Forest & Shade Tree - Insect & Disease Conditions for Maine

September 17, 2010

Maine Firewood Ban Progresses towards Final Regulations.

In response to the recognized threat posed by foreign pests like Asian longhorn beetle and emerald ash borer, the MFS and partners have focused considerable effort on making the public aware of the threat posed to Maine by casual movement of untreated firewood.  This local public information/education effort has coordinated with broader regional and national efforts and does seem to be raising awareness of the issue.  However, as clearly demonstrated by recent detections of emerald ash borer infestations into Kentucky and New York, firewood and associated pests are still being moved around the country.

In response to this continued threat, last spring the 124th Legislature passed LD 1607, An Act To Regulate the Transportation of Firewood, which banned import of untreated firewood into Maine.  As part of the transition to new regulation, the MFS worked with partners in the private and public sector to escalate the public education and outreach efforts, and inform the visiting public about the new ban.  On Sept 1, MFS Director Alec Giffen took the next step, signing an Emergency Order enacting regulations to implement that ban (on-line).  

The primary focus for 2010 remains education and information.  An initial effort was a firewood exchange for incoming tourists conducted by MFS forest rangers over Labor Day weekend.  We plan additional similar outreach efforts later in the year.  Heat treatment certification and labeling protocols are being finalized to ensure that commercial dealers and campers have ways to acquire treated firewood and will be made available to interested stakeholders.  Later this fall, the MFS will be conducting formal Rule Making for the final firewood rules and seeking input from stakeholders.

Bug Maine-ea at the Maine State Museum

This year over 1400 people attended Bug Maine-ea at the Maine State Museum on September 15th. Entomologists from all over the state join to showcase the fascinating world of insects and how they are a part of our world. The Maine Forest Service provides a hands-on table of collected insects that people may touch and inspect up close with hand lens. Given the constant crowd around the table, this is obviously a hit with the kids.  Out back of the museum is another favorite activity – collecting insects using MFS nets and collecting containers with identifications provided by MFS and Maine Entomological Society personnel. The MFS also festoons the trees and grounds with various types of traps and collecting equipment. 


Ash Spider Mites (Tetranychus homorus) – An unusual call came in from Strong via photos sent to Cooperative Extension. An ash tree trunk was covered in a continuous sheet of webbing from the ground up to about 12 feet including branches; it looked like the tree was wrapped in cellophane. The leaves were not covered but silk tubes ran from one branch to another with red frass or insects under some of the webbing (images).  A visit to the site revealed that it was mites that had made the webbing. Mites do well in dry hot weather so this summer was good one for high populations to develop.  The mites feed on the leaves during the summer apparently doing little damage and then move to the trunk to overwinter.  This webbing is not a common sight anywhere although the mites are reported to live throughout the United States. Cooler summers and rain may keep the phenomenon from occurring most years.

Browntail Moth (Euproctis chrysorrhoea) - The adult browntail moth were picked up in light traps in Topsham (not surprising right inside the current infestation), Hope, Mount Vernon, Sedgewick and Exeter.   If you live in central Maine you should be on the lookout for this insect.  The early instar larvae of the browntail moth are now skeletonizing leaves of host trees such as apple, crab apple and red oak.  The larvae are tiny right now and beginning to spin silk around the petioles of leaves in preparation for making a tight web at the outer tips of branches for the winter (image). If you find browntails wait until evening when they are gathered in the webbing, remove and either soak in soapy water or burn.  This winter look for leaves tightly webbed together at the tips of branches. Again, clip and destroy.  Low populations can often be completely removed from an area by this method.

Elongate Hemlock Scale (Fiorinia externa) - Nearly a year to the day from the first detection of elongate hemlock scale in Maine, Fiorinia externa was again confirmed in the state.  It is now known from three plantings of hemlock and at two of the sites has been detected on native hemlock and balsam fir.  This year’s find in Cape Elizabeth was spotted by an arborist who had learned about the scale in last summer’s Conditions Reports.  Given the coincidence of timing, it would seem that late summer, specifically after the fourth week of August, is a very good time of year to look for elongate hemlock scale.  Because of the discrete coloration and small size of this insect you really do need to be looking for it in order to find it before populations explode.  We have seen heavy populations on both hemlock and fir.  Elongate hemlock scale will infest other conifers as well.  In Armored Scale Insect Pests of Tree and Shrubs Miller and Davidson report hosts in the genera: Abies (fir), Pseudotsuga (Douglas-fir), Tsuga (hemlock), Cedrus (cedar), Picea (spruce), Pinus (pine) and Taxus (yew).  Communications from other state forest health departments dealing with this pest indicate that hemlock and fir are primary hosts for this pest. 

