Aromia bungii (Faldermann, 1835) (Coleoptera: Cerambycidae), the red-necked longhorn beetle is native to eastern Asia, where it is an important wood-borer of fruit and ornamental species of the genus Prunus. A. bungii is a quarantine pest in the European Union, following its accidental introduction and establishment in Germany and Italy, and is currently included in the list of priority pests. To confirm its infestations in outbreak areas, adult or larval specimens are needed to perform morphological or molecular analyses. The presence of A. bungii larvae inside the attacked trees makes the collection of specimens particularly difficult. Thus, we present two diagnostic protocols based on frass analysis with real-time PCR (probe and SYBR Green). The results obtained show that a non-invasive approach for detecting the presence of this harmful invasive pest can be a reliable and accurate alternative diagnostic tool in phytosanitary surveys, as well as to outline a sustainable pest management strategy.
Bactrocera dorsalis is considered among the most destructive and economically important invasive fruit flies worldwide. Native to Southeast Asia, in just a few years, it has spread almost throughou...
25 July 2021 in Journal of Plant Diseases and Protection
Anoplophora glabripennis (Motschulsky 1853) (Coleoptera: Cerambycidae), the Asian Longhorned Beetle, is native to temperate and subtropical areas of China and the Korean peninsula. Due to its wide range of host plants, it is considered among the most economically important invasive plant pests. The morphological identification of A. glabripennis larvae can be confirmed by DNA barcoding, but obtaining the specimens from infested trees can be a demanding and challenging task. Therefore, non-invasive diagnostic tools based on DNA extracted from frass samples can be of key importance in phytosanitary surveys. In this study, an in silico generated real-time quantitative PCR test was developed for the detection of A. glabripennis DNA from frass material, which is naturally extruded from larval tunnels through cracks in the bark. Specificity was confirmed against a wide range of other wood-boring insect species frequently encountered during phytosanitary surveys and inclusivity was demonstrated for different populations of A. glabripennis from all main European outbreak areas. The test proved sensitive and reliable in detecting A. glabripennis DNA extracted from woody frass material of Acer saccharinum and Aesculus hippocastanum at least up to the 100-fold dilution. Furthermore, the test allowed the molecular identification of any life stage of the insect, including eggs and young larvae, whose morphological identification is impossible or very challenging. This study provides a reliable and sensitive molecular tool to detect A. glabripennis DNA in woody frass material, thus allowing a non-invasive sampling approach.
The potential for population genomics to elucidate invasion pathways of a species is limited by taxonomic identification issues. The Oriental fruit fly pest, Bactrocera dorsalis (Hendel) belongs to a complex in which several sympatric species are attracted to the same lure used in trapping and are morphologically cryptic and/or reported to hybridize. In this study, we evaluated the taxonomic ambiguity between B. dorsalis and 2 major cryptic species, based on morphological expertise and 289 target specimens sampled across the whole distribution range. Specimens were then subjected to DNA sequence analyses of the COI mitochondrial barcode and the EIF3L nuclear marker to evaluate the potential for molecular identification, in particular for specimens for which morphological identification was inconclusive. To this aim, we produced reference datasets with DNA sequences from target specimens whose morphological identification was unambiguous, which we complemented with 56 new DNA sequences from closest relatives and 76 published and curated DNA sequences of different species in the complex. After the necessary morphological observation, about 3.5% of the target dataset and 47.6% of the specimens from Southeast Asian islands displayed ambiguous character states shared with B. carambolae and/or B. occipitalis. Critical interpretation of DNA sequence data solved morphological ambiguities only when combining both mitochondrial and nuclear markers. COI discriminated B. dorsalis from 5 species; EIF3L and ITS from another species. We recommend this procedure to ensure correct identification of B. dorsalis specimens in population genetics studies and surveillance programs.
A molecular and morphological analysis of the species of Aclees native to Taiwan allowed for recognition of a new species, that is described here as Aclees aenigmaticus Meregalli & Boriani, sp. n. The study also revealed that the species of Aclees that has been introduced into Italy and France has identical morphology and mitochondrial cox-1 gene sequence with specimens of A. taiwanensis from Taiwan. Taiwan is thus assumed to be the country of origin of the specimens introduced into Europe. A key to the species of Aclees present in Taiwan is provided. A lectotype is designated for Aclees foveatus Voss, 1932, and some remarks on A. hirayamai Kôno, 1932 are given. Pagiophloeus visayus Heller, 1929 from the Philippines is transferred to the genus Aclees, comb. n.
Red-banded thrips Selenothrips rubrocinctus is a polyphagous pest widely distributed in tropical and subtropical regions. Various fruit trees such as cacao, cashew, mango, avocado, and guava in certain habitats are attacked. This is the first report of the spontaneous occurrence of outdoor populations of this species of thrips in Europe. This species has been found in northern Italy on Liquidambar styraciflua, Carpinus betulus, and other ornamental forest species in urban areas. Barcode sequences of the Italian specimens were obtained.