Cold storage affects survival and growth of Erwinia amylovora on the calyx of apple

Aims: To determine the effect of cold storage on the survival of Erwinia amylovora. Methods and Results: The survival of E. amylovora was assessed during storage at 2 degreesC. Populations of E. amylovora inoculated into phosphate-buffered saline remained static, whereas in nutrient media populations increased at low temperatures. In contrast, populations of E. amylovora on tissue in the apple calyx decreased during cold storage. Conclusions: Erwinia amylovora has the ability, in nutrient media, to multiply at low temperatures. However, populations of E. amylovora on tissue in the apple calyx decrease with the time spent in cold storage. Significance and Impact of the Study: Cold storage of apples will provide assurance that mature fruit from orchards, free of fire blight, or even with low levels of fire blight, may be exported with a negligible risk of introducing the disease into countries free of fire blight.