Ross, DON'T DO IT! I killed lots of orchids by believing another caffeine paper by the same authors. At that dosage (1%), it is highly toxic to orchids. I should have tried on a few orchids at first, but stupidly I sprayed it onto hundreds of orchids. Caffeine is known to suppress root growth in many plants, and it had a very quick response with orchids (growing root tips disappeared within 1-2 days). Phals were affected heavily, Dendrobiums seem to be relatively ok, Paphs and Cattleyas were affected. I don't know how the authors didn't see any phytotoxicity to orchids.
Are you trying to control bush snails (Zonitoides arboreus)? They are the worst pest for me. To be honest, I probably caused more damage by trying all kinds of controls. At the end, I had to do complete repotting, and clean out the area over this summer. Hopefully, they won't come back. But if complete repotting is not an option, try Sevin (Carbaryl) at the recommended concentration (1.5oz/gallon), possibly with Neem oil. I think Sevin is somewhat similar to Mesurol (methiocarb) in action (I didn't check this in detail, so I may be wrong). Mesurol is highly effective, but you need a license to get it. Dr. Hollingsworth's paper (the other caffeine paper) mentioned that Neem oil makes them hungry. So instead of staying them in the shell when they encounter toxin, they will move around and get exposed to the toxin. So it is probably a good thing to add.
Another thing you can tank-mix is Deadline liquid form (metaldehyde) + dish soap. I think I calculated that 2TBS/gallon is about right. It is a bit messy. It is compatible with Carbaryl. I think the paper mentioned that it causes the snails to produce excessive mucus. However, if the environment isn't dry, production of excessive mucus isn't so lethal. Deadline by itself wasn't so effective. It reduces the population, but not complete elimination.
Physan 20 (1-1.5 tsp/gallon) can also kill snails. I think it weakens the cell membranes. Physan 20, Sevin, Deadline can knock down the population, but it couldn't eliminate them. I have tried tank-mixing Sevin, Deadline, Physan 20, and Neem Oil near the end of my battle since they attack on the different aspects. But I didn't check the effectiveness of the combination because I decided to do complete repot, so I didn't have enough time to see the effect of this combo.
Ted, the bush snail paper by Hollingsworth showed that none of the baits were effective for bush snails (they are effective for other snails) because bush snails didn't show any interests eating them. Some were dead by accidentally touching the bait.
If there are only a few pots (or mounts) infested, soaking them under water for a couple hours will chase them out. But be careful not to forget about it. I forgot about the soaking plants for 24-36 hours and drowned about 20 mounted orchids....
The time for the egg hatching is about 2 weeks at 25C, they mature in 3 months. This information will give us an idea of repeated treatment intervals.
