Pineus Strobi Research Articles

INVASION SPECIES OF HERMES <i>PINEUS STROBI </i>(HARTIG 1839) (HEMIPTERA: ADELGIDAE)<i/>ON<i> PINUS STROBUS </i>L. IN CENTRAL REGIONS OF EUROPEAN RUSSIA

During forest-pathological monitoring in the plantings of Weymouth pine Pinus strobus L. in three regions of the central part of European Russia - Voronezh, Kursk and Oryol - an invasive species of Weymouth pine pest, Hermes Pineus strobi (Hartig 1839), was identified. The vector of hermes invasion in a given territory, degree and rate of spread, localization of colonies on trees, dynamics of development in industrial, experimental forest cultures and clone archives were established. Sources of distribution of the pest in the Voronezh Region are Weymouth pine cuttings from the Oryol and Kaliningrad regions.

A New Species of Lestodiplosis (Diptera: Cecidomyiidae) Preying on Pineus (Hemiptera: Adelgidae), with a Redescription of Lestodiplosis juniperina (Felt)

A new species, Lestodiplosis pinei Gagné (Diptera: Cecidomyiidae), from the United States is described from males, females, pupae and larvae. Larvae are egg predators of Pineus strobi Hartig, Pineus pini Goeze and Pineus cembrae (Cholodkovsky) (Hemiptera: Adelgidae). This is the first North American record for P. cembrae, which was found feeding on Pinus cembra L. planted at Arnold Arboretum in Massachusetts. Lestodiplosis juniperina (Felt) is redescribed as similar to L. pinei and for having once been considered to include specimens now identified as L. pinei. Lestodiplosis cerasi Felt and Lestodiplosis novangliae Felt are new synonyms of L. juniperina.

INFESTACIÓN POR Pineus strobi Hartig (Hemiptera: Adelgidae) EN UNA RESTAURACIÓN CON DOS ESPECIES DE PINO

Los herbívoros invertebrados son un factor limitante para la supervivencia de las plantas en condiciones de restauración, pero existen pocos estudios en los que se haya abordado este tema. En un experimento con una duración de cuatro años que se realizó en Michoacán, México con Pinus pseudostrobus y P. montezumae , crecieron, saludablemente hasta 2006, cuando fueron atacados por Pineus strobi (Hemiptera: Adelgidae). En consecuencia se evaluó el efecto de los adélgidos sobre el arbolado. En 2006 la infestación, a pesar de ser grande, no tuvo efectos significativos sobre el crecimiento de ninguna de las dos especies de pinos. En 2007 se realizó un experimento para eliminar a P. strobi mediante la aplicación del insecticida Decis ® y evaluar su efecto sobre los árboles. Durante ese año se midió la infestación de los insectos y el desarrollo de los árboles mensualmente, durante la temporada de crecimiento. Los resultados muestran que el producto aplicado redujo la infestación de P. strobi en Pinus montezumae , pero no en P. pseudostrobus ; además su uso afectó negativamente el incremento en diámetro basal de P. montezumae . Pinus pseudostrobus no fue dañado por el insecticida, ni por los insectos, y los individuos de P. montezumae infestados por Pineus strobi registraron un crecimiento (altura) mayor que los controles en dos años consecutivos (2006 y 2007). La presencia de Pineus strobi en los taxa evaluados tuvo poca relevancia, puesto que no incidió en su crecimiento.

Predators associated with the pine bark adelgid (Hemiptera: Adelgidae), a native insect in Appalachian forests, United States of America, in its southern range

AbstractThe pine bark adelgid,Pineus strobi(Hartig) (Hemiptera: Adelgidae), is an herbivore native to eastern North America that specialises on eastern white pine,Pinus strobusLinnaeus (Pinaceae). Little is known aboutP. strobi, especially in its southern range in the Appalachian Mountains, United States of America, and the composition of its predator complex has not yet been documented in this region. The current study identifies arthropod predators associated withP. strobiin Appalachian forests of Virginia based on a two-year survey. Predators were identified using morphology and DNA barcoding. Predator species include:Laricobius rubidusLeConte (Coleoptera: Derodontidae),Leucopis piniperdaMalloch (Diptera: Chamaemyiidae), andLeucopis argenticollisZetterstedt (Diptera: Chamaemyiidae), that are known adelgid specialists. Also found were predators from the families Cecidomyiidae (Diptera), Coccinellidae (Coleoptera), Chrysopidae (Neuroptera), Hemerobiidae (Neuroptera), and Syrphidae (Diptera). The Cecidomyiidae were especially diverse, with 14 different species inferred from their DNA barcodes. Knowledge of this predator complex is particularly valuable for anticipation and detection of potential interactions between native predator species and those that are being considered for the introduction for biological control of invasive adelgid pests within the southern Appalachian ecosystem.

