Most wild plants are suseptible to molds and fungus and bacterias growing on them. Roses are especially suseptible to aphids and other foliage eating insects. The best thing to do is to get an organic spray to rid your plants of the bugs. as for the bacteria it could have, you will have to scrub it down very carefully.
Rosette disease is common in wild roses. If the plant has stunted leaves and deformed buds and flowers this may be the problem. It's caused by a virus.
Wild Rose diseases may be from the roots all the way to pests that are infecting the roses. Stem canker is one of the most popular disease caused by over watering. If it is hot where you live it they may be sick due to having the fungus Black Spot.