whiteflies. I hate them. google insecticidal soap. dr bronners does the trick very well.

Looks like it could be Rose Slug damage... When you first start seeing any white marks or holes in leaves is the time to take action in the Spring so damage does not get bad... Yes they are little green worms usually on the underside of leaves that can vary in size from tiny up to 1 inch long depending on how mature they are... Your choice: either pick them off the leaves...Try hosing off the leaves with water, spray, or do nothing and hope the good insects etc. take care of them. In your case you had a overwhelming bunch of them munching... Least toxic effective spray is Safer insect killing soap...It must be sprayed directly on the Rose Slugs to be effective as it only kills by contact of the spray... Spinosad spray is effective but can harm bees so best sprayed right when sun goes down and bees are gone for the day...Spinosad kills by contact and by insect ingesting it... Always follow directions and spot spray the bush before applying spray to entire bush as some roses/leaves might be sensitive to the spray... Not sure whats going on with the yellowing could be a number of different things...

My stag horn has white spots on top of the fronds what would cause this?

Is the white area powdery? Does it wipe off fairly easily? Could be Powdery Mildew. https://extension.psu.edu/powdery-mildew I have found either of these effective in control of PM. 1 teaspoon of Baking Soda mixed in 1 quart of water or a 50/50 mix of fat free milk and water sprayed as often as necessary.