Western Pacific Tropical Research Center
Invasive Plant Under Attack by UOG Scientist
It has taken more than five years of planning by UOG scientist G.V.P. Reddy to begin eradication of an invasive species that has taken over an estimated 1500 acres in Saipan, 500 acres in Guam and 5 acres in Rota. This invader is a vine, Coccinia grandis, commonly called ivy gourd and it covers anything in its path including power lines and trees. A rapidly growing climbing or trailing vine, it is a native of East Africa but has naturalized in Asia, Australia, Pacific Islands and the Caribbean Islands. In recent years it has become an invasive weed in Hawaii, Guam, Saipan and Rota by forming thick mats that overgrow forest and roadside vegetation, walls, fences, and utility poles. Ivy gourd is also a host for most of the pests of cucurbitaceous crops such as cucumber worm, (Diaphania indica), pumpkin beetle (Aulacophora foveicollis), melon fly (Bactrocera cucurbitae), melon aphid (Aphis gossypii), leafminers (Liriomyza spp.), leaf footed bug (Leptoglossus australis), whiteflies and others. Suppression of this weed is a prerequisite to starting a melon fly eradication program in the Mariana Islands.
|Ivy gourd covering trees.
Biocontrol insect Melittia oedipus.
The biocontrol insect Melittia oedipus (Lepidoptera: Sesiidae) has been successful in controlling the ivy gourd in Hawaii. The larvae of this small moth are a natural enemy of the ivy gourd and kill the plant by boring into the stem to feed. In March 2005, a culture of Melittia oedipus was brought from Kona, Hawaii to the containment laboratory at the University of Guam. An Environmental Assessment draft prepared by Drs. G.V.P. Reddy and R. Muniappan has been reviewed and the USDA has issued permits to Dr. Reddy to field release Melittia oedipus in Guam and Saipan.
Dr. Reddy and Zerlene Cruz attach
larvae to ivy gourd vine as a biocontrol measure.
Asian Cycad Scale Grant
The U.S. Fish and Wildlife Service awarded $33,000 to Dr. Aubrey Moore, University of Guam Cooperative Extension Service, to support a project entitled “Cycas micronesica protection from Asian cycad scale”. The objective of this project is protect wild, endemic cycads growing on the Guam National Wildlife Refuge at Ritidian Point. These cycads, commonly known as fadang or the federico palm, were listed as the most numerous tree-sized forest plants in a 2002 forestry survey. However, death of about 30% of these plants since arrival of the Asian cycad scale in late 2003 has resulted in Guam’s endemic cycad, Cycas micronesica, being placed on the IUCN Red List of Threatened Species. The grant will pay for emergency insecticide treatments applied by direct injection of cycad trunks. Duration of the grant is one year. Massive mortality Guam’s cycads from the cycad scale infestation is an environmental disaster which may rival the impact of Guam’s best known invasive species, the brown tree snake.
Biodiversity Monitoring Grant
The National Science Foundation has awarded $680,000 to Dr. Eric Wan, Oregon Health & Science University and Dr. Aubrey Moore, University of Guam Western Pacific Tropical Research Center to fund a project entitled “Instrumentation for in situ biodiversity monitoring and automatic classification of flying insects”. The objective of this project is to develop field instrumentation which automatically counts and classifies individual flying insects. This work is based upon an optical sensor and digital signal analysis system invented by Dr. Moore.
National Science Foundation Funds Guam Research
The University of Guam was recently awarded a research grant from the prestigious National Science Foundation. The funding will support ongoing ecology research on one of Guam’s important forest trees. “We began trying to figure out what it takes for Guam’s fadang plants to make seeds during preliminary studies last year,” said UOG Professor Thomas Marler. “We used this preliminary information to convince the NSF that continuation of the research was essential.”
Dr. Irene Terry monitoring Guam cycad.
Marler partnered with Dr. Irene Terry to capture the attention of the NSF. Terry is an international expert on the relationship of insects and reproduction of primitive seed-bearing plants. “Guam’s fadang belongs to a group of plants known as cycads,” said Terry. “These plants are commonly called dinosaur plants because of their antiquity.”
In order to produce seeds, plants use various methods to transfer pollen from one plant to another. The plants that make flowers are highly effective at using insects to do this job. But cycads do not make flowers, and were colonizing the earth long before any of the flowering plants. For these reasons, scientists once believed that cycads used wind instead of insects to transfer pollen from plant to plant. However, Terry and other biologists have shown in recent years that cycads do use insects to move pollen from one plant to another as the prerequisite for successfully making seeds for reproduction.
