Progress 06/01/07 to 09/30/08
Outputs
OUTPUTS: The cycad aulacaspis scale (CAS), Aulacaspis yasumatsui Takagi (Hemiptera: Diaspididae), a pest of cycads, is of Southeast Asian origin, specifically the region between Thailand and peninsular Malaysia in the west and southern China in the east. Within a relatively short period of its introduction, CAS has threatened with extinction of the endemic species, Cyacs micornesica in Guam. Currently the options available to tackle the menace of this pest are chemical and biological control methods. Chemical control is feasible only in the urban areas and it is difficult to adopt in the habitats of the native and endemic cycads. Further it is cost and labor intensive and risk interference with insect pollinators. Biological control is the most cost and labor-effective method for controlling CAS and it is the standard approach for long-term control of introduced exotic scale pests. A parasitoid Cocobius fulvus has been imported several times from Florida to University of Guam Quarantine Facility since August 2005 and it is being cultured in caged scale infested sago palm plants. To date we have received 3165 adults (1015 were used for lab culture while 2150 were field released). In January 2006, it was first field released in Marbo Cave, Dededo and Tolofofo. The following are the objectives: 1) Introduce the Thailand and China strains of C. fulvus in two different parts of Guam, 2) Record their spatial and temporal spread, 3) Evaluate their efficacy in the laboratory and field, 4) Determine the intraguild predation (IGP) of R. lophanthae on C. fulvus, and 5) Introduce and evaluate the parasitoid, Arrhenophagus chionaspidis from Florida. PARTICIPANTS: Dr.Ru Nguyen, Florida Department of Agriculture and Consumer Services, Gainesville, Florida TARGET AUDIENCES: Guam Department of Agriculture and farming community. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
At Marbo cave location one exit hole was observed. This indicates that there is a possibility that this parasitoid will be established. Currently we are concentrating on laboratory rearing of the parasitoids so that a large number of them could be field released. Part of the problem in field establishment seems to be the predation of the parasitized scales by the introduced ladybeetle, Rhyzobius lophanthae Blaisdell (Coleoptera: Coccinellidae). Additional shipments of this parasitoid from Florida are also expected. Scale infested cycad leaves are collected every month to monitor the establishment of the parasitoid and the population dynamics of the scale in relation to the weather factors. We believe this parasitoid is in the environment and will be established as long as prey is available.
Publications
- Muniappan, R., G.V.P. Reddy, and A. Raman, eds. 2009. Biological Control of Tropical Weeds using Arthropods. Cambridge University Press, Cambridge, UK, 495 pp.
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Progress 01/01/07 to 12/31/07
Outputs
OUTPUTS: Chromolaena odorata is a serious invasive weed in Guam and rest of the Micronesia in the Pacific Basin. It is highly allelopathic, fire prone and toxic to animals. It suppresses native vegetation. It invades disturbed forests, vacant lands, road sides, and plantation crops. It is one of the top ten weeds in Micronesia. University of Guam has been involved in biological control of chromolaena since 1985. We have organized six international workshops and published 15 newsletters on chromolaena. Proceedings of these workshops can be viewed from the link: http://www.ehs.cdu.edu.au/chromolaena/siamhome.html. Introduction and establishment of the arctiid, Pareuchaetes pseudoinsulata has considerably reduced the thickets of this weed in Guam. Owing to the insect induced defense in C. odorata to P. pseudoinsulata and abiotic factors, this weed exists in scattered patches. Introduction of C. connexa is expected to complement the defoliation effect of P. pseudoinsulata as it reduces the seed production and vigor of the plant. Recently C. connexa has been established in Indonesia, Papua New Guinea, Palau, Guam, Pohnpei, Saipan and Rota. It is being cultured in quarantine in India, Taiwan and the Philippines. However, an evaluation of the efficacy of C. connexa in suppression of chromolaena and its interaction with P. pseudoinsulata are yet to be studied. Detailed studies on biological and ecological aspects of this insect are to be documented for the science. PARTICIPANTS: Z.T. Cruz, carry out laboratory and field studies involved in biology of the gallfly, histology, surveys, chemical analysis, pot culture experiments etc for this project. Ray Guamtaotao , Field Technician, assists in growing the plants and maintaining the insect cultures in the laboratory. TARGET AUDIENCES: Scientific communities: The final results will be disseminated to the scientific community by publishing in journals and technical reports. Farming community: Farmers are being informed of the benefit of project through demonstration and outreach activities. General public are being informed through news media, brochures and publishing in local newspapers. PROJECT MODIFICATIONS: This experiment will be repeated during the months of February-April as to evaluate the number of flowers and viable seeds produced as Chromolaena odorata flowers only during these months in Guam.
Impacts
Chromolaena odorata, a neotropical plant that has become an invasive weed in the humid tropics of Asia, Africa and Micronesia. An arctiid moth, Pareuchaetes pseudoinsulata and a tephritid gallfly, Cecidochares connexa are the two promising natural enemies currently used in the classical biological control of this weed. Pareuchaetes pseudoinsulata has been introduced and established on Guam in 1985. The caterpillars of this moth defoliated and killed C. odorata that occurred in thickets. Owing to the insect induced defense in C. odorata to P. pseudoinsulata and abiotic factors, sparsely scattered populations of this weed are not controlled. In May 2003Cecidochares connexa has been introduced and established in the central part of Guam. It is expected that the gallfly to complement the moth in suppressing C. odorata. I propose to study the biology of this gallfly and histology of the gall; investigate the nutrient sink caused by the gall, spatial and temporal spread of the gallfly from the release site, effect of the gall on plant growth, local natural enemies recruited by the gallfly and the interaction between P. pseudoinsulata and C. connexa in suppressing C. odorata.
Publications
- Cruz, Z.T., Muniappan, R. and Reddy, G.V.P. 2006. Establishment of Cecidochares connexa (Diptera: Tephritidae) in Guam and its effect on the growth of Chromolaena odorata (Asteraceae). Annals of the Entomological Society of America, 99: (4): 845-850.
- Muniappan, R., Englberger, K. and Reddy, G.V.P. 2007. Biological control of Chromolaena odorata in the American Pacific Micronesian Islands, In: Proceedings of the Seventh International Workshop on Biological Control and Management of Chromolaena odorata and Mikania micrantha, (Editors: Lai, P-Y, Reddy, G.V.P. and Muniappan, R.), National Pingtung University of Science and Technology, Taiwan, pp. 49-52.
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