Spider mites. I think you’re supposed to let it dry? Then rinse it off? I don’t think it should stay on there because it can damage/clog the stomata of the leaves but I’m curious what other people do. Think I’m just gonna look it up on YouTube or something. I bought this “3-in-1” from Amazon & should get it Wednesday. What pests are you dealing with?

The plant might or not might rebloom right away even if healthy - depends on the type of rose.

I would dead head it, spray it with pesticide and anti fungal and fertilize it. There are a lot of weeds around it too.

I recommend either Neim oil or bio advanced insect, disease and mite control

BioAdvanced 701290B Insecticide... https://www.amazon.com/dp/B000RUJZS6?ref=ppx_pop_mob_ap_share

try this Amazon.com : BAYER CROP SCIENCE 701290B Insecticide Fungicide Miticide 3-in-1 Insect, Disease & Mite Control, 24 Oz : Insect Repellents : Garden & Outdoor

This: https://www.amazon.com/dp/B000RUJZS6/ref=cm_sw_r_cp_api_glc_fabc_1tqZFb5QC9AH6

I’m probably gonna get a lot of hate for sharing that, but it works. It’s basically putting your plant on prescription medication. Never use it on anything you would plan on eating since it will persist in the plant for months. And it kills bees. I use it very sparingly.