The warm, dry weather in recent days has helped move growth in apple and pear along. Orchards in Essex, Chatham-Kent, Middlesex, Elgin, Norfolk and Niagara regions are now reaching bloom.
Fire blight risk predictions maps have been updated for May 17-23. With the warmer temperatures and rain predicted over the long weekend, fire blight risk has increased in many regions.
For the apple fire blight prediction maps: http://www.omafra.gov.on.ca/english/crops/facts/fireblight-2apples.htm
For the pear fire blight prediction maps: http://www.omafra.gov.on.ca/english/crops/facts/fireblight-2pears.htm
It is important to note that these risks are based on accumulated temperature over a period of days, which is likely why many regions have seen (and continue to see) lower risk with this cool spring. However, any area in bloom with a CAUTION – particularly those orchards with active fire blight – should be monitoring the forecast closely as the possibility of infection increases if weather becomes warmer and wetter.
If antibiotic materials are not being used, blossom protection with other materials should be initiated 1-2 days prior to entering a high infection risk period. Continue appropriate protective sprays until the infection risk drops below the HIGH threshold.