Field research has shown that gypsy moth is capable of completing its development on spruce, fir or Douglas fir and may subsequently lay egg masses on those trees. It has also been shown that inspection alone for these particular species of trees does not guarantee absence of egg masses, due to the dense nature of the needles and branches. The Michigan Department of Agriculture generally requires a preventative treatment for gypsy moth on these species of trees. If gypsy moth is detected in the field perimeter or in the field itself, MDA requires a regulatory treatment with an USDA approved compound.

What is preventative treatment?

Recent findings show that spruce, fir and Douglas fir support all gypsy moth life stages. It has been the experience of the MDA that a visual inspection alone is not adequate to certify that cut Christmas trees are free of gypsy moth. Therefore, spruce, fir and Douglas fir grown in gypsy moth-infested counties and destined for areas that are not infested must be treated before they can be inspected and certified by the MDA.

What pesticides can the grower use as a preventative treatment?

The grower can use any pesticide that is labeled for the site. The pesticide must be used in accordance with the label directions. If one or more of the following sites are listed on the label then the pesticide is acceptable for use on Christmas trees. Labels which only say "woody ornamentals, ornamentals or nursery stock" are not acceptable for use on Christmas trees.

Acceptable site language for Christmas tree applications

Plantations Forest trees
Conifers Forest tree plantings
Tree species Forest tree nurseries
Evergreens non-ornamental trees

What documentation is the grower required to maintain?

The grower must maintain a record of each pesticide application made and must make such records available to the MDA, when required to do so.

Who should the grower contact for more information?

Mike Bryan
Nursery Program Manager
Michigan Department of Agriculture
Lansing
(517) 241-2977
bryanm@state.mi.us

Brian Verhougstraete
Pesticide Registration Manager
Michigan Department of Agriculture
Lansing
(517) 373-1087