Electropenetrography (EPG) Study of Nezara viridula (L.) (Heteroptera: Pentatomidae) Adults Feeding on Canola Stem and Silique.

This research aimed to study the feeding behavior of Nezara viridula (L.) adults on canola stems and siliques using the electropenetrography (EPG) technique. Three distinct phases were identified: non-feeding (waveform Np), pathway (waveform Nv1-which was divided into three subtypes Nv1a, Nv1b and Nv1w), and feeding (waveforms Nv2 and Nv3), which follow previously identified waveforms for this species on soybean. The Nv3 waveform was divided into two subtypes (Nv3a and Nv3b). Biological meanings of the waveforms were proposed by correlating them with visual observations and histological studies. The waveform Np was correlated with insect resting/walking on plant surface; Nv1a with initial stylet insertion and secretion of gelling saliva to create a salivary sheath; Nv1b with deep stylet penetration plus secretion of more gelling saliva; Nv1w with stylet withdrawal, and Nv2 with xylem ingestion, as previously observed for N. viridula nymphs on soybean. Nv3a was correlated with laceration/maceration activities; and Nv3b with ingestion of the lacerated/macerated tissue. Regarding comparative analysis, the initial penetration and stylet withdrawal were both significantly longer on stems. Xylem ingestion did not differ significantly between substrates. Feeding events were more common on siliques, and overall duration of ingestion was greater on this substrate. Although no difference in overall duration of laceration/maceration (cell-rupture feeding strategy) was observed between stems and siliques, the average duration of each laceration/maceration event was greater on stems. Significantly more time was spent on non-feeding activities on siliques compared with stems.