Trapping Laries

That's Laricobius beetles for the uninitiated. And yes, this is a Fraser fir blog, but every once in awhile I like to put something in about other conifer pests like hemlock woolly adelgid (HWA).

One of the predators being released for HWA is Laricobius nigrinus. Last week I went out with Jim Hamilton, Watauga County Director, and Bill Sweeney with the Bent Creek Experiment Station, to learn how to trap for these beetles.

Sweeney is looking at the traps every week to see if any Lari beetles are coming up out of the ground to feed on HWA. These beetles pupate in the duff under the trees. This first trap is a bucket placed over the ground with bait at the top (infested hemlock branches) where the beetles, if they were present, would congregate.

Each week he puts in fresh shoots in the container at the top. When the week-old shoots are removed from the trap, the foliage is beaten over a sheet to look for beetles. This photo shows Bill and Jim looking for beetles.

A second trap is placed around the hemlock trunk so that any beetles moving up the tree will be captured.

Unfortunately, we didn't find any Laricobius last Wednesday when we looked in Valle Crucis. I don't know if Bill found any at his other locations.

These beetles were released at Hemlock Hill behind Lees-McRae College in Banner Elk. Jerry Moody, the County Extension Director in Avery County, and I looked at these hemlocks on Friday. It had been a long time since I had been there.

Sadly, most of these huge trees have died. Here Jerry stands beside a dead giant. We also took some beats from younger hemlocks that are still alive, but we didn't find any Lari beetles.

HWA is having a sad impact on our forest hemlocks. Each time we have droughty conditions, it seems like more hemlocks die.

On a brighter note, Jerry and I visited a site where we had treated hemlocks with a trunk spray of either Safari or Merit + Pentrabark. The Safari treated trees at the low rate of 12 oz/gallon had only dead adelgids. We only took a quick sample of Friday, but the results were very encouraging. We'll make additional observations this spring.