When my dahlia blooms open they are not nice and filled with tiny bugs. The plant looks very healthy,though. What can I spray them with?
You need to get a bug ID. There is no spray that is good for every possibility. There are websites that help with bug ID or you can check with your county extension service. Search for "[your state] extension service". They will know if any bugs are particularly active in your area as well as provide help with ID and control measures. I just did a search for "insect ID" and saw some great results.