Sylvester Lynch, a resident of Villa and a former Agricultural Officer in the Ministry of Agriculture, Forestry and Fisheries, successfully defended his Ph.D. thesis: “Management strategies for papaya diseases in St. Vincent and the Grenadines.”{{more}}

This he did on October 19, 2009, at the Cave Hill Campus, UWI. Lynch’s study assessed the status of the two most important papaya diseases reported in St. Vincent and the Grenadines, papaya bunchy top (PBT) and papaya bacterial canker (PBC). His work has provided new and useful information in the understanding and practical means of controlling these diseases.

The PBT is a very devastating disease. There is significant fruit loss and ultimately death of the papaya trees. In SVG, incidence of PBT is 71.3% and severity 75.4%. Commercial papaya cultivation has dwindled throughout the Eastern Caribbean as a result of this disease. It is deemed that PBT is caused by a bacterium, Rickettsia, and transmitted by leafhoppers (insects). The study revealed that PBC is a slow epidemic, but severe cankers on the stem can lead to death of the papaya plants. PBC can be managed through proper crop husbandry.

Lynch reported on the successful control of the PBT. He conducted an experiment that sought to isolate papaya plants from the leafhopper vectors by cultivating papaya in insect-proof nethouses / enclosures and compared the extent of PBT infestation within the nethouses and open fields. The experiment was also used to compare plant growth and development and fruit characteristics of papaya cultivated in nethouses and open fields, as well as the micro-climate of both plant cultures.

The results of the experiment showed that there was no incidence of PBT in the nethouses, whereas in the open fields there was 100% incidence. Plant growth and fruit production indices of papaya grown in the nethouses were not compromised and fruit quality met the required standards for the export markets. Also, that this system of papaya cultivation is likely to be economically feasible.

Lynch thanked Professor Leonard O’Garro, his supervisor, and Philmore Isaacs, former Chief Agricultural Officer, for their steadfast support during the course of the study. Lynch received very high commendation from UWI for the quality of his study; it was quite extensive and very well researched. The study is relevant and timely in the economic context of the rapid decline of the banana market and the need for agricultural diversification since SVG’s agricultural economy could not be sustained on the banana monoculture. Commercial papaya cultivation can be expanded now that the constraints of the significant diseases have been addressed. Papaya is a highly acclaimed fruit and great potential exists for export to North America and Europe.

Sylvester Lynch is a Plant Health Specialist. He holds a B.Sc. degree in Agricultural Biology: Pest Management, from Dalhousie University, Nova Scotia, Canada, and a Master’s degree in Entomology / Plant Pathology, with specialization in Integrated Pest Management, from Cornell University, Ithaca, New York. Lynch also has specialized training in Pesticide Management and Pesticide Application Technology from the Imperial College, University of London, also in Plant Quarantine Systems Analysis from The Professional Development Center in Maryland, USA.