A wallet card identification aid (300 kb pdf) for elongate hemlock scale and hemlock woolly adelgid has been developed in cooperation with the US Forest Service and New Hampshire and Vermont forest health departments; it will be printed soon.  In the meantime, you can find it on our Website:, follow the link for Quick Tips at the top of the page. 

*Gypsy Moth (Lymantria dispar) – Gypsy moth trapping in the transition zone is coming to a close.  Although traps are still being collected, results indicate we’ll be spending some time doing egg mass scouting this fall.  Male moth counts in the traps have triggered plans for scouting in at least Flagstaff Twp, Hersey, T3 R7 WELS, T4 R7 WELS, T5 R7 WELS and T6 R7 WELS.  If you are out and about in those areas and you happen to see a gypsy moth egg mass, you could assist us by taking a photo and a GPS coordinate if possible and reporting the information to or (207) 287-3147.  Hunting season is a great time to spot those egg masses because they are bright, shiny, new and there is not very much foliage to obscure them.  Our surveys for population levels in the regulated area have not yet started, but will be underway soon.  The gypsy moth quarantine regulates movement of material (firewood, logs, bark and more) between the quarantine area in the southern two-thirds of the state and the unregulated area to the north and beyond our borders. 

*Hemlock Woolly Adelgid (Adelges tsugae) - Hemlock woolly adelgid is now known to be established in 26 towns in Maine.  This is a phenomenal increase from the eight (8) towns known in May of this year, and more detections would not be surprising.  Division surveys to date have been conducted in most coastal towns from Owl’s Head to Cape Elizabeth.  We are limited in the amount of time we can spend looking for adelgid in each town, so a negative survey result does not necessarily mean adelgid is not in that town.  These finds highlight the importance of looking for signs of hemlock woolly adelgid on your hemlocks in areas that are climatically vulnerable to damaging levels of the pest.  In Maine, this appears to be within about 20 miles of the coast.  Although previous generations’ wool may be present, the adelgid may be hard to see until it begins to feed and develop wool again in mid-to-late October. 

Map of towns with known infestations of HWA and towns surveyed by MFS as of September 15, 2010

This time of year the adelgid is settled and there are no eggs present.  It is a good time of year to conduct management activities in infested stands and ornamental hemlocks because there is limited risk of spreading the pest.  However, limitations on movement of material from the quarantine area apply.  More information is available in our new hemlock woolly adelgid fact sheet:

Hickory Tussock (Lophocampa caryae) – The fuzzy white caterpillars with a black stripe down its back and four black tufts of hair are widespread across the state (image). We have received many reports of the caterpillars but no reports of noticeable defoliation on hardwoods.  These hairy caterpillars feed on a wide array of trees including ash, oak, willow and elm. The larvae are active now searching for a place to overwinter.  They will form a hairy cocoon in the leaf litter and the adults will emerge next June. The caterpillars can cause a rash in sensitive individuals so use caution in handling them.

Sumac Leaf Gall Aphid (Melaphis rhois) – The sumac leaf gall aphid was observed in North Yarmouth on smooth sumac (Rhus glabra) this past week.  The galls are largely inconsequential to plant health, but are an interesting biological curiosity (images).

Diseases and injuries

Balsam Fir Tip Blight (Delphinella balsameae) – A recent visit to Frenchville (Aroostook County) was made, and an examination of one of the areas where balsam fir tip blight had occurred earlier this spring (reported in the July 16th, 2010 issue of the Conditions Report) was conducted.  The trees examined were Concolor fir, which showed extreme tip dieback and significant and sometimes apparently complete bud mortality.  Published literature indicates that the disease is of little consequence, at least on balsam fir.  However, the damage inflicted to Concolor fir does appear more serious.  Significant branch mortality and even possible tree mortality is now expected, even for affected individuals in the larger sapling (4 in.-plus dbh) size class.  The affected balsam firs that were examined did appear to still support good bud development, and are expected to recover. (Canadian Forest Service)

Beech Bark Disease (Neonectria faginata and Cryptococcus fagisuga) – The survey examining the relationship between the biophysical regions of Maine and the incidence of beech scale populations is near complete, with only two of the 25 townships in the survey left to evaluate.  To date, 4,600 beeches have been rated for relative scale population levels on both North and South aspects of tree boles.  Additional survey work including a quality control check and the final analyses will be conducted in the coming year.

