Pruning Hazelnuts for Management of Eastern Filbert Blight

The pruning effectiveness on yield loss due to eastern filbert blight (EFB) was studied on mature, bearing hazelnut trees in a replicated trial. This case study was originally set up as a fungicide effectiveness trial but then converted to a pruning trial at the hazelnut industry's request. Growers wanted to know if severely cutting back heavily infected trees and then regrowing a tree from sucker sprouts would be an effective technique for managing EFB. Detailed pruning of cankers was also investigated. The former non-fungicide-treated trees were cut back to a 15-cm stump, followed by selection of 4 to 6 shoots to reform the trees. Severely cut trees never yielded as much as non-pruned or detailed pruned trees over the next 7 years. There was no difference in yield between detailed pruned trees and trees not pruned at all. Extensive wood rot developed in many trees in each treatment group, which contributed to the declining health of these trees over time. Growers with heavily infected orchards can reduce costs by forgoing canker removal while maintaining yields until such time as the orchard can be replaced.