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Pressure Inoculation as a Technique for Postharvest Studies on Fungal Pathogens of Pome Fruits. P. Sholberg, Research Scientists, Agriculture Canada Research Station, Summerland, British Columbia V0H 1Z0, Canada. M. Meheriuk, and W. McPhee. Research Scientists, Agriculture Canada Research Station, Summerland, British Columbia V0H 1Z0, Canada, and Okanagan Similkameen Cooperative Growers Association, Oliver, British Columbia V0H 1T0, Canada. Plant Dis. 73:260-262. Accepted for publication 2 November 1988. Copyright 1989 Department of Agriculture, Government of Canada. DOI: 10.1094/PD-73-0260.

The total number of freshly harvested apples that decayed when pressure inoculated with a suspension of 103 conidia per milliliter of Penicillium expansum depended on the cultivar: 85% decayed for Spartan, 77% for McIntosh, 75% for Golden Delicious, and only 33% for Red Delicious. Puncture and dip inoculation provided 100% infection with all four cultivars. Pressure inoculation of McIntosh with 0, 103, and 106 conidia per milliliter of P. expansum showed a highly significant linear relationship between conidial concentration and total number of fruit decayed. The incidence of rot in Bosc pears pressure inoculated with 104 conidia per milliliter of P. expansum, Botrytis cinerea, or Phialophora malorum was 62, 43, and 30%, respectively. Addition of 4% CaCl2 to a suspension of conidia of P. expansum at 104/ml or greater reduced the number of decayed Golden Delicious apples from 63 to 50%. When 350 ppm of benomyl was added to 4% CaCl2 in a suspension of 105 conidia of P. expansum per milliliter, the percentages of decayed fruit of McIntosh, Golden Delicious, and Spartan were further reduced from 39, 37, and 23% to 8, 1, and 0%, respectively. Pressure inoculation disrupts lenticels and allows an avenue of entry for infection by hyphae. Pressure inoculation permits large quantities of fruit to be inoculated at one time and can be useful in determining the efficacy of current and new fungicides.