Search Results (3)

A partial mitochondrial DNA Cytochrome Oxidase subunit I (mtCOI) gene haplotype variant of the coconut rhinoceros beetle (CRB) Oryctes rhinoceros, classed as ‘CRB-G (clade I)’, has been the focus of much research since 2007, with reports of invasions into new Pacific Island locations (e.g., Guam, Hawaii, Solomons Islands). For numerous invasive species, inference of invasion biology via whole genome is superior to assessments via the partial mtCOI gene. Here, we explore CRB draft mitochondrial genomes (mitogenomes) from historical and recent collections, with assessment focused on individuals associated within the CRB-G (clade I) classification. We found that all Guam CRB individuals possessed the same mitogenome across all 13 protein-coding genes and differed from individuals collected elsewhere, including ‘non-Guam’ individuals designated as CRB-G (clade I) by partial mtCOI assessment. Two alternative ATP6 and COIII partial gene primer sets were developed to enable distinction between CRB individuals from Guam that classed within the CRB-G (clade I) haplotype grouping and CRB-G (Clade I) individuals collected elsewhere. Phylogenetic analyses based on concatenated ATP6–COIII genes showed that only Guam CRB-G (clade I) individuals clustered together, and therefore Guam was not the source of the CRB that invaded the other locations in the Pacific assessed in this study. The use of the mtCOI and/or mtCOIII genes for initial molecular diagnosis of CRB remained crucial, and assessment of more native CRB populations will further advance our ability to identify the provenance of CRB invasions being reported within the Pacific and elsewhere. Full article

Exotic ants and termites, including Solenopsis invicta, are frequent hitchhikers intercepted from miscellaneous nonfood commodities. In particular, S. invicta has been intercepted in Korea in imported nursery plants, stone, and lumber products, which increases the potential for establishment of this destructive invasive pest in Korea. In this study, we conducted commercial-scale fumigation trials to evaluate ethyl formate (EF) as a potential alternative of methyl bromide using two species of imported rubber plants and pieces of marble as representative good and workers of Reticulitermes speratus as an EF-resistant surrogate for S. invicta. An EF treatment at 35 g/m³ for 4 h at >15 °C, the dose required for LCt_99% (lethal concentration × time product required for 99% mortality of R. speratus), resulted in the complete control of R. speratus workers tested with rubber plants (Ficus benghalensis and F. retusa) and marble, 9% (w/v) and 60% (v/v) loading ratios, respectively. EF treatment did not adversely affect the leaf chlorophyll content, leaf color, and overall health of rubber plants or the visual appearance of the marble. Our results suggest that EF fumigation is a potential alternative to methyl bromide for the disinfestation of hitchhiking invasive termites and ants, including S. invicta, on imported rubber plants and stone products. Full article

Agrilus planipennis is a devastating invasive pest of ash trees in European Russia, Ukraine, and North America. To monitor the north-western limit of its European invasive range, in June 2018 we established 10 study plots along the federal highway M10 (Russia) that runs between Moscow and Saint Petersburg through Tver’ City (approx. 180 km from Moscow), and lined with ash trees. On each plot, 2–4 Fraxinus pennsylvanica trees with heights ranging 6.1–17.0 m and diameters ranging 7.0–18.0 cm were girdled, i.e., 50 cm of their bark were removed. The study plots were visited and girdled trees were examined in September and November, 2018, and in October, 2019. Observations revealed that the current continuous north-western limit of A. planipennis range in European Russia coincides with the north-western border of Tver’ City and this range limit has not distinctly shifted north-westward during 2015–2019. In spite of the rich food supply (due to abundant F. pennsylvanica and F. excelsior plantings) in Tver’ City and along roads going to and from, the population density of A. planipennis in the area is currently low. Recent (September 2020) sudden detection of a spatially isolated A. planipennis outbreak approx. 520 km far north-westward from Tver’ (in Saint Petersburg) suggested that A. planipennis most likely had arrived at Saint Petersburg not by gradual stepwise (flying tree-to-tree) expansion of its continuous invasive range in Tver’ City, but as a result of its accidental introduction by means of, e.g., “insect-hitchhiked” vehicles, transported plants for planting, and/or other commodities. The proximity of the reported A.planipennis outbreak to the borders of the EU (approx. 130 km to Estonia and Finland) requires urgent measures for its containment and control, and constant monitoring. Full article