Safari Control of HWA

In February 2011 when this photo was taken, these trees had no HWA.

In June of 2010, I made a post on some hemlocks at my office that I had treated for HWA. (See post: HWA Control).

I looked at those trees today and they are covered with HWA and with EHS. The controls worked for 3 years, which wasn't bad.

It seems to me like there is a lot of HWA this spring -- not just on these trees but everywhere. It might be because of the warm winter.

Has anyone else observed how long Safari has controlled HWA? If so, make a comment about your situation.

Saving the Hunger Games Set!

The same chemical that you may be using on your cat or dog to control fleas is helping to save centuries old hemlocks in the DuPont State Forest in western North Carolina.

Today I helped Brian Heath and Craig Lawing with the NC Forest Service train staff members at the DuPont on how to treat hemlocks for hemlock woolly adelgid (HWA) using a trunk application of Safari (dinotefuran). We just happened to be working at Bridal Veil Falls -- soon to be famous as a filming location for "The Hunger Games" which comes out this weekend.

The DuPont State Forest started controlling HWA several years ago. This has included releasing the predatory beetles, Sasajiscymnus tsugae, and applying the insecticide imidacloprid, often using CoreTect tablets (click here for the label) which are buried in the soil at the base of the tree. Still there are many trees that haven't been protected -- many of which couldn't be treated with a soil application. Sadly, there are still many trees at the DuPont which are in a state of decline.

Safari is more versatile than imidacloprid, as it can be applied as a spray directly to the trunk of the tree. This systemic insecticide is then taken up by the tree, moving to the foliage where the adelgids are killed. It also works well against elongate hemlock scale, another introduced pest that is commonly found in the DuPont. Left unchecked, these pests can kill eastern hemlocks.

Today we worked with two educational rangers with the Forest -- Eric Folk, who worked with the film crew, and Roberta Belcher. We showed them how to calculate the rates for application and how to apply the chemical with a backpack sprayer. Below are some pictures showing the process and the state of some of the trees.

First, the trees are measured to determine the rate. Here Brian
and Craig are determining the tree's diameter while Eric writes down the measurements.
It is important to keep good records as treatments may be several years apart.

Some of the trees are in good condition because of past imidacloprid applications.
This is one of the better looking hemlocks I've seen lately.

 These trees didn't look as good. One of them is already dead.
They had never been treated with imidacloprid as there is hardly any soil for
a soil application. Trunk applications with Safari are the only
hope of saving them.

Eric applies the Safari while Roberta times the application and keeps up with records.

The insecticide is only applied to the trunk of the tree.
You can see where the tree is wet.
The chemical is very safe -- remember it's used in products you can put on your pets.

Roberta has been working at the DuPont for more than 10 years. She said when she first started working, you couldn't even see the falls from the parking area. Now, with so many hemlocks in decline, you can. Hopefully with these and other control methods, these stately and important trees will thrive once more for generations to come.

Getting the Most out of Safari

On Monday and Tuesday I was applying the active ingredient, dinotefuran (aka Safari), to hemlock trees for hemlock woolly adelgid control. Learning how well this works should help with elongate hemlock scale control in Fraser fir, so even though this project isn't related to Christmas trees, I think it's still important.

The label for the trunk application with Safari has a range of rates from 12 to 24 ounces per gallon. However, in other literature that the chemical company, Valent, puts out, it says just to use the 12 ounces per gallon rate, so that is what I did on Monday when I treated hemlocks by myself at a site in McDowell and on Tuesday when I worked with NC Forest Service folks, Brian Heath and Craig Lawings treating trees at the Crossnore Nursery in Avery County.

The label also says that one gallon should treat about 40-50 inches cumulative trunk diameter. Therefore, one quart would treat a 10-inch diameter tree. However, it also says to treat until run-off. When I applied the product on Monday, I was treating until run-off and ended up treating about 100 cumulative inch trunk diameter -- or twice as much. We'll see if well it works. On Tuesday we tried to stick to one gallon treating 40 inches. The first thing we did was calibrate to see how long it took to spray out an ounce. This photo shows Craig spraying and Brian keeping track of time.

