Lygus bugs are known for attacking canola, alfalfa and sunflowers (you can probably blame the lygus for that gross seed), but they can also be a significant pest in fababeans — especially after their canola food source is harvested.
In general, lygus bug species like to feed on the reproductive parts of plants.
“Similar to other crops, the lygus bug will pierce the fababean when the seed is still soft. They will also pierce the flowers and the pods,” explains Héctor Cárcamo, entomologist with Agriculture and Agri-Food Canada in Lethbridge. “So they feed on the reproductive structures: the flowers, the pods, and the seeds.”
In fababeans, the main concern of the lygus bug is the loss of quality.
“The punctures on the seeds will develop into these dark spots, and when the grain is marketed for human consumption, it may lose it’s quality and it may be rejected,” notes Cárcamo in this Pulse School episode.
Cárcamo says research so far shows the economic threshold for control is around 5 lygus per 10 sweeps at the late flower to early pod stage.
To learn more about Cárcamo’s research with thresholds, control options, and where some of the strains of lygus bug come from, check out this Pulse School video: