This is all I could find. It's similar to a fungus that attacks the tomatoes.
How to tell my plant is suffering from cannabis leaf septoria?
The most telling sign of a cannabis plant suffering from cannabis leaf septoria is the formation of yellow and brown spots on the upper and lower sides of your plant’s leaves. On average, these spots measure anywhere between 1.5 to 6.5 mm across in length.
This fungal infection begins with spots being small, round, and light in color, but they progressively get larger, darker, and more irregular in shape. You may notice that some spots have a reddish-brown perimeter. This observation is the result of infected plant tissue, which has fallen off. Meanwhile, other spots may have a stiff growth in the middle, similar to a pimple.
