With regard to translating "イモ", having the listener imagine the image and flavour of the vegetable is infinitely more useful than merely a convenient translation. I have seen "イモ" translated as "potato" several times. But, I am suspicious.
I am from the Southeastern USA region, and most of us consider a "potato" to be the one, and only one, classic "baking potato" (usually grown in Idaho). There are also "sweet potatoes" and "yams", but we draw no distinction. "Sweet potatoes" and "yams" are both called "sweet potatoes".
If someone asks me "what is an イモ?", I am not comfortable with just saying "Ah. It's a potato." I've never seen or eaten an イモ. Using terms that a native English speaker would use in daily conversation, what is a very short way to get the image of an イモ into the mind of someone who knows nothing about Japan?
note: I did google images, but I believe some of the "イモ" images are mislabeled. So, I'm confused. Who has eaten a real イモ and can explain what it is in terms that native English speakers use in daily conversation?