If you have ever had to take a chainsaw to a 60 ft. pine tree on your property, then you know the pain of losing a featured landscape tree. Here in Kansas, we are losing many stately trees to “pine wilt,” which has affected my older neighborhood severely.
Pine wilt is caused by a plant parasitic nematode, referred to as the pine wood nematode, which is carried on the pine sawyer, an ugly insect in itself which tends to have a taste for our “exotic” pine trees. As the pine sawyer feeds, the nematodes hop off, infect the tree and live and reproduce in the resin canals of the branch and trunk of the tree. An infected tree will die within a few months. Of course, landowners are asked to remove and burn the wood immediately to contain the disease.
Our summer field based botany class visited the John Pair Horticultural Research site last week, just south of Wichita, and reviewed some of the research being conducted on pine wilt. As an aging facility, the research site has trees affected by pine wilt as well as healthy evergreens for comparison. Their current research is to determine wilt resistant trees for landscape use.
In a small greenhouse located at the site, insect collection chambers have been set up to determine infestation rates. Filled with dead trees of varied species, emergent pine sawyers are counted and documented. The degree of infection can then be determined and attributed.
Recent sawyer collections have recently been applied to young pine trees thought to be resistant. The trees will then be observed and documented for resulting infection.
I suppose the importance of trees of an “exotic” nature in this area might be questioned, but I have always been a softy for any tree that is clearly beneficial. Of course, the advice of the extension service is to plant native trees that are resistant to wilt, but one hates to lose a tree for any reason. Especially as older elms and weaker trees are removed, the landscapes take years to recover.
The research at John Pair research center is encouraging in that it hits at the heart of city folks who treasure the trees that have taken generations to grow.