How to Protect Your Blooms from Rose Midge
Effective midge control starts in the soil, where midge pupates.
Audrey McLaughlin | Editor, New England Rosarian
July 2026
Why aren’t my healthy rose bushes flowering?
If your roses look healthy, but aren’t flowering, one potential culprit is the rose midge, Dasineura rhodophaga. A light midge infestation may appear as a few “blind canes,” or stems without flowers. A heavily-infested garden may be completely without blooms.
What is rose midge?
Midge is a species of fly that lays its eggs on the sepals and developing buds of roses. The larvae then eat the bud tissue, preventing the bud from developing. Midge is present in many areas of the United States, but it is an especially frustrating pest in New England and the Midwest. First identified in the early twentieth century in New Jersey, it was thought to be mainly a greenhouse pest. Recently midge has become a troublesome pest for home gardeners, with many members of NERS reporting midge damage on their roses.
My battle against midge
In May of 2025 something was wrong in my garden. None of the roses in my front garden bed were blooming. Princess Anne, Dark Desire, Amorosa, Olivia, and Desdemona all had healthy foliage, but refused to develop buds. I was puzzled because these were the healthiest roses in my garden. I had been growing roses for five years at that point and thought I understood the basics of pest management. But this clearly wasn’t damage from aphids, sawflies, thrips, or beetles. Stumped, I remembered that Master Rosarian Dave Cannistraro told me earlier in the year that midge can lead to blind canes. I decided to take a closer look at my roses.
Signs of midge damage
Midge larvae are tiny and difficult to see. The easiest way to identify a midge infestation is to look for damaged leaves and buds. The ends of infested canes appear distorted, with brown or black dried leaves where buds should have formed. Once this happens, the cane will not bloom again and must be removed. Tip damage is usually first visible in May, and intensifies as the growing season progresses, peaking in July.
Understanding midge’s life cycle is key to controlling it
Midge lives in different parts of the garden during different stages of its life cycle. Understanding where it lives at different times of year is key to preventing damage.
Midge follows the same life cycle as other species of fly. Their larvae (also known as maggots) hatch from eggs, transform to pupae, and then emerge as adults. The new adults lay their eggs in the developing buds and the life cycle continues. Midge reproduces quickly. The entire process from larvae to adult takes 12-21 days, allowing several generations to reproduce in one growing season. The last generation overwinters in the first few inches of mulch under the rose.
Prevention with pre-emergents
Early control is key to preventing damage during the growing season. Midge is difficult to control because by the time bud damage is visible the larvae have already dropped to the soil to pupate.
One option is a pre-emergent soil treatment. Timing of this treatment is important because you want to eradicate pupae before they emerge as adults. Midge adults are active as soon as roses begin to grow, in April. Pre-emergent treatments must be applied before adults emerge to be most effective.
Don Gabel, the Integrated Pest Management coordinator at New York Botanical Garden, recommends applying a pre-emergent when soil temperature is between 42-44 F, or about when roses have 1-2 inches of new leaf growth for products with a 1-2 week uptake time. For products with a quicker uptake time, apply when the soil temperatures reach 55 F.
Chemical control
Dave Cannistraro recommends applying GrubEx (active ingredient chlorantraniliprole) around the base of roses as a pre-emergent.
Researchers at Oregon State University found that a soil treatment of Merit 2 granular insecticide (imidacloprid) applied as a pre-emergent almost completely eliminated tip damage throughout the growing season.
In a presentation to the American Rose Society Rich Baer of the Pacific Northwest District recommended a product called Bayer Advanced Complete Insect Killer (imidacloprid and diazanon.)
Biological control
Beneficial nematodes may also be effective in controlling midge, although there is little research in this area. Stephen Scanniello, curator of the Cranford Rose Garden at Brooklyn Botanic Garden, recommends Hydronmermis conopophaga as a beneficial parasitic nematode. S. feltiae and S. carpocapsae are more widely available from commercial suppliers such as Arbico Organics and perform the same function.
Physical control
It may be possible to control midge by removing and replacing the first several inches of mulch early in the spring. The pupae are relatively weak, do not burrow deeply, and live in the first few inches of mulch. Theoretically removing and discarding this layer could prevent midge damage. Some gardeners report success with physical barriers such as plastic sheeting applied around the base of the rose.
Control during the growing season
Later in the growing season the best option is to treat both the pupae in the soil and the larvae in the buds. Both spraying and soil treatment may be needed. Midge reproduces rapidly, so you need to spray twice a week to prevent the larvae from developing into pupae.
There are several spray options. John Hefner of the Indiana Rose Society recommends Cyonara 9.7 (lambda-cyhalothrin) biweekly for two weeks to control midge.
The Oregon State University study used foliar Tempo 2 (cyfluthrin), which reduced midge tip damage from about 50 percent of tips damaged to 2 percent of tips damaged.
Heavy infestations may require a combination of contact and systemic sprays. In an article published in the Spring 2026 issue of American Rose Christopher Gordon of New Jersey recommends using cyfluthrin on a weekly basis and spirotetramat on a monthly basis. Spirotetramat is a systemic insecticide that remains in the plant’s tissues. Once his midge population is under control, Gordon switches to monthly spirotetramat and twice-monthly abamectin.
Spinosad is an option for those who want to maintain an organic garden.
My midge regimen
I took an aggressive approach to controlling midge. In July 2025 I sprayed the roses and the soil surrounding them with Cyonara 9.7 every three days for two weeks. I used a hose attachment formatted for applying the chemical to lawns instead of my regular sprayer. I’m not sure this is necessary, but I do think it helped me quickly saturate the soil with the drench.
This quickly solved the issue.
By the end of the two weeks bud tissue was developing normally. Following this, I switched to my regular 7-10 day application of spinosad. I did start to see some midge damage appear in September in beds that were not treated with the Cyonara 9.7 in June.
This year I was determined to prevent a repeat issue. In late March 2026 I applied Grubex granules to all rose beds. In mid-April I applied S. feltiae nematodes only to the front bed that was heavily infested in 2025. I believe they are providing a level of control because as of July 2026 the bed treated with nematodes is the only one with zero midge activity.
Success is possible! I am happy to report that a year after I lost the entire first flush in my front garden to midge, there are no signs of midge in that bed. I have noticed midge damage on a few canes in other beds, but now that I know what to look for I can treat it quickly and prevent it from becoming an issue.
Success!
Photo: My Princess Anne in August 2025, a month after treating for midge. Lots of normal buds developing.
Photo credit: Audrey McLaughlin
RELATED LINKS
Mad about Midge article in American Rose (must be logged in)
Rose Midge Presentation to ARS by Jim Baer, PNW dDstrict
Rose Midge John Hefner, Indianapolis Rose Society