With the sprayer he had, it took about 9 seconds to spray out an ounce. Therefore on most trees we treated, Craig sprayed between 2-4 minutes on a single tree trunk. This photo is a close-up of the bark of a good sized tree after treatment. You can see the foamy bubbles of the chemical on the trunk.

You are supposed to treat all the trunk including the root flares to about 5 foot. This photo shows a tree trunk after treatment. These trees were previously measured and marked by Brian and Craig -- you can see the metal tag on this tree with the identification number.

One question we had was if the chemical would be taken up well by trees with a lot of lichen as is shown in this photo. We tried to make note of trees with exceptional amounts of lichen so we can follow them over the coming months.

Here is a photo of Craig spraying as well as a video. Many of these trees are right on the Linville River. This is a recommended treatment for trees near surface water as you are just spraying the trunk of the tree and not the soil.

A link to Joe Chamberlin from Valent applying the trunk application is found here. The video is on YouTube and is for emerald ashe borer, but it is the same basic method.

Many of the trees we treated on Tuesday were hard to get to. Brian had to get out a machete and hack a path to the tree then hack around the tree so Craig could get to it with his sprayer. That's why it's a new kind of hack and squirt!

These trees aren't doing well. We'll see if the material can bring them back. This photo shows the state of some of the trees as seen from the highway.

We did more than 30 trees on Tuesday. Brian and Craig will end up treating more than 70 trees this spring. That will give us a percentage of how successful we end up being! The trees I treated on Monday are in a bit better shape. This photo shows some of them taken last summer. But then I also used about 1/2 the recommended rate, so that will also be interesting to follow. I treated close to 30 trees on Monday.

As usual, I will post additional results and observations as they become available.

How Things Have Changed

I found an important photograph quite by accident about a week ago. It was on a postcard in The Muses bookstore in Morganton. The photographer is Christopher Smith (www.christophoto.com), who is in Asheville and specializes in weddings and landscapes. I contacted Mr. Smith and he graciously allowed me to use his sopyrighted photo in my blog and my talks on hemlock woolly adelgid.

Why the interest in his photo? It was taken in 2001 at Linville Falls. His photo clearly shows the hemlocks growing in the spring against the dark shadow (note the magnolia blooming). This was before the HWA had made an impact. I didn't have a photo from this time, and even if I didn't, it wouldn't have been that good. You can compare it to my own photograph which I took on Labor Day 2010. The difference? A picture is worth a thousand words, and words can't describe the irreplaceable loss this pest has made in western NC and elsewhere along the east coast.

Chris Smith photo, 2001

My photo, 2010

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.

Some HWA Pics

OK, I know this is a Fraser fir IPM blog. But I work some with HWA on hemlocks and can't help but post a few things about that too.

Five years ago, I took some photos of hemlocks in the Linville area. Today I went back and visited some of those trees. Mostly the hedges looked really good. But many of the trees that I know had been treated are now gone. Others don't look much better.

Here are the pictures:

This picture was taken five years ago.

This is the same tree five years later. It is still hanging on, but doesn't look much better.

This tree is no longer there. It had been treated with Merit, but didn't seem to be doing too well five years ago when this picture was taken.

These trees are in the same yard as the previous picture. They don't look that good either, but are at least still alive. The hedge, however, looks great.

My last photo is dead hemlocks along the Parkway.

HWA Control

OK, I know this is a Fraser fir blog, but I had to include a photo of these hemlocks. They are at my office in Mills River. I treated them 2 years ago for hemlock woolly adelgid with Safari using a soil drench, and they are still growing like gangbusters. We'll be looking closer at Safari for the control of balsam woolly adelgid.