Try putting one or two of the cats on a plant from the second flat you purchased (the supposedly non-treated one), and monitor them for a few days. If they both are fine after a few days then I would say your parsley is not chemical-treated.

I see you're in zone 6, and I'm in zone 6b. I'm still looking for BST cats (and adults)...they are on my wanted list for caterpillars to rear and butterflies to add to my collection. A couple years ago we had a dill plant with a couple cats on them, but that was before I knew anything about caterpillars. So now I have some dill "mammoth" that I started from seed, and it's looking good and is about 10" tall now. I've also started parsley but it looks terrible, and only 2 of the seedlings have the first (and very small) true leaf. I'm guessing it was the crappy Sta-green garden soil I started them in, so I put them in the garden next to the carrots (also started from seed and waiting for BST cats) and hopefully they'll revive and take off without any fertilizer.

Thanks catman529; I'm going to wait a few more days, and give them all a few more sprays/washings. I definitely don't need to move them yet; they're still tiny and not eating much, although I should move as many as I can as soon as possible. I often worry about predators. I recounted 18 last night. I'll definitely use the supposed non treated first; hopefully I'll need the other flat later on in the season. I had only gotten 2 BST cats in September last year; my very first two. I put them in an cage, that I had planned to use for monarch cats, but my milkweed had gotten too big for it. So instead, I put the parsley pot with the 2 cats in it. One escaped, but one pupated on the screen. I had put loads of sticks/stakes in the pot, hoping for it to pupate on one of those so I could bring it into the garage for the winter. Of course it was going to pupate on the screen, that's just my luck. I did cover the cage with a sheet, for a little protection. I tried to find out if they'd survive the winter outside, but nobody had an answer for me, and I didn't find anything useful on the net. Needless to say, my chrysalid is still outside, and all I can wonder is if it's still alive or not, if it'll eclose. Time will tell I guess. Did you ever overwinter BST's outside?

Generally speaking, they don't use chemicals on plants that are consumed by humans, like most herbs. But a good wash and drenching are not without warrant. I plant mine in spring, and our spring rains usually take care of a good washing. The nursery I go to sells their parsley plant along with BSTs included. So, I know they don't spray their herbs.

Susan

Susan, if I ever saw plants with caterpillars already on it, I'd simply freak. You should see me checking out the milkweeds, looking high & low for monarch cats. Never found any, but it kills me to imagine someone buying a host plant, finding cats, and killing them, not knowing. Ugh...

The nursery people at the store I frequent are quite knowledgeable about caterpillars and butterflies. This is where i get my Rue, parsley, passion vine, helichrysum, gnaphaliums, pussytoes, etc. They don't spray their butterfly plants either.

Susan

Wouldn't you know it; I checked the parsley and found, get this, ONE caterpillar, lots of ladybug larvae too; I did notice quite a few aphids. And no, I didn't mistake the cats for ladybug larvae; I just can't read coupons and pill bottles, LOL. My eyesight might be awful, but they were all clearly BST cats. I knew it, I just knew it. Same thing last year with the monarch cats; I snooze, I lose. So I took the lonely critter, put it on one of the new plants, and into the cage it went. I can only hope it stays put and doesn't wander out.

Well, at least I have plenty of parsley ;)