No. 8 — May 13, 2019
In general, Pestalotipsis spp have been classified as endophytes meaning that the fungus lives within the plant. At least in the case of Pestalotiopsis and grapevines the association does not appear to cause disease during part of the funguses life cycle. Here in Missouri over the past few years, we have learned that Pestalotiopis can cause leaf blight (Figure 1) and has caused fruit rot in Norton. My colleague Lucie Morton in Virginia has also demonstrated that Pestalotiopsis causes the berries to stall out during the ripening process and sugars simply do not rise within the berries. Lucie and I have shown that Captan and mancozeb can control the Pestolotiopsis in culture on potato dextrose agar. What remains unanswered is can Captan or mancozeb have any efficacy on Pestalotiopsis once inside the grape tissue. There are still a lot of unanswered questions, but we are making progress.