Analysis of Lygus feeding behavior associated with scarring damage in faba bean seeds

Lygus bugs are pests that feed on various cultivated plants, including faba beans (Vicia faba). They use their piercing-sucking mouthparts to inject salivary enzymes into the plant tissue, causing hull perforations. This damage leads to reduced yield and economic losses due to downgraded quality. To quantify the association between insect numbers, feeding duration, and damage to faba bean seeds, we employed no-choice bioassays and the electrical penetration graph (EPG) technique. Additionally, choice bioassays were conducted to provide insights into Lygus host preferences relative to faba beans.In all experiments, Lygus bugs were confined to plants at the R4-R5 growth stage. In the no-choice bioassay, insects were allowed to feed for 1, 3, 6, and 24 hours, after which the insects were removed and the pods were examined for feeding damage. In the EPG experiments, plants were exposed to adult and third-stage nymph Lygus lineolaris for 3 and 6 hours. Finally, in the choice bioassay, five different plant species were tested against faba beans as a control. These experiments provide valuable information for a better understanding of Lygus feeding behavior on faba beans.