Feeding impact of Lygus lineolaris (Heteroptera: Miridae) on Vitis vinifera: a behavioural and histological study

Abstract

Nymphs and adults of the tarnished plant bug ( Lygus lineolaris (Palisot de Beauvois)) feeding on grapevine were videorecorded in the laboratory to determine the short-term impact of feeding punctures at various phenological stages. Feeding behaviour was significantly different between nymphs and adults in the number of punctures but not in the feeding time spent. Observations by light and scanning electron microscopy showed that, from phenological stages B (bud burst) to F (visible cluster), feeding did not cause plant damage and injuries did not impact the meristems, which were coated with viscous or filamentous pectin. During phenological stages H (florets separated) and I (flowering), feeding was restricted to nectar glands, and as there is no functional relationship between nectaries and ovaries, feeding had no impact on normal development of ovaries. In later phenological stages J (berry set) to L (cluster closure, berry touch), most damage was on the pedicels of berries. Pedicels attacked at the next phenological stage show no evidence of injuries. Grapevine appears to tolerate punctual feeding made by this insect; damage is minimal and berry production is not threatened.