The most important factor for determining the number of plants infected in a single season by a pathogen with a monocyclic disease cycle is the

What kind of organism is.

Explanation:

The several organisms that may affect plants can be fungi, bacterias, viruses, nematods, parasitic plants, etc; to identify which part of organism is, is the most important factor to determine the number of plants infected in a single season because that depends on the kind of tretament the plants will get and the type of cycle they have.

it would be a lot of diff ones. hope this ! < 3 : )