Evaluation of "Insect Spy” approach for monitoring Xylella fastidiosa in symptomless olive orchards in the Salento peninsula (Southern Italy)

Xylella fastidiosa (Xf) is a gram negative and xylem inhabiting bacterium that has been recently reported on olive trees associated with "olive quick decline syndrome" in Apulia region (south Italy). The spread of this bacterium at moment seems limited to the west coast of the Salento Peninsula (Lecce province) and has not yet been recorded in the rest of Italy and Europe. Due to the quick dissemination of Xylella fastidiosa, an effective approach is required for monitoring this bacterium in the symptomless areas surrounding the infection sites (buffer zone). Therefore, an evaluation of the possibility to utilize the Xf-positive insects (spy insect) as indicators of the presence of this vector-borne bacterium in apparently uncontaminated areas (e.g. in the buffer zones) was carried out. From May to June 2014, insects were collected from a restricted Xf-outbreak at Trepuzzi (in Lecce province), and from the area surrounding it (buffer zone). The study focused on species in the Auchenorrhyncha, a group that includes known vectors of Xylella fastidiosa. The bacterium was successfully detected by PCR in 3 out of 6 species of Auchenorrhyncha captured in the buffer zone, i.e. Phileanus spumarius, Neophileanus campestris and Euscelis lineolatus. Infected adults of these species were detected throughout the buffer zone up to a distance of 1 Km far from the infection site, thus confirming their important role as “spy insects” to early reveal the presence of the pathogen in apparently free areas before symptoms become visible on the plants

Seasonal distribution of Philaenus spumarius and Neophilaenus campestris in Apulian olives groves

A two years investigation was performed in Apulia region to study the population in olive groves of Philaenus spumarius and Neophilaenus campestris, the vector and the putative vector of Xylellafastidiosa, respectively. Adults of these two species were monthly collected from ground vegetation and olive canopy in four severely infected olive groves. This study showed that adults of both species were present from May to December. During this period abundance of P. spumarius was constantly increasing to reach its peak in September with no significant difference between ground and canopy levels. Conversely, the pick of population of N. campestris was noticed in May-June with a significant decrease until December due to the absence of grassland. However, the latter was greatly preferred by N. campestris with respect to the olive canopy. Our findings confirm that weed control in olive groves during Spring could reduce the population of both species. Interestingly, this study shows that treatments against adults of P. spumarius should be applied at canopy level during Summer months

Suppressive effect of cured compost from olive oil by-products towards Verticillium dahliae and other fungal pathogens

After oil extraction from olives, large amounts of by-products are generated every year. If subjected to advanced biotechnologies of composting they can be re-used in agriculture as eco-compatible amenders, fertilizers and/or natural pesticide. In this regard, olive oil by-products composted in a pilot scale olive plant were characterized and assayed for suppressive activity against fungal plant pathogens. Some cured composts consistently reduced the growth in vitro of Verticillium dahliae and other important fungal pathogens. The efficacy of composts decreased or disappeared when the composts were autoclaved before using. The inhibitory activity seems due to the beneficial residual microbial population selected during the composting process. In experiments performed on young olive plants grown on soil artificially contaminated by V. dahliae microsclerotia (MC), the incorporation of 15% (w/w) of a selected cured compost or the antagonistic fungus Trichoderma viridae as well as 15% (w/w) of cured compost and T. viridae applied together significantly reduced the density of V. dahliae MC in the soil. The results of this investigation indicate that composted olive by-products are very promising to control fungal pathogens of olive and other crops in organic and integrated agriculture systems. Monitoring of V. dahliae MC in the soil by a semi-selective media was compared to a molecular method based on Real-Time Scorpion PCR. The latter technique, which enables V. dahliae detection by a specific increase of fluorescence during amplification, drastically reduced the time required for the assessment of V. dahliae MC in the soil, as compared to the microbiological cultural techniques

Seasonal fluctuations of sap-feeding insect species infected by Xylella fastidiosa in Apulian olive groves of Southern Italy

