... I'm thinking fungal too mate, Ca defc, spotting usually isn't that symmetrical, or that color or size,... nor does it hit lowers like that first (it's considered poorly/non mobile within the plant) ... do you have high RH% and /or low night T? poor air movement down low? ...yup, more pics may help pin it down,.... pure neem oil is a good broad spectrum choice, and use a wetting agent with it to help coat and stick better, plus it helps emulsify it better!