First report ofPineus strobi(Hartig, 1839) (Hemiptera: Adelgidae) in western North America

The pine bark adelgid, Pineus strobi (Hartig, 1839) (Hempitera: Adelgidae), is native to eastern North America and is found throughout the natural range of its main host species, eastern white pine, Pinus strobus L. (Pinaceae), which stretches from the Atlantic coast, west to Ontario and Minnesota (Drooz 1985). For the first time, we confirmed the presence of P. strobi west of this range in Washington, Colorado, and Saskatchewan by identification of contemporary samples using morphology and DNA barcodes. We also include information from existing slide-mounted specimens of P. strobi putatively originating from Oregon that are deposited in the United States National Museum of Natural History (NMNH) Entomology Collection. To our knowledge, this is the first published report of this species in western North America.

Phenology of the Pine Bark Adelgid, Pineus strobi (Hemiptera: Adelgidae), in White Pine Forests of Southwestern Virginia.

The pine bark adelgid, Pineus strobi Hartig (Hemiptera: Adelgidae), is a native herbivore of eastern white pine, Pinus strobus L. (Pinales: Pinaceae), in eastern North America. P. strobi does not appear to have any dominant overwintering lifestage in southwest Virginia, as it does in its northern range. Eggs can be found consistently from late March through early December and may be produced sporadically later throughout the winter during warm periods. Two distinct generations were observed in the spring, after which life stage frequencies overlapped. Adult body size varied seasonally and was greatest in the spring. The present study constitutes the first recording of phenological details of the P. strobi in its southern range, informing biological control efforts aimed at closely related invasive pests. The phenological plasticity observed between northern and southern P. strobi populations provides insight into the potential effects of climate on the population dymanics of this and related species.

Host Range Specificity ofScymnus camptodromus(Coleoptera: Coccinellidae), A Predator of Hemlock Woolly Adelgid (Hemiptera: Adelgidae)

Scymnus (Neopullus) camptodromus Yu and Liu (Coleoptera: Coccinellidae) was brought to the United States from China as a potential biological control agent for hemlock woolly adelgid (Adelges tsugae Annand) (Hemiptera: Adelgidae). Scymnus camptodromus phenology is closely synchronized with that of A. tsugae and has several characteristics of a promising biological control agent. As a prerequisite to field release, S. camptodromus was evaluated for potential nontarget impacts. In host range studies, the predator was given the choice of sympatric adelgid and nonadelgid prey items. Nontarget testing showed that S. camptodromus will feed to some degree on other adelgid species, but highly prefers A. tsugae. We also evaluated larval development of S. camptodromus on pine bark adelgid (Pineus strobi (Hartig)) (Hemiptera: Adelgidae) and larch adelgid (Adelges laricis Vallot) (Hemiptera: Adelgidae); a small proportion of predator larvae was able to develop to adulthood on P. strobi or A. laricis alone. Scymnus camptodromus showed no interest in feeding on woolly alder aphid (Paraprociphilus tessellatus Fitch) (Hemiptera: Aphididae) or woolly apple aphid (Eriosoma lanigerum (Hausmann)) (Hemiptera: Aphididae), and minimal interest in cotton aphid (Aphis gossypii Glover) (Hemiptera: Aphididae) in choice and no-choice experiments. Scymnus camptodromus females did not oviposit on any host material other than A. tsugae-infested hemlock. Under the circumstances of the study, S. camptodromus appears to be a specific predator of A. tsugae, with minimal risk to nontarget species. Although the predator can develop on P. strobi, the likelihood that S. camptodromus would oviposit on pine hosts of this adelgid is small.

