Progress 01/01/08 to 12/31/08
Outputs
OUTPUTS: While preliminary estimates suggested that 60 to 70 percent of C. micronesica have been killed by aulocaspis yasumatsui prior to the establishment of Ryzobius lophanthae on Guam, no estimates had been made for trees located on Guam's inaccessible cliff lines. Approximately 1000 photographs of the cliff line perimeter of northern Guam were taken from a helicopter in April 2007. The number of healthy, unhealthy and total number of cycads per ha were estimated, and comparisons were made between cycads observed in the western, northern and eastern cliff lines. There were 6537 cycads, all Cycas micronesica, counted in the 80 photographs that were analyzed, resulting in a distribution of approximately 0.8 trees/ha. Of these trees, 2160 (33%) exhibited leaf yellowing, drooping leaves, or defoliation while the others appeared green and vigorous. There were no statistically significant differences between the numbers of trees in the western, northern and eastern cliff line areas sampled, although there were fewer trees observed in the eastern sector. However, there were significant differences in the distribution of healthy trees, with a greater proportion of healthy trees found in the western and northern cliff line area than in the eastern cliff line area (F[2,79] = 3.714; P = 0.03). Objective 6. Evaluate natural enemy efficacy and study ecological/physiological basis for interactions. Beetle density estimates in areas where R. lophanthae had originally been released were computed in 2008 by counting the number of beetles observed on a tree in 60 seconds, and averaged 0.72 (SE = 0.063) beetles/tree/min across all plots, with a range of 0 to 35. Predation efficiency was computed as the mean number of adult male and female scales evidencing feeding damage due to R. lophanthae occurring in ten 25mm2 squares on 20 leaflets, with one leaflet randomly selected from each tree within each plot. Predation efficiency averaged 65.07% across all scale-infested living trees across all plots. Of the 1149 trees sampled in this study, 733 (63.79%) were infested by one of more adult scales, while the remaining trees were scale free. Goal B: Conserve Natural Enemies to Increase Biological Control of Target Pests. Objective 8. Identify and assess factors potentially disruptive to biological control. R. Miller continued to survey invasive ants on the islands of Guam, Saipan, Tinian, and Rota in the Mariana Islands during 2008. Goal D: Evaluate environmental and economic impacts and raise public awareness of biological control Objective 14. Develop and implement outreach activities for biological control programs. In March 2008 about 30 quarantine personnel on Guam, the CNMI, the Republic of Palau, the Republic of the Marshall Islands, and the Federated States of Micronesia were trained in the importance of natural enemies in regulating populations of invasive insect pests in Micronesia, with special recognition of the potential impact of aphids and ants if not intercepted or detected at or shortly after introduction to the islands. PARTICIPANTS: Principal Leader: Ross H. Miller: rmiller@uog.edu; CNAS-WPTRC, University of Guam, Mangilao, GU 96923; Tel: (671) 735-2141; Fax: (671) 734-4600 Cooperators: Keith S. Pike: Department of Entomology, Washington State University, Prosser, WA; kpike@tricity.wsu.edu Robert Foottit: Eastern Cereal and Oilseed Research Centre, Agriculture and Agri-Food Canada, Ottawa; foottitrg@em.agr.ca Konrad Engelberger: Secretariat of the Pacific Community, Kolonia, Pohnpei, FSM; ppmicronesia@mail.fm Thomas Marler, Western Pacific Tropical Research Center, University of Guam, Mangilao, Guam Aubrey Moore, Pacific Tropical Research Center, University of Guam, Mangilao, Guam R.Miller, A. Moore and K. Engelberger conducted a training workshop for PPQ workers in Micronesia in April 2008 at the University of Guam. Topics covered included basic entomology, invasivie species identification and management, and permitting requirements for biocontrol introductions and biodiversity assessments. TARGET AUDIENCES: Plant protection and quarantine officers in Guam, the Commonwealth of the Northern Mariana Islands, the Federated States of Micronesia, and the Reublic of Palau were trained in basic entomology and the identification, interdiction and mitigation of invasive insect pests. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
We now know that while Asian cycad scale appears to be under good biological control in many areas of Guam, cycad mortality is likely higher than was previously estimated, and that many if not all trees that appear to have recovered from scale infestation following scale predation by R. lophanthae may actually be at great risk of being toppled in the next typhoon due to undetected bole necrosis.
