Yeast biocontrol agents that were applied to 'Bose' and 'Anjou' pears in the field
up to three weeks prior to harvest were found to survive on the fruit at high population
levels on both pear varieties. Cryptococcus infirmo-miniatus, Cryptococcus laurentii,
and Rhodotorula glutinis maintained populations averaging 5 x 10��� cfu/fruit for three
weeks. Candida oleophila had high initial populations, but the population size quickly
declined to levels similar to the total yeast populations on untreated fruit. After a
storage period of 2-4 months, fruit that were treated with C. infirmo-miniatus three
weeks before harvest showed significantly lower incidence of decay at wounds than did
untreated fruit.
Combinations of biocontrol agents with reduced rates of the postharvest
fungicides captan and thiabendazole were effective in reducing incidence and severity of
blue mold decay caused by Penicillium expansum on 'Bosc' pears. Calcium chloride was
also effective in combination with some biocontrol agents. Chitosan caused reductions
in decay when used alone, but not when combined with most biocontrol agents. The
compounds L-asparagine, L-proline, and 2-deoxy-D-glucose were not consistently
effective either alone or combined with biocontrol agents.
Storage of 'Bosc' and 'Anjou' pears in atmospheres with carbon dioxide
concentrations of 12% or 20% for up to six weeks significantly reduced incidence and
severity of gray mold decay caused by Botrytis cinerea, but decay was not reduced when
the atmospheres was only 3% CO���. In contrast, the 12% or 20% CO��� atmospheres did
not have significant effects on decay caused by P. expansum. Use of the biocontrol
agents C. infirmo-miniatus, C. laurentii, or R. glutinis led to reductions in decay in all atmospheres, with C. infirmo-miniatus being the most consistently effective. The biocontrol products BioSave-110 (EcoScience Corp.) and Aspire (Ecogen Corp.) were less effective than the yeasts C. laurentii, R. glutinis, and C. infirmo-miniatus which were grown in the lab. / Graduation date: 1999
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/33580 |
| Date | 30 June 1998 |
| Creators | Benbow, Jesse M. |
| Contributors | Sugar, David |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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