Proline (prothioconazole), a Bayer product, has been registered for blueberries. This is another demethylation inhibitor (DMI), FRAC Group 3 fungicide – similar to Indar, Orbit, and Quash, though it is listed in a triazolinthione chemical group, as opposed to a triazole group.
In Georgia, we do not have blueberry research data with this fungicide, but research will be conducted this year. There are very few research trials that have been reported for this product on blueberries. However, from the four trials I could find, it does appear the Proline will provide equivalent control of mummy berry to that of Indar. As a DMI, I would recommend that it be tank-mixed with Captan, just as Indar, when utilized in the bloom sprays. Proline appears to have some activity on both Botrytis and anthracnose fruit rots as well, and though not reported, I would expect leaf spot activity (likely Septoria and rust). There is no data available relative Exobasidium management, but as a DMI, it may have activity, especially when tank-mixed with Captan during bloom – no guarantees though. Producers may wish to take a “wait and see” approach till we have more data, but some may be interested in this product.