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K-State Turfgrass

Month: March 2018

Cut down and destroy dead pines to help prevent spread of pine wilt

Now you see it:

call-hall-2012-10-09_17-20-05_109

Now you don’t:

Call-Hall-now-gone-2012-10-25_17-20-32_596

This tree had pine wilt disease, and it was cut down and chipped or burned to reduce the risk of spread to other trees.

Pines have several disease and insect problems. One of them is pine wilt disease. It kills the entire tree quickly.

Pine wilt is caused by the pinewood nematode, a microscopic worm. The nematode is spread by the pine sawyer beetle. 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 starting 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 has gradually spread west. There have been pockets of infection in the western part of the state, but we’d like to keep it out. Also, sanitation efforts will help reduce spread even in the east where the disease is common. Here is a map of pine wilt from our Kansas Department of Agriculture colleagues based on recent survey data:

 

 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. With pine wilt, eventually the whole tree dies, within a few months. 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 website with color photos and descriptions at the following link:

http://muextension.missouri.edu/explorepdf/miscpubs/mx0858.pdf

There are images to compare and contrast pine wilt with other pine diseases here:

http://www.ksre.ksu.edu/bookstore/pubs/l722.pdf

With the other diseases (tip blight, needle blight) only parts of the tree turn brown. With pine wilt, the whole tree is brown and dead.

If you aren’t sure if your tree has pine wilt or something else, contact your local K-State Research and Extension Office or the K-State Diagnostic Lab (clinic@ksu.edu).

If a tree has pine wilt,  the tree should be cut down by  April 1  to make sure there is time to destroy the wood by May 1, when the beetles start to some out. 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 pine wood around for firewood.

Volunteers Needed for Irrigation Installation at Rocky Ford Turf Research Center

K-State’s turfgrass research group is starting a high profile project in cooperation with the USGA and the Toro Co, and we need your help!

The goal of the project is to improve the use of soil moisture sensors to control irrigation while minimizing water applications and maintaining good quality turf.  This will require 3 years of intensive study of the science of using these sensors.

However, before we can do that, we need to install an in-ground irrigation system.  That is where we need your help!  We are organizing work days at the Rocky Ford Turfgrass Research Center on Friday, March 23 and Saturday, March 24.  All the irrigation supplies are in-hand and we are working on getting a trencher.  Bayer has indicated they will sponsor lunch on Friday and we are working on getting sponsors for lunch on Saturday.

This irrigation system will be used for years to come, well beyond the 3-year study, and all turfgrass managers will benefit from the research.  Therefore, we would be most grateful for any time you could contribute, whether it is for 1 or both days.

Please email Christy Dipman at cdipman@ksu.edu to let her know what day(s) you will be available to assist with the installation.