Callisto Herbicide Injury to Brambles

Callisto (a.i. mesotrione) has been labeled for blueberries for the past five years, but the label was expanded to include brambles this year. We used it at the 3 fl. oz. per acre rate on our bramble plantings in Lafayette and significant damage occurred on several varieties. Both blackberries and raspberries were affected. The floricanes appear to be more heavily damaged than primocanes. In some cases, damage is so severe that a complete loss of the summer crop is expected. At this time, primocanes appear to be relatively normal, but we will know more in a few weeks. We have heard of similar damage from commercial growers. If you used Callisto on brambles this year, please contact Bruce Bordelon (bordelon@purdue.edu) whether you had damage or not. We would like to know the full extent of the problem.