Characterization of hazelnut kernel responses to brown marmorated stink bug [Halyomorpha halys Stal (Hemiptera: Pentatomidae)] infestations: Changes in bioactive compounds and fatty acid composition

Abstract

The brown marmorated stink bug (BMSB) (Halyomorpha halys Stal) has become a global threat to hazelnut yield and quality in the last decade by establishing a considerable population in hazelnut orchards in some countries. For the first time ever, we conducted an analysis on metabolic response of a necrotic hazelnut kernel, which is one of the most important damage types caused by BMSB feeding. In the present study, we investigated how hazelnut kernels respond to BMSB infestations in terms of the individual phenolics and fatty acid compositions in four different kernel types [i.e., control/healthy kernel (HK), whole of damaged kernel (WDK), healthy part of damaged kernel (HPDK), necrotic part of damaged kernel (NPDK)]. Individual phenolics were significantly affected by BMSB. Especially, epicatechin and catechin from flavan-3-ols, rutin from flavonol, and caffeic from phenolic acids increased significantly in kernel injured by BMSB. Major fatty acids were significantly affected by BMSB, except for palmitic. Oleic acid decreased in kernel injured by BMSB (WDK, HPDK and NPDK) compared with the HK, while palmitic, stearic, and linoleic acids increased. As from our results, it was revealed that BMSB affected the secondary metabolites in hazelnut and had a remarkable effect on epicatechin, rutin, caffeic acid and p-coumaric acid.