K. S. Pike

Hymenopteran parasitoids and dipteran predators found using soybean aphid after its midwestern United States invasion.

Abstract Parasitoids and predatory flies that can attack soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), in soybean, Glycine max (L.) Merr., fields were identified 3 to 4 yr after the aphid was first sighted in the north central United States. We detected 15 species by exposing soybean aphid to ovipositing parasitoids and predatory flies at two locations in southern Michigan. The species detected were (in order of the number of specimens recovered from high to low) Aphidoletes aphidimyza Rondani (Diptera: Cecidomyiidae), Lysiphlebus testaceipes Cresson (Hymenoptera: Braconidae), Allograpta obliqua Say (Diptera: Syrphidae), Aphidius colemani Viereck (Hymenoptera: Braconidae), Eupeodes americanus Wiedemann (Diptera: Syrphidae), Leucopis glyphinivora Tanasijtshuk (Diptera: Chamaemyiidae), Aphelinus asychis Walker (Hymenoptera: Aphelinidae), Sphaerophoria contigua Macquart (Diptera: Syrphidae), Binodoxys kelloggensis Pike, Starý & Brewer (Hymenoptera: Braconidae), Eupeodes volucris Osten Sacken (Diptera: Syrphidae), Paragus hemorrhous Meigen (Diptera: Syrphidae), Toxomerus marginatus Say (Diptera: Syrphidae), Aphelinus albipodus Hayat & Fatima (Hymenoptera: Aphelinidae), Syrphus rectus Osten Sacken (Diptera: Syrphidae), and Praon sp. (Hymenoptera: Braconidae). These species were capable of finding, attacking, and completing development on soybean aphid in soybean fields. Based on a literature review, host aphid ranges of the species detected varied widely, with a tendency toward broader host ranges. These data add to the existing information on the predatory complex currently known to attack soybean aphid in the north central United States. Implications for biological control of soybean aphid are discussed.

Invasive aphids attack native Hawaiian plants

Invasive species have had devastating impacts on the fauna and flora of the Hawaiian Islands. While the negative effects of some invasive species are obvious, other species are less visible, though no less important. Aphids (Homoptera: Aphididae) are not native to Hawai’i but have thoroughly invaded the Island chain, largely as a result of anthropogenic influences. As aphids cause both direct plant feeding damage and transmit numerous pathogenic viruses, it is important to document aphid distributions and ranges throughout the archipelago. On the basis of an extensive survey of aphid diversity on the five largest Hawaiian Islands (Hawai’i, Kaua’i, O’ahu, Maui, and Moloka’i), we provide the first evidence that invasive aphids feed not just on agricultural crops, but also on native Hawaiian plants. To date, aphids have been observed feeding and reproducing on 64 native Hawaiian plants (16 indigenous species and 48 endemic species) in 32 families. As the majority of these plants are endangered, invasive aphids may have profound impacts on the island flora. To help protect unique island ecosystems, we propose that border vigilance be enhanced to prevent the incursion of new aphids, and that biological control efforts be renewed to mitigate the impact of existing species.

Hymenopteran parasitoids and dipteran predators of Diuraphis noxia in the west-central Great Plains of North America: Species records and geographic range

