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.