Mario Baldessari

Antispila oinophylla new species (Lepidoptera, Heliozelidae), a new North American grapevine leafminer invading Italian vineyards: taxonomy, DNA barcodes and life cycle

Abstract 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.

Effectiveness of five insecticides for the control of adults and young stages of Cacopsylla melanoneura (Förster) (Hemiptera: Psyllidae) in a semi-field trial

BACKGROUND Cacopsylla melanoneura (Förster) is a vector of Candidatus Phytoplasma mali, the causal agent of one of the most serious diseases in European apple orchards, apple proliferation (AP). The aim of this study was to evaluate the toxicity of five insecticides from different chemical groups (carbamates, chitin inhibitors, insect growth regulators, organophosphates and pyrethroids) towards overwintered adults and young stages of C. melanoneura under semi-field conditions. RESULTS The organophosphate chlorpyrifos and the pyrethroid etofenprox caused higher mortality of overwintered adults than diflubenzuron, fenoxycarb and abamectin, with mortality values exceeding 90%. All the pesticides tested reduced the number of progeny per female and, except for abamectin, were highly effective against young stages, with a long-lasting effect. CONCLUSION An integrated management of the vector is currently required to prevent the spread of AP. The reference insecticides, chlorpyrifos and etofenprox, have a strong toxicity and persistence against all stages of the vector. In apple orchard IPM programmes, the chitin inhibitors and the insect growth regulators could be part of an alternative and more sustainable strategy for the control of C. melanoneura owing to their effectiveness against immature stages.

Population Dynamics of Cacopsylla melanoneura (Hemiptera: Psyllidae) in Northeast Italy and Its Role in the Apple Proliferation Epidemiology in Apple Orchards

ABSTRACT In the current study, incidence of ‘Candidatus Phytoplasma mali’ in an experimental apple orchard in northeast Italy, in addition to abundance and phytoplasma infectivity of Cacopsylla melanoneura (Förster) (Hemiptera: Psyllidae) was determined and the role of this psyllid as a vector of ‘Ca. P. mali’ in this region was reviewed. Insect samples collected in the orchard by the beating method indicated high abundance of C. melanoneura (up to 7.92 specimens/branch); however, the psyllid C. picta was not observed. Molecular analyses revealed presence of ‘Ca. P. mali’ in 6.25% of overwintered psyllids. This infection rate is quite high in comparison to other localities where C. melanoneura is known as the main vector of the phytoplasma. This finding supports the assumption that C. melanoneura also is paramount in the epidemiology of the apple proliferation disease also in northeast Italy. Moreover, we correlated immigration dynamics to the temperatures registered in the apple orchard, and defined an immigration index to predict the progressive arrival of the overwintered adults from winter sites. Psyllids start to reach the apple orchards when either the average of the maximum temperature of the 7 d is above 9.5°C or the immigration index has a positive value. This index will be a useful tool for the growers to prevent apple proliferation phytoplasma spread with well-timed insecticide treatments targeted against C. melanoneura. However, further research is needed to validate or adjust the index to other apple growing regions, which may affect more efficacious management of this disease and psyllid vector.