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Spongy Moth Certification for Christmas Trees Frequently Asked Questions

pQ1. What is my responsibility, as a Christmas tree grower, in shipping cut trees out of Michigan?

A1. The Michigan Department of Agriculture and Rural Development will assist you in getting your trees certified for shipment to your desired destination state or country, where possible. This effort needs to be one of cooperation on the part of the grower and the department. Be aware that pest interceptions on Michigan Christmas trees in other states or countries could put the Michigan Christmas tree industry at risk. You should scout your plantation and surrounding areas in late winter, checking for egg masses; and also during the growing season, checking for any signs of Lymantria dispar (spongy moth) activity. Treatment with a recommended pesticide must occur for spruce, fir and Douglas-fir plantations and should occur, following label instructions, when there is any indication of Lymantria dispar or other quarantine pests.

Q2. I sometimes hear rumors about changes in the process or other needs for certification. How can I obtain facts or clarification?

A2. Make sure that you completely read any correspondence received from the MDARD. There is a lot of information in the correspondence. A diligent attempt has been made to give you enough information to lead you through the process. If you have a question, contact the Export and Compliance Specialist, Amber Neils, at or 517-449-0786.

Q3. When should I spray my Christmas trees?

A3. Successful pesticide application is dependent on treating during a window of opportunity, frequently called a "spray window" or the time when the target insect pest is most susceptible to a pesticide application. Information on proper timing of pesticide applications can be obtained by contacting MDARD or through the MSU Extension website or the MSU Enviro-weather website. If pesticide applications are not made within the spray window, the field is not eligible for inspection.

Q4. Should I spray a buffer around my plantation?

A4.  If your plantation is adjacent to prime Lymantria dispar habitat (apple, aspen oak, willow, etc.) you  might want to consider treating it if you own it, or can get permission from the owner. The less nearby pest pressure, the better your chance of successful certification. If 5 of more egg masses are found within 100 feet of the planation, the entire field will be restricted. 

Q5. Which pesticide(s) should I use?

A5. MDARD works closely with the USDA and MSU to determine which pesticide treatments will be acceptable for certification. The treatment requirements are based on inspection results from the previous year. For previously unrestricted fields, any of the several pesticides that are labeled for use on Christmas trees may be used as a preventative treatment. For previously restricted fields, growers should consult the list of USDA-approved regulatory treatments for spongy moth. This list is updated yearly and is available through MDARD district inspectors and is posted on the MDARD website at NOTE: Some pesticides have a Special Local Needs (SLN) label that the user must obtain prior to using the product. Make sure the SLN label is current.

Q6. I plan on shipping spruce, fir, or Douglas fir trees out of Michigan, but I haven't sprayed them. Can I get a certificate to ship them out-of-state?

A6. No. If the trees haven't been treated with a recommended and properly timed insecticide they will not be certifiable for shipment out of Michigan. The visual inspection process is not completely satisfactory, in and of itself, and thus requires MDARD to use the combined treatment/visual inspection. However movement within the quarantine area is permitted.

Q7. I only plan to ship Scotch pine out-of-state. Do I need to spray them?

A7. No, unless the field was restricted last year for Lymantria dispar. However, if  your  pre-season scouting reveals egg masses in surrounding woodlots or on the Christmas trees, you would be wise to apply preventative controls.

Q8. I only plan to ship Christmas trees within Michigan. Do I need to participate in the certification program?

A8. No. Christmas trees shipped within Michigan need not be certified.

Q9. Why do I need to return the required applications in August, when I don't know which trees will be sold and shipped out of state at that time?

A9. MDARD faces a large task each year to process the paperwork and organize its inspection force for an efficient effort in the fall. Timely submission on the grower's part allows MDARD inspectors to begin field work early enough to avoid last minute inspections. MDARD realizes that some field inspection requests are submitted on a speculative basis. This may be an unavoidable alternative to not having fields inspected in time for cutting and shipping out of state.

Q10. When will the MDARD inspectors be inspecting my trees?

A10. Inspectors will try to begin fieldwork on or about September 1, following the completion of spongy moth egg deposition.

Q11. Will I be notified of the pass/fail status of my trees?

