Pine Wilt Disease is making its’ presence known in the community.  Pratt County is in the “transition zone” for the state of Kansas. 


Pine Wilt Disease is making its’ presence known in the community.  Pratt County is in the “transition zone” for the state of Kansas. 
We’re beginning to get more and more occurrences of this as the months progress. 
The Kansas Department of Agriculture, the Kansas Forest Service and K-State Research and Extension are all working to slow the progression of this disease.
So, you ask, “what is pine wilt disease and how serious is it?” Perhaps some more information is in order.
• Background:
Pine wilt is caused by the pinewood nematode, a microscopic worm. The pine sawyer beetle spreads the nematode.
The nematode feeds and multiplies in the tree’s resin canals, causing wilting and death in several weeks to several months. The nematode and beetles spend the winter in the infected tree.
In spring, the beetles emerge around May 1, carrying nematodes to new trees and continuing the cycle of infection.
The disease is common in the eastern half of the state, and it is spreading west around 10 miles per year.
Scots pines are particularly susceptible, and many Scots pines in eastern Kansas have been killed. Austrian pines are also susceptible.
Western Kansas is not yet infested. In the last few years there have been several isolated pine wilt cases in western Kansas, including Colby and Dodge City in 2006, and Hays and Garden City in 2007.
Some of those findings were affiliated with infested firewood coming from the east. It is not sure if the Hays finding is due to accidental introduction, or by natural movement of the beetle.
These particular introductions have been eradicated through timely sanitation and scouting.
• Symptoms:
In Kansas, new pine wilt infections are most visible from August to December. Trees wilt and die in a short period of time, from several weeks to a few months.
In the first stages, the needles turn grey or green, then yellow and brown. The discoloration sometimes occurs branch by branch, sometimes all at once.
The brown needles stay on the tree for up to a year after the tree has died. Another key symptom is reduced resin. On a healthy tree, sticky resin bleeds from the site of a wound.
In contrast, if a tree has pine wilt the resin is often reduced or absent, and branches become dry or brittle.
There is a Web site with color photos and descriptions at the following link:
So, what can we do?
• Sanitation.
The most important step is sanitation. If a tree is suspected to have pine wilt, contact the Extension office, the Kansas Forest Service, or the K-State Plant Disease Diagnostic lab and a sample can be collected and sent to a pathology lab.
If the test is positive, the tree should be cut down by May 1 at the latest, before the beetles emerge.
In fact, April 1 would be a better deadline just to make sure no beetles emerge.
Cut the tree to the ground — don’t leave a stump. Chip or burn the wood immediately to destroy the beetles and nematodes. Don’t keep pinewood around for firewood.        • Avoid stress.
The beetles are attracted to drought-stressed trees, or trees affected by other diseases or insects. If possible, provide water during dry periods to prevent drought stress.
• Preventative injections.
There are two products on the market for prevention of pine wilt. There is nothing available to cure pine wilt. The two products are called Greyhound and Pinetect.
Both products contain two percent of the active ingredient abamectin, and both are injected into the tree.
Both products need to be applied be a trained tree care professional. The Nebraska Forest Service studied the
Greyhound product, and the precursor to Pinetect were studied at K-State. In both studies, trees with preventative injections had about an 80 to 90 percent survival rate compared to 40 to 50 percent in untreated trees.
So, it is not a 100 percent guarantee, but it did increase survival. Remember:  it only works preventatively — there is no curative activity.
The label and other information about Greyhound is available here:
Information about Pinetect is available by contacting Rainbow Treecare (go to the “contact us” link)
Injections can be costly and need to be repeated every two years.
• Prevent new infestations (especially in Pratt county and west).
Don’t import pine firewood from contaminated areas. Be wary of pine nursery stock from infested areas, and monitor nursery stock carefully.
If pine wilt is introduced, remove the tree, and continue to monitor surrounding pines to make sure it has not spread.
Careful scouting and sanitation can eliminate sporadic outbreaks before they get out of control.
Contact K-State, the Kansas Forest Service, or Kansas Department of Agriculture for assistance.