Host range estimation using historical records and field-based host specificity tests was performed with Tachardiaephagus somervilli, an encyrtid parasitoid selected for the biological control of the invasive lac scale Tachardina aurantiaca on Christmas Island, Indian Ocean. T. aurantiaca is tended by the invasive ant Anoplolepis gracilipes and its honeydew supply is implicated in formation of ant supercolonies that threaten native biodi-versity and disrupt ecosystem processes in island forest. Historical data indicated that T. somervilli and other Tachardiaephagus spp. have narrow host ranges restricted to lac scales (Kerriidae). Furthermore, none of the 40 encyrtid species known to parasitize lac scales has a host range extending beyond the Coccoidea, and no encyrtid species is known that bridges the phylogenetic distance between their kerriid hosts and the families of any endemic Hemiptera found on Christmas Island. No-choice host specificity tests conducted in the field in the native range of Tachardina aurantiaca showed that none of the eight test species (Coccoidea) were parasitized by T. somervilli. These results predict that release of T. somervilli on Christmas Island will have negligible risks of non-target impacts. More broadly, host-specificity testing in the native region should play a greater role in assessment of potential biological control agents.

A survey for etomopathogenic nematodes and fungi in alfalfa snout beetle Otiorhynchus ligustici (L.) infested fields was conducted in Hungary, where this beetle is native, and in New York State, where the alfalfa snout beetle is an invasive species. Soil samples were collected in Hungary and in New York in alfalfa snout beetle infested alfalfa fields in spring 2002. Galleria mellonella (L.) larvae were used as bait insects. The entomopathogenic fungi Beauveria bassiana and Metarhizium anisopliae were found in Hungary and New York. The frequency of plots with entomopathogenic fungi was not significantly different between locations in Hungary and New York. The entomopathogenic nematodes Steinernema carpocapsae and Heterorhabditis sp. were found in Hungary and New York and S. feltiae was only found in Hungary. The frequency of plots with entomopathogenic nematodes was not significantly different between locations in Hungary and New York. S. carpocapsae and S. feltiae were found in coexistence at one location in Hungary.

The alfalfa snout beetle, Otiorhynchus ligustici L., is the most serious pest of alfalfa in northern New York State. Recent research efforts focused on the biological control of this insect require the availability of all life stages. With a 2-year lifecycle and a mandatory diapause, the artificial rearing of a laboratory culture appears to be a non-viable option at present, but methods described here can be used to obtain sufficient numbers of eggs and larvae over an extended period of time for research purposes. The crowding of adult beetles in egg production units (cups) had a significant, negative effect on egg production per beetle but the total egg production per cup was still higher with higher number of beetles per cup resulting in a significant saving of labor per egg produced. Larval survival rates in alfalfa-planted cans were surprisingly low given the protected conditions of the greenhouse. The larval survival rates were not significantly different among the dates for the second instar and later instars, suggesting that larval mortality occurs in the first instar in alfalfa-planted cans.

The long term field persistence of Steinernema carpocapsae Weiser, strain NY001, S. feltiae Filipjev, strain Valko and Heterorhabditis bacteriophora Poinar, strain Oswego was investigated in an alfalfa field infested by the alfalfa snout beetle, Otiorhynchus ligustici L. Nematodes were applied in single-species, two-species and three-species combinations at a total of 2.5 × 109 infective juveniles per hectare. Soil samples were taken approximately every two weeks from mid/late May to late October in 2004 and 2005. Two soil samplings were conducted in 2006 at the end of May and in early July. All nematodes persisted in the field at the time of the last sampling in July 2006, over two years after application suggesting long term persistence of these nematodes and the potential to coexist in combinations. Steinernema feltiae Valko was not detected in the three-species combination after June 8, 2005, approximately one year after nematode application suggesting that S. feltiae Valko cannot compete effectively when a specialized ambusher nematode (S. carpocapsae NY001) and a specialized cruiser nematode (H. bacteriophora Oswego) are present simultaneously. In 2006, two years after nematode application, a marked movement of nematodes into experimental plots where they were not applied was observed. S. carpocapsae NY001 was found in the highest number of plots where it wasn’t applied. Given the ambusher behavior of S. carpocapsae NY001, it is suspected that its movement occurred via infected, but still live adult alfalfa snout beetles.

