RESEARCH ON DISEASES OF TRADITIONAL PACIFIC ISLAND CROP PLANTS.

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: COMPLETE
• Funding Source: HATCH
• Reporting Frequency: Annual
• Accession No.: 0210494
• Project Start Date: Jun 1, 2007
• Project End Date: Sep 30, 2012
• Program Code: [(N/A)]- (N/A)

Recipient Organization
UNIVERSITY OF GUAM UOG STATION
(N/A)
MANGILAO,GU 96913

Performing Department
Experiment Station

Non Technical Summary
Traditional crop plants of the Pacific Islands are plagued by a number of important diseases. A disease of coconuts was described on Guam, with an unknown causal agent, called Tinangaja. Taro Leaf Blight, caused by the fungus Phytophthora colocasiae, devastated the entire taro crop in South Pacific Islands. Banana Bunchy Top, Black Leaf Streak, and Panama Wilt are some of the most important banana diseases in the Pacific. Betel nut bud rot, caused by Phytophthora palmivora, recently caused epidemics on Sipan and Guam, killing thousands of valuable betel nut palms. Papaya Ringspot Virus is the most important papaya disease on Guam The main purpose of this project is to look into ways of reducing the negative economic and environmental impacts that these diseases may have on their corresponding crop plants in our region.

Animal Health Component

(N/A)

Research Effort Categories

Basic

(N/A)

Applied

(N/A)

Developmental

(N/A)

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
212	2499	1160	100%

Knowledge Area
212 - Pathogens and Nematodes Affecting Plants;

Subject Of Investigation
2499 - Plant research, general;

Field Of Science
1160 - Pathology;

Keywords

plant diseases

papaya

butle nut

coconut

banana;

Goals / Objectives
1. Develop the most sensitive technique possible for the detection of the Coconut Tinangaja Viroid (CTiVd) in order to be able to detect it at the earliest possible infection stage. 2. Investigate ways of reducing the spread of CTiVd from infected to healthy coconut trees. 3. Search for ways of reducing the negative impact of banana diseases on local production by reducing the likelihood of spread of important pathogens such as BBTV, Mycosphaerella fijiensis, and Fusarium oxysporum f. sp. cubensis. 4. Research the ways of managing taro leaf blight, caused by Phytophthora colocasiae, and other important taro diseases. 5. Study betel nut bud rot to find ways of minimizing its impact on the island?s crop. 6. Continue to work with PRV to find ways of controlling this disease on papaya.

Project Methods
In order to develop a more sensitive technique for the detection of CTiVd, we will try one based on reverse transcriptase polymerase chain reaction, which at this time is the most advanced molecular technique for such purposes. Collaboration with another institution or private growers will be sought in order to carry out field tests; sanitation measures will be put into effect in test plots and compared with similar plots in which traditional pruning and harvesting activities are continued. Banana bunchy top does spread mechanically, that is, by cutting tools or by contact. Therefore, reduction of bunchy top incidence is contingent upon the removal of infected material, a reduction in the aphid population, and avoidance of the use of infected planting material. We will test commercially available kits capable of detecting BBTV. Alternatively, fluorescence microscopy may be investigated. An education campaign is needed to teach growers how to identify bunchy top and about the need to avoid infected planting material. Black leaf streak caused by the fungus Mycosphaerella fijiensis, can burn up the leaves in a banana plant. Several of these recently introduced cultivars are available at our experiment station. Observations to verify their resistance to black leaf streak, and to catalogue their agronomic traits are needed. m Panama wilt and Nematodes will be controlled by usage of clean planting material from tissue culture. Spread of taro leaf blight caused by the fungus Phytophthora colocasiae will be controlled by usage of resistant cultivars. We will continue to evaluate our taro collection and monitor taro leaf blight incidence. We will continue to work on bud rot of betel nut. So far we have already identified the causal agent of this devastating disease, and carried out a survey of Guam?s southern region where an outbreak occurred in 2003 and 2004. We will continue to work to find ways of reducing its impact. We will continue to work on papaya ringspot virus to look for resistant cultivars or to find other ways of minimizing yield losses.

Progress 06/01/07 to 09/30/12

Outputs
OUTPUTS: Diseases of traditional Pacific island crops were studied until P.I retired in 2012. PARTICIPANTS: Not relevant to this project. TARGET AUDIENCES: Not relevant to this project. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
Results of research findings were published in formal and informal manner.

