Roses (​Rosa​ spp. and cultivars) may be the centerpiece of your garden, but if people "ooh and ahh" over a rose, so do multiple insects and pests of all kinds. Once these pests descend, you may find rose leaves that are black, chewed, malcolored, or distorted. Aphids, mites, and beetles are the most common pests that attack rose bushes. You can hose off mites to remove their eggs and larvae. Japanese beetles can be removed by hand (dropped into a bucket of soapy water). They can do a lot of damage in a short period of time, so quick action is important. A multitude of diseases can also attack your roses, such as downy mildew and black spot fungus. Problems With Roses: Common Diseases For Rose Bushes (gardeningknowhow.com)