Wow, that's a big one! They are SO hard to locate, aren't they? Even the big ones blend in so well.

Other than hand-picking, I think the best treatment is to spray the plants with Bt, the all-natural bacteria that is parasitic on caterpillars. It won't hurt bees or other non-caterpillars. You just mix a slurry with water and wet ALL of the foliage and the caterpillars stop eating within a day and die several days later.

That being said, I DO let the caterpillars have their way with my daturas and nightshade plants (although I relocate them to larger plants when they victimize smaller plants). They become those amazing night-flying hovermoths/hummingbird moths, so I tolerate the damage on daturas.

There are several brands of Bt out there, but if you go to a nursery or hardware store garden section and tell them what you want, they'll find it. Here's the brand I keep on hand, just in case (works on all caterpillars by the way).

Great pic! Let us know what you do and how it works out,

Happy gardening!

Grant

You are brave sordle, brave! I scream like a girl when I happen to touch one. Actually, if I even see them. Ugh! they are ugly.

Grant's advise is spot-on, as usual. I recently purchased a spray nozzle that will spray upside-down, to get the undersides of leaves. It's great!!

Thanks for the input, Grant. I've been a-lurkin' round GardenWeb for a long time, and you always seem to have something useful to add. I'll definitely be checking in to the bacillus thuringiensis.

Will Neem oil have any effect on them?