Field assessment of hybridization between Laricobius nigrinus and L. rubidus, predators of Adelgidae

Two adelgid predators, Laricobius nigrinus Fender and Laricobius rubidus LeConte, were recently discovered to produce hybrid progeny in the eastern United States. L. rubidus is native to eastern North America where it feeds on pine bark adelgid (Pineus strobi Hartig) and L. nigrinus is native to western North America and was introduced to the eastern United States in 2003 for biological control of hemlock woolly adelgid (Adelges tsugae Annand). Currently, L. nigrinus and L. rubidus form a mosaic of hybrid zones throughout the eastern United States. It is not known whether these zones will be maintained over time and whether hybridization will impact the efficacy of biological control or result in displacement of L. rubidus. Sampling from 2007 to 2012 on eastern hemlock (Tsuga canadensis Carrière) showed a clear increase in L. nigrinus, a decrease in L. rubidus, and a steady proportion of hybrids. Sampling from 2010 to 2012 on both eastern hemlock and white pine (Pinus strobus L.) at ten sites showed that L. nigrinus was more dominant on hemlock and L. rubidus was more dominant on white pine, which may demonstrate habitat preference and promote segregation between the two species. Site factors were tested for a relationship with the proportion of hybrids. The number of years L. nigrinus had been present at the site was the only factor that showed a relationship. The results suggest that L. nigrinus may displace L. rubidus on hemlock, but not on white pine at sites where they are both present.

The Pine Bark Adelgid, Pineus strobi, Contains Two Novel Bacteriocyte-Associated Gammaproteobacterial Symbionts

Bacterial endosymbionts of the pine bark adelgid, Pineus strobi (Insecta: Hemiptera: Adelgidae), were investigated using transmission electron microscopy, 16S and 23S rRNA-based phylogeny, and fluorescence in situ hybridization. Two morphologically different symbionts affiliated with the Gammaproteobacteria were present in distinct bacteriocytes. One of them ("Candidatus Annandia pinicola") is most closely related to an endosymbiont of Adelges tsugae, suggesting that they originate from a lineage already present in ancient adelgids before the hosts diversified into the two major clades, Adelges and Pineus. The other P. strobi symbiont ("Candidatus Hartigia pinicola") represents a novel symbiont lineage in members of the Adelgidae. Our findings lend further support for a complex evolutionary history of the association of adelgids with a phylogenetically diverse set of bacterial symbionts.

Hybridization between a native and introduced predator of Adelgidae: An unintended result of classical biological control

Hybridization between introduced biological control agents and native species has the potential to impact native biodiversity and pest control efforts. This study reports progress towards predicting the outcome of hybridization between two beetle species, the introduced Laricobius nigrinus Fender and the native L. rubidus LeConte. L. nigrinus is a predator from western North America introduced to hemlock stands in the eastern United States as a biological control of the hemlock woolly adelgid [Adelges tsugae Annand (Hemiptera: Adelgidae)]. Laricobius rubidus is a closely related eastern species that also feeds on A. tsugae but prefers pine adelgids (Pineus strobi Hartig) on white pine (Pinus strobus L.). Six microsatellite markers plus mitochondrial COI haplotypes were used to examine genetic structure of these two Laricobius species across North America. In their native ranges, major geographic features have impacted gene flow: the intermountain region in the West, and the Appalachian Mountains in the East. Analysis of 1229 individuals from adelgid-infested hemlock trees in release sites in the eastern United States found widespread hybridization with asymmetrical introgression towards L. nigrinus on hemlock. The ultimate outcome of hybridization could therefore be a complex mosaic of genetic introgression across the landscape, depending on the distribution of hemlock and pine. This study confirms the importance of evaluating the potential for introduced biological control agents to hybridize with their native relatives. This system also provides an excellent opportunity to improve our understanding of emerging hybrid zones by tracking its progress over time.

