SHORELINE PINE SUCCUMBS TO WHITE PINE BLISTER RUST
by Tom Cox
Sarah and I were disheartened a couple of summers ago when, having jumped into the lake for our first swim of the season, we turned around to view our shoreline and discovered that one of our beautiful youngish (40-year-old) white pines was beginning to turn brown from the top down. Hoping the tree would heal itself, we ignored the change for a season, only to discover last year that the browning had progressed further down the tree, and was beginning to make the tree look very sick indeed. When we went for our first swim this summer, on June 15th, we saw that the tree was dead fully two thirds of the way from the top and, clearly, would have to come out.
Such has been our introduction to white pine blister rust, which we've learned is a fungal disease relatively common in the upper Midwest. White pine blister rust, caused by the fungus Cronartium ribicola, is a fungus of the type that passes through the different stages of its life cycle on alternate and often unrelated hosts.
Interestingly, the disease does not leap from tree to tree, but harbors in its alternative hosts which include all species of the genus Ribes, (currant and gooseberry bushes). Sadly, there is no cure, so unless the disease can be caught very early, when it is still only on the tree's branches, which must be cut off and destroyed, the whole tree will eventually succumb. It's best to remove a tree once the infection has lodged in the trunk.
For a much more complete look at the disease, its causes and effects, go to Google.com on the Internet and search for "white pine blister rust." There you'll find a rich array of articles on the disease, many with excellent pictures. Two particularly good sites are:
 | http://ohioline.osu.edu/hyg-fact/3000/3205.html (this site treats White Pine Blister Rust on Currants and Gooseberries), and |
| http://plantclinic.cornell.edu/FactSheets/wpineblister/wpineblister.html (contains a wealth of information on the disease). |
