Tree problems · Disease
Pine wilt: signs and what to do
Pine wilt is a tree disease, often seen on scots pine, austrian and Japanese black pine, some other pines, including red and jack pine. Look for: needles that fade to a dull gray-green or yellowish color, then turn brown.
General information, not a diagnosis. A certified arborist or your county extension office can confirm.
- Disease
- Scots pine (the most often hit; not in our species library)
- Austrian and Japanese black pine
- Some other pines, including red and jack pine (less often)
- Eastern white pine (tends to be more resistant)
Signs to look for
Tick what you see. More ticks make it more likely, but only an on-site look can confirm.
0 of 6 signs ticked. Ticks stay in this browser only.
Season
Symptoms can appear from midsummer to late fall. A pine infected in spring is often dead by late summer or early fall. Large trees may take longer to die.
How it spreads
Pine wilt is caused by a tiny worm called the pinewood nematode. A native longhorn beetle, the pine sawyer, carries it from dying pines to healthy ones when it feeds on the twigs.
Where it is found
Pine wilt is found in parts of the central and eastern United States and in some other areas. Check your state official map; ranges change.
Official sources
What to do
- 1
Look at the pine for fading needles and note how fast the change happened. Take clear photos.
- 2
Do not guess. Stress and transplant shock can look similar, and a lab test is needed to confirm pine wilt. Ask your county extension office how to send a sample.
- 3
If the test is positive, ask about removing the tree quickly, because dead pines are where the beetles breed.
- 4
Ask your extension office how to dispose of the wood so the beetles cannot use it.
- 5
Do not move firewood or logs from a dying pine to other places.
- 6
Water and care for the other pines on your property so they are not stressed.
Safety first: do not climb, do not cut near power lines and do not use a chainsaw on storm-loaded wood. Call the utility for downed lines and 911 if anyone is in danger.
Prevention
Keep pines healthy with good watering, mulch and root protection, because stressed pines attract the beetle. Remove dead and dying pines promptly and ask your extension office how to handle the wood. When you replant, choose species that do well in your area and mix them, so one problem cannot take out the whole row. Ask a certified arborist about preventive treatment for a high-value pine, and ask for the full cost over the years.
When to call a pro
Call a certified arborist if a pine browns fast in summer or fall, or stands near a house, driveway or line. A pine that is dying quickly is often brittle, so removal needs a trained and insured crew.
Not sure who to call? Read how to hire a tree service or check is my tree dangerous?
Trees it affects
Usually seen on: Scots pine (the most often hit; not in our species library), Austrian and Japanese black pine, Some other pines, including red and jack pine (less often), Eastern white pine (tends to be more resistant).
See all species in our tree library, or pick a tougher tree with the tree picker.
For tree companies
How to explain pine wilt to a customer
Explain that a fast-browning pine can have more than one cause and that a lab test is how you confirm pine wilt. Do not promise to save a tree that is already infected. Help the owner get a sample tested, give them a clear removal plan if the result is positive, and tell them how you will dispose of the wood.
Send this page to the customer after your visit so they can read the signs in plain words. See also selling plant health care and the job photo checklist.
Questions
What is pine wilt?
It is a disease of pines caused by a tiny worm, the pinewood nematode, that clogs the tree's water-carrying system. The needles fade and the tree dies.
Which pines get it?
Scots pine is the most often hit in the Midwest. Austrian and Japanese black pine are also very susceptible. Eastern white pine tends to be more resistant. Other pines fall in between.
How fast does it kill a tree?
A pine infected in spring is often dead by late summer or early fall. Large trees may take up to a couple of years. It can look like a sudden change.
Can a pine with pine wilt be saved?
Once a tree is infected, treatment usually does not work. The usual advice is to remove it so beetles cannot breed in it. A certified arborist can discuss protection for healthy, high-value pines.
How is it confirmed?
A lab test is needed, because drought, root problems and other diseases can cause similar browning. Your county extension office can tell you how to send a sample.
What should I do with the wood?
Ask your extension office. The usual advice is to destroy infected wood so beetles cannot use it, and not to move it or keep it as firewood.
Can it spread to my neighbor's pines?
Yes, the beetles can carry the worm from a dying pine to healthy pines nearby. That is why quick removal of a confirmed tree is advised.
Should I plant Scots pine?
In areas with pine wilt, many extension offices advise against it. Ask a local nursery or your extension office which pines suit your area.
Can Lirevon diagnose pine wilt on my tree?
No. Lirevon is a remote marketing team for tree service companies and does not do tree work. This page is general information, not a diagnosis. A certified arborist or your county extension office can confirm what is wrong with your tree.
How do I find a good local pro for this?
Search Google Maps for certified arborists or tree services near you, read their reviews and ask for proof of insurance. Get two or three written quotes. Our guide on how to hire a tree service lists the questions to ask.
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