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Orientus ishidae (Matsumura) (subfamily Deltocephalinae) is an Asian species now widespread in Europe, and a vector of 16SrV phytoplasmas agents of grapevine Flavescence dorée (FDP). Embryonic and post-embryonic development, spatial distribution, and relationships with grapevine of nymphs were studied under field and laboratory conditions. Egg-hatching dynamics and post-embryonic development of nymphs were studied by collecting grapevine wood from managed and unmanaged vineyards (including bot European Vitis vinifera L. and wild American rootstocks) and storing it inside rearing cages at T = 21–23°C. Field sampling of nymphs were made on both grapevine and two elective host plants of O. ishidae: hazelnut and hornbeam. Taylor's Power Law was applied to assess the aggregation coefficient of early- (first and second) and late- (third to fifth) life instars on leaves and shoots of host plants. More nymphs were obtained from wood collected in unmanaged rather than managed vineyards. Under lab conditions, the embryonic development lasted 34–48 d, whereas the whole post-embryonic development averaged 27 d. Under field conditions, early instars peaked at the end of May, and late instars peaked 2–4 wk later. The aggregation patterns decreased from early to late instars, and from leaves to shoots. Very few nymphs were observed on unmanaged grapevine, either European or American, and none on managed European grapevine. Some behavioral and FDP epidemiological consequences of the results obtained are discussed. [ABSTRACT FROM AUTHOR]

Flavescence dorée (FD) is one of the most devastating diseases threatening grapevine cultivation in Europe. The causal agents are phytoplasmas, which reside in phloem vessels of infected plants and in the body of leafhopper vectors, the most important being Scaphoideus titanus. Current control mainly relies on vector management, which is often insufficient to prevent from disease outbreaks. Suitable methods to interfere with phytoplasmas in planta are constantly sought to support insecticide sprays. We tested a biocomplex containing trace elements and soluble sugars, with potential systemic spread and antimicrobial activity, with the aim to verify its capability to penetrate plant phloem and to interfere with phytoplasma survival in vector-inoculated plants, using two FD isolates (FD-C and FD-D). The penetration into the plant phloem, as well as its acquisition by phloem-feeding vectors, were tested using an iridium-marked biocomplex. Phytoplasma infection was detected by real Time PCR and compared in plants exposed to biocomplex treatment before inoculation (short-time and mid-time preventive application), and to treatment after inoculation (curative application). We also assessed if the biocomplex interferes with the vector competence of S. titanus, by conducting phytoplasma transmission trials with sequential inoculation steps, where untreated and biocomplex-treated grapevine plantlets were sequentially offered to infectious leafhoppers. Foliar treatment with the biocomplex supported the penetration of phloem tissues, and the product was successfully acquired by the experimental phytoplasma vector Euscelidius variegatus after feeding on the phloem of treated plants. When the biocomplex was applied on grapevines, it induced a significant reduction of phytoplasma infection regardless of FD isolate, both as a preventive and curative treatment, indicating an antibacterial activity in the plant. Moreover, sequential inoculation experiments showed a decrease of S. titanus inoculation rates after vector exposure to a biocomplex-treated plant, suggesting a reduction of transmission efficiency that was higher using the FD-C rather than FD-D isolate. Our results indicate the tested biocomplex as a promising tool for the creation of anti-phytoplasma formulations to support vector management in FD containment. • An experimental biocomplex was tested against grapevine Flavescence dorée phytoplasma. • The biocomplex effectively penetrated phloem vessels after foliar spray. • Leafhopper vectors acquired the biocomplex through phloem feeding. • Lower phytoplasma infection was found in vines after preventive and curative treatment. • Insect inoculation efficiency was reduced after exposure to sprayed plants. [ABSTRACT FROM AUTHOR]

