Quantifying the relationship between Lygus feeding and faba bean seed damage

In western Canada, Lygus are pests of numerous cultivated plants including canola, seed alfalfa and buckwheat. They also significantly impact pulse crops, particularly faba beans. Their feeding behavior leads to hull perforations, seed coat discoloration, seed pitting, localized tissue wilting, and necrosis, causing a decline in quality. Depending on the region, four Lygus species: Lygus lineolaris, Lygus borealis (Kelton), Lygus elisus (Van Duzee), and Lygus keltoni (Schwarts), can inflict damage on faba beans. To investigate the potential correlation between insect abundance and seed damage for three Lygus species, we conducted no-choice bioassays. In these experiments, 1 and 4 Lygus were confined to plants at the R4-R5 stage and allowed to feed for observed durations of 24, 48, 96, and 120 hours. Subsequently, the insects were removed, and the pods were examined for signs of feeding damage. Pods exhibiting Lygus damage were collected and compared with the corresponding seed damage.