Economic control thresholds for lygus bugs are based on adult and late instar counts. As an example, when canola prices are $12 per bushel and application costs are $12 per acre, the threshold is 11 adults or late instar bugs per 10 sweeps.
Before spraying, consider the pre-harvest interval for the chosen insecticide. Products with the shortest pre-harvest intervals still require 7 days between spraying and cutting, so if the field is within a week of swathing, then spraying is no longer an option. In fields that close to cutting, many pods are hardening and lygus will not be able to penetrate and cause damage anyway.