Pine wilt is one of the most fatal diseases for our Scots Pines, and can also infect our Austrian Pines. The older these trees are, especially for Scots pine trees over 10 years old, the greater the risk of pine wilt. Unfortunately, we have seen a pine wilt outbreak recently in our Scots Pines in the area. The pine wilt nematode lives in the wood of dead and dying pines, which is why it is so important to prune any dead branches in your pine trees and why removing and disposing of pine trees that have died or that have been infected by pine wilt is so important. Dying pines attract pine sawyer beetles and other bark beetles. The pine sawyer beetles lay their eggs under the bark of these dead or dying trees. Once the eggs hatch, the grubs will feed until they pupate and the adult beetle emerges in late spring to early fall. So, when we dispose of these dead and dying trees, we are also reducing number of these beetles that carry the pine wilt nematode with them to healthy, uninfected trees.
The pine wilt nematode needs the pine sawyer beetle for transportation. So, as these beetles fly from tree to tree, the beetle will feed on healthy twigs and branches. The feeding does little to no damage to the health of the tree, however, the openings, or the wounds from the feeding, allows the hitchhiking nematodes to enter the branches of the tree. In time, the nematodes spread and multiply, then basically clogs the trees water-moving system and kills the tree. The tree can die as quickly as in a few weeks, and sometimes will take a few months, depending on the overall health of the tree and the degree of infestation. Once the tree has been infected however, there is nothing that can be done to save it. Once pine wilt has been detected, the tree needs to be removed and destroyed, including the stumps. The tree should be removed quickly, and should be removed before mid to late spring to eliminate any beetles that may be emerging from the tree. The young beetles are generally the ones carrying the nematodes when they emerge in the spring, so it is very important to destroy the tree prior to these beetles emerging.
There have been recent insecticides developed that will help protect our pines from the threat of pine wilt, however, as mentioned before, there is no cure for those already infected. Keeping your pine trees healthy and clean of dead wood are some things you can do to reduce the risk of your trees being infected by pine wilt as well as other diseases. Make sure they are being watered during these dry spells, even in the winter, to help reduce the stress of inadequate moisture, as the beetles are attracted to stressed, dying trees. Lastly, if severe, quick branch die back is noticed in a pine tree in the area, please have the tree looked at and tested as soon as possible to diagnose and help prevent the possible spread of pine wilt in our area. To learn more or if you have concerns, call myLawn! Turf & Tree at 620-282-2076 or find them on Facebook.