Yes, Termidor SC will work for Formosan termites. Formosan termites are a species of subterranean termites and Termidor SC is labeled for subterranean termites.
We are not sure if are asking if you can use Termidor SC on edible vegetables or if you accidentally treated near a garden, but Termidor SC should not under any circumstances be applied near or on anything edible. You should keep Termidor treatments at least 10 feet away from any garden. If you treated on or near your garden, you should discard anything that may be contaminated with Termidor SC. If you are looking for something to treat your garden with, we do have many products that are for use on gardens.
We would highly suggest trenching and treating instead of only treating inside the cinder block wall. Termidor is meant to bond to soil and be applied into the ground. It will not last very long just treating into the cinder block walls. Cinder blocks are also very porous, so they will soak up a lot of the termidor and you might get a few months of protection instead of 10 years when applying it into the ground.
You should follow the instructions as outlined in our How To Do A Termite Treatment article to treat the exterior and underside of your crawl space.