New York State IPM Program

Invasives IPM Update: ALB and oak wilt stand-ins

Back in mid-July, during Invasive Species Awareness Species Week, we wrote a post using asian longhorns beetle (ALB) and oak wilt as stand-ins for the multitude of invasive species already here or knocking at our doorstep.

And we promised we’d tell you what to do should you suspect these two big-time baddies might be in the neighborhood or down the road — info you can draw from to report other invasives too.

Of course, first you have to know what the symptoms of ALB and oak wilt are. After all, an accurate ID is key to IPM. So zip over to the NYS Department of Environmental Conservation’s website for their ALB and oak wilt info.

Killer beetle has distinctive markings. DEC tip line: 866-702-9938. Photo credit Kyle Ramirez.

You’ll learn that trees under attack by ALB often have wilted foliage and canopy dieback. But here are the main things to look for:

  • Round exit holes, ⅜” to ½” in diameter. Beginning from late July on, those mark where adults are exiting trees. Stick a pencil in there to see if the hole is at least an inch deep.
  • Round depressions — egg-laying sites, ½“ — in the outer bark.
  • Sap oozing from egg-laying sites and exit holes.
  • Sawdust (aka frass) in small mounds at the tree’s base or branch crotches.

To corroborate what you’ve seen, take pictures of the holes, including something for scale — a coin or ruler, for instance. Be sure to note the location — intersecting roads, landmarks or GPS coordinates.

Then call the ALB tip line: 866-702-9938.

You’ve got other options too, but best you go to DEC’s website for them.

On the loose and here at last. DEC tip line: 866-650-0652. Photo credit ISU.

And oak wilt? It’s scary. This killer pathogen — Ceratocystis fagacearum — can take down a red oak in as little as a few weeks. Where tree roots overlap, it can travel via those roots from one oak to the next, the next … sometimes taking down miles of forest. Then too, fungal mats from under their bark and exude a sweet odor that attracts bark or sap-feeding beetles, which carry the spores from one tree to another, another — sometimes miles away.

Put together, the red and white oak tribes include dozens of species. Many are common to the Northeast. But white oaks are luckier; years can pass before they die. Why? Mainly because the wilt doesn’t suffuse through the root systems of neighboring trees, nor does a sweet-scented spore mat form under the bark. But it kills them all the same.

Yes, it might seem odd that an organism first found in Iowa and Texas took more than 50 years to get to New York. But such is the way with nature. At any rate, it’s here now, an implacable foe — and all the lessons learned in the Midwest help bolster ours.

Our space is limited, so for now let’s just consider red oaks. Scarlet, blackjack, and pin oak belong to this clan. The main things to look for?

  • Outer leaf edges turn a tan, coppery, or reddish brown, progressing toward the mid-veins.
  • Branch dieback starts at the top of the tree’s canopy and works its way down — quickly engulfing the entire tree.
  • Leaves suddenly wilt in the spring and summer and often fall while still partly green.

Think you’ve seen oak wilt? Call 866-650-0652. If you need to prune trees —and even if you don’t — check out DEC’s two-minute video. Because regardless — this is one of those situations where citizen awareness and involvement matter. A lot. Prevention (key to IPM) and protective zones, for instance — learn more about them while you’re on DEC’s website too.

Solutions — chemical or biocontrol (especially biocontrols)? If only. But we’re just not there yet.

Author: Mary M. Woodsen

Pests and pesticides — both can cause harm. How can we protect ourselves the least-toxic way? IPM is the sound, sensible, science-based approach that works wherever you do. The New York State Integrated Pest Management Program develops and offers tested tactics for pests new and old, whether on farms, offices, orchards, schools, parks, vineyards, more.... Wherever you find pests, you find IPM.

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