Cooperative Extension: Maine Wild Blueberries

5.25.16 Botrytis risk, May 23 to May 25

Print

With the last bit of wet weather we have had from none to moderate risk of Botrytis infection, if it is already in your field.  You need to have the fungus present in your field in a number of clones before we get the wet weather conditions to get any spread of Botrytis.   We have found  the risk of Botrytis infection does NOT translate into actual Botrytis infection unless the fungus has already been found in the field.

Please scout your fields for this disease before applying any fungicides to control it.    If you see symptoms of the disease (dead flowers WITH black “hairs” coming off of them) during mid-bloom AND there is a chance of a lot of wet weather coming up, then a fungicide application may be needed.  Otherwise, I do not recommend applying fungicide for this disease.  We have seen variable levels of Botrytis each year with no consistent pattern of it showing up in any field we have monitored.  If you do have a field that consistently does have Botrytis, I would be very interested in visiting it and using it for a fungicide trial if you are agreeable to that.

– Seanna Annis

Questions marks in the chart below are due to estimates due to gaps with the weather stations.