Michigan Hemlock Wooly Adelgid Update  

TOPIC: Michigan Hemlock Woolly Adelgid update

== 1 of 1 ==
Date: Sat, Feb 9 2008 7:56 pm
From: "Paul Jost"

Apparently, www.pestcompact.org describes a nationwide effort to financially
support eradication of outbreaks of invasive species by governmental
agencies. This is the only place that I have been able to find any recent
information on the hemlock woolly adelgid infestation in the northwest
corner of Michigan's lower peninsula. Here is the link and the text:

From <http://www.pestcompact.org/reports/2007%20Annual%20Report.pdf>

Claim Reports

Hemlock Woolly Adelgid Survey and Management Activities in Michigan

(2007 Mid Year Report - August 1, 2007)

Recipient Party: Michigan

Requesting State: Ohio

Claim Year: 2007

Claim Amount: $75,000

Date Claim Approved: 02/07/07

Date Project Completed:


On August 21, 2006 an insect sample collected from a landscape hemlock in Emmet County, 
Michigan was identified as Hemlock Woolly Adelgid (HWA). In at least 20 years of HWA
survey activities in Michigan, this is only the third time this pest has been found in the state.
However, the previous two findings were restricted to nursery stock and quickly destroyed on
site. This is the only time HWA has been found on naturally occurring hemlock in Michigan.
Rapid tracebacks revealed that this tree was one of 10 planted on the property from a lot of 30
shipped from West Virginia to a local landscaper in 2003. The remaining 20 trees were
accounted for, and found to be located on three properties within two miles of the initial find.
All sites were initially delimited August 23-24, 2006 and it was determined that two of the four
sites contained infested trees.

Since that time, extensive nursery tracebacks, survey, and treatment activities have taken place
through funding made available through the Interstate Pest Control Compact and the U.S. Forest
Service. Three additional positive sites were detected, all sites were treated with insecticides,
additional plantings of potentially infested nursery stock were located, and large-scale 
delimiting/detection surveys took place. The following report details these activities through
June 30, 2007.

Tree Removals.

On September 11, 2006, the landscaper responsible for importing and planting
the infested hemlock trees, removed and incinerated 31 infested or adjacent hemlock. Root
balls were removed and destroyed and the trees replaced with eastern white pine. A
single infested hemlock tree was left intact to monitor the development of HWA for timing of
survey activities.  This tree was removed and destroyed in late winter.

Pesticide Treatments.

Applications of Merit 75 WSP (imidacloprid) using Kiortz soil injectors 
were performed by West Michigan Tree Service on November 13-14, 2006.
Applications were made at the highest labeled rate of 1.6 oz. per 24-inches DBH.
A total of 127 hemlock trees growing near the four known positive sites were treated.

Applications of Safari 20 SG (dinotefuran) using Kiortz soil injectors were performed
by MDA staff on June 4-5, 2007.  Applications were made at a rate of 0.20-0.26 oz. 
active ingredient per one-inch DBH. This application rate was recommended by a sales 
representative with Valent, the manufacture of the product. A total of 158 hemlock trees 
growing near the five known positive sites were treated.


Extensive tracebacks at two local nurseries known to utilize hemlock from out-of-state were 
performed. Twenty-four "invoice" sites - sites where potentially infested nursery stock had been
planted - with a total of 54 hemlock trees were identified, inspected, and found to be negative for
HWA. A fifth positive HWA site was located during this process. The MDA identified an
additional 2,000 hemlock trees that had been imported into Michigan from West Virginia since
2002, but the locations of these trees has not been ascertained.


Large-scale surveys were performed around the five positive sites and the 24 invoice
sites using a modified version of U.S. Forest Service protocols. Using public land survey
quarter-quarter-quarter sections, the area within 1/2-mile of each positive site and 1/4-
mile of each invoice site was divided into ten-acre plots. Up to 300 and 100 hemlock
trees per plot around the positive and invoice sites, respectively, were inspected
for HWA ovisacs. A total of 392 ten-acre plots was surveyed and 16,251 hemlock
trees inspected. No additional HWA positives were detected.

Conclusion and Future Plans.

The immediate removal of the infested trees, two pesticide applications
around the known positives, and extensive traceback and survey activities represent
aggressive actions that have been taken to define, contain, and eradicate this HWA infestation. Two
additional invoice sites have been identified through nursery tracebacks and await intensive surveys
in 2007. If funds remain following these surveys, targeted surveys of high-risk sites
(including subdivisions and dense hemlock stands) will be performed in the vicinity of Harbor Springs. A
fall pesticide application is being considered and will be based on recommendations from
forest entomologists with the U.S. Forest Service and Michigan State University.

The activities described herein were funded through equal grants from the Interstate Pest Control
Compact and the U.S. Forest Service, with the IPCC funds being utilized as MDA's cost-share
for the USFS funds. The IPCC funding expires on October 23, 2007 and the USFS funding
expires on December 31, 2007. Because of MDA's aggressive response to this infestation and
the successes documented to date, the USFS has committed to continued funding of this
eradication program in 2008 and 2009. The MDA will utilize these funds - to the extent that
matching funds are available - to continue large-scale surveys around positive and invoice sites
and to continue pesticide treatments.