It is now the time of year, until about mid-October, that the crawler stage of the beech scales is active and can be distributed by birds, other animals, and wind.  It is also the time they are most vulnerable to being removed from infested trees.  The crawlers are extremely tiny and difficult to see, but most of them will develop under the white, waxy wool-like covering which the adults produced over the summer.  The boles of individual ornamental trees can be washed with a moderately strong hosing (not strong enough to injure bark) to dislodge and effectively remove the old wool and the crawlers. (fidl, USFS)

Pine Tip Blight (Sirococcus conigenus) – Tip blight of hard pines has caused serious damage in recent years due to the wet weather conditions that have prevailed.  Apparently the disease has slowly developed and spread through native red pine plantations and natural stands only in the last 10 to 15 years or so.  This summer an encouraging observation was made by a forester for a major landowner in the Downeast area.  He has reported a noticeable reduction in infected tips of red pines this summer – possibly as a result of the respite from the near-constant wet conditions that we had in 2009 and in previous years. (fidl, USFS)  

Upcoming Workshops and Events

If you would like an opportunity to see some of the insects and diseases in this bulletin or ask questions of us in person, catch us at one of the following places.  You will notice this is a new section of the report.  Let us know if you find it useful.  Note some events require pre-registration (R) or have fees ($) or donations suggested (D):

September 18:  Edgecomb.  Looking for something to do on Saturday?  8:30 to 3:00, Allison Kanoti will have a table and lead workshops at the Annual Tree Farm/SWOAM Forestry Field Day at Wind Ridge Farm in Edgecomb.

September 23Baldwin. (R), ($). Preregister by Monday, Sept. 20 at 12:00 noon.  Maine SAF and the Center for Research on Sustainable Forests-Family Forest Research Unit are sponsoring a workshop entitled Managing Growth, Diversification and Change in Forest Resource Management. The agenda and registration form can be downloaded from the Maine SAF website,

September 17th – October 3rd: West Springfield, MA. ($). Bill Urquhart will be representing our division at The Big E courtesy of the Office of Tourism September 21st-25th.  He will be talking up the firewood ban to one of our prime target audiences: tourists.  Stop by and see him at the Maine Office of Tourism booth.

September 24th – 26th: Thorndike. ($). Common Ground Country Fair.  Saturday from 2-3pm, Bill Ostrofsky will give a talk on Tree Diseases, Wounds and Injuries.  You can also visit the Maine Forest Service booth in the Low Impact Forestry area throughout the event.

September 30th Lewiston. (R). Rain date October 1st.  Survey for Asian longhorned beetle, emerald ash borer and other invasive insect threats with Maine Department of Agriculture, Maine Forest Service and volunteers.  E-mail or call(207) 287-3892.

October 2: East Orland. (D). Rain date Oct 9th, Great Pond Mountain Conservation Trust Walk on the Wild Side:1-4 pm, 2nd annual 5-mile walk/ride/run on the trust’s wildlands. You can start at North or South Gate and walk, run, ride a bike or a horse and enjoy refreshments and surprises at each mile along the way.  See samples of invasive insects and their damage and ask your forest insect and disease questions at our table.

October 3-10: Fryeburg. ($).Stop by the Maine Forest Service booth at the Fryeburg Fair.

November 3, 4, 16: Caribou, Brewer, Belfast.  (R), ($). Trees, People and Roads:  mainly geared towards municipal and roads workers, but open to others, these day-long workshops cover a wide range of topics including invasive forest insects.  For more information, or to sign up, call Peter Coughlin at (207) 624-3266. 

TBD: (R). Hemlock Health Threats: learn about hemlock woolly adelgid, elongate hemlock scale and hemlock tip blight and how to survey for them.  Place(s) and time(s) to be determined.  This will be a half day workshop with field and classroom portions.  Please e-mail or call (207) 287-3147 for more information. 

Conditions Report No. 6, 2010
Maine Forest Service
Forest Health and Monitoring Division