Q: The edges of my rose petals are brown and ragged. What causes this?

A: Rose thrips hide inside rose buds and chew on the edges of petals. When the bloom opens, the damage is evident for all to see.

Slap an open bloom on a piece of white paper and look for tiny yellowish creatures skittering across the page.

Because they hide themselves so effectively, thrips are difficult to control. Systemic insecticides (click for sources) can be helpful. Sprays containing spinosad (click for sources) are also effective.