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agInnovation Research Center | Plant Pathology

agInnovation Research Center | Plant Pathology

Plant pathology research at UOG

Western Pacific Tropical Research Center plant pathologists are engaged in research of the diseases of traditional Pacific island plant crops as well as other plants cultivated in the islands. Given Guam's unique environment and endemic plant species, much of our lab's work is on pathogens unique to Guam.

The Plant Pathology Lab utilizes a combination of classical microbial culturing techniques and molecular diagnostics to identify pathogens. 

Why it's important

Ecological and agricultural needs in Guam guide the scientific study of plant diseases. Guam’s tropical environment supports several diverse ecosystems with many uncommon and unique native plant species. These plant species provide habitats and nutrition for higher organisms, such as the Marianas fruit bat and the endangered Mariana eight-spot butterfly. Similarly, these same plants are utilized in local CHamoru diets and traditional healing practices.

As a regional transport hub, international movement of cargo in and out of Guam exposes the island and region to foreign plant disease. Non-native agricultural crops and a robust ornamental plant trade contribute to the island’s plant diversity but also carry additional biosecurity risks.

Plant diseases are caused by pathogens (biotic) and environmental conditions (abiotic). Plant pathogens threaten many native species, yet they remain largely unidentified and undocumented. 

Sustainability of the island’s flora requires a higher understanding of the pests and diseases that threaten their health. Rapid identification of these pathogens creates better informed actions on quarantine and eradication. 

Past impacts

Work in the Plant Pathology Lab under previous faculty researchers Dr. Andrea Blas and Dr. Robert Schlub has resulted in:

The Plant Pathology Lab has recently isolated and identified two Erwinia different species that are the causal agent of mushy canker on papaya. Ongoing work will identify virulence factors and the role of cell-cell communication in these pathogens. Additional work looks at the role of mollusk vectors in the spread of the pathogens.

Funding source: Hatch

Anthracnose is the leading cause of yield reduction in local hot pepper (doni, Capsicum annum and Capsicum frutescens) production. Colletotrichum spp. are the presumed pathogen. Undergraduate students are creating a culture collection of fruit pathogens to identify and characterize. Variety trials with individual pathogens and various management techniques will guide local growers’ production practices.

Cycas micronesica, the endemic Guam cycad tree, was once Guam’s most common tree but is now endangered due to human development/habitat reduction and an assault of various foreign pests and diseases. Considerable effort at the University of Guam is invested in nursery propagation for future out-planting. Microscopic observation has identified two novel foliar pathogens. Ongoing work focuses on getting pathogens into culture, completing Koch’s postulates, and completing DNA sequence analysis for identification. Future work will survey for diseases in wild cycad populations and identify best management practices to reduce negative impacts on the plants’ growth. 

Funding source: None

 

USDA logoThe work of UOG Land Grant is supported by the U.S. Department of Agriculture’s National Institute of Food & Agriculture and the government of Guam. USDA and UOG are equal-opportunity providers.

 

Last updated: August 2023


RESEARCHER:

Glenn Dulla, Ph.D.
ALS Bldg., Room 217 
Phone: (671) 735-2140 
Email: dullag@triton.uog.edu