There are many insects that will visit your garden. Because some are actually beneficial, I don’t recommend spraying insecticide unless you have an insect problem. The trouble with insecticides is that most of them don’t kill selectively, so keep that in mind and learn what to look for.
The first critter you are likely to stumble upon is the common aphid. These typically appear in the early spring and late fall when temperatures are cool. Aphids feed themselves through sucking mouthparts called stylets. Don’t be fooled by their small size as they can do major damage to your young growth by literally sucking the moisture right out of your plant. The good news is that normally, they are easily controlled with insecticidal soaps or neem oil. If that doesn’t do the job, you may have to resort to chemical insecticides like Orthene or Merit.
Again, the thing to remember is this: Spray for insects that are damaging your roses, HOWEVER, keep in mind that most chemical insecticides will also kill the good/predator insects like ladybugs and praying mantis. If you eliminate these from your garden by preventively spraying insecticides, you will end up with spider mites come summer. (A future blog.)
Ladybugs are a friend to the Rosarian!