Detailed assessment of scale insect (Hemiptera: Coccoidea) faunas on islands may help predict impacts of invasive ants (Hymenoptera: Formicidae) and inform options for their management, including biological control. Mutualism between scale insects and the invasive ant Anoplolepis gracilipes on Christmas Island, Indian Ocean, threatens the conservation of the island's endemic land crab fauna, alters rainforest structure and composition, and disrupts ecosystem processes. Diversity and endemism of the scale insect fauna were assessed through broad survey across rainforest, targeted search on endemic plant species, and inspection of ornamental and horticultural plants in settled areas. Emphasis was placed on honeydew-producing species that sustain ant supercolonies and detection of endemic scale insects that could be non-target species in a biological control programme for honeydew-producing scale insects. Origins of the fauna were inferred using scale insect databases and interception records at Ports-of-Entry for the United States and Korea. Twenty-eight scale insect species in seven families are identified for the island. Four honeydew-producing species, the lac scale Tachardina aurantiaca (Kerriidae) and three soft scale species (Coccidae), are abundant in rainforest and tended by ants. No endemic species were found. Compositionally, the scale insect fauna resembles that of many other tropical islands: almost all species are biogeographically widespread, host-plant generalists, and routinely intercepted in human-mediated dispersal pathways. The likely source bioregion is Sundaland where 27 of the 28 species on the island have been recorded and which has been the major pathway for movement of plant material to the island for over a century.

Pulvinaria urbicola Cockerell, a pulvinariine soft scale (Hemiptera: Coccidae), is a broad host-plant generalist, produces honeydew and is commonly tended by ants, including the invasive yellow crazy ant Anoplolepis gracilipes Smith and big-headed ant Pheidole megacephala (Fabricius). Pu. urbicola is implicated in dieback of forest dominated by Pisonia grandis (Nyctaginaceae) on many Indo-Pacific islands. Here we report detection of Pu. urbicola on Christmas Island (Indian Ocean), describe the potential impacts of the association of this trophobiont with introduced ants, and briefly outline biosecurity and management issues. On Christmas Island, Pu. urbicola represents a threat to stands of Pi. grandis, potentially threatens the dominant forest tree Pi. umbellifera, and could exacerbate supercolony formation and impacts of the yellow crazy ant.

Two papaya (Carica papaya L.) seedlings growing in one planting hole often results in angular or non-vertical growth of the trees. Data on trunk angularity, or leaning, (deviation from the vertical line of reference) and white peach scale, Pseudaulacaspis pentagona Targioni-Tozzetti (Hemiptera: Diaspididae), densities on paired papaya trees were collected approximately 1year after infestation of a papaya field was discovered. Paired trees showed a significantly higher degree of leaning than single trees. White peach scale densities were significantly higher on tree trunks with a greater departure from vertical in paired comparisons. Therefore, paired tree planting practices may facilitate the development of economic infestations of white peach scale populations in papaya orchards.

Pre-introductory host specificity tests were performed with Encarsia diaspidicola, a biological control candidate against the invasive white peach scale, Pseudaulacaspis pentagona. False oleander scale, P. cockerelli, coconut scale, Aspidiotus destructor, cycad scale, Aulacaspis yasumatsui, greenhouse whitefly, Trialeurodes vaporariorum, green scale, Coccus viridis, and long-tailed mealybug, Pseudococcus longispinus were tested in quarantine using traditional no-choice tests and examined for wasp emergence. The Hawaiian endemic palm scale, Colobopyga pritchardiae was also tested using no-choice tests and evaluated using species-specific molecular markers. All tests used unexposed non-target cohorts and no-choice exposure of white peach scale to the parasitoid as controls. None of the non-target exotic species yielded wasp emergence, and exposure to wasps had no effect on the mortality of the non-target species examined. Molecular tests with the endemic palm scale showed no evidence of parasitism by E. diaspidicola. These results strongly support that E. diaspidicola has a narrow host range and that its release in Hawaii will have negligible risk of non-target effects.

