These droplets can harbor pathogens. They also create small, dark, circular patches on the pod surface and on the underlying seeds. In Western Canada, lygus bugs typically damage up to seven per cent of the seed. In 1997, damage estimates were as high as 40 per cent in the most heavily infested areas. The damage caused by lygus bugs in canola is related to the weather conditions at the time of the infestation.
Weather affects the development of both lygus bugs and the crop.
Monitoring Begin monitoring canola when it bolts and continue until seeds within the pods are firm. Because adults can move into canola from alfalfa, check lygus bug numbers in canola when nearby alfalfa crops are cut. The economic threshold for lygus bugs in canola is applied between the end of the flowering and the early pod ripening stages. Once the seeds have ripened to yellow or brown, the cost of controlling lygus bugs may exceed the damage they will cause prior to harvest. Sequential sampling for lygus at late flowering stage Table 1.