Scaphoideus titanus fitness on grapevine varieties with different susceptibility to Flavescence dorée phytoplasma

Abstract

Scaphoideus titanus (Ball) is a Nearctic leafhopper (Cicadellidae: Deltocephalinae), monophagous on Vitis spp., naturalized in European vineyards since the 20th century. Following its introduction and establishment in Europe, S. titanus became the main vector of Flavescence dorée phytoplasma (FDp) to grapevine. FDp causes heavy economic losses to viticulture in Europe. The control of the disease mainly relies on insecticide applications against the vector and on the removal of infected plants. The exploitation of plant resistance or tolerance against pathogens and pests can represent a valuable tool for a more sustainable viticulture. The first step in identifying resistance traits in grapevine varieties towards S. titanus is the evaluation of insect fitness parameters on different grapevine genotypes. Therefore, in this work, nymph mortality and developmental time, adult survival and prolificacy of S. titanus have been studied on three grapevine varieties, characterized by different susceptibility to FD. Scaphoideus titanus showed highest fitness when reared on Barbera, whereas the worst performances were recorded on Moscato, with a significant reduction in nymph and adult survivals, a slowed nymph development, and a decreased number of available eggs. On Brachetto, S. titanus showed an intermediate level of fitness parameters. Consistently with previous studies on feeding behaviour, Barbera is the most suitable host for the FD‐vector. The high suitability of Barbera for S. titanus may partly explain the high susceptibility to FD of this variety. On the contrary, the low suitability of Moscato, poorly susceptible to FD, may be due to antibiosis and antixenosis defence mechanisms that act against S. titanus.

Longevity of the whitefly parasitoid Eretmocerus eremicus under two different climate scenarios

“…All statistical analyses were conducted using R software v 4.1.2 employing methodology as described by Ripamonti et al (2022) with slight modifications. Individuals that died in the first 24 h of the experiment were excluded from analysis as this mortality is likely a result of their manipulation.…”

‘Candidatus Phytoplasma ziziphi’ Changes the Metabolite Composition of Jujube Tree Leaves and Affects the Feeding Behavior of Its Insect Vector Hishimonus hamatus Kuoh

“…In the table of original recording data, each row corresponded to a single recording (a unique combination of one leafhopper and one sex), while each column represented an EPG variable. Univariate analyses were conducted starting from the Generalized Linear Model (GLM): quasi-Poisson for counts and Gamma or inverse-Gaussian for positive continuous variables [ 33 , 34 ]. Pairwise comparison (post hoc) between effects due to JWB infection status and sex was calculated with estimated marginal means and 95% confidence intervals with the function emmeans from the “ emmeans ” package and p -value adjustment using the method of Tukey [ 35 ].…”

“…Understanding the probing and feeding behavior of H. hamatus on both JWB-infected and non-infected jujube plants is crucial for unraveling the epidemiology of JWB. The use of electrical penetration graphs (EPGs) provided real-time insights into hemipteran feeding behaviors [ 32 , 33 , 34 , 35 ]. Therefore, in this study, 8 h recording and analysis of H. hamatus probing and feeding behavior on ‘ Ca.…”