Prey Suitability and Phenology of Leucopis spp. (Diptera: Chamaemyiidae) Associated With Hemlock Woolly Adelgid (Hemiptera: Adelgidae) in the Pacific Northwest

Leucopis spp. (Diptera: Chamaemyiidae) from the Pacific Northwest previously were identified as potential biological control agents for the hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae), in the eastern United States. We collected Leucopis spp. larvae from A. tsugae infested western hemlocks in Oregon and Washington and reared them on an unidentified Pineus spp., Pineus strobi (Hartig), Adelges cooleyi (Gillette), Adelges piceae (Ratzeburg), and A. tsugae in three no-choice tests. Leucopis spp. survival on A. tsugae was significantly higher than on A. piceae during the 2010 progrediens generation test and significantly higher than on P. strobi and A. cooleyi during the 2010 sistens generation test. However, across all three tests, some larvae completed development to adult on all four of the alternative adelgid species. Larvae that survived to the adult stage were identified as Leucopis argenticollis Zetterstedt and Leucopis piniperda Malloch. These results suggest that populations of L. argenticollis and L. piniperda in the Pacific Northwest may not be specific to A. tsugae. We also studied the phenology of Leucopis spp. on fourteen A. tsugae infested western hemlock trees in Oregon and Washington over a period of 14 mo. Leucopis spp. larvae were collected year-round, but highest densities coincided with the presence of progrediens and sistens eggs and adults of A. tsugae. There was a positive correlation between Leucopis spp. and A. tsugae abundance.

Comparison between a native and exotic adelgid as hosts for Laricobius rubidus (Coleoptera: Derodontidae)

Laricobius rubidus LeConte, native to eastern North America whose primary host is Pineus strobi Hartig, has been observed in association with Adelges tsugae, an exotic and lethal pest of hemlock trees in eastern North America. Pineus strobi and A. tsugae were used to evaluate host preference and suitability of this predatory beetle to determine in part its suitability as a potential biological control agent of A. tsugae. In a paired-choice oviposition test, L. rubidus preferred to oviposit in P. strobi ovisacs over those of A. tsugae. However, in the no-choice oviposition test, there was no significant difference in the mean number of eggs laid by L. rubidus females in P. strobi or A. tsugae ovisacs. There were no significant differences in larval developmental time or survivorship for L. rubidus reared on a diet of either P. strobi or A. tsugae. Laricobius rubidus completed development to the adult stage on A. tsugae indicating that it is a suitable host and therefore has the potential to contribute to biological control of A. tsugae in the eastern United States. The introduction of a congener, Laricobius nigrinus to eastern North America may result in competition with L. rubidus on A. tsugae, but the inability of L. nigrinus to complete development on P. strobi suggests that the two congeners will not compete on the primary host of L. rubidus.

Feeding Preference of Three Lady Beetle Predators of the Hemlock Woolly Adelgid (Homoptera: Adelgidae)

In a laboratory study, we tested the feeding preferences of three coccinellid predators of hemlock woolly adelgid, Adelges tsugae Annand, an introduced pest of hemlock in the eastern United States. The species tested were Sasajiscymnus tsugae Sasaji & McClure (formerly Pseudoscymnus tsugae) from Japan, Scymnus ningshanensis Yu & Yao from China, and Harmonia axyridis (Pallas), a generalist species introduced from Asia that is currently widespread in eastern hemlock, Tsuga canadensis Carriere, forests. We measured the feeding preference of each beetle species when given the choice of A. tsugae and either 1) Pineus strobi (Hartig) on Pinus strobus L.; 2) Adelges laricis Vallot on Larix decidua Mill.; 3) Adelges cooleyi (Gillette) on Pseudotsuga menziesii (Mirb.) Franco; or 3) Paraprociphilus tessellatus (Fitch) on Alnus serrulata (Ait.) Willd. We evaluated beetle preference for adults, nymphs, and eggs of each prey species. Generally, when adult or nymphal prey stages were compared, S. tsugae preferred A. tsugae adults to P. strobi, A. cooleyi, A. laricis, and P. tessellatus. S. ningshanensis showed less preference between adelgid species, but it did not prefer P. tessellatus nymphs. When preferences for adelgid eggs were assayed, S. tsugae and S. ningshanensis showed no preference between A. tsugae and A. cooleyi or P. strobi, but S. tsugae did prefer A. tsugae to A. laricis. Larvae of S. tsugae were unable to survive on P. tessellatus nymphs. H. axyridis adults readily consumed both A. tsugae and P. tessellatus, but H. axyridis larvae did not complete their life cycle on A. tsugae. Our host range tests suggest that S. ningshanensis and S. tsugae may feed on several species of Adelgidae and that A. tsugae is often preferred.

