It loos like edema to me (also written as oedema). This is not an infectious disease but is a problem of water supply.
These are swellings and/or blisters or calluses on leaves caused by rupturing epidermal and inner leaf cells. The plant is taking up water too quickly and cannot release it from the leaf, leading to rupturing of the cells in the leaves and this characteristic warty appearance.

Edema occurs when water is absorbed from the soil faster than it can be transpired through the leaves and is caused by soil being warmer than the surrounding air. Is the soil waterlogged? Check to see if you can improve the drainage