This is an important time of year to be thinking about diseases in strawberries. Gray mold or Botrytis and Anthracnose fruit rot are the most likely diseases to cause yield loses at this point in the game. Gray mold is by far the largest concern. The plants below look good and we can see some blooms present. From the truck, these look fine.
Below is a dead flower with gray mold growing on the stem. It is underneath the healthy leaves and difficult to see unless the leaves are pushed aside. The spores, which appear grey and fuzzy (not to be confused with the fine hairs on the stems) will be disseminated by the wind and rain splash to healthy parts of the plant. Once the plant has ripening fruit, this will be a big problem and we want to control it as much as possible.
We should start a fungicide program at first bloom and spray every 7 to 10 days rotating between two or more of the following: Captan, CaptEvate, Switch, or Captan + Fontelis. End applications 26-30 days before final harvest. Rotation is very important for fungicide resistance management. If Anthracnose becomes a threat, a slightly different approach will be necessary. Consult the 2015 Southeastern Strawberry IPM Guide for more info.
Guido Schnabel, Plant Pathologist with Clemson Extension, offers resistance screening to test for fungicide resistance. Samples can be taken from individual farms and sent to Guido where he will test the samples and make an individual report for that farm to show which fungicides will be the most effective for controlling gray mold. This is great information specific to each farm. If you would like to sample your farm, contact your local Agent or take a look at these instructions.
For more production information look at the Southeastern Regional Small Fruit Consortium.