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United States Department of Agriculture

Agricultural Research Service


item Norelli, John (jay) - Jay

Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: 7/17/2003
Publication Date: 8/1/2003
Citation: Norelli, J.L. 2003. Survival and growth of 'Erwinia amylovora' on apple shoots. Phytopathology. 93(6)Supplement:S66.

Interpretive Summary:

Technical Abstract: When 'Royal Gala' apple shoots were inoculated with 'Erwinia amylovora' (Ea) and incubated in a growth chamber at 24.5 degrees C, Ea populations dropped from 10 4/leaf to below detectable limits within 48 hrs. Low Ea populations (<10/leaf) were detected six and 14 days after inoculation. Under orchard conditions in June, Ea was detected on leaves after rain events but were short lived. However, in July Ea populations recovered from leaves significantly increased following a thunderstorm that occurred on a hot day (35 degrees C). Low numbers of Ea were detected 10 July the day after the storm. On 15 July higher numbers of Ea were detected when leaf washings were plated on media but not when leaves were printed directly onto media, suggest the bacteria were within the leaf. Following 4 cm of rain on 16 July, Ea was detected by both washing and printing. A gfp labeled strain of Ea developed to study epiphytic growth was found to be less fit and virulent than the wild-type parent strain.

Last Modified: 10/19/2017
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