The resistance that is noticeable in natural infections under field conditions is not discernible during the controlled experimental conditions of resistance tests. This type of resistance is expressed when the inoculum potential is low and is highly sensitive to environmental factors. Horizontal resistance typically falls under this category, but it’s important to note that horizontal resistance and field resistance are not interchangeable terms. The former specifically refers to the absence of differential interactions between host varieties and pathogen races. Meanwhile, the term “field resistance” doesn’t suggest anything about the mechanism of resistance or how it’s genetically regulated. Field resistance is frequently polygenic but should not be conflated with polygenic resistance.