of just accidentally wandering in.

If you have houseplants, you have probably had the gnats. They live off fungus and other yummy (to them) things in soil matter. According to the CSU Extension, during their seven-to-ten-day lifespan, a single female can lay up to 200 eggs in soil. So an infestation can escalate quickly.

Although the adults do not fly well, they emerge when the soil is disturbed, like during watering. They do not bite and are not harmful, just super off-putting as they tend to gravitate toward your face. The larvae, however, can damage the roots of plants if the population gets too big.

Usually, experts recommend letting soil dry out between waterings to control fungus gnats. There’s also the sticky traps. And repotting. My friend Rachele gave me some beneficial nematodes, which can also help control gnat outbreaks.

Not to be confused with a Neematoad.

I am careful not to overwater my plants so they do not get root rot. I put new bags of potting soil in the freezer, hoping that kills gnats before I use the dirt. I usually repot my plants once a year. The nematodes did seem to help. I thought I had everything under control. Then my daughter brought home a little pot of dirt in which she planted a cucumber seed at school. Enter: gnats. At least this time, I had a plan.

Last summer, I had a terrible, very irritating infestation of fungus gnats, which I think started with my giant Fiddle Leaf Fig and spread to the other houseplants. The FLF has a 20” pot, which provides the gnats plenty of soil to feed on. I am rather attached to this tree, which is probably twelve feet tall at this point, so I was desperate to get the situation under control.

I decided to try Sacred Soil Tonic, which includes cold-pressed neem oil, aloe, nettle, soapnut, and other ingredients meant to treat the soil while nourishing plants. I got a small bottle that enabled me to tame two outbreaks of soil gnats over the course of a year before purchasing another. I sometimes sell houseplants, so keeping the gnats out of them is especially important, and I have been satisfied with the results of the tonic.

Once the gnats were under control, I started to think about how unrealistic it is to have plants in the house and not expect to occasionally have bugs. Maybe we think of this barrier between inside and outside as something we control. The door shuts, and now I am inside, and nature is over there. The Miller moths and the soil gnats are a good reminder that the barrier is artificial and permeable. There are more obvious examples, like the mountain lions who wander up to people’s back doors. Or, you know, the domesticated wolf asleep at my feet. But really, I am keeping a rather large plant native to African forests in my living room. How dare I not expect a bug or two hundred? Obviously, I will strive to keep gnats under control, but I will also try to be more sage about it.

Have you experienced the Miller moths? On a scale of 1 to 10, how annoying do you find fungus gnats? Tell me in the comments.