ISHS Acta Horticulturae 124: III International Symposium on Pear Growing
THE EFFECT OF RELATIVE HUMIDITY ON SPORE GERMINATION OF PEAR DECAY FUNGI AND D'ANJOU PEAR DECAY |
| Authors: | R.A. Spotts, B.B. Peters |
| Abstract:
The effect of high relative humidity (RH) on conidial germination of five pear decay fungi was studied at -1.1, 10, and 20°C. At 100% RH, Mucor piriformis, Botrytis cinerea, Pezicula malicorticis, Penicillium expansum, and Phialophora malorum germinated at -1.1, 10, and 20°C. At -1.1°C, no germination occurred at 97% RH, and only B. cinerea germinated at 99% RH. At 10°C, no germination occurred at 90% RH, and only P. expansum germinated at 95% RH. At 20°C, no germination occurred at 80 or 90% RH. Days required for germination of fungal spores at -1.1°C were as follows: B. cinerea - 14, P. malorum - 21, P. malicorticis - 42, M. piriformis - 45, P. expansum - 51. When wounded d'Anjou pears were inoculated with conidia of the five fungi and placed at 97, 99, or 100% RH at -1.1°C, B. cinerea, P. expansum, and P. malicorticis caused decay at all RH levels. M. piriformis and P. malorum decay occurred only at 100% RH. The RH in commercial bins of d'Anjou pears during storage at -1.1°C was 98 to 100% RH, and free water may be present due to fluctuating temperature. | |
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