From what I read, brown edges is a sign of potassium deficiency. EarthCo., the soil-testing company that tested my soil to be deficient in potassium, stated that 1/3 of soil are tested deficient in potassium.

Potassium helps plant to retain water. Best bet is to put fresh banana peels around rose bushes - they decay into a nice dark color. Hopefully the yellow bugs will eat the banana peels rather than your rose buds. I'll post some pics. on how to retain more water in a garden in my helpmefind account: Chicago IL 5a. If you search for HMF member with the name "Chicago", you'll see my garden and the pics. I posted.

Cowgirlculture, the fast tiny bugs may be thrips. They are almost microscopic, but can be seen running when you open rose petals. They are very difficult to eradicate even with pesticides which I won't use. Usually the damage is less later in the season when beneficial insects which prey on thrips show up.

You can find more information on the internet.

Here is a link that might be useful: Does the damage look like this?