Last year the pair of researchers quantified the daily pattern and magnitude of heat production by fadang cones, and then identified some aromatic chemicals that the cones released into the air. Insects that effectively transfer pollen from other previously studied cycads are attracted to the cone’s aroma. “So we already know how the fadang plant seduces the insects,” said Marler. “We just need to continue the research in order to prove which insects are being seduced.” Terry was attracted to the Guam-based research primarily because fadang belongs to a cycad family that pre-dates the cycads she has been studying in Australia. “Our observations from last year seem to indicate that the insects we know are pollinators of these other younger cycad families actually do not pollinate fadang on Guam,” said Terry. “Thus, the Guam studies are critically important because they may give insights into the earliest years of how the world’s plants began to use insects to facilitate seed production.”
Dr. Terry inspects male fadang cone for pollen and insects.
Cycads were effectively growing and reproducing long before flowering plants began to colonize the earth. So the more we can learn about these primitive pollination systems, the more we can understand and care for modern-day flowering plants. “Since flowering plants contribute most of the food supply for humans and other mammals, this Guam-based research carries both scientific and practical importance,” said Dr. Harold Allen, University of Guam President. “The quality of our ongoing ecology research at the University is validated by this grant from the NSF.”
Asian cycad scale and cycad blue butterfly have taken an enormous toll on the only native gymnosperm in the Mariana Islands, Cycas micronesica. The introduction of the scale-eating ladybug beetle Rhyzobius lophanthae as a biological control agent has been successful, but may not be enough to save Guam's cycads. Fortunately, Thomas Marler has been actively setting up nurseries of cycad seedling stock from Guam in Tinian and Thailand with funding from the U.S. Navy. Cycas micronesica is currently listed as endangered on the International Union for Conservation of Nature and Natural Resources (IUCN) Red List of endangered species, thanks to the work of Dr. Marler and his colleagues.
The mortality rate of heavily infested, untreated Cycas micronesica (above) is 100%.
Bob Bourgeois and Aubrey Moore are protecting cycads growing in the Guam National Wildlife Refuge at Ritidian by injecting them with two types of insecticides, one aimed at the scale insects, and another aimed at the cycad blue butterfly caterpillars. At this time it is not certain whether the injection method will damage plant tissue or how it will affect the introduced bio-control beetle.
Bio-diesel on Guam?
The answer may be yes if Mari Marutani has her way! Her newest project has her students creating a survey for local restaurants to determine the amount of possible cooking oil available for bio-diesel processing in the future. She is also investigating potential local plants for use in producing ethanol. The information obtained from this project will be valuable in developing possible solutions for decreasing our dependence on fossil fuels.
Entomologists Aubrey Moore and Ross Miller and plant pathologists Bob Schlub and George Wall, in conjunction with the Western Plant Diagnostic Network (WPDN) are working to keep uninvited guests from setting up housekeeping on Guam. A "First Detector" workshop was held on campus November 2006 to train the public on how to respond to a possible encounter with a plant, animal, or plant disease system suspected of entering Guam without an invitation. Rapid detection and implementation of an emergency response plan will reduce economic and environmental damage caused by invasive species. For information on becoming a "First Detector" contact Dr. Moore at 735-2141 or 735-2086. WPDN has issued an alert regarding the threat of the red imported fire ant (Solenopsis invicta) and little fire ant or electric ant (Wasmannia auropunctata). These ants have been living in New Caledonia for about 30 years and have an extremely painful bite. Last June these ants were found in Cairns, Australia, which is of concern to Guam since there is a direct flight from Guam to Cairns.
Field of Dreams
Soil scientist Mohammad Golabi's dream field would include the plant vetiver, his answer to saving coral reefs and improving the quality of Guam's water supply. Extensive research in over 100 countries has found that vetiver is highly suitable for stabilizing riverbanks and preventing soil loss and landslides, which saves corals from suffocation due to silting. Sedimentation and soil erosion directly impact tap water quality. An example would be the Ugum River, an important water source for the southern part of the island. After heavy rains, the Guam Water Authority is forced shut down the Ugum River pumps due to sedimentation. Golabi's studies have shown that these problems could be mitigated if vetiver-planting techniques were implemented. For more information on vetiver or the soils of Guam please contact Dr. Golabi at 735-2134.