Biology subjects

Fereres, A.

Publications and source records attributed to Fereres, A..

4 recordsLinked to original sources

bioRxiv2022

Degree-day-based model to predict egg hatching of Philaenus spumarius (Hemiptera: Aphrophoridae), the main vector of Xylella fastidiosa in Europe

Philaenus spumarius L., the main vector of Xylella fastidiosa (Wells) in Europe, is a univoltine species that overwinters in the egg stage, and its nymphs emerge in late winter or spring. Predicting the time of egg hatching is essential for determining the precise times for deploying control strategies against insect pests. Here, we monitored P. spumarius eggs from oviposition to egg hatching together with the daily temperatures and relative humidities at four field locations that were located at different altitudes in central Spain. The collected data were used to build a growing degree day (GDD) model to forecast egg hatching in the Iberian Peninsula. Furthermore, the model was validated with field observations that were conducted in Spain. The model was then used as a decision-support tool to calculate the optimum timing for applying control actions against P. spumarius. Our results suggest that controlling nymphs at two different dates would target the highest percentages of nymphal populations present in the field. Our model represents a first step for predicting the emergence of nymphs and adopting timely control actions against P. spumarius. These actions could limit disease spread in areas where X. fastidiosa is present.

animal behavior and cognition↗

bioRxiv2022

Global predictions for the risk of establishment of Pierce's disease of grapevines

The vector-borne bacterium Xylella fastidiosa is responsible for Pierces disease (PD), a lethal grapevine illness that originated in the Americas. The international plant trade is expanding the geographic range of this pathogen, posing a new threat to viticulture worldwide. To assess the potential incidence of PD, we have built a dynamic epidemiological model based on the response of 36-grapevine varieties to the pathogen in inoculation assays and on the vectors distribution when this information is available. Key temperature-driven epidemiological processes, such as PD symptom development and recovery, are mechanistically modelled. Integrating into the model highresolution spatiotemporal climatic data from 1981 onward and different infectivity (R0) scenarios, we show how the main wine-producing areas thrive mostly in non-risk, transient, or epidemic-risk zones with potentially low growth rates in PD incidence. Epidemic-risk zones with moderate to high growth rates are currently marginal outside the United States. However, a global expansion of epidemic-risk zones coupled with small increments in the disease growth rate is projected for 2050. Our study globally downscales the risk of PD establishment while highlighting the importance of considering climate variability, vector distribution and an invasive criterion in obtaining accurate risk maps to guide policy decision-making in plant health.

plant biology↗

bioRxiv2021

Scaphoideus titanus Ball feeding behaviour on three grapevine cultivars with different susceptibilities to Flavescence doree

Scaphoideus titanus (Ball) is a grapevine-feeder leafhopper, and the most important vector of Flavescence doree of grapevine (FD), a disease associated with phytoplasmas belonging to ribosomal subgroups 16Sr-V-C and -D. FD is a major constraint to viticulture in several European countries and, so far, its control has relied on roguing of infected plants and insecticide applications against the vector. Detailed knowledge on different levels of the multifaceted phytoplasma-plant-vector relationship is required to envisage and explore more sustainable ways to control the disease spread. In the present work, S. titanus feeding behaviour was described on three grapevine cultivars: Barbera (susceptible to FD), Brachetto, and Moscato (tolerant to FD) using the Electrical Penetration Graph (EPG) technique. Interestingly, no differences were highlighted in the non-phloem feeding phases, thus suggesting that the tested cultivars have no major differences in the biochemical composition or structure of the leaf cuticle, epidermis or mesophyll, that can affect the first feeding activities. On the contrary, the results showed significant differences in leafhopper feeding behaviour in terms of the duration of the phloem feeding phase, longer on Barbera and shorter on Brachetto and Moscato, and of the frequency of interruption-salivation events inside the phloem, higher on Brachetto and Moscato. These findings indicate a possible preference for the Barbera cultivar, a better host for the leafhopper. Scaphoideus titanus feeding behaviour on Barbera correlates with an enhanced FDp transmission efficiency, thus explaining, at least in part, the higher susceptibility of this cultivar to FD. The mechanisms for the possible non-preference for Brachetto and Moscato are discussed, and an antixenosis is hypothesized. We propose that breeding for resistance against FD should take into account both plant traits associated with the response to the phytoplasmas and to the vector.

animal behavior and cognition↗

bioRxiv2020

The risk of Xylella fastidiosa outbreaks will decrease in the Mediterranean olive-producing regions

The bacterium Xylella fastidiosa (Xf) is a worldwide distributed invasive insect-borne plant pathogen, which causes lethal diseases to many economically-important crops including olives, citrus, almonds and grapes as well as numerous forest, ornamental, and uncultivated plants. The Mediterranean basin is the top supplier of olive oil with 93% of the world production and is consequently highly concerned about the recent invasion of Xf in Europe. Recently, bioeconomic models estimated putative losses induced by the spread of Xf across the European olive-producing area ranging from 1.9 to 5.2 billion euros over 50 years; however, such models did not take into account the insect vectors, which constitute a key driver of Xf spread. In the present study, we used bioclimatic species distribution models to predict the current and future climate suitability of the Mediterranean area for the main efficient or putative transmitters of Xf to olive (i.e. Philaenus spumarius, Neophilaenus campestris and Aphrophora alni). An important part of the total extent of the Mediterranean olive-producing area, mainly situated in southern Spain, Turkey and Greece, is predicted as currently poorly suitable for these vector species. Moreover, models forecast that nearly the totality of the Mediterranean olive-producing regions will likely become climatically little suitable for these vectors by 2050 due to climate change. In Europe, Xf outbreaks have occurred so far only in localities predicted as climatically suitable for these main vector species (e.g. the Apulia region of Italy) while the areas predicted as poorly suitable are still apparently Xf-free, which suggests that climate tolerances of vectors might play a main role in shaping Xf outbreaks patterns. This pattern highlights the crucial necessity of accounting for vectors when assessing risk of Xf outbreaks, and when considering vector-borne diseases in general. The risk maps presented here will have important practical application for the optimization of current and future strategies to control Xf in the Mediterranean region.

ecology↗