A11. Due to the large number of fields inspected, it is difficult to notify each grower when fields are inspected and passed. However, a diligent attempt will be made to notify growers by mail, phone, or in person of any restricted fields so that backup locations may be inspected, if necessary, as time permits.

Q12. If I spray my trees and egg masses are still found could I ship these trees out-of- state?

A12. These trees can be shipped only to areas already quarantined. See current map for quarantined areas. Such trees cannot be transported through a non-quarantined area. Spraying or inspection alone will not certify your trees. A combination of spraying and inspection must be used to ensure that trees will not be shipped  with egg masses.

Q13. If live egg masses are found in my Colorado blue spruce field, why must the entire field be restricted? Why isn't the same true for pine?

A13. Research has shown that spongy moth can live their entire life cycle on blue spruce, and can build a population on this species and to a lesser extent on fir and Douglas-fir. This requires stricter field tolerances than in pine, where spongy moth cannot thrive as well.

Q14. If only one egg mass is found in my blue spruce field, why must the entire field be restricted? Why can't an intensive inspection pass the remaining trees?

A14. Remember that Lymantria dispar can live completely on blue spruce and partially on fir and Douglas fir. If one egg mass is found on these suitable host species, then the likelihood of more egg masses being laid in the field is high. Also, it is extremely difficult to find egg masses in these types of trees. MDARD cannot guarantee that 100% of the remaining trees are completely free of egg masses. A combination of pesticide treatments and visual inspections works best to assure that certified trees are free of Lymantria dispar.

Q15. Are the larvae harmful to my Christmas trees? Why are we so worried about a few egg masses?

A15. Lymantria dispar larvae will feed on some species of Christmas trees (e.g. Colorado  blue  spruce, white  pine). However, the most serious problem is not feeding damage, but rather the fact that egg masses can hitchhike on these species and t hen hatch in areas of hardwood trees, which are much more vulnerable to defoliation. Each egg mass can contain 100-400 individual eggs. This potential threat is of great concern to other states as well as Michigan.

Q16. How can I be certain that my certified cut tree shipments will move to the planned destinations without problem?

A16. Complete and use the certificates provided under the MDARD compliance agreement as instructed. Other states will have been notified of what certificate format to expect. Any deviation from these certificates could  be  challenged. Fill the certificates out clearly and completely. Certificates that are unclear, or incomplete, will cause the shipper or receiver problems. Provide a certificate for each drop, so that the receiver will have a document to support each receipt of Michigan trees. Use only the certificates which have been issued to you for your use. If you need more certificates, contact your MDARD district inspector or the Export and Compliance Specialist, Amber Neils, at or 517-449-0786.

Q17. What is the procedure for using and returning certificates?

A17. Please review your Christmas tree packets for instructions on how to correctly complete the certificates. You are also required to return used certificates on a weekly basis during the shipping season to the MDARD Lansing office. Then, at the close of the shipping season you are to return all voided and unused certificates to the MDARD Lansing office by January 15th.

Q18. How much pesticide should I apply?

A18. You must make pesticide applications in accordance with the label using the maximum label rate. Fields with pesticide application done at less than maximum rate will not be inspected by MDARD.

Q19. Is it possible to have some blocks of trees restricted for spongy moth and others certified on the same farm?

A19. When MDARD restricts a block of trees, other blocks may be certified if they are free of Lymantria dispar and are a substantial distance away. The distance between the block must be large, such as separation by a woodlot or several cut-over rows. Situations like this are handled on a case-by-case basis and must be clearly agreed upon by all parties.

In a similar manner, partial blocks of trees may qualify for certification under the New Perimeter Protocol. This applies when egg masses are found in areas adjacent to spruce, fir, and Douglas fir but not in the block itself. To qualify, growers must also have applied the required pesticides, must sign a compliance agreement with MDARD and will have to submit the cut trees for inspection. Under this protocol, Christmas trees on the perimeter of the field are not eligible for certification.

Q20. Sometimes questions come up as the process moves along. How can I get answers to these questions?

A20. Contact your MDARD district inspector, or the Export and Compliance Specialist, Amber Neils, at or 517-449-0786.