Planted Tank Guru
Join Date: Mar 2009
Location: Madison, Wisconsin
I don't know if you would even have much trouble with spider mites in your area, but around here we get them a lot in the summer. They go after tomato plants and other outdoor plants and then find their way indoors. Sometimes they get on houseplants too. If you do a Google search you can find out what they look like and what sorts of damage they do. Generally they cause leaf splotching and drying.
It is real easy to treat Acorus for bugs. Just dunk the whole thing underwater right in the planter and leave it there overnight. Unlike many plants Acorus can withstand being under water for several days with no trouble. Really I wouldn't worry about it too much and you might not need to do this treatment, but it is a good idea to have a close look at your riparium plants every once in a while to make sure that pests haven't gotten in there.