A few of my hills were experiencing a problem where the outer perimeter of the leaves would turn yellow before dying. I thought that the problem was due to a nutritional problem. However, it turned to be a pest-related problem; namely, leaf hoppers. It appears that leaf hoppers suck the juices out leaves before excreting a toxin that causes the edges to turn yellow and die. If your hop leaves look like the one shown below, you may have a leaf hopper infestation.
On another note, wheel bugs are starting to show up. Wheel bugs are large predatory insects that are members of a collection of bugs known as "assassin bugs." They lay waste to Japanese beetles. I had never encountered a wheel bug until we moved into our current residence. If you encounter one these spooky looking creatures, do not kill it. If you have wheel bugs, you have a pest problem.