Slug damage

It was suggested to my that the damage to the leaves seen previously may be due to slugs eating them. While searching for images of slug damage I found this:

Which in my eyes looks a lot like this:

Snail and slug damage would also explain why the newer leaves are nearly untouched and I have not caught any in the act. The past few weeks here have been very dry and less than ideal conditions for slugs. When things get wetter and more humid I will need to be vigilant. Hopefully in the meantime I can come up with a good slug countermeasure.

Ooooops!

I thought that my watering solution was going to mean that I could go away for three weeks without worrying about my hops. I came back to find this:

What I hope is obvious from this pic is that the Columbus on the left has basically stopped growing at just over 10 feet. The Cascade on the other hand has continued, mostly growing straight up the bamboo poles. I also found that the Columbus has well developed cones:

The Cascade had still to produce any burrs. The earth in the raised bed was very dry. Apparently we had had no rain at all during three weeks away. My initial thought was that the drip line had not been programmed for long enough. Upon inspection of the timer I found that I had inadvertently set it to every other day rather than every day. Needless to say I have now returned it to the daily setting. The very same evening I made the change we had a torrential downpour so now I'm worrying if they'll drown. I have also picked the cones that are present and put them in a sealed bag in the freezer. They smell great and I'm hoping that picking them will inspire the plant to producing some more. Despite the apical meristem coming to a stop there are signs of new growth, so hopefully upward mobility can be restored.

Another potential problem I came home to is leaf damage:

This looks very much like the leaves have been eaten by bugs of some sort but I have been unable to catch any red handed. In this same photo there is also evidence of fresh growth that hasn't been eaten yet so I'm hopeful that both plants can recover.