Good on you! I have not seen hardly any BSTs. I so bummed! My bronze fennel is untouched.

I have not seen 4 in a row either.

I received eleven eggs on my dill yesterday. Some were underneath the leaves which was odd. Had to look at the plants from different angles to hopefully have found all that were left. Previously this year, I've found two pillars on my curly parsley and one pillar on my golden Alexander. Was looking like a very poor BST year until yesterday.

I have had years with very few or even zero BSTs. Last year I had so many it was ridiculous - I gave a friend over 2 dozen eggs/babies because I couldn't keep up with them all! This year I had some in late spring, then nothing until recently. I'll never figure them out!

KC Clark, My BSTs almost always lay their eggs under the leaves - and my main host plant is rue, so looking under all of those type of leaves takes determination - lol!

Wow, that's neat that you got four in a row! I've been raising BSTs for about 10 years and have never had that happen. Even two in a row doesn't happen all that often. I agree about those butterflies being so unpredictable. I think we've gotten them every year but never know if it will be a little or a lot.

This is post was almost a year old but sure would like to know what plant that the eggs were on. thanks.

It's Rue (Ruta graveolens). It's my favorite for attracting black swallowtails, and the occasional giant swallowtail will also use it. It's a pretty plant, and comes back every year. I cut it down in early spring and it quickly explodes with new growth. I have some in half sun, and others in full sun. It's really a carefree plant. I let mine flower and have had a few new plants show up. It can be easily moved if needed. It gets about 2' x 2' in my garden. The BSTs almost always lay their eggs on the underside of the leaves.

It is not the same as Meadow Rue, which is not a host plant.

If you are in St. Louis, Greenscape Gardens off Barrett
Station road carries it, as well as Bowood Farms in the city. I only buy
mine from those two nurseries as I'm confident that they have not been
treated with pesticides or Bt.

Some people have an allergic reaction when handling rue, I am not one of them. The oil/sap in the Rue reacts to the Ultraviolet rays and causes what is called phytophototoxicity. So if you get some and find you're one of the unlucky ones, handle it before the sun hits that part of the garden, and wash your hands/arms/face after handling. Or wear long sleeves/gloves. The rash/blisters can take a day or more to show up.

Random note: I dug out all of my fennel last year because it seemed to attract ichneumon wasps, which will inject their eggs into caterpillars. It was the first time I had a wasp come out of a chrysalis instead of a butterfly. This happened twice last year. I bring all of the eggs inside to raise, but occasionally I miss some and bring in 1st or 2nd instar cats. Those are the ones who got hit by the wasps :(