Bayer sytemic all in one rose and flower control contains Imidacloprid and tebuconazole.
Imidacloprid stops the sucking and chewing insects and the tebuconazole is a fungicide. It works well and lasts about 6 weeks.
I use it only when I cannot control the issues any other way.
Certain times of the year in the rainy season, I would have to spray the roses every week with sulfur to control the blackspot and mildew. I don't have a lot of sucking pests on the roses because I have a streetlight and I have under planted the roses to attract beneficial insects.
I still have to use the systemic rose care on my potted hibiscus to control erineum mites. But I switched from Bayer tree and shrub which persists for a year to systemic rose care which only lasts 6 weeks. During that time, I do have to disbud the hibiscus and anything near it.
Imidacloprid is very harmful to beneficial insects and bees and that is why I only use it as a last resort. I disbud the flowers while the chemical is active in order to minimize the impact on the bees and I don't spray every plant, just the hibiscus and it is in a pot that I can isolate to lessen the impact on the beneficial insects.
Actually, pruning the roses after each bloom cycle will open up the plant more and make them less prone to fungal issues and the flowers will be larger if you cut out the twiggy growth and new stems come from thicker branches.
If you buy more roses, get roses that have glossy leaves, they do better against fungal disease than the matte leaves.
Happy gardening in Hawaii. Gardens are where people grow.