Diplodia Tip Blight: A Blight on Pine Trees

Do you have a pine tree that isn’t thriving? Are new shoots stunted and turning brown? Have you noticed black fruiting bodies at the end of needles? While pines trees can exhibit some of these stressors from other ailments—air pollution, pine shoot borer, other insects and diseases—the culprit just might be Diplodia tip blight.

Diplodia Tip Blight

Diplodia tip blight (Diplodia pinea) is a fungus. It mostly affects pine trees, but some conifers like Norway spruce, Colorado blue spruce, and Douglas fir trees are also susceptible. While Austrian pines tend to get hit hardest, all pine trees are vulnerable to it. If left untreated, the tree becomes stressed and can eventually die.

While coniferous trees normally retain their needles throughout the year, this one has very few needles left due to the presence of Diplodia pinea

More often than not, Diplodia tip blight affects older pine trees. It often occurs in ornamental trees where site conditions are less than favourable; compacted soil, root restrictions, drought, insect infestations, and injury are all contributing factors. It can easily spread from one tree to another through airborne spores. The spores are released from the pycnidia (fungal fruiting bodies) at the base of infected needles and cones. They travel via insect, animals and the wind. Once the spores move to another host tree, they begin the cycle anew; newly developing shoots turn brown and fail to elongate, and by season’s end are dead.

Dead needles and dried cones are all that is left of this Scots pine that succumbed to Diplodia tip blight

If you have a pine tree on your property, don’t despair. While the fungus is quite virulent throughout the growing season, pine trees are most at risk during spring when their shoots, or candles, are growing. As the fungus is found in dead needles, twigs and cones, you can reduce the risk to your trees by pruning out damaged areas and raking up dead debris. The disease tends to start in lower branches, which makes this job easier. Don’t forget to thoroughly clean and disinfect all tools used, to reduce the risk of inadvertently spreading spores yourself.

If you are concerned that your pine tree is suffering, a call to your local arborist is in order. They can advise you of how bad your tree may be infected, and whether it can be saved. They can also prune and treat your tree with fungicides as necessary, as well as help with the necessary steps to improve your site’s conditions; ie. water, aerate, improve air circulation, fertilize. CLC Tree Services would always rather treat a tree then have to remove it, so call at the first sign of infection.