White-berried grapevines as hosts for polyphagous aphids: analysis of probing behavior, plant leaf anatomy and allelochemicals

Aphids (Hemiptera: Aphididae) are herbivorous insects which deprive plants of nutrients by feeding on the phloem sap and transmission of plant viruses. In the present study, the susceptibility of selected white-berried grapevine (Vitis spp.) cultivars Aurora, Bianca, Muskat Letni and Solaris to the black bean aphid (Aphis fabae Scop.) and the green peach aphid (Myzus persicae (Sulz.) was evaluated using the Electrical Penetration Graph (EPG) technique. The content of major flavonoids and stilbenoids in grapevine leaves and leaf anatomy parameters that might have affected aphid probing were also analyzed. Based on the success rate in reaching the phloem vessels and feeding on phloem sap, the studied grapevine cultivars can be assigned to various groups of susceptibility. Cultivars Bianca and Muskalt Letni are susceptible to A. fabae and M. persicae, respectively (aphids reach phloem phase and show short bouts of sap ingestion); Muskat Letni shows low susceptibility to A. fabae, while Aurora and Bianca to M. persicae (only 50% aphids reach phloem phase and no sap ingestion occurs); Solaris is resistant to A. fabae and M. persicae (no phloem phase present). Anatomical structure of leaves was similar in all cultivars and no mechanical barriers for aphid probing were observed. However, the content of individual flavonoids and silbenoids differed among cultivars. We hypothesize that the high content of piceid in the leaves of Solaris may be responsible for the rejection of this cultivar by both aphid species. The study demonstrated that the risk of the direct damage due to A. fabae and M. persicae feeding on grapevines is low. However, considering the intense aphid probing activity within leaf epidermis and mesophyll, A. fabae and M. persicae may pose a serious threat as vectors of non-persistent and semi-persistent viruses to white-berried grapevines.

Automated summary

In this study, the susceptibility of different white-berried grapevine cultivars to black bean aphid and green peach aphid was evaluated using the EPG technique. The study also analyzed the chemical composition and leaf anatomy parameters of grapevine leaves. The results showed that different cultivars had varying degrees of susceptibility to aphids, which may be related to the chemical composition of the leaves. The study also revealed that while the direct damage caused by aphids to grapevines is low, they may pose a serious threat as vectors of viruses.