ABSTRACT
The focus of this chapter is to examine how understandings of yield loss apply to the practical problem of managing pests. Yield loss is only one expression of plant stress, so one cannot talk about yield loss in isolation. Even in agricultural systems, the affect of stressors on yield is not the only issue of concern; quality and plant longevity are as important as, if not more important than yield for some crops. However, for many practical issues yield is taken as the final arbiter of stress, and it is the parameter most closely tied to economic impacts of stress. So focusing on yield loss as an index of plant stress is appropriate in an agricultural context.
