Questions About Pine Tip Blight

Pine tip blight is a fungal disease that can affect Austrian, Scots, ponderosa, and mugo pines. The disease is most severe on mature trees (20 years or older). Repeated infections over several years can kill large sections of trees or entire trees.  Here are some Frequently-Asked-Questions about tip blight.

1)   What is the pathogen?

Tip blight is caused by a fungus that has been called both Sphaeropsis and Diplodia over the years.  Don’t let the name changes trouble you.  The most important consideration is to recognize the disease, and to be able to distinguish it from other pine problems.

2) When does the disease occur?

Tip blight is a spring disease.  The fungus survives the winter in previously-infected tissue.  Then, during spring rains, the fungal spores splash around and infect the newly developing pine shoots candles just as they start to grow (usually in mid-late April).

3) What are the symptoms of pine tip blight?

The symptoms become obvious in late May or early June when the infected shoots and needles are not growing right. The shoots are stunted, and the emerging needles are stunted and brown.

Small, sticky resin droplets often form on the infected needles. The damage usually starts in the lower branches and works its way up over several years.

There are exceptions, though.

There may be a lot of tip blight in the top of the tree:

In trees that have been repeatedly infected for many years, damage is distributed throughout the crown. In addition to infecting the newest growth, the fungus can invade older tissues when trees are highly stressed or if they are wounded (by hail, storm damage, etc.).

Interestingly, white pines are not susceptible to the tip blight phase, but they are susceptible to this “canker form” of the disease if they are wounded.

In late summer or fall, tiny black spore-producing structures called pycnidia are formed on the scales of 2-year-old cones — it looks like black pepper has been shaken onto the undersides of the cones.

Tip blight can be confused with winter damage or infestation by the pine tip moth. However, winter damage usually causes shoot or needle death before the new needles emerge in the spring, and it is sometimes restricted to one side of the tree the side facing the prevailing wind). Unlike tip blight, the tip moth causes a hollowed-out area in the tip/bud area, and the larvae are sometimes present.  Plus, tip moth is more common in young trees.

In extreme cases tip blight can be confused with pine wilt.  To avoid confusion, look carefully at the symptoms and compare them to the descriptions and photos in the website listed below and in other resources.  Pines can be infected with both diseases simultaneously.  If there is any doubt, bring a sample to your local K-State Research and Extension office to be forwarded to the K-State diagnostic lab.

For more color images of tip blight, please visit the following website:
http://www.oznet.ksu.edu/library/plant2/l722.pdf

Printed copies of the fact sheet can be ordered by calling (785) 532-5830