Jamikand (also written jimikand) means suran / elephant-foot yam – a big underground root.

Jains generally don’t eat jamikand for the same reason they avoid other kand-mool (root / underground vegetables):

1. Uprooting kills the whole plant

To take out jamikand, the entire plant is dug out and destroyed. This is considered more himsa (violence) than plucking fruits, grains, or above‑ground vegetables.

1. Many small lives in the soil

When digging for such a big root, a lot of soil is disturbed. In Jain view, there are countless tiny living beings (nigod, microorganisms, insects) in and around the root. Digging and washing it harms many of them.

1. More one-sensed lives in the root itself

Root vegetables are believed to contain or support more prāṇ (life units) than many above‑ground parts of plants. So eating them leads to more bondage of karma.

1. Tradition in both sects

- Śvetāmbars: generally list jamikand under kand-mool to be avoided. - Digambars: also treat it as a root vegetable to be avoided by those following proper Jain food rules.

So, Jains don’t eat jamikand mainly to follow ahimsā more strictly and reduce harm to as many living beings as possible.

You can read a simple explanation about jamikand here