Inactivation of Cymbidium mosaic potexvirus (CymMV) and Odontoglossum ringspot tobamovirus (ORSV) using chemical disinfectants

Date

6-2015

Degree

Bachelor of Science in Agriculture

Major Course

Major in Plant Pathology

College

College of Agriculture and Food Science (CAFS)

Adviser/Committee Chair

Johnny F. Balidion

Abstract

Cymbidium mosaic potexvirus (CymMV) and Odontoglossum ringspot tobamovirus (ORSV) remain to be the most economically important orchid viruses worldwide. The mechanical nature of CymMV and ORSV leads to the risk of spread by cutting tools. During vegetative propagation and harvest, multiple cuttings are taken from one plant to another increasing the risk of virus spread. Disinfecting tools is a critical process in preventing the spread of disease during this farm operation. To directly address this concern, efficacy of various commercially available disinfectants and related chemicals were tested against CymMV and ORSV. A total of twelve test chemicals were screened using a local lesion indicator host plant, Cassia occidentalis. Rub inoculation of 1:1 (vol/vol) part ratio of the inoculum and 1% initial concentration of the test chemicals was done 30 seconds after the chemical and the crude sap has been mixed. Only five test chemicals showed significant reduction in CymMV and ORSV infection. These chemicals were NaOH, Virkon® S, STOP, Beloran, and Bestaquam. The minimum inhibitory concentration (MIC) of these chemicals was determined using the same host. For NaOH, STOP, and Bestaquam, the MIC was at 0.5% concentration while Virkon® S and Beloran need 1% concentration to inactivate CymMV and ORSV. Confirmation of these results was done in Dendrobium UH hybrids using the same inoculation scheme, with a high and low dose relative to the MIC determined for each test chemical. After 30 and 60 days from the inoculation time, portions of the inoculated leaf and youngest leaf of the test plants were collected and assayed for the presence of the target viruses using I-ELISA and/or RT-PCR. Results confirmed that the identified test chemicals were successful in the inactivation of CymMV and ORSV except Beloran. However, STOP and Bestaquam have phytotoxic effects to the test plants. NaOH and Virkon® S remain to be the most effective test chemical in inactivating CymMV and ORSV and are recommended for disinfecting cutting tools.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

LG 993.5 2015 A3 /B33

Document Type

Thesis

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