Publications
- Bamba, J.P., R.H. Miller, G.V.P. Reddy, and R. Muniappan. 2008. Studies on the biology, host specificity, and feeding behavior of Acythopeius cocciniae O'Brien and Pakaluk (Coleoptera: curculionidae) on Coccinia grandis (L.) Voigt (Cucurbitaceae) and Zehneria guamensis (Merrill) Fosberg (Cucurbitaceae). Micronesica (in press).
- Moore, A. and R. H. Miller. 2008. Daphnis nerii (Lepidoptera: Sphingidae), a new pest of oleander on Guam, including notes on plant hosts and egg parasitism. Proc. Hawaiian Entomol. Soc. 40 [in press].
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Progress 01/01/07 to 12/31/07
Outputs
OUTPUTS: The Asian cycad scale (ACS), A. yasumatsui, believed to have arrived on Guam on Cycas revoluta (king sego palm) nursery stock in 2003, has rapidly spread throughout populations of introduced C. revoluta and indigenous Cycas micronesica (fadang). Rhyzobius lophanthae, which was introduced from Maui, Hawaii, is now distributed throughout much of the cycad growing area of Guam. However, we estimate that 60 - 70% of C. micronesica have been killed by the scale. C. micronesica was placed on the IUCN Red List of Threatened Species in 2006. Twenty five circular plots incorporating nearly 600 ACS-infested trees were established at the Guam National Wildlife Refuge at Ritidian Point in northern Guam. Along with observations on tree health and survivorship, data on ACS infestation levels and the degree of predation on ACS by R. lophanthae were collected. Data indicate very high predation levels of ACS by R. lophanthae, averaging 95% in beetle release areas at Ritidian Point. Predation rates elsewhere on Guam are also extremely high. We feel that Rhyzobius lophanthae has established throughout the island and is helping to control the Asian cycad scale infestation on wild and ornamental cycads. R. Miller continued to survey invasive ants on the islands of Guam, Saipan, Tinian, and Rota in the Mariana Islands during 2007. This activity is part of an ongoing USDA-APHIS-CAPS project on the surveillance of Wasmannia auropunctata and Solenopsis invicta on Guam and other Mariana Islands. Ant surveys in areas with ACS-infested cycads show that a recently introduced lycaenid butterfly pest of cycads, the cycad blue butterfly, Chilades pandava, is attended by Anoplolepis gracilipes, the yellow crazy ant. C. pandava caterpillars feed on developing cycad leaves, and may kill the tree if it has been weakened by ACS infestation, drought, or typhoon damage. A. gracilipes protection of C. pandava may disrupt natural enemy predation and parasitism on C. pandava eggs and larvae. Analysis of morphometric and DNA (microsatellite flanking region analysis and barcoding data from the COx1 locus) data continued on the TSTAR-sponsored project "Genetic, morphological and ecological variation in Aphis gossypii." Morphometric and DNA data have been generated for the banana aphid, Pentalonia nigronervosa, and strongly suggest that this aphid may consist of at least two separate species, one that is restricted to banana and is likely the principle vector of banana bunch top virus (BBTV), and another which occurs frequently on ginger and taro, but may also colonize banana. Previous studies have described other Pentalonia species, namely Pentalonia gavarri which is a very small aphid occurring on grasses in the Philippines and Australia, and Pentalonia kalimpongensis which occurs on plants in the family Zingiberaceae in India. PARTICIPANTS: Principal Leader: Ross H. Miller: rmiller@uog.edu; CNAS-WPTRC, University of Guam, Mangilao, GU 96923; Tel: (671) 735-2141; Fax: (671) 734-4600 Cooperators: Keith S. Pike: Department of Entomology, Washington State University, Prosser, WA; kpike@tricity.wsu.edu Robert Foottit: Eastern Cereal and Oilseed Research Centre, Agriculture and Agri-Food Canada, Ottawa; foottitrg@em.agr.ca Konrad Engelberger: Secretariat of the Pacific Community, Kolonia, Pohnpei, FSM; ppmicronesia@mail.fm Thomas Marler, Western Pacific Tropical Research Center, University of Guam, Mangilao, Guam Aubrey Moore, Pacific Tropical Research Center, University of Guam, Mangilao, Guam Laurel D. Hansen, Department of Biology, Spokane Falls Community College, Spokane, WA TARGET AUDIENCES: Plant protection inspectors and customs/quantine officers in Guam, Commonwealth of the Northern Marianas, Republic of Palau, Federated States of Micronesia, Republic of the Marshall Islands. Naturual resource managers and agriculturists on Guam. PROJECT MODIFICATIONS: No Project Modifications information reported.
