Hi, Well it sounds like your roses got off to a rocky start this year with the frost that probably weakened them enough that other problems could follow. Black Spot is a disease that is made worse in wet, humid weather. All you can do is remove the dead foliage and use the rose fungicide. It generally won't kill your roses, but certainly makes a mess of them when infected. I don't know what kind of roses you have, but I recommend you consider using disease-resistant roses such as Rugosas or some of the new landscape roses such as the Oso Easy line that are bred to be resistant to Black Spot. This disease mostly hits old-fashioned Hybrid Teas, Floribundas and Grandifloras. Personally, I don't even plant them anymore and have a wonderful rose garden with disease resistant types. Japanese beetles can be a nightmare. I'd go to your local Garden Center and find a product that's designed to kill them. Beetle eradication can be difficult if you live where the insect populations are thick and organic controls won't always work.