What is in this article?:
- Cold winter has damaged Southeast blueberries
- Watch plants carefully
• The cold weather damage to blueberries is immediate, but there is a secondary danger of significant infection and disease caused by Botryosphaeria fungi that causes blueberry stem blight disease.
The following article is prepared based on a synopsis of information provided by Phil Brannen (UGA), Gerard Krewer (UGA Professor Emeritus), Bill Cline (NC State), Dave Lockwood (University of Tennessee), and Danny Stanaland (UGA); relative to a suggested response to the recent extensive cold damage observed on blueberries in Georgia. The extent of the damage may vary throughout the state, but it is somewhat universal for blueberries grown anywhere along the same latitude as Georgia and is observed in southern Alabama. Based on initial reports and opinions based on past observations by field specialists, it is predicted that this cold damage will have a significant impact on yield this year, but that remains to be seen.
The November-January cold snaps have caused significant tissue damage on blueberries, especially young plants. Generally, plants may not have "hardened off" well in the fall, as the temperatures were exceptionally high up to the point they were exceptionally low.
Young rabbiteyes grew extensively in the fall, because of the 80 degree plus days in late November. This was immediately followed by a drop to 22 F eight days later. Tips of the most vigorous shoots are often dead and the core of the shoot is dead 3 inches to 4 inches below this point. Spring shoots are reported to look better, but in many cases, the leaves are "fried." The problem varies by cultivar, as one might expect.
The damage is immediate, but there is a secondary danger of significant infection and disease caused by Botryosphaeria fungi that causes blueberry stem blight disease. Stem blight takes a while to move into cold-injured blueberry shoots, but it will definitely invade them eventually.
Pruning is required in the late January to early February timeframe to address this situation. Even though there is not sufficient information of a cost/benefit ratio, in a year such as this, it is highly likely that pruning out the infected plant parts will pay off in the current season and for seasons to come.
Krewer says that “We have seen dead shoot tips before in association with copper deficiency. Some growers who left them in 2008 and 2010 had a serious stem blight problem in the spring and had to do massive pruning to save the plants.”