Impacts
About 25 quarantine personnel on Guam, the CNMI, the Republic of Palau, the Republic of the Marshall Islands, and the Federated States of Micronesia were trained in aphid and aphid natural enemy collection and identification techniques as part of an annual PPQ workshop hosted by the University of Guam and sponsored jointly by the Secretariat of the Pacific Commission and USDA-APHIS. Surveys leading to the identification of the various strains/species comprising the Aphis gossypii and Pentalonia nigronervosa complex, along with the identification of associated natural enemies, will allow correct matching of natural enemies to the host pest in various regions of the Pacific. Asian cycad scale appears to be under good biological control in many of the cycad growing areas of Guam, although tree mortality has been high. However, the introduction of C. pandava poses further threats to Guam's ornamental and endemic cycad populations, and must be dealt with. A website entitled "Western Micronesia Invasive Species Committee Wiki" was set up to facilitate sharing information on invasive species throughout Western Micronesia. [http://gisac.guam.net] Links to a BioLink database to generate comprehensive checklists for specified insect taxa were established. Island distribution data is included in the database. [http://202.131.176.14:8080/MAD/CheckList2.htm]
Publications
- Idechiil, O., R. H. Miller, K.S. Pike and L.D. Hansen. 2007. Aphids (Hemiptera: Aphididae), ants (Hymenoptera: Formicidae) and associated flora of Palau with comparisons to other Pacific Islands. Micronesica 39: 141-170.
- Miller, R.H. 2007. Imported insect pest management in Micronesia. Proc. TSTAR Tropical Fruit Production and Handling Workshop. Miami, FL July 6-8. 2007. pp. 82-84.
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Progress 01/01/06 to 12/31/06
Outputs
The Asian cycad scale, A. yasumatsui, believed to have arrived on Guam on Cycas revoluta (king sego palm) nursery stock in 2003, has rapidly spread throughout populations of introduced C. revoluta and indigenous Cycas micronesica (fadang). Heavily infested trees of both species are less abundant than observed in previous years, and the coccinellid, Rhyzobius lophanthae, which was introduced from Maui, Hawaii, appears to be distributed throughout much of the cycad growing area and exerting effective control in many areas. We estimate that about 50% of C. micronesica initially infested by A. yasumatusi, have been killed by the scale. C. micronesica has therefore been placed on the IUCN Red List of Threatened Species. R. Miller conducted a survey of invasive ants that affect the survival and efficiency of homopteran parasitoids on the islands of Guam, Saipan, Rota in the Mariana Islands. This activity was part of USDA-APHIS-CAPS projects on the surveillance of Wasmannia
auropunctata and Solenopsis invicta on Guam and other Mariana Islands. Checklists of invasive ants are being prepared for each island. Analysis of morphometric and DNA (microsatellite flanking region analysis and barcoding data from the COx1 locus) data continued on the TSTAR-sponsored project "Genetic, morphological and ecological variation in Aphis gossypii." Morphometric and DNA data was also generated for the banana aphid, Pentalonia nigronervosa, and suggested that this aphid may consist of two separate species, with the species commonly found on banana being the principle vector of banana bunch top virus (BBTV). About 20 quarantine personnel on Guam, the CNMI, the Republic of Palau, the Republic of the Marshall Islands, and the Federated States of Micronesia were trained in aphid and aphid natural enemy collection and identification techniques as part of an annual PPQ workshop hosted by the University of Guam and sponsored jointly by the Secretariat of the Pacific Commission and
USDA-APHIS.
Impacts
Mortality due to A. yasumatsui on C. micronesica will allow an evaluation of the efficacy of biological control releases performed against A. yasumatsui. This will allow us to decide if further biological control introduction, or other mitigation measures are warranted against this pest. The delineation of the species complex comprising what is currently known as banana aphid will allow us to revise agricultural practices aimed to protect bananas against bunchy top virus in Pacific Islands.
Publications
- Idechiil, O., R. H. Miller, K.S. Pike and L.D. Hansen. 2007. Aphids (Hemiptera: Aphididae), ants (Hymenoptera: Formicidae) and associated flora of Palau with comparisons to other Pacific Islands. Micronesica (in press).