Publications

• No publications reported this period

Progress 01/01/10 to 12/31/10

Outputs
OUTPUTS: We planted some banana observation plots at Yigo and Inalajan Experiment Stations. Various banana cultivars were imported in tissue culture. They are intended for propagation. We have obtained disease-free material from Belgium and Fiji and have started to multiply it in vitro; cultivars, locally known as Manila and Macau, have already been received and are being prepared for mass propagation and release to growers. A plan to survey the island of Guam for the Coconut Tinangaja Viroid and the Coconut Cadang Cadang Viroid, two lethal diseases of the tree of life, is under way. Only CTiVd is known to occur on Guam; it has been more than 10 years since the last survey. At the Inalajan Experiment Station we maintain a Taro collection; currently the collection has been moved to the screenhouse in Mangilao. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
A book illustrating some of the taro varieties in our collection was published just recently; our taro collection includes materials obtained from many islands in our region, observed in our experiment station for a number of years. It describes agronomic traits for each cultivar, as well as taste, texture and any resistance to diseases or pests such as taro leaf blight, taro leaf aphid, or taro hornworm for each cultivar.

Publications

• Wall, G. C. and Wiecko, A. T. 2010. Guam taro guide. Western Pacific Tropical Research Center, Plant Pathology Lab, University of Guam. 38 pp.
• Wall, G. C. 2010. Evaluation of lateral flow test for transgenic papaya. Proceedings of L APS-CD Annual Meeting, Managua, Aug. 24-27, 2010.

Progress 01/01/09 to 12/31/09

Outputs
OUTPUTS: DNA samples from all entries in our TARO collection have been collected and are ready for testing by PCR for TaBV. The F 1 generation of crosses between red and yellow Dagua PAPAYA were planted at Yigo and Inalajan Experiment Stations on Guam, and at As Perdido Experiment Station on Saipan. We now have 7 disease free tissue cultured BANANA accessions obtained from SPC in Fiji and Bioversity International in Belgium; these are ready for in vitro propagation. A method of applying phosphorous acid to ARECA NUT for control of bud rot without trunk injections was tested; the fungicide was applied through adventitious roots. New RNA extraction procedures were tested as a possible means of improving our current viroid testing protocol for CTiVd, a lethal disease of COCONUT; in addition, a real-time PCR cycler was obtained by our research unit at WPTRC which will further improve our existing viroid testing protocol. A Guam survey of 2 ORCHID viruses was completed and results were published. PARTICIPANTS: Part of this work was done in collaboration with Guam Department of Agriculture; two individuals received training in banana tissue culture techniques. We also collaborated with individuals from the Northern marianas College on Saipan; we trained 1 person from this organization to do ELISA for Papaya Ringspot Virus; he also received training in papaya breeding techniques. TARGET AUDIENCES: Not relevant to this project. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
Development of a simplified PCR techinque and a cost effective DNA extraction method to test for TaBV are important steps toward our goal to screen our TARO collection; using room temp. PCR reagents and a home made DNA extraction (CTAB) eliminates the need for expensive dry ice shipments and costly extraction kits. Our PAPAYA breeding program is advancing towards PRV resistance; we are now producing F2 seed. The tissue culture lab is almost ready to start operating at Guam Department of Agriculture to propagate disease free BANANAS. An alternative to trunk injections for the application of fungicide in the control of bud rot of ARECA NUT is available and we will continue to seek approval for this technique. Better RNA extraction and more sensitive real time PCR techniques should improve the sensitivity of our current viroid testing protocol to continue COCONUT research. Our ORCHID survey revealed the presence of 2 important viruses already on Guam's nurseries and private collections.

Publications

• Wall, G. C. and Wiecko, A. T. 2009. Sondeo de enfermedades virales y de otra indole en orquideas importadas a Guam. P. 215 IN Libro de Resumenes del XV Congreso Latinoamericano de Fitopatologia y XVIII Congreso Chileno de Fitopatologia, Santiago, Chile, 12-16 enero.
• Wall, G. C. and Wiecko, A. T. 2009. Survey of orchid viral diseases on Guam. Abstract IN Proceedings of the National Plant Disease Network Meeting, Miami, FL, Dec. 6-10.
• Wall, G. C. 2009. Levels of P in Areca catechu leaves following phosphorous acid application through adventitious roots. IN Proceedings of the Annual Meeting of the American Phytopathological Society, Caribbean Division, Orlando, FL, June 16-19.
• Wall, G. C. and Wiecko, A. T. 2009. Orchid Virus Disases. Plant Disease Series Brochure. CNAS/WPTRC, University of Guam.
• Wall, G. C. 2009. Banana Bunchy Top. Plant Disease Series Brochure. CNAS/WPTRC, University of Guam.
• Wall, G. C. 2009. Bud Rot of Betel Nut. Plant Disease Series Brochure. CNAS/WPTRC, University of Guam.
• Wall, G. C. 2009. Papaya Ringspot Virus. Plant Disease Series Brochure. CNAS/WPTRC, University of Guam.

Progress 01/01/07 to 12/31/07

Outputs
OUTPUTS: This project has started several months ago. Nothing significant to report at this time. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
This project has started several months ago. Nothing significant to report at this time.

Publications

• No publications reported this period