Which method is NOT a characteristic of proper field sampling for pathogens?

The method of only sampling areas with visible disease symptoms is not a characteristic of proper field sampling for pathogens. Proper field sampling aims to comprehensively assess the health of the entire field, rather than focusing solely on areas exhibiting symptoms. By limiting sampling to visibly symptomatic areas, important information regarding pathogen presence in asymptomatic or less apparent regions can be overlooked. This can lead to an underestimation of the disease's spread and impact on crop health, potentially resulting in inadequate management strategies.

In contrast, effective sampling strategies include collecting samples from various locations within the field, which helps ensure a representative understanding of the pathogen's distribution. Utilizing different sampling patterns, such as gridding, enhances spatial analysis and improves the statistical validity of the findings. Additionally, taking samples at multiple growth stages allows for the assessment of pathogen dynamics over time, giving a more complete picture of their lifecycle and the plant's susceptibility. These methods collectively contribute to a more thorough understanding of plant health and the prevalence of pathogens throughout the field.