The South American tomato leafminer, Tuta absoluta Meyrick (Lepidoptera: Gelechiidae), is an invasive Neotropical pest. After its first detection in Europe, it rapidly invaded more than 30 Western Palaearctic countries becoming a serious agricultural threat to tomato production in both protected and open-field crops. Among the pest control tactics against exotic pests, biological control using indigenous natural enemies is one of the most promising. Here, available data on the Afro-Eurasian natural enemies of T. absoluta are compiled. Then, their potential for inclusion in sustainable pest control packages is discussed providing relevant examples. Collections were conducted in 12 countries, both in open-field and protected susceptible crops, as well as in wild flora and/or using infested sentinel plants. More than 70 arthropod species, 20 % predators and 80 % parasitoids, were recorded attacking the new pest so far. Among the recovered indigenous natural enemies, only few parasitoid species, namely, some eulophid and braconid wasps, and especially mirid predators, have promising potential to be included in effective and environmentally friendly management strategies for the pest in the newly invaded areas. Finally, a brief outlook of the future research and applications of indigenous T. absoluta biological control agents are provided. [ABSTRACT FROM AUTHOR]

The article presents a study on the isolation and identification of leaf saponins against Cameraria ohridella, which causes damage to the white-flowering horse chestnut in Europe. Based on spectroscopic analyses, Aesculus pavia HBT genotype leaves shows a repellent effect on C. ohridella moth and that no mines were observed. In conclusion, exogenous saponins and their translocation and accumulation from the roots to the leaf tissues ensure a degree of protection against the leafminer.

Castanea sativa is an important multipurpose species in Europe for nut and timber production as well as for its role in the landscape and in the forest ecosystem. This species has low tolerance to chestnut gall wasp (Dryocosmus kuriphilus Yasumatsu), which is a pest that was accidentally introduced into Europe in early 2000 and devastated forest and orchard trees. Resistance to the gall wasp was found in the hybrid cultivar 'Bouche de Bétizac' (C. sativa × C. crenata) and studied by developing genetic linkage maps using a population derived from a cross between 'Bouche de Bétizac' and the susceptible cultivar 'Madonna' (C. sativa). The high-density genetic maps were constructed using double-digest restriction site-associated DNA-seq and simple sequence repeat markers. The map of 'Bouche de Bétizac' consisted of 1459 loci and spanned 809.6 cM; the map of 'Madonna' consisted of 1089 loci and spanned 753.3 cM. In both maps, 12 linkage groups were identified. A single major QTL was recognized on the 'Bouche de Bétizac' map, explaining up to 67–69% of the phenotypic variance of the resistance trait (Rdk1). The Rdk1 quantitative trait loci (QTL) region included 11 scaffolds and two candidate genes putatively involved in the resistance response were identified. This study will contribute to C. sativa breeding programs and to the study of Rdk1 genes. [ABSTRACT FROM AUTHOR]

One emerging disease of grapevine in Europe is Bois noir (BN), a phytoplasmosis caused by "Candidatus Phytoplasma solani" and spread in vineyards by the planthopper Hyalesthes obsoletus (Hemiptera: Cixiidae). Here we present the first full characterization of the bacterial community of this important disease vector collected from BN-contaminated areas in Piedmont, Italy. Length heterogeneity PCR and denaturing gradient gel electrophoresis analysis targeting the 16S rRNA gene revealed the presence of a number of bacteria stably associated with the insect vector. In particular, symbiotic bacteria detected by PCR with high infection rates in adult individuals fell within the "Candidatus Sulcia muelleri" cluster in the Bacteroidetes and in the "Candidatus Purcelliella pentastirinorum" group in the Gammaproteobacteria, both previously identified in different leafhoppers and planthoppers. A high infection rate (81%) was also shown for another symbiont belonging to the Betaproteobacteria, designated the HO1-V symbiont. Because of the low level of 16S rRNA gene identity (80%) with the closest relative, an uncharacterized symbiont of the tick Haemaphysalis longicornis, we propose the new name "Candidatus Vidania fulgoroideae." Other bacterial endosymbionts identified in H. obsoletus were related to the intracellular bacteria Wolbachia pipientis, Rickettsia sp., and "Candidatus Cardinium hertigii." Fluorescent in situ hybridization coupled with confocal laser scanning microscopy and transmission electron microscopy showed that these bacteria are localized in the gut, testicles, and oocytes. As "Ca. Sulcia" is usually reported in association with other symbiotic bacteria, we propose that in H. obsoletus, it may occur in a bipartite or even tripartite relationship between "Ca. Sulcia" and "Ca. Purcelliella," "Ca. Vidania," or both. [ABSTRACT FROM AUTHOR]