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Tree Talk

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Pine Tip Blight
Anyone who spends any time driving around Arlington cannot help but notice the large numbers of Scotch and Austrian pines that are in decline. The cause is a fungus called Saphaeropsis sapinea, also known as Diplodia pinea.

This disease caused browning and death of branch tips. Infected cankers can girdle branches, and eventually the entire tree dies. The disease is most common on trees thirty years of age or older as old cones can harbor large quantities of the fungus. It is spread most easily in the wet conditions of spring, often beginning in the lower branches of trees. Stressed and crowded pines with poor air circulation are most likely affected, but this fungus can affect healthy trees if conditions are right. It is difficult to control. Pruning and destruction of infected branches must be done, care being taken to sterilize the pruning tools between cuts to avoid spreading fungal contamination with the pruning tools. Antifungal sprays also can help, but trees must be sprayed three times during the elongation phase of the new shoot "candles". This can still fail to give full protection if frequent rains wash away the sprays. The difficulty of control of this problem has led to almost the complete elimination of Scotch and Austrian pines from the local nursery trade.

All two and three needle pines can harbor this fungus. Pines are classified by how many needles grow from each fascicle or needle cluster. Two needle pines include Lacebark pine (Pinus bungeana), Ponderosa pine (Pinus ponderosa),Pitch pine (Pinus rigida) and Loblolly pine (Pinus taeda). Three needle pines include cultivars of the Japanese Red pine (Pinus densiflora), Mugo pine (Pinus mugo), Austrian Pine (Pinus nigra), Scotch pine (Pinus sylvestris) and the Japanese Black Pine (Pinus thunbergiana). None of these trees should be planted in any quantity- they should only be planted as isolated specimens in hopes that the diplodia fungus is less likely to find them and spread. The Scotch and Austrian pines planted by the hundreds years ago by Scout troops and Arbor Day arborists are now the ones biting the dust in huge numbers. The tree commisioner's grove of native Ohio trees on the east side of the Lane Road Park is on land that formerly grew a large number of Scotch pines which declined and died.

Fortunately, five needle pines are spared. These include Bristlecone pine (Pinus Aristata), Swiss Stone pine (Pinus cembra), Limber pine (Pinus flexilis), Korean pine (Pinus koraiensis), Japanese White pine (Pinus parviflora), Balkan pine (Pinus peuce), and Eastern White pine (Pinus strobus). Spruces and firs are also immune and they can also be beautiful alternatives.

Diplodia tip blight is yet another example of problems that result when single types of trees are overplanted. The next time you go tree shopping, go to a reputable merchant , tell her your size requirement, and specifically buy a tree that you have never heard of before. You may just end up delighted.

Parks & Forestry Division
Parks & Recreation Department
City of Upper Arlington
3600 Tremont Road
Upper Arlington, OH 43221
Phone: 614-583-5340