Jennifer, 

Thanks for your question regarding your roses, I'm sorry to hear you're having issues! There are a number of common pests that plague roses in Ohio. Based on your picture, there may be a few things going on.

First, the chewed up leaves and browning spots look like damage from a type of rose slug/sawfly. Sawfly larvae create damage to the leaves by eating only partway through, creating a "windowpane" sort of damage that can eventually wilt to that brown color. As they become adults, they will also eat entirely through the leaves which it appears you are also experiencing. These insects will be small, caterpillar looking and you will probably see them on the underside of the leaf. The good news is that rose slug/sawfly generally cause mostly cosmetic damage.

There are a number of ways to deal with these pests: You can try hand removing any you see and/or spraying the leaves (both top and underside) with a strong spray of water to knock off the insects. Insecticidal soaps or neem oil may also help to reduce their presence, but ensure you get good coverage on both the tops and bottoms of the leaves. There are also chemical options to help with sawflies, including organic options like pyrethrins or spinosad, or more conventional insecticides. The literature I am finding also is careful to point out that insecticides that contain Bacillus thuringiensis (commonly called Bt) are not effective against these pests. If you are using any chemical options, please ensure the label speaks to rose slugs/sawflies and that you follow all the instructions on the label. In particular, pay attention to any mixing or application requirements and the types of personal protective equipment you should wear while using the product. 

Here are a few helpful websites about rose slug/sawfly for more information:

https://content.ces.ncsu.edu/roseslug-or-rose-sawfly

https://www.missouribotanicalgarden.org/gardens-gardening/your-garden/help-for-the-home-gardener/advice-tips-resources/insects-pests-and-problems/insects/sawflies/rose-and-pear-slugs-sawflies

However, the slugs/sawflies should not be causing the black spots on the stems you also mention. That is most likely a type of fungus. Because it does not appear to be showing up on the leaves, it looks like it could be a rose stem canker causing this issue. Unfortunately, for stem canker the best thing to do is carefully prune away the diseased canes below the black spots and discard of them away from your plants. Because this is a fungus, it could easily transmit so ensure you wipe clippers after each cut with alcohol and throw the clippings away. (Composting will likely not kill the fungus so it is also not safe to compost this foliage.). You can also consider treating the plant with a fungicide, particularly on the cut areas, to help reduce fungus. If you start to notice black spots on leaves, or that your flowers seem to be molding, it could another type of fungi. All can be treated in similar ways: removing and discarding dead or diseased plant parts and using appropriate fungicides. There are a range of both organic and conventional fungicides available and many specifically targeted for roses. You will again want to carefully read the label, and note that fungicides often need reapplied regularly. 

Here is some information about rose fungal diseases:

https://hgic.clemson.edu/factsheet/rose-diseases/

https://ipm.illinois.edu/diseases/rpds/626.pdf

This is a great resource with pictures of a number of rose issues, that may be helpful for you in the future: http://www.missouribotanicalgarden.org/Portals/0/Gardening/Gardening%20Help/Visual%20Guides/Rose%20Problems.pdf

I hope this information can help you. If you have additional questions, or have additional pictures you would like me to review, please feel free. Have a great day and good luck with your roses.