Termite bait stations in New Orleans’ sidewalks

In honor of Mardi Gras I thought I’d make a short post about the small circular metal plates on sidewalks (banquettes) in the French Quarter of New Orleans. When I visited there in February, I initially thought they were surveyor control points or property markers, but that made no sense because there were sometimes a dozen per block, plus the bolts in the center seem to show signs of wear and tear as if they were being used a lot. A reverse image search quickly revealed they had something to do with termites, specifically the introduced species, Coptotermes formosanus, that arrived sometime on or before 1957. Details below (as it were).

The plates are remnants of Operation Full Stop, a USDA-led project that was funded in 1998 by a $5 million earmark in the Federal budget. Part of the funding was to develop a bait system that would deliver poisons to deserving termites in a 15-block area of the French Quarter. Inside a 3″ hole drilled into the sidewalk and deep enough to reach the soil level is a bait station supplied by Terminix. I think the station is manufactured by Sentricon and included a chitinase that killed the termites by preventing their ability to molt. Here’s a bait station inside a hole that was missing its cap plate:

The cap plate is a rather clever device that makes a water-tight seal as the snake eye bolt on the plate is tightened. It was the brainchild of the late Edgar S. Bordes, Jr., I gather.

Per Martin 2016, this baiting effort caused a reduction in termite populations from 1998 to 2011, the year the funding ran out. And most of the ~3000 homeowners that received the bait stations have opted to pay a pest-control service to maintain them. But this article implies that many of the termites are in the walls of homes and businesses and perhaps don’t regularly visit the ground level and so might not encounter the poisons inside the bait stations. Therefore, many homeowners are hiring specialists to examine their walls with infrared cameras, acoustical detectors, miniature radars, and snake scopes. If I invested in a home in New Orleans I would spend tens of thousands of dollars to buy all of those devices so I could monitor my walls whenever I wanted.

If you’d like to see more plates, just browse Google Maps of the French Quarter in Street View mode. E.g., here’s the sidewalk in front of 916 St. Louis St.

Happy Mardi Gras!

Alley near House of Blues with two termite bait stations (bottom of pic).

Happy holidays

In case anyone stumbles onto this page today, here’s a festive Christmas lichen (Cryptothecia rubrocincta) that I photographed several years ago in Myakka River State Park, Florida.

The red projections in the middle are isidia, vegetative outgrowths that can break off and form new lichens. Each little piece will have bits of the requisite fungal (Cryptothecia rubrocincta) and algal species (Trentepohlia sp.) that team up to bring us this lichen.

Bti honeypot traps for killing mosquito larvae

An easy way to kill thousands of mosquitoes each summer is to set out a container of water, add a handful of leaves or hay, then drop in 1/4 of a Mosquito Dunk, a compressed, shelf-stable form of Bacillus thuringiensis israelensis (“Bti”) that kills larvae. Pregnant females will oviposit onto the water surface as well as onto the sides of the container and when the larvae begin to feed they’ll be killed by the toxins produced by the bacteria. Just add a fresh chunk of Mosquito Dunk every three weeks to ensure the system is operating as needed.

Tips

  1. Cover the container with chicken wire or netting to prevent birds and chipmunks from drowning. You can also use hydroponic lids that have a built-in basket or use a 3D printer to fabricate spacers. Or drill a bunch of 1″ holes in the bucket lid. If you have toddlers around make sure they can’t fall inside (drowning risk).
  2. Add a long stick that can fit through the mesh so that innocent insects that fall into the water have a way to crawl back out. The presence of wet wood will also increase the oviposition rate of certain species of mosquitoes (e.g., Aedes spp. will deposit eggs directly on the wood).
  3. Add a white yogurt lid so that you can more easily see whether there are larvae wriggling around. I like to cut the rim off the lid so that it sinks a few mm lower. Alternatively, spray-paint the bottom of the bucket white.
  4. Deploy multiple traps to maximize the effect (I have six in my 1/4-acre yard). More is better in part because some mosquito species (e.g., Aedes) exhibit skip-oviposition behavior, leaving just a few eggs in a bucket and then flying off in search of more sites.
  5. Set traps out in early spring so that the leaves have time to decompose and become attractive to female mosquitoes.
  6. Site near vegetation or at the bases of larger trees. Avoid areas that get a lot of direct sunlight.
  7. Set up a reminder on your phone to add more Mosquito Dunks. NB: if you forget, the buckets will be generating mosquitoes.
  8. If you’re traveling for more than three weeks during the summer, dump out all your buckets and start over when you return.
  9. Purge your yard of all other objects that might retain stagnant water so that mosquitoes are forced to leave their eggs in the trap.
  10. Make some for your neighbors, especially those who are spraying pyrethroids. Include a print-out of this page so that they understand how to use it.
  11. Get local folks on board by writing a letter to your local paper (e.g., here’s my March 2026 blurb in The Swarthmorean). The more people who use these traps the better.

Are they working?

To determine whether mosquitoes are ovipositing, look for egg rafts on the surface of the water. You can also check for eggs of Asian tiger mosquitoes (Aedes albopictus) on the edges of the container, above the waterline, or on pieces of wood that are floating on the surface. If there are eggs and no larvae (video below), the Bti is doing its thing. If you see larvae in the water, dump everything and start over or add some fast-acting Mosquito Bits (kills in minutes, just as safe) along with a fresh chunk of Mosquito Dunk. If you don’t trust yourself to ID larvae, send me a pic or tag me on social media. Mosquito larvae look a lot like newly-hatched tadpoles, fyi.

Safety

Bti toxins are completely nontoxic to mammals, birds, and all insects except mosquitoes, black flies, and fungus gnats. For an overview of the mode of action and safety, please see this report (PDF).

Sources of Bti

If you can’t find Mosquito Dunks search for any of the following: Biosolutions Bactive, Bonide Mosquito Beater Water Soluble Pouches, Bactimos Briquets, Terro Mosquito Larvacide Pouches, VectoBac Water Dispersible Granules.

Printable version

I made a 2-page PDF of the above in case anyone needs something to hand out to friends and neighbors.

Other sites with similar information

See also