Alternative lawns sign for Mosquito Shield

If you give presentations on the non-target effects of pyrethroid mosquito sprays, here are some modified lawn signs to download and use. I’ve based them on an actual sign from Mosquito Shield, below.

Mosquito Shield lawn sign

First, here’s a sign that simply has an additional part that shows the name and molecular structure one of the two chemicals used by Mosquito Shield (they also use cyfluthrin). It would be nice to have signs like this because it educates neighbors on what is actually in these types of sprays (the companies don’t like to disclose).

Mosquito Shield lawn sign with active ingredient listed

Here’s a mocked-up sign that informs neighbors that the homeowner has also eliminated his/her butterfly and moth problem.

Butterfly Shield lawn sign

Here’s a Firefly Shield sign. It’s really the only beetle people care about and, unfortunately, the numbers of fireflies is plummeting. There are thousands of other beetle species in a typical backyard and none deserves to be dosed with a neurotoxin.

Firefly Shield lawn sign

Spiders are also killed by Mosquito Shield sprays. I suspect many people would see this is a plus but spiders are likely important predators of mosquitoes … and spiders are not hurting humans.

Spider Shield lawn sign

Many bird species depend on insects and spiders to feed themselves and their young, so when you hire Mosquito Shield to nuke your yard you are indirectly reducing the numbers of birds that can survive in an area. I think few homeowners realize this, and Mosquito Shield (and other companies) are unlikely to spell out that consequence.

Bird Shield lawn sign

Finally, pyrethroids get washed into nearby bodies of water and end up killing fish. This might be rare in towns where there is just one person who subscribes to Mosquito Shield … but if everyone in town decided to get sprayed the fish would really take a hit.

Fish Shield lawn sign

More details here.

Guide to building mason bee houses

DIY bee hotels can be filled with (1) routered nesting trays (with our without with paper inserts), (2) drilled wood blocks with paper inserts, (3) drilled wood blocks without inserts, or (4) hollow stems. Or, like house in the photo below (construction details here), all four types — each type has pros and cons.

The key is to build the hotel so that everything can be removed to make room for fresh nests each year. I.e., you replace everything except the house itself. Note: you can reuse drilled blocks of wood (or sections of logs) if you re-drill them (to remove debris) and then kill any residual mites and pathogens by briefly submerging in bleach (or baking, or freezing). Similarly, nesting trays should be cleaned and sterilized (Crown Bees has nice video of that).

Below are some links to houses I admire.

If you’re lazy but want a mason bee house ASAP, just buy one. Here’s a draft listing of companies that make good mason bee houses. Here’s a guide to avoiding death-trap bee houses.


Or just want to show off your mason bee house? Email me.

If you post your house pic online and want to tag me, I’m @colinpurrington on Twitter, @colin_purrington on Instagram. If you want to see pics of all the beasties that show up at my mason bee houses, I have them all on iNaturalist.

Where to buy mason bee houses

The following companies or individuals sell bee houses that have 6″ (152 mm) nesting holes, have disposable or cleanable components, have protective roof overhangs (usually), are not suspended with string, and do not use bamboo. Some of these sites also sell cardboard and paper inserts, routered nesting trays, etc.

  1. Bee Built
  2. Beediverse
  3. Bee Foster
  4. Buzz Heroes
  5. CJ Wildlife (UK)
  6. Crown Bees (has excellent newsletter, Facebook page, Instagram)
  7. Farmstand Supply
  8. Forest Flower Shop
  9. Grass Roof Company (UK)
  10. Good Riddance Farm
  11. Healing Farm
  12. Hive and Garden
  13. JC’s Wildlife
  14. Kinsmen
  15. Knox Cellars
  16. MasonbeesUK (UK; check out their tube exchange program)
  17. Mason Bee Central
  18. Mystery Seller
  19. Nurturing Nature (UK; has great blog, too)
  20. One Green World
  21. Osmia Bee Company
  22. Park Seed
  23. Pollen Bee Nest
  24. Potting Shed Creations
  25. Rock Pond Nursery
  26. Territorial Seed Company
  27. Two Bees Apiary
  28. Welliver Outdoors
  29. West Coast Seeds
  30. Windowbox
  31. Woodlink

If I’ve missed somebody, send me a note and I’ll update this post.

Here’s a guide to avoiding death-trap bee houses. If you’re handy, you can also make your own.