The death of honey bees, Apis mellifera L., and the consequent colony collapse disorder causes major losses in agriculture and plant pollination worldwide. The phenomenon showed increasing rates in the past years, although its causes are still awaiting a clear answer. Although neonicotinoid systemic insecticides used for seed coating of agricultural crops were suspected as possible reason, studies so far have not shown the existence of unquestionable sources capable of delivering directly intoxicating doses in the fields. Guttation is a natural plant phenomenon causing the excretion of xylem fluid at leaf margins. Here, we show that leaf guttation drops of all the corn plants germinated from neonicotinoid-coated seeds contained amounts of insecticide constantly higher than 10 mg/l, with maxima up to 100 mg/l for thiamethoxam and clothianidin, and up to 200 mg/l for imidacloprid. The concentration of neonicotinoids in guttation drops can be near those of active ingredients commonly applied in field sprays for pest control, or even higher. When bees consume guttation drops, collected from plants grown from neonicotinoid-coated seeds, they encounter death within few minutes.

The taxonomic identity of the hereditary prokaryotic symbiont of the olive fly Bactrocera oleae (Diptera: Tephritidae) was investigated. In order to avoid superficial microbial contaminants and loosely associated saprophytic biota, flies were surface-sterilized at the larval stage and reared under aseptic conditions until adult emergence. B. oleae flies originating from different geographical locations and collected at different times of the year were tested. Bacterial isolation was undertaken from the cephalic oesophageal bulb, which is known to be a specific site of accumulation for the hosted microsymbionts in the adult insect. Despite evidence of multiplication cycles taking place within the insect, attempts at cultivation of the isolated bacteria ex situ were not productive at any stage, leading to the choice of unculturable status definition. PCR amplification and nucleotide sequencing of the entire 16S rRNA gene consistently yielded a single sequence that displayed marked similarity with enterobacterial lineages, with closest matches (97 %) to Erwinia persicina and Erwinia rhapontici. The novel taxon differs from common intestinal bacterial species of fruit flies and from instances of culturable bacteria previously described in B. oleae raised without sterility precautions, which we also observed as minority occupants or occasional contaminants. The symbiont's identity is also distinct from Pseudomonas savastanoi. In all observations, the numerically dominant inhabitant of the olive fly oesophageal organ was the same unculturable organism, whose presence at later stages was also regularly observed in the midgut. A novel species is proposed, by virtue of its unique properties, under the designation ‘Candidatus Erwinia dacicola’.

BackgroundIn the Veneto region (north-eastern Italy) an entomological surveillance system has been implemented since the introduction of the Asian tiger mosquito (Aedes albopictus) in 1991. During the routine monitoring activity in a tiger mosquito-free area, an unexpected mosquito was noticed, which clearly did not belong to the recorded Italian fauna.FindingsAt the end of May 2011, twelve larvae and pupae were collected in a small village in Belluno province (Veneto region) from a single manhole. Ten adults reared in the laboratory were morphologically and genetically identified as Aedes (Finlaya) koreicus (Edwards, 1917), a species native to Southeast Asia. The subsequent investigations carried out in the following months in the same village provided evidence that this species had become established locally. Entomological and epidemiological investigations are currently ongoing in the surrounding area, to verify the eventual extension of the species outside the village and to trace back the route of entry into Italy.ConclusionsThis is the first report in Italy of the introduction of the exotic mosquito Ae. koreicus. This species has been shown experimentally to be competent in the transmission of the Japanese encephalitis virus and of the dog heartworm Dirofilaria immitis and is considered a potential vector of other arboviruses. Thus, the establishment of this species may increase the current risk or pose new potential threats, for human and animal health. This finding considerably complicates the entomological monitoring of the Asian tiger mosquito Ae. albopictus in Italy and stresses the importance of implementing the entomological surveillance for the early detection of and the rapid response against invasive mosquito species.

Losses of honeybees have been reported in Italy concurrent with the sowing of corn coated with neonicotinoids using a pneumatic drilling machine. Being unconvinced that solid particles containing systemic insecticide, falling on the vegetation surrounding the sown area, could poison bees foraging on contaminated nectar and pollen, the effect of direct aerial powdering was tested on foragers in free flight near the drilling machine. Bees were conditioned to visit a dispenser of sugar solution whilst a drilling machine was sowing corn along the flight path. Samples of bees were captured on the dispenser, caged and held in the laboratory. Chemical analysis showed some hundred nanograms of insecticide per bee. Nevertheless, caged bees, previously contaminated in flight, died only if kept in conditions of high humidity. After the sowing, an increase in bee mortality in front of the hives was also observed. Spring bee losses, which corresponded with the sowing of corn-coated seed, seemed to be related to the casual encountering of drilling machine during foraging flight across the ploughed fields

A grapevine leafminer Antispila oinophylla van Nieukerken & Wagner, sp. n., is described both from eastern North America (type locality: Georgia) and as a new important invader in North Italian vineyards (Trentino and Veneto Region) since 2006. The species is closely related to, and previously confused with Antispila ampelopsifoliella Chambers, 1874, a species feeding on Virginia creeper Parthenocissus quinquefolia (L.) Planchon., and both are placed in an informal Antispila ampelopsifoliella group. Wing pattern, genitalia, and DNA barcode data all confirm the conspecificity of native North American populations and Italian populations. COI barcodes differ by only 0–1.23%, indicating that the Italian populations are recently established from eastern North America. The new species feeds on various wild Vitis species in North America, on cultivated Vitis vinifera L. in Italy, and also on Parthenocissus quinquefolia in Italy. North American Antispila feeding on Parthenocissus include at least two other species, one of which is Antispila ampelopsifoliella. Morphology and biology of the new species are contrasted with those of North American Antispila Hübner, 1825 species and European Holocacista rivillei (Stainton, 1855). The source population of the introduction is unknown, but cases with larvae or pupae, attached to imported plants, are a likely possibility. DNA barcodes of the three European grapevine leafminers and those of all examined Heliozelidae are highly diagnostic. North American Vitaceae-feeding Antispila form two species complexes and include several as yet unnamed taxa. The identity of three out of the four previously described North American Vitaceae-feeding species cannot be unequivocally determined without further revision, but these are held to be different from Antispila oinophylla. In Italy the biology of Antispila oinophylla was studied in a vineyard in the Trento Province (Trentino-Alto Adige Region) in 2008 and 2009. Mature larvae overwinter inside their cases, fixed to vine trunks or training stakes. The first generation flies in June. An additional generation occurs from mid-August onwards. The impact of the pest in this vineyard was significant with more than 90% of leaves infested in mid-summer. Since the initial discovery in 2006, the pest spread to several additional Italian provinces, in 2010 the incidence of infestation was locally high in commercial vineyards. Preliminary phylogenetic analyses suggest that Antispila is paraphyletic, and that the Antispila ampelopsifoliella group is related to Coptodisca Walsingham, 1895, Holocacista Walsingham & Durrant, 1909 and Antispilina Hering, 1941, all of which possess reduced wing venation. Vitaceae may be the ancestral hostplant family for modern Heliozelidae.