We genetically characterized Encarsia diapsidicola Silvestri and Encarsia berlesei Howard (Hymenoptera: Aphelinidae) by two molecular methods: phylogenetic analysis of the cytochrome oxidase subunit I gene (COI) and intersimple sequence repeat-polymerase chain reaction (ISSR-PCR) DNA fingerprinting. These two closely related endoparasitoids are candidate biological control agents for the white peach scale, Pseudaulacaspis pentagona Targioni-Tozetti (Hemiptera: Diaspididae), in Hawaii. We developed species-specific COI molecular markers that discriminated the two species, and we tested the utility of the E. diaspidicola-specific COI marker to detect parasitism of white peach scale. The COI sequence data uncovered 46-bp differences between the two Encarsia spp. The level of COI genetic divergence between the two species was 9.7%, and the two clustered into their own clade on a parismonious phylogram. ISSR-PCR readily discriminated the two Encarsia spp. because each was observed with fixed species-specific banding patterns. The COI molecular markers were specific for each species because cross-reactivity was not observed with nontarget species. The E. diaspidicola-specific COI markers were successful at detecting parasitism of white peach scale by E. diaspidicola by 24 h. Both molecular marker types successfully discriminated the two Encarsia spp., whereas the COI markers will be useful as tools to assess levels of parasitism in the field and to study competitive interactions between parasitoids.

2 USDA-ARS, U.S. Pacific Basin Agricultural Research Center, 64 Nowelo St, Hilo, Hawaii 96720 Abstract. Metabolic stress disinfection and disinfestation (MSDD) is a postharvest treatment that combines short periods of low pressure (vacuum) and elevated CO 2 with ethanol vapor to control pathogens and arthropod pests on commodities. The system was tested against white peach scale, Pseudaulacaspis pentagona (Targioni- Tozzetti) (Homoptera: Diaspididae), a serious pest of papaya in Hawaii. Treatment with low pressure (125 mm Hg) and high CO 2 (>99%) alone had no effect on mortality of second stage nymphs, whereas a combination of low pressure, high CO 2 and ethanol vapor (75 mg l -1 ) killed 98% of the individuals tested. This combination treatment has potential to disinfest fresh commodities of surface pests.

Multiple-species natural enemy approach for the biological control of the alfalfa snout beetle, Otiorhynchus ligustici (L.) (Coleoptera: Curculionidae), was compared with using single-species of natural enemies in the alfalfa ecosystem by using entomopathogenic nematodes with different dispersal and foraging behaviors. Steinernema carpocapsae NY001 (ambush nematode), Heterorhabditis bacteriophora Oswego (cruiser nematode), and Steinernema feltiae Valko (intermediate nematode) were applied in single-species, two-species combinations, and one three-species combination treatments at 2.5 x 10(9) infective juveniles per hectare. All nematode species persisted for a full year (357 d). S. carpocapsae NY001 protected the plants from root-feeding damage better than H. bacteriophora Oswego but allowed for higher larval survival than all other nematode treatments. S. feltiae Valko protected the plants better than H. bacteriophora Oswego and controlled alfalfa snout beetle larvae better than S. carpocapsae NY001. H. bacteriophora Oswego allowed for similar root damage compared with control plots but reduced larval populations better than S. carpocapsae NY001. The combination of S. carpocapsae NY001 and H. bacteriophora Oswego provided significantly better protection for the plants than the control (unlike H. bacteriophora Oswego alone) and reduced host larva survival more than S. carpocapsae NY001 alone. The combination S. feltiae Valko and H. bacteriophora Oswego could not be statistically separated from the performance of S. feltiae Valko applied alone.