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Progress 01/01/05 to 12/31/05
Outputs
We continued to examine the morphological, genetic and ecological differences in Aphis gossypii in new aphid collections from the Federated States of Micronesia islands of Pohnpei, Chuuk and from Guam and the Commonwealth of the Northern Mariana Islands (CNMI). Additional aphid collections were made on the Hawaiian islands of Oahu, Molokai and Hawaii. These data were combined with those from previous collections in Micronesia and North America to expand the our comprehensive aphid catalogue, with emphasis on A. gossypii. The presence of aphidiid parasitoids, where present, was noted and the aphidiid identified. Morphometric analysis and DNA sequencing also continued for aphids collected previously. Ants collected in association with aphids, and that may have a role in altering the effectiveness of aphidiid biological control agents, were also identified. Ongoing DNA analysis seeks to confirm previous results suggesting that genetic variation in A. gossypii was found
to vary by host plant and then by geographic provenance of the sample, while morphometric variation was most closely correlated to geographic provenance. A. gossypii reared on various hosts, and then switched to a new hosts, were collected following the third generation and are presently being mounted for morphometric analysis. A coccinellid predator, Rhyzobius lophanthae, of Asian cycad scale (ACS), Aulacaspis yasumatsui, was mass reared and released in areas throughout Guam where Cycas micronesica and C. revoluta were found infested. Sticky traps were used to monitor scale densities and estimate vagility. Tree mortality due to ACS and predation rates of R. lophanthae are being monitored. Another introduced pest of Cycas sp., Chilades pandava (Lycaenidae), was observed infesting new growth on C. micronesica, and being tended by at least four different ant species.
Impacts
We now understand the make-up of aphid-parasitoid-ant complexes on crops and ornamental plants in many of the islands of Micronesia and Hawaii. Pest managers can identify the major aphid pests they encounter at ports of entry and on crops and ornamentals on the various islands using keys developed in this activity. The association between many tramp ant species and specific aphid species has been described. R. lophanthae is now abundant and widespread on commercial and indigenous cycads throughout Guam. While it is too early to determine if R. lophanthae will exert adequate control to protect large stands of Cycas sp., predation rates are high and dispersal is good. We are now aware of the threat that C. pandava poses to the cycads of Guam, and have begun to plan for its management.
Publications
- Pike, K.S., R.G. Foottit, R. H. Miller, O. Idechiil and D. W. Allison. 2005. Uroleucon formosanum (Takahashi) and Uroleucon sonchellum (Monell) (Hemiptera, Aphididae): Morphological Comparison and Diagnosis. Proc. Hawaiian Entomol. Soc. 37: 49-64.
- Idechiil. O. 2005. Biodiversity of aphids and ants on Palau, with comparisons to other Pacific islands. MS. Thesis, University of Guam, Mangilao, Guam.
- Moore, A. T. Marler, R.H. Miller, and R. Muniappan. 2005. Biological control of cycad Aulacaspis scale on Guam. The Cycad Newsletter 28: 6-8.
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Progress 01/01/04 to 12/31/04
Outputs
Progress: Morphological, genetic and ecological differences in Aphis gossypii were examined in aphid collections from the Federated States of Micronesia islands of Yap and Kosrae, from the Republic of the Marshall Islands (Majuro), American Samoa, and Japan. Additional aphid surveys were performed for the Hawaiian islands of Oahu, Kauai, Maui and Hawaii. These data were combined with that originating from A. gossypii and other aphid collections from Micronesia and North America toform a comprehensive catalogue of aphids within Micronesia, and A. gossypii variation worldwide. The presence of aphidiid parasitoids, where present, was noted and the aphidiid identified. Ants collected in association with aphids, and that may have a role in altering the effectiveness of aphidiid biological control agents, were identified. Genetic variation in A. gossypii was found to vary by host plant and then by geographic provenance of the sample, while morphometric variation was most
closely correlated to geographic provenance. A. gossypii reared on taro were not able to establish viable colonies on other plant hosts, while A. gossypii reared on some cucurbits were able to successfully establish colonies on taro.
Impacts
We now understand the make-up of aphid-parasitoid-ant complexes on crops and ornamental plants in many of the islands of Micronesia and Hawaii. Pest managers can identify the major aphid pests they encounter at ports of entry and on crops and ornamentals on the various islands. We more fully understand the relationship between phenotype and genotype in A. gossypii. The association between many tramp ant species and specific aphid species has been described.
Publications
- Pike, K.S., R.G. Foottit, R. H. Miller, O. Idechiil and D. W. Allison. 2005. Uroleucon formosanum (Takahashi) and Uroleucon sonchellum (Monell) (Hemiptera, Aphididae): Morphological Comparison and Diagnosis. Proc. Hawaiian Entomol. Soc., in press.
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