Answer: You didn't mention what pest you are trying to control. Aphids suck sap from new growth and flower buds. They leave behind a sticky residue that may turn black if infected with mold. They are tiny, and usually green or perhaps black.
Rose midges are teeny, tiny bugs that cause new growth, especially buds, to shrivel and turn black. You might need a magnifying glass to see them, or tap a bud over a piece of white paper and see if they fall out. Insecticidal soap can help.
Finally, thrips feed on flower petals causing them to be deformed when open. Unopened buds may be tipped over at an angle.
Aphids can be controlled with a strong, daily blast of water from the hose. Beneficial insects such as lacewings and lady beetles help control both aphids and thrips. Insecticidal soap works on all three; however midges are usually the toughest to get rid of.
If you suspect aphids or thrips, if damage isn't too bad, you might wait a week or two to see if benenficials show up to control the population. I hope this information helps!
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