Multipiece sand columns were used to study the dispersal and interspecific interactions at different depths among three nematode species with different foraging strategies. Steinernema carpocapsae Weiser, strain 'NY001', an ambusher nematode, Heterorhabditis bacteriophora Poinar, strain 'Oswego', a cruiser nematode, and S. feltiae Filipjev, strain 'Valko', an intermediate nematode were applied to multipiece sand columns in single-, two-, and three-species combinations 7 d before host introduction. The effect of interspecific interactions on nematode performance was estimated by comparing the percent host infected by a nematode species at specified depths when applied alone to the performance of the same nematode species when applied in combination with other nematode species. All three nematodes were capable of infecting some proportion of hosts down to the 32.5-cm depth when applied singly. In nematode combinations, interspecific competition occurred, but negative impacts of competition on nematode performance were not observed at all depths. S. carpocapsae 'NY001' was only affected negatively in the surface layer when combined in the three-species combination but not in the two-species combinations. S. feltiae 'Valko' was positively affected by the presence of S. carpocapsae 'NY001' at 26- and 32.5-cm depths in the two-species combination. In the presence of S. carpocapsae 'NY001' and S. carpocapsae 'NY001' + S. feltiae 'Valko', the performance of H. bacteriophora 'Oswego' was positively affected at 32.5-cm depth. The results suggest spatial niche separation of nematodes with different foraging and dispersal strategies that may contribute to coexistence in the field.

Horseweed is a winter or summer annual plant, native to North America and distributed worldwide in temperate climates. This plant is considered an important agricultural weed because it can reduce agricultural yields by 90% at high densities and becomes problematic under low-tillage agriculture. Seed production is robust with an estimated 200,000 seeds produced per plant, and seed dispersal is wind-assisted. The confirmation of glyphosate-resistant horseweed in Delaware in 2001 and the rapid spread of the resistant biotype, currently covering more than 44,000 ha, has necessitated a change in the discussion about weed dispersal. Large radiocontrolled airplanes were used to sample the lower atmosphere for the presence of horseweed seeds during a 3-d period in early September 2005 in southern Delaware. The collection of multiple seeds at heights ranging from 41 to 140 in above ground level strongly suggests that horseweed seeds are entering the Planetary Boundary Layer (PBL) of the atmosphere, where long-ranged transport of aerial biota frequently occurs. With wind speeds in the PBL frequently exceeding 20 in s-', seed -dispersal can easily exceed 500 km in a single dispersal event.

Colobopyga pritchardiae (Stickney 1934) (Hemiptera: Halimococcidae), an endemic Hawaiian scale insect associated with Pritchardia sp. was recorded for the first time on the Big Island. Notes on sites of collection, infested areas of host plants, and some behavioral aspects of the insect are provided.

White peach scale, Pseudaulacaspis pentagona (Targioni-Tozetti) (He- miptera: Diaspididae) is a serious economic and quarantine pest of papaya, Carica papaya L. The parasitic wasp Encarsia diaspidicola (Silvestri) (Hymenoptera: Aphelinidae) was brought from Western Samoa into a quarantine containment facility in Hawaii for evaluation and potential release against white peach scale. E. diaspidicola was considered an ideal biological control candidate for release in Hawaii because it is reportedly highly host specific. Host range testing in quarantine with several exotic diaspidids and related taxa, including a native palm scale, indicated that E. dispidicola is unlikely to attack non-target species or cause harm to the environment if released for control of white peach scale in Hawaii. The Hawaii Department of Agriculture and USDA APHIS issued permits for its release. Releases of E. diaspidicola were made beginning in February 2013 in a papaya field in Kapoho on the Big Island. Yellow sticky trap monitoring suggests that the wasp has established in the area of release. Infested papaya logs are being used to spread the wasp to new areas.