Funk on my hop leaves

There is something funky on both my Centennial and Cascade plants. Both are growing uncontrollably and budding.

Each are second year plants.

Not all leaves are affected, but I want to be careful to nip this in the bud (no pun intended).

Attached are pics from an affected Centennial leaf. It is also darker than the rest and more rigid.

Any ideas what this is? Should I be concerned?

Is it possible you are over-fertilizing? That looks something like salt buildup, the leaves push out the fertilized water and then the water evaporates, leaving a salt residue which burns the leaves.

I suppose that is possible. Both root stocks are sitting in a pretty big pile of steer manure. Would that do it?

How long was the steer manure there before you put the plants in it? Manure needs to break down a bit before you put it directly on or near the plants. You need to compost your manure before placing it down on plants.

Looks like you may have aphids on those leaves also.

Is the best solution for this to continually wash off the leaves? We're in Australia and have that issue with our Columbus hop plant...

Looks like mildew: http://www.uvm.edu/extension/cropsoil/wp-content/uploads/PowderyMildew.pdf

Start by removing the infected leaves. Make sure not to place them in your compost - this can spread the mildew.

There are also many chemical treatments. A simple water/baking soda spray works for other mildews (changes PH), but I have not tried it on hops.

I'm thinking the steer manure may be the culprit. The salts present in steer manure could lead to similar problems to what you have pictured. While steer manure can be an okay input, you should go easy with it. Try dumping a pile on the lawn--you'll see that it can burn the grass, so same is true for hops. If chicken manure is available, I'd argue that it's a better choice. The good news is that the problem may correct itself as the salts leach out through watering. Maybe a good deep soaking is in order.

Note that if these affected leaves are mainly on the lower regions (say the first two meters) then I wouldn't worry about it too much. Same goes for the aphids, the pants can handle some pests. In fact spraying down the plants too much can lead to problems, like mildew and sunburn, in particular climates.

It looks like you might have overdone the fertilizer. Uncomposted manure is too "hot" with forms of minerals that can easily burn plants. Composting allows microorganisms time to convert ammonia into nitrites and then nitrates; forms more friendly to plants.

Staight compost or manure can also remain too soggy after watering (not enough air/moisture). Your roots need oxygen as well as water. Without it, anaerobic bacteria can wreak havoc on your root zone.

If it is a fungus, it looks more like rust than powdery mildew. There are plenty of safe products to get rid of either. I would recommend actinovate, green cure, or serenade.

What parts of the plant are affected? Lower, higher? Newer or older growth? Any and all?

Thanks for all the input, all. The fertilizer appeared to be the culprit this year. Things cleared up after a few weeks (before all kinda other sh*t presented itself...i.e. a heat wave that lead to a 30' hermaphroditic Cascade plant) .. but that is a story for another day.

Cheers!