Christie, I don't know if sooty mold will hurt the cats, but it couldn't help and might hurt - I'd clean it off any leaves I fed them.
I can't remember how long tulip tree leaves stay fresh in water, but it can take a while for a tiger egg to hatch, so I'd leave the leaf with the egg on the tree for at least 3 or 4 days before cutting it off. If the leaf it's on has mold, I'd try to very carefully clean that off, too.
Tigers have a greater death rate than many other caterpillars, so if yours doesn't make it, it doesn't mean you've done anything wrong. They also don't eat as much as other caterpillars, relative to their size. Hopefully, all will go well with your egg/cat.

I've got a tulip tree in a pot, and none of the female tigers that have visited my garden have laid any eggs on it - maybe they will eventually.
Sherry

Last year was my first year with a young tulip tree but I had no luck with raising the few eggs that were laid. This year, the tree has really grown and I have lots of leaves. So far, I have 2 babies in a container and one egg on the tree. I am watching carefully and will replace the leaves as needed. BTW, I leave the eggs on the tree and bring in the cats a few days after hatching - when they start moving around. I started placing the colored plastic coated paper clips on the leaves so I can keep track of the cats until I move them to a container. I'm new to tiger swallowtails so this will be a learning experience for me as well.

Thanks Sherry - Maybe I can switch it to something else after I bring it in. I came across a link that says they will use red maple and I have those. I have black cherries too but those become VERY toxic after the branches are broken off and the leaves are in the wilting stage, so I don't think I want to mess with those.

Tresor - What happened last year if you don't mind my asking? Did you bring the eggs in or leave them on the tree?

Black Cherry last a long time in water. Tigers will easily transfer to the Black Cherry from the Tulip tree.

I've been using those 5 gallon net paint strainers and some landscaping tape to protect eggs outside. I've actually been raising Spicebush on the Spicebush trees with them. So far, I'm having success, but I'm making sure the twig is centered in the paint strainer. I caught a huge assassin bug canvassing one of my nets.

Christie;
Our butterfly house used to have a tulip tree in it (till it got too big and it was cut down). It would get powdery mildew all the time and the tigers did fine. That being said, it is always better to give healthy food material to the caterpillars. A stressed plant does not have the same nutritional value and it can take longer for the caterpillars to grow. This exposes them to more disease and predation.

What do you mean by the black cherry becoming more toxic after being cut?

Eggs left on trees will disappear pretty quickly as a lot of things like to eat them. They can also be infected with parasitoids. So, it is up to you if you want to leave it there, net it as runmede does, or bring it in.

Good luck,
Elisabeth

I've never seen/had experience with or heard of tiger swallowtails eating red maple - in my experience, it's red maple that's very toxic, even cattle shouldn't eat it. My wild black cherry stays fresh in water for a long time, and they do very well on that.
Where did you get the information about them eating red maple, Christie? This sounds like more misinformation out there.
I've never lost any eggs, other than sulphurs, to predators, so I wait and bring them in when they're hatchlings - 'works for me, but maybe all types of butterfly eggs get eaten in some parts of the country.
Sherry

The caterpillar host plant database says they do eat Acer. But, I find that butterflies have different preference in different localities. Here, I've seen them lay on tulip tree, black cherry, and ash.

Here is a link that might be useful: Tiger Swallowtail (Papilio glaucus) Host Plants

Christie - the cats just didn't survive very long. I only had two last year so the experience didn't give me much to go on.

First, I collect the eggs by netting a female tiger. Most female butterflies are gravid (pregnant)--that's their first order of business for survival. Then, I put her into my 5' net container with the host plant (host plant must be touching top of cage (use a stool to elevate) and a pot of Zinnias. I keep her for maybe a day or two. Then I let her go. After the eggs hatch, you can cut Black Cherry for them (I put the cuttings into a gallon spring water jug and stuff papertowel in the top to keep the caterpillars from getting down into the water), but be careful with spiders and other predators. I've found large spiders where I'm sure they were tiny when they sneaked in. I also make sure I mist the plants and cuttings once a day. For some reason, Tigers need this extra moisture (a friend taught me this). I keep the container in a mostly shaded area--too much full sun can bake caterpillars/pupae in a container.