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Hemlock woolly adelgid (HWA), Adelges tsugaeAnnand, is a major forest pest in the eastern United States responsible for killing millions of eastern hemlock, Tsuga canadensis(L.) Carrière and Carolina hemlock, T. carolinianaEngelmann. The US biological control program for HWA has largely invested in the rearing and release of Laricobius nigrinusFender and more recently L. osakensisMontgomery and Shiyake. Though the establishment of L. nigrinushas been well-documented in the southern, mid-Atlantic, and coastal portions of the northeastern United States, documentation in interior areas of the northeastern United States is limited. Establishment of L. osakensisin the northeastern United States has not yet been documented. Release locations in the northeastern United States were surveyed for L. nigrinusand L. osakensisestablishment to examine the relationship between establishment success and winter temperatures, as winter minimum temperatures likely limit the northern range of introduced Laricobiusspecies. Our results suggest that L. nigrinusestablishment is limited by winter minimum temperatures and that the probability of establishment declines as absolute minimum temperature declines. We found L. nigrinusestablished at sites in Maine, New York, and Pennsylvania, but did not recover any L. nigrinusin Massachusetts, New Hampshire, or Vermont. Similarly, we found L. osakensisestablished at sites in New York and Pennsylvania and recovered individuals in Maine, though further sampling is necessary to confirm presence of the F3generation. We also report the first field observation of reproduction of silver flies, Leucotaraxis argenticollis(Diptera: Chamaemyiidae), released predator of HWA, in the eastern United States.

The European winter moth, Operophtera brumataL. (Lepidoptera: Geometridae), was accidentally introduced to North America on at least 4 separate occasions, where it has been hybridizing with the native Bruce spanworm, O. bruceataHulst, at rates up to 10% per year. Both species are known to respond to the same sex pheromones and to produce viable offspring, but whether they differ in the seasonal timing of their mating flights is unknown. Therefore, we collected adult male moths weekly along 2 transects in the northeastern United States and genotyped individuals using polymorphic microsatellite markers as males of these 2 species cannot be differentiated morphologically. Along each transect, we then estimated the cumulative proportions (i.e., the number of individuals out of the total collected) of each species on each calendar day. Our results indicate that there are significant differences between the species regarding their seasonal timing of flight, and these allochronic differences likely are acting to promote reproductive isolation between these 2 species. Lastly, our results suggest that the later flight observed by winter moth compared to Bruce spanworm may be limiting its inland spread in the northeastern United States because of increased exposure to extreme winter events.

Aspidiotus nerii Bouché (Hemiptera: Diaspididae), oleander scale, is a cosmopolitan pest that feeds on >100 families of plants. A previous study of mitochondrial DNA variation in A. nerii suggested a possible Australian origin for the species. Here, we expand upon that study to include four gene regions and multiple Australian samples. We sequenced fragments of three nuclear genes (CAD, elongation factor 1a, and 28S rDNA) and one mitochondrial region (spanning parts of cytochrome oxidase I and II), for a total aligned sequence length of 2448 bp, from 22 individuals identified as A. nerii. We infer an allele genealogy for each gene region, and we interpret branches that are congruent across gene regions as indicative of species boundaries. Using this criterion, we recognize three species within our sample of A. nerii. One of these corresponds to the cosmopolitan pest species and the other two are found only in Australia. The two putative Australian species have overlapping ranges and both are found on multiple hosts. Contrary to previous suggestions, the cosmopolitan sexual and parthenogenetic lineages of A. nerii are not recognized as distinct species by both of our methods of phylogenetic reconstruction. Cryptic diversity within what seem to be single cosmopolitan armored scale insect species is a potential serious problem for plant quarantine.

‘Hass’ avocado, Persea americana Miller, fruit being imported into California from Mexico are infested with high levels of a previously unknown species of armored scale insect (Hemiptera: Diaspididae). This species has recently been described and given the name Abgrallaspis aguacatae Evans, Watson & Miller. However, the validity of morphological characters used to diagnose genera within the tribe Aspidiotini (Diaspididae) is the subject of continued debate. Here, we seek to circumnavigate the inherent problems associated with interpretation of somewhat plastic phenotypic characters. We use two different nuclear gene regions (28S and Elongation Factor 1a) and three different analysis methods (maximum parsimony, maximum likelihood, and Bayesian analyses) to infer phylogeny from DNA sequence data for 35 aspidiotine species. Our analyses suggest that the new species is misplaced in the genus Abgrallaspis Balachowsky and that this genus and several closely allied genera are paraphyletic or polyphyletic. The findings of our analyses are discussed specifically in relation to the current placement of A. aguacatae and more broadly in relation to the long-recognized problem of defining generic boundaries between Abgrallaspis, Diaspidiotus Berlese, and Hemiberlesia Cockerell.