Parasitoids and predatory flies were sampled in the wheat production region of the west-central Great Plains (southeastern Wyoming, western Nebraska, and north-central Colorado) of North America using plant material infested with the Russian wheat aphid, Diuraphis noxia (Mordvilko) (Hemiptera: Aphididae). Samples were taken April through October in 2001 and 2002, which was 15–16 years after first detection of D. noxia and 5–6 years after the last release of natural enemies for its control in this region. The natural enemies detected were (in order of high to low detection frequencies across three states and 2 years): Aphelinus albipodus Hayat and Fatima (Hymenoptera: Aphelinidae), Eupeodes volucris Osten Sacken (Diptera: Syrphidae), Lysiphlebus testaceipes (Cresson) (Hymenoptera: Braconidae, Aphidiinae), Leucopis gaimarii Tanasijtshuk (Diptera: Chamaemyiidae), Aphidius avenaphis (Fitch), Aphidius matricariae Haliday, Diaeretiella rapae (M’Intosh), Aphidius ervi Haliday, Praon yakimanum Pike and Starý (Hymenoptera: Braconidae, Aphidiinae), and Aphelinus asychis Walker (Hymenoptera: Aphelinidae). The results confirmed establishment of one of the 10 exotic parasitoid species released for D. noxia control (A. albipodus) in the west-central Great Plains. It is unknown whether detection of A. asychis, A. matricariae, and D. rapae can be attributed to exotic introductions or preexisting populations. Other species detected in this study have been previously documented from the western US, although the recognized distributions have expanded for A. avenaphis, L. gaimarii, and P. yakimanum compared to the first few years after initial detection of D. noxia. Thus, there is definitive establishment of one exotic introduced for D. noxia and considerable range expansion of preexisting species that prey upon D. noxia.

Search for, and release of, parasitoids for the biological control of Russian wheat aphid in Washington State (USA)

Abstract Parasitoids of Russian wheat aphid, Diuraphis noxia (Kurdjumov), from Morocco, and the Middle East were imported, reared, and mass produced for classical biological control use in Washington State. In total, more than 200 000 parasitoids were released over 53 sites from 1988 to 1992. Some species have established, but the long term effect of the program has yet to be documented.

Review and Key to the World Parasitoids (Hymenoptera: Braconidae: Aphidiinae) of Aphis ruborum (Hemiptera: Aphididae) and Its Role as a Host Reservoir

ABSTRACT A review and illustrated key of the aphidiine parasitoids of Aphis ruborum (Börner and Schilder) are presented including their distribution. The parasitoid spectrum of A. ruborum in the West Palaearctic is rich, composed of Aphidius colemani Viereck, Aphidius matricariae Haliday, Binodoxys acalephae (Marshall), Binodoxys angelicae (Haliday), Ephedrus persicae Froggatt, Lipolexis gracilis Förster, Lysiphlebus confusus Tremblay and Eady, Lysiphlebus fabarum (Marshall), and Praon abjectum (Haliday), and supplemented by the introduction of Lysiphlebus testaceipes (Cresson). In the Americas the parasitoid complex of A. ruborum consists of A. colemani, Aphidius ervi Haliday (South America), and L. testaceipes (South and North America). Furthermore, the reservoir role of A. ruborum in various ecosystems was investigated in Europe (France) and South America (Chile). Faunal peculiarities and relationships of the parasitoid taxa are discussed together with a synopsis of their potential as biocontrol agents.

Molecular Markers for Identification of the Hyperparasitoids Dendrocerus carpenteri and Alloxysta xanthopsis in Lysiphlebus testaceipes Parasitizing Cereal Aphids

Polymerase chain reaction (PCR)-based molecular markers have been developed to detect the presence of primary parasitoids in cereal aphids and used to estimate primary parasitism rates. However, the presence of secondary parasitoids (hyperparasitoids) may lead to underestimates of primary parasitism rates based on PCR markers. This is because even though they kill the primary parasitoid, it’s DNA can still be amplified, leading to an erroneous interpretation of a positive result. Another issue with secondary parasitoids is that adults are extremely difficult to identify using morphological characters. Therefore, we developed species-specific molecular markers to detect hyperparasitoids. A 16S ribosomal RNA mitochondrial gene fragment was amplified by PCR and sequenced from two secondary parasitoid species, Dendrocerus carpenteri (Curtis) (Hymenoptera: Megaspilidae) and Alloxysta xanthopsis (Ashmead) (Hymenoptera: Charipidae), four geographic isolates of the primary parasitoid, Lysiphlebus testaceipes (Cresson) (Hymenoptera: Braconidae), and six aphid species common to cereal crops. Species-specific PCR primers were designed for each insect on the basis of these 16S rRNA gene sequences. Amplification of template DNA, followed by agarose gel electrophoresis, successfully distinguished D. carpenteri and A. xanthopsis from all four isolates of L. testaceipes and all six cereal aphid species in this laboratory test.

