- Dec 8, 2021
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Hello, I have a pear tree with fireblight, and I've been told I should spray it with horticultural oil in the winter when the leaves are off. I'm in western Vermont, and we don't have too many days above 40 degrees Fahrenheit in the winter (when the manufacturer says the oil can be applied), but we are forecasted to have a 45 degree day next week, without the possibility of rain that day or the day after, so it looks like that will be a possibility. Since many growers mix in copper fungicide with the oil to kill off the blight, I'm wondering if that would be the time to do it as well. (I've no experience with fireblight). The horticultural oil apparently acts to smother the blight, though the blight IS apparently dormant in winter in a colder region like mine. Thanks in advance for your advice!