The cure in my garden seems to be placement and timing. On the windward side of the house, where roses are exposed to both wind and thrips from adjoining weedy lots, it's hopeless for white roses after the once-bloomers finish. Thrips kick in here after the spring flush.

On the leeward side of the house, protected from both prevailing winds and blowing thrips, one or two whites are passable.

As as general rule, though, after the spring flush, they're trouble for me. Darker roses have just as many thrips, just show the damage less.

I don't have that problem with Crepuscule until the blooms are spent, but most whites do not do well for me. I can tolerate Elina as she does not get that so bad and neither does Ducher or Paloma Blanca but most whites are thrip magnets and crisp in the heat. Insects love the lightcolored roses. Mermaid, of course, does not have this problem and to a lesser degree, neither does Sally Holmes, but then you don't get the multi-millions of petals. I have a friend who grows more than 1000 roses and will not grow white or lightcolored roses for that reason, too many thrips, aphids, etc., attracted to them.

What's wierd is my Souvenir de la Malmaison does not seem to have any thrips in her flowers. I've looked and can't find any. She's planted near Trinity. I wonder if some rose give off a "do not bug me or else" vibe? It could also be that Souvenir got frightened when I threatened the shovel. I'm glad I didn't remove that one because I think it deserves some time to evolve. We'll see if it continues to look good. I don't expect perfection, but I would like the roses I grow to look good most of the time.

Most of my David Austin roses, including the whites, don't seem to show damage either. Abraham Darby at times will show some damage, but is one of my favorites.

My Elina was a mess all the time, so I removed that one.

Do you think if a rose bush is a thrips magnet that it is attracting thrips to other roses that would not otherwise be too bothered by them?

Y'all owe yourselves plants of either R. spinosissima altaica or R. bracteata. The clarity of the whites on both is dazzling.
Bracteata's continual repeat coupled with totally healthy deep green foliage make it's flowers glow, down in the species garden, over a tenth of a mile from my kitchen window, yet each bloom even looks white from this distance. Up close, they please as well. Here, bracteata's not the invasive problem it is in TX, but here it does demand attention to its thorns.
Most of the white noisettes seem to be less problem-filled than modern roses. Maybe it's my view of them as cluster flowered blooms rather than looking for the perfect single white bloom, but Mary Washington and Aimee Vibert among others are the clear whites, showing their kinship with R. moschata. BUT they don't have the deep green foliage that makes some of the species so striking.

Still, Ann -- As much as I love them (and I do!) none of those cluster-flowering Blush Noisette types drop their petals here for me, They hold onto their petals like old brown tissue paper, and HAVE to be deadheaded, one way or another.
We don't have that problem with the Tea Noisettes, tho.

Jeri

Sandy, no, there is no cure for most white roses turning "dirty". You have done those looking for a white rose a great favor by bringing to the public attention that 'Ducher' is an exception to the rule, and stays clean with a nice self-cleaning habit of dropping it's petals before they discolor.

Having said that, if you look hard enough, a person can find a few pale pinks that do not show much thrip damage at all. A prime example in my garden is David Austin's 'Heritage'. At times, that rose is a very light blush almost white, yet its petals glow with cleanliness in my garden, even when rained upon.

Randy

My Mlle de Sombreuil is packed with petals, no signs of browning edges or thrip damage at all. I don't know if it drops petals cleanly, I must admit because I find myself cutting the many flowers it produces!