The primary objectives of this research are to determine effective biological and alternative control strategies of insect and disease pests in order to reduce harsh chemical use during greenhouse crop production and transport s. This research includes two separate studies: 1) testing the practical viability of rearing and storing four species of entomopathogenic nematode (EPN), Steinernema feltiae, Steinernema carpocapsae, Heterorhabditis bacteriophora, Heterorhabditis indica; and, 2) the efficacy of UV-C radiation applied, pre-transport, as a preventative disease control strategy against Botrytis cinerea. A study was conducted testing EPN infectious juvenile (IJ) rearing production counts and IJ viability after a six-day storage period. When all four species are compared, S. feltiae had a greater number of infectious juveniles emerge from the wax moth cadavers and S. carpocasae had the least. All four species survived the six day storage period but EPN infectious juvenile counts were significantly different among species. Our second study tested the efficacy of UV-C radiation as an alternative control to traditional fungicides to deactivate B. cinerea in vitro and to determine plant tolerance to UV-C. The crops tested were poinsettia (Euphorbia pulcherrima) and primula (Primula vulgaris). All the UV-C doses, 1.0, 2.8, 3.7 or 4 W/m2, significantly decreased B. cinerea conidial germination in vitro and resulted in zero percent damage on poinsettia bracts. However, all UV-C doses during both replications caused minor damage, 15% or less, to primula flowers. / Master of Science in Life Sciences / Entomopathogenic nematodes (EPN) shows promise in being non-chemical and environmentally friendly solution for greenhouse pest and disease control. These can also be referred to as Biological Controls (Biocontrols). Entomopathogenic nematodes are used widely to control multiple greenhouse plant pests which include both Lycoriella spp., Fungus Gnats, and Frankliniella spp., Western Flower Thrips. However, there are challenges with EPN viability and storage from the manufacture to the greenhouse producer. We studied four EPN species, Steinernema feltiae, Steinernema carpocapsae, Heterorhabditis bacteriophora, Heterorhabditis indica, which were reared and stored to determine differences in production viability between species. Results show that the EPN species do not respond the same to storage and produce different amounts of infectious juveniles during rearing when conditions are the same. Separate from, but just as concerning as greenhouses plant pests are plant diseases. Ultraviolet radiation in the C spectra is known to be germicidal due to its narrow wavelengths. Because of this, UV-C has been shown to deactivate many different plant pathogens on contact and is being considered as a possible Biocontrol alternative to harsh traditional fungicides and bactericides. One disease that is known to contribute to the highest volume of annual crop losses is Botrytis cinerea. Botrytis cinerea is a plant disease that impacts floricultural crops to vegetables during propagation through the production supply chain to shipping and storage. We evaluated UV-C radiation at different doses, to determine if it could be used to replace a traditional fungicide before plants are shipped to reduce B. cinerea infection during transport. We found that UV-C successfully deactivated B. cinerea in vitro, but the viability of the application to plant tissue before transport has yet to be proven successful as a practical method of reducing B. cinerea during transport.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/106591 |
| Date | 10 November 2021 |
| Creators | Higginbotham, Matthew Travis |
| Contributors | Horticulture, Latimer, Joyce Griffin, Baudoin, Antonius B., Scoggins, Holly L. |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | ETD, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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