A Worm’s Tale: Water, Leaves and Pesticides

On the morning of the October Hunter’s Moon supermoon (Oct. 17) I started down the driveway with my dog for a walk. As we made our way toward the street, I noticed a few dried earthworms on the pavement. Once we got to the street, my eyes flew wide open as I observed numerous earthworms in the road. All of the earthworms were dried up and dead. Another unique observation was that all the worms were on one side of the street. And, they were only in front of my house. The neighbor across the street had no dead worms on her side of the street. It was an odd sight.

A neighbor walked past as I was counting the worms in front of my house. He commented on how strange it was to see so many worms in one location and that he had never seen anything like it. I agreed. I stopped counting the worms when I reached 100. I estimate there were at least 150 worms in a 50-foot-long stretch of road. And, again, they were only on one-half of the street. The whole scene sparked my interest enough for me to grab my camera and take a few photos of the scene.

When I resumed walking the dog down the street, I looked for more dried earthworms in the road. Nowhere did I see as many earthworms as I did in front of my house. There were a few houses with maybe 10 or 20 dead worms in front, but no one had nearly as many as I did in front of my house. What in the world was going on, I wondered.

For the rest of the day, I found myself looking for dead earthworms. And, sure enough, I began to observe them in other areas. I happened to travel to St. Simons Island that same day. While walking around, I saw several locations with dead, dried-up earthworms on the pavement. And, a few of those locations had large numbers of earthworms dried on the pavement like I did at my house.

Of course, I had to investigate what was going on with all these worms dying en masse on the night of the full moon. And, why were they only in certain locations?

There are thousands of described earthworms. In Florida there are at least 51 species. Most species reproduce by cross-fertilization. And, a few species can reproduce by parthenogenesis (reproduction without fertilization.)

According to the University of Florida Institute of Agricultural Sciences, certain earthworms migrate in the spring and fall each year. They can move through soil underground. However, they can move further distances if they move on top of the soil. Either way they migrate, they must remain moist.

Researchers have discovered that earthworms form herds. When earthworms come together to form a group it is technically called a “bed, clew, bunch or a clat of worms.” They swarm together to make “group decisions” according to the journal Ethology. Researchers further describe how social cues influence earthworm behavior. However, exactly why earthworms form herds remains a mystery. It is possible they swarm to protect themselves or to find a mate.

I discovered that when we have a lot of rain, worms can sometimes float into the street. Most will dry out on the pavement before making it back to moist soil. In the case of the mass death of worms in front of my house, flooding did not carry these worms into the road. It had not rained here in about a week. And, my yard does not have flooding issues, thank goodness. Also, I do not irrigate my yard.

Earthworms are highly beneficial for our lawns. Decomposing plant matter such as oak leaves are ingested and expelled in a broken-down form, speeding up decomposition. Worms return valuable nutrients to the soil. Tunneling earthworms break up soil and improve aeration and water absorption. Earthworms are a principal food source for birds, reptiles, insects, and moles.

In the spring, when the oak trees shed their leaves, I leave the leaves on the lawn. Leaves break down and provide food and cover for all kinds of beneficial insects. The leaves return nutrients to the trees by breaking down over the root system, thus allowing the tree to reabsorb nourishment.

The other question I had was why there were so many earthworms in front of my house and in front of other houses in the neighborhood. Then, it dawned on me. I am one of the very few people in my neighborhood who does not use herbicides or pesticides on the lawn. Each month a tiny sign appears in the yard of most lawns in my neighborhood. These signs warn me and my dog not to walk on treated lawns for at least 24 hours due to toxicity. Too bad this information is not communicated to beneficial insects and other wildlife.

When I thought about it, I realized most of my neighbors treat their lawns with chemicals. And, all of them rake up and throw away falling oak leaves each spring. This may explain why I had hundreds of worms in my yard and others did not.

 At some point during the night of the full October supermoon, many worms in my yard got the cue to migrate. Unfortunately, the herd of worms went the wrong direction. They all dried up on the pavement before finding their way to a new ground. This is my best guess as to why there were so many worms dried out on the pavement in front of my house.

If you want to learn more about earthworms, the Nassau County Extension is hosting a composting workshop called “Therm n’ Worm Compost & Learn” on Nov. 16, 2024 in Callahan, 2-4 p.m. The workshop will teach you how to create rich soil for starting seeds, amending your vegetable garden, reducing food waste, and improving the environment. Tickets for the workshop can be purchased here.