Fire blight infection risk continues to be high to extreme/exceptional from May 24-29 in many regions of the province according to the OMAFRA prediction maps for apples and pears. Later regions will be in bloom shortly. Early regions should watch for rattail bloom in any blocks that are in petal fall.
Growers should keep a protective program until the risk drops back down below high. The rain, windy days and increasing pollinator activity this week will have moved bacteria to open blossoms, particularly if fire blight has been an issue in the orchard or neighbourhood. Infection will occur with any wetting event if a protectant program is not in place under high to extreme risk conditions. Under extreme risk, even orchards that did not have fire blight last year are likely to see infection.
Fire blight prediction maps for apples: http://www.omafra.gov.on.ca/english/crops/facts/fireblight-2apples.htm
Fire blight prediction maps for pears: http://www.omafra.gov.on.ca/english/crops/facts/fireblight-2pears.htm