Beach does kill a lot of fungus and may also kill mycorrhizae which is a greatly beneficial fungus. Most of the plants on the planet cannot use the fertilizers we feed them before it has been eaten by mycorrhizae and then fed to the plant. Also, aspirin does not do anything at all, pro or con, for the different rots. The theory was that the aspirin helped boost, or kicked into gear, the rhizomes immune system. I don't know if it worked or if the irises were just going to come back to life anyway. I do know that it did not hurt the environment and will not contaminate ground water and will not kill mycorrhizae. smiles