Climate change consequences pose a risk to apple cultivation

Fire blight is a bacterial pathogen which is able to kill not just individual trees but entire orchards. It spreads easily during the blooming season. This is not a new problem for apple growers, but its presence became larger with warmer and rainier springs that favor tree infections.

According to Terry Bradshaw, a research assistant professor at the University of Vermont, US, cider apple growers are at higher risk because the European varieties they rely on are biennial, which makes them specifically vulnerable to fire blight. Fire blight also poses a risk to other apple varieties and fruit crops such as pears.

According to Karen Lewis, a regional fruit tree specialist with the Center for Precision & Automated Agricultural Systems at Washington State University, in 2016-2018, there were considerably more days of fire blight risk during bloom than in the previous 10 years. In areas where climate change results in warmer springs, fire blight risk will grow.

Fire blight can be easily spread by wind, insects or rain, so stopping it in one part of a grower’s orchard can help to reduce the risk of spreading it further. 

According to Francis Otto, the orchard manager for Cherry Bay Orchards, Michigan, last year, he was able to ward off fire blight by utilizing sprays based on copper sulfate and streptomycin.

Marcus Robert, general manager at Tieton Cider Works, says it is vital to visually inspect the orchard for any infection signs, prune bad stems off the trees, take them out of the orchard and burn them. 

source: seattletimes.com

photo: goodfruit.com