I am not going to address your insect problem because I don't have a clue as to what I would do if I had the same problem ...
As far as growing roses in containers, it can be a little tricky, but roses like to grow, so if you give them the right conditions, you shouldn't have problems growing them in containers.
The most important thing you need to consider when growing roses in a container is drainage. If your drainage is too slow and the soil in your pot stays wet, your roses will get root rot and die. Roses don't like wet feet. So whatever soil you are using has to have good drainage.
You may want to do a perk test by filling a container with the soil you intend to use and watering it thoroughly. If it is very slow draining, you will need to add something like Perlite to your soil mix before planting to lighten the soil mixture up for better drainage.
You should also lift the pot up from the hardscape. You don't need to buy fancy pot feet, you can use anything that lifts the pot up enough so that water can drain out of the pot. You also do not want to use plant trays with your container grown roses. If you leave the rose in a tray with water, the water will wick up through the drainage holes.
Roses will do poorly if they are over watered ... too much love ... and if they are under watered ... too much neglect. So how do you know when to water ? When you first plant your rose, before you water it in, lift the side of the pot. That's how it feels when the soil is totally dry. Then water your new rose in and lift the pot again. That's how it feels when the soil is fully saturated .. heavy. So, when you think you need to water, lift the side of the pot. If it is heavy, you don't need to water. If it is light, the plant needs to be watered.
Your goal is to have the weight of the pot somewhere between heavy and light. You don't want to let your roses dry out completely. You want to just have the soil moist most of the time. Your weather will be an indicator as to when you need to add more water, too.
When you first plant your rose, don't feed it anything until you see new top growth. There is no way you can plant a rose without damaging the feeder roots, so the first thing the rose will be doing is growing roots. When you see new top growth, you know the root system is working and can take up nutrients. Then you can feed your rose.
To feed your roses, water them heavily the day before you feed them so that the soil is totally saturated. Then feed with half strength or less with a liquid fertilizer. No time released or granular fertilizers. Because you are using diluted fertilizer, you want to feed them lightly and often.
As for the insect problem, maybe
@Sooby can address that issue.
Good luck with your roses.