Host specificity of Laricobius nigrinus Fender (Coleoptera: Derodontidae), a potential biological control agent of the hemlock woolly adelgid, Adelges tsugae Annand (Homoptera: Adelgidae)

Host specificity tests of Laricobius nigrinus Fender (Coleoptera: Derodontidae) were conducted under quarantine in Blacksburg, Virginia, to determine the suitability of this beetle as a biological control agent of the hemlock woolly adelgid, Adelges tsugae Annand (Homoptera: Adelgidae), in the eastern United States. Members of the genus Laricobius are known to feed on adelgids. L. nigrinus, native to western North America, was tested on three other adelgids and three non-adelgid species of Homoptera in three families. A. tsugae is an exotic insect pest of eastern (Tsuga canadensis (L.) Carrière) and Carolina (T. caroliniana Engelmann) hemlocks. In paired-choice and no-choice oviposition tests, L. nigrinus females preferred to oviposit in A. tsugae ovisacs over the other test species. Feeding tests showed that L. nigrinus consumed more eggs of A. tsugae than eggs of Adelges piceae (Ratzeburg) and Pineus strobi (Hartig), but not of Adelges abietis (L.). In larval development tests, L. nigrinus only completed development on A. tsugae. These results suggest that L. nigrinus has a narrow host range and that it has potential for biological control of A. tsugae. Based on these results, L. nigrinus has been cleared for field release by USDA APHIS.

BIOLOGY AND IMMATURE STAGES OF LEUCOPIS PIMCOLA AND CHAMAEMYIA POLYSTIGMA (DIPTERA: CHAMAEMYIIDAE)

AbstractThe life cycles and larval feeding habits of Leucopis (Neoleucopis) pinicola Malloch and Chamaemyia polystigma Meigen were studied in northeastern Ohio. The larval stages of L. pinicola are predators of the pine bark aphid, Pineus strobi (Hartig) (Homoptera: Adelgidae). Probably there are only two generations a year, and overwintering occurs as mature larvae or pupae that are in diapause. Larvae of C. polystigma prey on the blue grass mealybug, Heterococcus nudus Green (Homoptera: Pseudococcidae), that infests perennial rye grass, Lolium perenne L. This species has three generations a year and overwinters as diapausing mature larvae and pupae.The eggs, three larval instars, and puparia of both species are described and illustrated.

Releases in North America and Reviews of Bionomics in Europe of Insect Predators of the Balsam Woolly Aphid, Adelges piceae (Ratz.) (Homoptera: Adelgidae)

The balsam woolly aphid, Adelges piceae (Ratz.), causes serious damage to balsam fir, Abies balsamea (L.) Mill., in Eastern Canada. It was introduced from Europe before 1900 (Balch, 1952) and has also become established in the northeastern United States. In continental Europe A. piceae is common on Abies alba Mill. but is not so serious a pest as in Canada. It has an extensive complex of insect predators in both Canada (Balch, 1934) and Europe (Delucchi, 1954). Balch (1934, 1952) found those in Canada inadequate as control agents. Some of the predators of Pineus pini Koch and Pineus strobi (Htg.) studied by Wilson (1938) in England, and recommended for introduction to new areas, were imported to Canada and released against A. piceae. Predators were first introdnced from Ensland in 1933 and later from continental Europe beginning in 1951.

Studies of Predators of the Balsam Woolly Aphid,Adelges piceae(Ratz.) (Homoptera: Adelgidae): III. Field Identification and some Notes on the Biology ofNeoleucopis pinicolaMall. (Diptera: Chamaemyiidae)

Neoleucopis pinicolaMall. is a common predator on the pine bark aphid,Pineus strobi(Htg.) in New Brunswick. The host adelgid occurs throughout most of the United States and southern Canada on white pine,Pinus strobus, L., Scots pine,Pinus sylvestrisL., and Austrian pine,Pinus nigraArnold (Craighead, 1950). It is also an occasional predator on the balsam woolly aphid,Adelges piceae(Ratz.) (Brown and Clark, 1956b). No reference toN. pinicolawas found in the literature other than Malloch's (1921) description.