I find that most of the papers use "number of insects per one leaf" or "number of insects per 100 leaves" to describe the infestation or density of insects on a plant. So, my question is, how many leaves are in one potato plant?
It may vary very much. The largest number of leaves per plant with 5 haulms that I found - 280
OLIVEIRA, CARLOS ALBERTO DA SILVA. Potato crop growth as affected by nitrogen and plant density. Pesq. agropec. bras. [online]. 2000, vol.35, n.5 pp.940-950.