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  • rose midge

    Created by O’Linda Jansupka on June 1, 2017 at 9:02 am

    I have fifty rose bushes, rose midge is a real problem. What do you suggest for controlling them? I prefer not to use Merit or other chemicals, and I know about plastic under the plants, any suggestions or evidence that nematodes are effective?

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  • June 1, 2017 at 11:49 am #239256

    Eric Vinje
    Keymaster

    Hello O’Linda –

    You’re not the only one who loves roses. The rose midge (Dasyneura rhodophaga) adores them as well. Symptoms include:

    • Brown/ black or deformed buds with no flowers
    • Buds may fall off the bush
    • Healthy plants with no blossoms

    To combat this destructive pest, always start with the least harmful method of treatment and only “escalate” if you’re not getting results. Also, weigh the damage of the infestation against how much time and money you want to spend. Strive for a balance that will create the healthiest rose bushes at the lowest cost to you and the environment. Here’s a list of our recommendations:

    • Purchase bare root roses or remove the soil and rinse the roots of plants brought in from your local nursery or garden store.
    • Remove and destroy affected new growth to break the pest’s life-cycle.
    • Pupae overwinter in the top 1-2 inches of soil/ mulch. If you use mulch, remove it and replace with fresh material at the end of each growing season.
    • Black plastic or other physical barrier applied in the fall will prevent the pest larvae from dropping to the ground and pupating in the soil. It will also make it difficult for adults to leave the soil in early spring.
    • Beneficial nematodes (Scanmask®) may be effective against the larval/pupal stage found in the soil.
    • Azatrol EC is an azadirachtin insecticide that acts as an antifeedant, insect growth regulator and as a repellent and oviposition deterrent.
    • Monterey Garden Insect Spray is a relatively new insect killer containing spinosad that has been mentioned as a potential remedy. Do not apply to blooming parts of plants if bees may be foraging.
    • Surround WP is sprayed on as a liquid which evaporates leaving a protective powdery film on the surfaces of leaves, buds, and stems. This film will attach to insects when they contact it, agitating and repelling them. It will also coat the buds making them unsuitable for egg-laying.
    • Least toxic, botanical insecticides are usually ineffective against the larvae, which are protected deep within the tips.

    Good luck!

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