Why are my sunchokes/sunroots/Jerusalen artichokes (sunflowers, Helianthus) stalks broken?

[mark21531806]

I've been growing sunchokes for about 6 years. This is the first time I've seen this. The stalks are breaking. Some of the leaves are losing their brilliant green and turning gray with rust spots, could that be related? There are also a small number of small black bugs with thin legs and thick bodies that might be aphids but I've seen them in previous years and they didn't seem to be doing any harm so I left them be.

Sorry the images are out of focus, my phone was focusing on the background.

 

[Chuck]

Looks a lot like cutworm damage.

 

[mark21531806]

Would a cutworm go up like 4 feet above the soil? I thought they were primarily low pests.

 

[Chuck]

Would a cutworm go up like 4 feet above the soil? I thought they were primarily low pests.

Probably not a cutworm then. I have seen them go up about a foot but not 4 feet. Is there any visible damage around the broken area such as blackening or cutting/chewing, anything mechanical? Do you have deer?

 

[mark21531806]

It doesn't look like chewing in my opinion. It looks like breaking a green stick, just random fibers. We have deer and maybe they started eating the leaves but why would they break the stems? Also the shorter ones are broken near the soil.