It could be an explanation. Are there any studies to back this up? Perhaps singles in general are less susceptible as I have noticed Tooth Fairy and Ballerina are hardly ever bothered. But of course, not all rugosas are singles.

Very interesting you asked this, Moses. Just yesterday, I was thinking of asking, here, if others found some roses less midge-prone than others.

I don’t think I have ever seen midge damage on my Flower Carpets (Pink, White and Appleblossom - closely related to one another). All semi-double, I believe, vaporvac.

I never saw midge affect Purple Pavement and another mystery hybrid rugosa (sent as Dart’s Dash from Sam Kedem years ago; I don’t think it’s that) until this past summer. All 4 had midge damage this year.

All the others got hit by midge pretty bad until I started imidacloprid applied at the base of each rose ( except rugosas) once a year late Feb, if possible, or early March. It’s not 100% effective; I’d estimate 90% effective, compared to previous years. Though I now fight spider mites on a few roses (post neonic); Lions Rose and Lemon Fizz are particularly prone.

I never had midge until I planted a body bag Carefree Sunshine from a big box ( grower was Texas based, I believe). Ten or more years ago. First bloom good, then perfect foliage and dried growing tips. None even made it to the early bud stage. This went on undiagnosed/untreated for several more years. I then moved it to a bed with other roses, and they began to behave similarly. I eventually figured it out.

The pattern I have observed is when midge fly activity is light, as in spring when roses are in 'full steam ahead,' fast growth mode, the growing tips are becoming numerous, and the midge flies are still fewer in number, just having emerging from their pupal winter sleep, their selection of the choicest, fattest, tips are preferred.

Later on during summer as growth slows down, but midge fly populations swell, every possible growing tip: laterals just emerging from a dead headed cane, basal shoots, only a few inches high are targeted, any new growth effectively lengthening is fair game. These growths are the hardest to protect because even though the spray is systemic, it does not translocate to extended new growth since it is only absorbed into tissue it originally was sprayed upon.

I have found any rose bush, mostly polyanthas and similar growth abit rose, having numerous smaller flowers in large bud count clusters, is least midge fig plagued. It could be the scent trail is weaker or exactly where to deposit her eggs is difficult for the midge fly to determine with so many miniscule developing green buds, with no extremely dominant central bud present to make her choice easier.

Moses