Issue 16, September 14, 2009

Pine Wilt Suspects Easy to Spot

Pine wilt is a disease caused by the pinewood nematode. Infected trees are currently very easy to spot. This vascular disease causes mature pines to die within a season. The pathogen is not a fungus, virus, or bacterium. A nematode is the cause of vascular plugging, wilt and death of the trees. Refer to the Pine Wilt article in issue 5 of this newsletter (2009) for details.

The 2009 season has produced some very distinct cases of Pine Wilt. As you can see in the image of infected Scotch pines, infected trees clearly stand out amid the healthy trees nearby. Frequent rain events have resulted in lush green foliage on most trees and shrubs. Possibly the stark contrast between lush, healthy trees and brown, pinewood nematode infected trees explains why these trees are easy to spot. Regardless, use this fact to your benefit. Infected trees need to be removed to prevent further spread of the pinewood nematode by the Sawyer beetle vector. If you have pines like those in the image, consider removing them as soon as possible. If you prefer to have the wood tested for the presence of the nematode, refer to the Pine Wilt article in issue 5 for details on how this is done. Still, a dead pine is not going to recover, so do not waste time in removing the tree. Waiting could allow the nematode to be spread to other nearby, healthy trees.--Nancy Pataky

Nancy Pataky

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