Tip Blight of Two-Needled Pine Trees
This week’s podcast is on tip blight of pine trees. I’ve also included a short post on the subject and a few pictures below.
Pine trees are widely used for farmstead windbreaks. And it is not uncommon to see Austrian pine as the species of choice used in those windbreaks due to the low cost of Austrian pine and its’ relatively fast-growing nature. Unfortunately, Austrian pine are susceptible to Sphaeropsis sapinea (also referred to as Diplodia tip blight or tip blight). The disease can start with a few brown branches on an otherwise healthy tree, and quickly lead the tree to look like it is progressively dying. Ohio State University has an excellent publication Factsheet on this subject, and I encourage you to read this publication for detailed information. Here are the management options:
Sanitation: Prune off infected branches and destroy them…burn or bury. Pick up pinecones as they fall (the fruiting bodies on them will pop spores next year… you can probably see the tiny black spots on the bottom of the cones) and destroy them. Note that chipping and mulching with this stuff will just put the fungal fruit right back into the area, thus the recommendation to destroy the infected material.
Thinning: If there are clusters, consider opening them up. i.e. if you have a cluster of 3, remove one or two… preferably the most infected one… and destroy the infected tree.
Treatment regimen: If you want to keep these trees for a long time, fungicide treatment should also be a part of the diplodia management. It takes a series of treatments in the spring to hold it off, but it can be effective. The challenge occurs when the trees grow in excess of 15-20 feet in height. Once trees reach this height (and beyond) it becomes difficult to achieve thorough spray coverage of fungicides with hose-end sprayers or handheld sprayers. Professional equipment is usually required for large trees.
Begin replanting: The trees may continue to decline even with sanitation, thinning and treatment regimen. Plan now for replacing those trees. If space allows plan for companion trees to grow adjacent to the tip-blight affected pines. I recommend a multi-species approach to replacement trees; replacing your two-needled pine with a monospecies may lead to a different or unforeseen set of problems later down the road.