Aphids (Hemiptera: Aphididae and Adelgidae) of Hawai'i: Annotated List and Key to Species of an Adventive Fauna

Abstract: We provide a comprehensive compilation of 105 species of Aphidoidea adventive to the Hawaiian Islands based on literature records and a taxonomic analysis of available specimens. Seventeen species are recognized as new to the Islands. For each species information on synonyms, origins, distribution, and hosts is given. The average rate of introduction has been about 0.82 species per year. Approximately 35% of the species originate in East Asia, 35% from Europe and West Asia, and 21% from North America.

Differing contributions of density dependence and climate to the population dynamics of three eruptive herbivores

1. Although both endogenous and exogenous processes regulate populations, the current understanding of the contributions from density dependence and climate to the population dynamics of eruptive herbivores remains limited.

Primary and Secondary Parasitoids (Hymenoptera) of Aphids (Hemiptera: Aphididae) on Blueberry and Other Vaccinium in the Pacific Northwest

Abstract Blueberry scorch virus, a commercially important Carlavirus in highbush blueberry, Vaccinium corymbosum L., is vectored by aphids (Hemiptera: Aphididae). We surveyed the aphids, primary parasitoids (Hymenoptera: Aphelinidae, Braconidae), and associated secondary parasitoids (Hymenoptera: Charipidae, Megaspilidae, Pteromalidae) on highbush blueberry and other Vaccinium in the Pacific Northwest from 1995 to 2006, with samples concentrated in 2005 and 2006, to lay the groundwork for augmentative biological control. Ericaphis fimbriata (Richards) was the principal aphid. The dominant parasitoid species were Praon unicum Smith, Aphidius n. sp., A. sp., and Aphidius ervi Haliday. Their frequency in relation to the other primary parasitoids varied significantly with geographical area; P. unicum dominated the frequency distribution in southwestern British Columbia, A. n. sp., west of the Cascades, and A. sp. and A. ervi east of the Cascades. Among the secondary parasitoids, pteromalids dominated, and their frequency in relation to the other secondary parasitoids was lowest in southwestern British Columbia. The parasitization rate for P. unicum and A. n. sp. in southwestern British Columbia increased from May or June to a maximum of 0.080 ± 0.024 and 0.090 ± 0.084 (SD), respectively, in late July or early August. P. unicum emerged in the spring 4 wk before A. n. sp. The parasitization rate for P. unicum was lower in conventional than organic fields. Whereas aphid density increased monotonically, P. unicum had two spring peaks. A simulation model showed that these peaks could reflect discrete generations. Releases of insectary-reared P. unicum at 150 or 450 DD above 5.6 °C, summing from 1 January, may effectively augment the natural spring populations by creating overlapping generations.

Pentalonia nigronervosa Coquerel and Pentalonia caladii van der Goot (Hemiptera: Aphididae) and Their Relationship to Banana Bunchy Top Virus in Micronesia

Abstract: Geographical distribution of Pentalonia nigronervosa and P. caladii, and incidence of banana bunchy top virus (BBTV) were determined in Micronesia. Aphids and plant tissues were collected from banana and nonbanana hosts of Petrtalonia aphids in Palau, Yap, Guam, Rota, Tinian, Saipan, Pohnpei, Kosrae, and Majuro. Aphids were identified based on host species from which they were collected and on morphometric analysis of length of ultimate rostral segment. All plant samples were tested for presence or absence of BBTV using a triple antibody sandwich enzyme-linked immunosorbent assay (TAS-ELISA). TAS-ELISA analysis confirmed BBTV to be present on Guam, Saipan, and Rota, but BBTV was not detected elsewhere in Micronesia.