MAINE DEPARTMENT OF CONSERVATION
Maine Forest Service
Forest Health & Monitoring Division

Forest & Shade Tree - Insect & Disease Conditions for Maine

June 5, 2002

Link to Issue 1 - May 13, 2002

Spring, summer, spring or is it winter! The recent "see-saw" weather has even the insects wondering whether or not they should come out or go back for another "forty winks!" After an early start for some species, many had to hold up through cold and even snow! It does seem to be warmer for now, however, so devleopment should move rapidly. As we move about and look at development across the state it becomes even more apparent that overall we are on course and as the old timers have said "by the Fourth of July everything will level out." In the meantime, be sure and review the table from our last issue. We have added a few additional comments, updates and a conifer sawfly chart to this issue to bring you up to speed.

Insects

* Balsam Gall Midge (Paradiplosis tumiflex) - By the time you read this, adults should be out. While populations are expected to remain low, some woodland fir had moderate damage in 2001 so watch those Christmas tree plantings for signs of galls. Treatment with Diazinon or chlorpyrifos (Lorsban) after the new growth flares in the next week or so should do the trick.

*Birch Casebearer (Messa nana and Fenusa pusilla) - Developing mines are now evident in birch leaves in central and southern Maine and should be soon elsewhere. Soil systemics for these miners should already have been applied. Foliar treatments to preserve aesthetic quality of birch should be done as soon as the tiny mines appear. Acephate and carbaryl are registered for this purpose.

*Browntail Moth (Euproctis chrysorrhoea) - All cooperative control projects against this species in the Casco Bay area have been completed. Any other control projects should also have been completed as well. Most of the caterpillars are now in the fourth or fifth instar and are at the stage where the danger to people of developing dermatitis and respiratory problems from contact with toxic hairs has increased significantly. In infested areas, be especially careful on windy days or when mowing the lawn. It might be advisable to wear a surgical nose/mouth mask in such cases. The "browntail itch" will become more of a problem over the next two to three weeks. Once pupation is complete (early to mid July), the hairs will begin to settle to the ground and the incidence of the rash should diminish. Bathing exposed skin in cold water immediately after exposure to the browntail will help limit the rash, but if a severe rash develops it is best to consult your family physician for medical assistance. Inhaling these toxic hairs may also cause respiratory distress in some individuals.

Conifer Sawflies (Various) - A variety of sawflies should now be laying eggs on their respective conifer hosts across the state. Early detection and control should prevent serious and often rapid defoliation later. Larvae of most species feed gregariously at first so it is fairly easy to spot them. Where a problem is expected, treat with acephate or carbaryl, while larvae are still small. Of those species listed on the attached chart, the ones which are most likely to cause a problem this season are:

Introduced Pine Sawfly - A local problem. No widespread damage expected.
Jack Pine Sawfly - This species can be a problem along the coast in eastern Maine.
Larch Sawfly - Heavy defoliation over roughly 50,000 acres in central, eastern and northern Maine in 2001 and continued healthy populations portend a repeat this season.
Yellowheaded Spruce Sawfly - Although plantation problems with this species were down in 2001, many trees in open grown or ornamental situations were stripped. Eggs have now been laid in southern and central Maine and should be hatching by mid June.

*Gypsy Moth (Lymantria dispar) - The eggs of this species hatched later than expected. Tiny larvae began emerging and blowing around in the wind (ballooning) in most areas of southern Maine during the third week in May. Trees in infested areas of southwestern Maine should be monitored now for current populations. Acephate, Bt and carbaryl are registered for use in controlling gypsy moth.

*Hemlock Looper (Lambdina fiscellaria) - Tiny larvae of the hemlock looper have now been found in most infested areas of the State. Numbers so far appear to be lower than expected in infested stands in Hancock, Washington and souther York counties. Now is the time to monitor populations. If you are concerned about a potential problem in your area you could contact Hentry Trial, Jr., at Maine Forest Service, PO Box 415, Airport Road, Old Town, Maine 04468, Telephone: 827-1800 or check for information on our website. Bt is very effective against this pest but should be applied soon.

*Hemlock Woolly Adelgid (Adelges tsugae) - So far this year the hemlock woolly adelgid (HWA) has been found and eradicated on a total of 10 planted nursery stock trees in the towns of Camden, Rockland and York. This serious pest of hemlocks has never been found to be established in any of our native hemlocks. The most obvious evidence of hemlock woolly adelgid infestation is the conspicuous cottony egg sacs (resembling the tip of a cotton swab) present along the young twigs during most of the year. We ask that any one who sees suspected HWA contact Don Ouellette, Insect & Disease Laboratory, 50 Hospital Street, Augusta, ME 04330, Tel. 207 287-2431 or e-mail don.ouellette@state.me.us.

*Mountain Ash Sawfly (Pristiphora geniculata) - They're out and they grow fast and eat a lot so be prepared.

*Pine Shoot Beetle Quarantine (Tomicus piniperda) - The Maine Forest Service is now conducting a trapping survey to monitor the spread of this bark beetle in Franklin and Oxford county. Trapping will last until the end of June. No new records of this bark beetle have been confirmed in 2002.

*Ticks (Primarily the American Dog Tick and Deer or lyme tick) - There is a plentiful crop of ticks this season in southern Maine so don't forget to dress properly, use repellants and do those end of the day tick checks.

*White Pine Weevil (Pissodes strobi) - Infested terminal shoots on pine and spruce should begin wilting soon. Early detection and corrective pruning can minimize the long term impact of this pest.

Diseases and Injuries

Spring Frost - We have received many reports of frost damage especially from central and southern Maine during the past two weeks. Most damage apparently occurred the morning of May 20, where temperatures dipped below 23 degrees in many valley locations.

Reports of damage have been received thus far from York, Oxford, Kennebec, and Penobscot counties, with damage common on balsam fir, red oak, introduced larch species, and even American chestnut. Cone buds of most coniferous species seem to be especially susceptible to frost damage.

Another bout of frost earlier this week (the morning of June 4) caused light to moderate damage to emerging conifer growth in frost pockets statewide, especially in the St. John Valley west of Fort Kent. We will have an updated report of frost damage in our next newsletter.

White Pine Blister Rust - (caused by Cronartium ribicola) - While our white pine blister rust program still operates to control this disease on a town by town basis, we also directly assist individual landowners who have a blister rust problem anywhere in the state. If you have concerns about white pine blister rust on your property, feel free to call for site assistance. We will be happy to demonstrate procedures for chemical or cultural control of this problem to the extent time permits.

White Pine Decline (caused by drought stress to trees growing on sites which predispose to shallow root development) - After several years of studying the causes of white pine decline (trees growing in sites with less than twelve inches of rooting depth are those which seem to be most susceptible) our emphasis has now shifted to a study of ways to combat this problem.

This summer we will be working with SW Cole Engineering of Bangor, Maine to study the possible remediation of susceptible sites through soil subsoiling techniques, and with the University of Maine to identify broad geographical areas where sites are at risk of devleoping white pine decline. We also plan to work cooperatively with the USFS at the Massabesic Forest to determine whether various stand thinning regimes may reduce the impact of this problem on susceptible sites.

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Insect and Disease Laboratory, 50 Hospital Street, Augusta, Maine 04330-6514
Phone (207) 287-2431, Fax (207) 287-2432.

Compiled by Richard G. Dearborn and Clark A. Granger
02-2 Forest Health & Monitoring Division Augusta, Maine
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