Dear, your question is very general. You should specify at least if it is a controlled experiment, which uses explanatory variables, what level of measurement, if you have a large or small sample.
The data to be collected are from the natural field with the size of 1 hactare without any treatment and the explanatory variables are climate (temperature, relative humidity, rainfall) and inoculum density of the pathogen. While the response variables are the disease incidence and also disease severity.