Hello mxk3,

I assume you don't want to spray your milkweeds because you want them to be food plants for Monarch butterfly larvae (caterpillars).

" Will diatomaceous earth at the base of the plants work? "

It might. Earwigs usually depend on a heavy organic mulch as protection from sunlight during the day, and they feed at night, so you don't usually see them. So just removing the mulch might be sufficient. Replacing it with diatomaceous earth might increase the pressure on the earwigs. It might be sufficient to leave your organic mulch in place and apply diatomaceous earth to the mulch. I don't use diatomaceous earth, but I do use a sand mulch on my zinnias and tomatoes to create an unfriendly environment for pests like earwigs and pillbugs and slugs. I use a lot of washed river sand in my gardening.

ZM

There are various means of controlling earwigs but trapping seems to be the most efficient. Lots of online resources that explain how.....HERE is one to start. Also, Sluggo Plus attracts and kills earwigs as well but make sure it is Sluggo Plus. The 'plus' part is spinosad, which is what is effective against the non-gastropodal pests.

I always find earwigs in the soft young topmost leaves of my milkweeds, but I doubt they are doing the damage. They just like to hang out in a safe place. More likely weevils are doing the damage.

While earwigs are omnivorous they can be very damaging to plants. In particular, they burrow into flower buds and feed on the nectar and pollen in safety from predators. You see this frequently with roses, dahlias, clematis, hollyhocks, zinnias and marigolds. Since milkweed offers both pollen and nectar, doesn't surprise me at all to find them chewing their way into those flower buds as well.

They can also wreak havoc with tomatoes, berries and stone fruit. If you suspect you have a infestation, I'd suggest treatment soon.

Please don't ever use diatomaceous earth to kill anything! It will kill all the good pollinators that come near it. It's barbaric and I'm surprised some people still recommend using it. I've never seen earwigs eat milkweed flowers. I've seen them eat many other flowers and foliage. Diatomaceous earth kills indiscriminately.

If it's sprinkled on the ground, how would the pollinators (flying ones) get into it?

I had a bad earwig infestation one year. They were eating everything and making a mess. I couldn't find an insect during the day and someone suggested going out at night with a flashlight and sure enough, there they were. It took me a couple of weeks to get control of them and I haven't had a major problem again, since. I would go out at night with a flashlight when they are active. I would take a 16oz plastic cup of water with dishwashing liquid and just knock them into it with a gloved hand. Every night and gradually they got fewer and fewer over the next two weeks. It's really not hard and the soap suds helps if you don't enjoy watching them dropping in the cup, which I don't.

I have been very committed to organic gardening since 1980 and I always feel it's a lot easier and safer to just use nothing synthetic. I always felt that it happens too often that some authority figure persuades the public that something is safe to use only to find out years later, that it wasn't as safe as they thought it was because they didn't understand everything they needed to. Look at Round Up for instance, my neighbor mocked me that I wouldn't use it, but 10 years later, lots in the news about the damage it can do. I just stick to natural methods and materials and if knocking earwigs into a soapy cup is part of natural methods, I can live with that and equally important, it works.

Diatomaceous earth is a natural substance.

Diatomaceous Earth General Fact Sheet (orst.edu)

The soapy water trick does work great though. I use it for Japanese beetles, on the recent explosion of asparagus beetles, and just this morning -- slugs (ugh!). I have an old Mason jar and squeeze bottle of dish soap in the barn ready to go at all times LOL!

mxk3 - Gosh....slugs! I think I've seen two in 10 years. Thankfully, I don't have that issue, maybe my property is too dry. I would have a hard time dealing with the slimy bugs. lol Red lily leaf beetles were really miserable to deal with too. The larvae made such a mess.

I saw another lady bug yesterday. We had company and it landed on the edge of my cup and I got a real close up look at it. It was golden color with the black spots and I was surprised. I thought they were all red.

I have a tropical Hibiscus that last year, was covered with holes and as sometimes happens, I was late to notice it and do something about it. When I looked closer, I saw tiny little caterpillars that were pretty much the same color as the leaves and difficult to see. But once I did, it was easy to remove them. This year not one hole in a leaf so far and no sign of caterpillars. And I haven't seen a beetle on any of my roses yet, I don't know what is going on. I don't usually get a lot but at least some.

What I do have is a family of chipmunks just moving in. For the past 3 years I've seen one, a few times a season. This year I see one every day and I can hear them chirping if I get near them or they get frightened. Yesterday, I saw two in two locations one right after the other, so I'm getting a little nervous about a population explosion of those. I have no idea how much damage they can do. I hear they dig a lot of holes? I don't mind a few, I just hope I don't ened up with a colony of them.