A study on seasonal abundance of Auchenorrhyncha species and their infectivity by Xylella fastidiosa in the Apulia region of Italy was conducted to identify ideal periods for monitoring and adoption of potential control measures against insect vectors. Adult populations of Auchenorrhyncha species were monitored monthly over a 2-yr period from five olive groves. A total of 15 species were captured, identified, and tested for presence of X. fastidiosa by polymerase chain reaction (PCR). For three species, Philaenus spumarius L., Neophilaenus campestris (Falle` n), and Euscelis lineolatus Brulle´ , positive reactions to X. fastidiosa were obtained, on average, in 16.3, 15.9 and 18.4% of adult insects, respectively. Philaneous spumarius was the dominant species (39.8% of total Auchenorrhyncha captured) with the highest adult abundance in summer months. Adult P. spumarius and N. campestris were first detected between March and May in both years, and all insects tested during these periods (year 1: n=42, year 2: n=132) gave negative reactions to X. fastidiosa by PCR. Similarly, first adults of E. lineolatus that appeared from October to November (year 1: n=20, year 2: n=15) tested negative for presence of X. fastidiosa. Given the lack of transstadial and transovarial transmission of X. fastidiosa and considering that P. spumarius is univoltine, control measures against nymphal stages of P. spumarius should be investigated as means of population suppression to reduce spread of X. fastidiosa in olive groves

PESTOLIVE: a mediterranean research project for understanding and managing soil-borne parasites on olive using historical and ecological approaches

UMR AGAP - équipe AFEF - Architecture et fonctionnement des espèces fruitièresPESTOLIVE (Contribution of olive history for the management of soil-borne parasites inthe Mediterranean Basin) is a project funded by ARIMNet, an ERANET action supported bythe 7th European Framework Programme and by non-European Mediterranean countries.PESTOLIVE aims at producing knowledge and tools for a new and efficient management ofplant-parasitic nematodes (PPN) and plant-pathogenic fungi (PPF) in olive (Olea europaea L.)cropping systems and nurseries, while reducing the use of pesticides. Because of the anthropiccontinuum from Olea post-glacial refuges to Oleasters (domestication) and then to olive-trees(breeding and cropping), the fragmentation of the PPN and PPF communities and of theirnatural enemies could explain the scattered diversity of the control techniques (especiallyresistance rootstocks, biocontrol, cropping strategies) developed and applied all around theMediterranean Basin. The novelty of PESTOLIVE is based on: i) the analysis and themanagement of the parasite diversity (ecology of communities) instead of controllingemblematic species (population approach), and ii) the involvement of knowledge about thehistorical co-adaptation of soil-borne parasite and natural enemies communities to olive-treedomestication (origins and past assemblages) and breeding that follows the history of O.europaea around the Mediterranean Basin

PESTOLIVE: a mediterranean research project for understanding and managing soil-borne parasites on olive using historical and ecological approaches

UMR AGAP - équipe AFEF - Architecture et fonctionnement des espèces fruitièresPESTOLIVE (Contribution of olive history for the management of soil-borne parasites inthe Mediterranean Basin) is a project funded by ARIMNet, an ERANET action supported bythe 7th European Framework Programme and by non-European Mediterranean countries.PESTOLIVE aims at producing knowledge and tools for a new and efficient management ofplant-parasitic nematodes (PPN) and plant-pathogenic fungi (PPF) in olive (Olea europaea L.)cropping systems and nurseries, while reducing the use of pesticides. Because of the anthropiccontinuum from Olea post-glacial refuges to Oleasters (domestication) and then to olive-trees(breeding and cropping), the fragmentation of the PPN and PPF communities and of theirnatural enemies could explain the scattered diversity of the control techniques (especiallyresistance rootstocks, biocontrol, cropping strategies) developed and applied all around theMediterranean Basin. The novelty of PESTOLIVE is based on: i) the analysis and themanagement of the parasite diversity (ecology of communities) instead of controllingemblematic species (population approach), and ii) the involvement of knowledge about thehistorical co-adaptation of soil-borne parasite and natural enemies communities to olive-treedomestication (origins and past assemblages) and breeding that follows the history of O.europaea around the Mediterranean Basin