New map for 2007 gypsy moth spray window dates

Editor’s note: This article is from the archives of the MSU Crop Advisory Team Alerts. Check the label of any pesticide referenced to ensure your use is included.      

Each year the Michigan Department of Agriculture and MSU Extension evaluate the progress of gypsy moth egg hatch in order to set the opening and closing dates for the gypsy moth spray window. This year we have refined the process using historical degree day accumulation data available online through MSU IPM Resources at: http://www.ipm.msu.edu/landscapeipm/gddlandchart.htm . The state has been divided into five gypsy moth spray window zones that roughly correspond to historical degree day trends. These zones are comprised of the counties shown below.

2007 Gypsy moth spray window zones

Zone 1 - Counties of Berrien, Cass and Monroe.

Zone 2 -
Counties of Allegan, Barry, Branch, Calhoun, Clinton, Eaton, Genesee, Gratiot, Hillsdale,  Ingham, Jackson, Kalamazoo, Kent, Lapeer, Lenawee, Livingston, Macomb, Montcalm Oakland, Ottawa, Saginaw, Saint Clair, Saint Joseph, , Sanilac Shiawassee, Tuscola, Van Buren, Washtenaw and Wayne.

Zone 3 -
Counties of Antrim, Arenac, Bay, Benzie, Clare, Gladwin, Grand Traverse, Huron, Isabella, Lake, Leelanau, Manistee, Mason, Mecosta, Midland, Manistee, Muskegon, Newaygo, Oceana, Osceola and Wexford.

Zone 4 -
Counties of Alcona, Alpena, Antrim, Baraga, Crawford, Delta, Dickinson, Gogebic, Houghton, Iron, Iosco, Marquette, Menominee, Missaukee, Montmorency, Ogemaw, Ontonagon, Oscoda, Otsego and Roscommon.

Zone 5 - Counties of Alger, Charlevoix, Cheboygan, Chippewa, Emmet, Keweenaw, Luce, Mackinac, Presque Isle and Schoolcraft.

Gypsy moth spray window dates

The following chart shows actual and projected open/close dates for application of the two groups of pesticides used for regulatory treatment of gypsy moth in nursery stock and Christmas trees.


Zone

Open – Dimilin (150 DD*)

Open – all other compounds (200 DD)

Close – Dimilin
(700 DD)

Close – all other compounds (800 DD)

1

April 23

May 4

June 9 (projected) **

June 15 (projected)

2

April 30

May 11(projected)

June 15 (projected)

June 20 (projected)

3

May 3 (projected)

May 15 (projected)

June 21 (projected)

June 27 (projected)

4

May 14 (projected)

May 21 (projected)

June 28 (projected)

July 4 (projected)

5

May 20 (projected)

May 27 (projected)

July 3 (projected)

July 11 (projected)

* DD = Degree Days at base 50 degrees F.
** Projections are based on 30 year historical degree day data.

Since gypsy moth development will vary by location, you will need to monitor development around your farm. Weather conditions will affect caterpillar development and may effect end date of the spray windows. Growers should watch the Landscape CAT Alerts for additional announcements.

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