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DEPARTMENT OF CONSERVATION
Maine Forest Service
Forest Health & Monitoring Division
May 13, 2002
Welcome! Another field season has begun with all of its attendant opportunities and challenges. Our summary edition of this report for 2001 is nearly ready for printing and should reach you later this month. In the meantime, we will bring you up to speed on what is currently happening or of concern, and hope that you too, keep us apprised of developments in your area.
Although it may be too late to control a few of the early season pests in southern Maine, take a moment to review our Management Guide for those of current concern. We have highlighted (u) those needing more critical attention. A file of more detailed information can be provided for some items (*). Should you need to reach someone at the Insect and Disease Lab, we will be open weekdays from 7:30 a.m to 4:00 p.m., or at other times by appointment. Have a great season!
Reminder: Next Week, May 19-25 is Arbor WeekGuide to Pest Management for May
|Insect/Disease||Cultural Controls||Chemical Controls|
|*Balsam Gall Midge||The tiny mosquito-like adults should emerge between now and early June. Populations are expected to be low in most areas but Christmas tree growers are urged to watch their plantations and be ready to treat if necessary as the new needles emerge and flatten with Diazinon or chlorpyrifos (Lorsban).|
|Balsam Shootboring Sawfly||Too late now for chemical control.|
|*Balsam Twig Aphid||Last chance now for control in southern Maine. Control may be achieved in northern and eastern Maine as buds begin to break using Diazinon or chlorpyrifos (Lorsban).|
|uBalsam Woolly Adelgid||Rogue out and destroy infested stock from Christmas tree plantations and be sure that planting stock is from a clean source. In forested situations harvest ahead of mortality.||None known|
|*Birch Leaf Miner||Watch for black fly-like adults around the foliage from now through mid-June. Apply foliar treatment with carbaryl or acephate when small developing mines (seen as small translucent spots in the leaves) are evident.|
|*uBrowntail Moth||Avoid mowing or raking in infested areas using adequate protection to avoid stirring up the hazardous caterpillar hairs. Clip overwintering webs next winter.||Treatment against the caterpillar stage should be done now. Call for more information.|
|*uGypsy Moth||Begin watching for larval activity this season now. Tiny larvae frequently drift around on spring breezes. If found, be prepared to remove and destroy egg masses next fall.||Populations and defoliation may be high in portions of Androscoggin, southern Oxford and York Counties this season. Monitor populations now to determine whether or not control will be necessary. Disease has reduced some populations since 2001.|
|*uHemlock Looper||Populations may be high in 2002 in York, Hancock and Washington Counties. Watch for tiny Looper larvae with black heads in early June. Survey methods are available and should be done in early June for this season. Treat in late June if necessary with Bt.|
|*uHemlock Woolly Adelgid||Please contact us.||Please contact us.|
|Larch Casebearer||Too late now for control.|
|Locust Leafminer||Heavy populations occur throughout the range of black locust in Maine. Treat infested trees with carbaryl (Sevin) as the orange and black beetles emerge (usuallly at the same time as the leaves).|
|*Mountain Ash Sawfly||Remove and destroy infested leaves early as egg pouches or tiny larvae appear in late May.||Treat older larvae with acephate (Orthene), carbaryl (Sevin) or methoxychlor.|
|*uPine Shoot Beetle||Please contact us.||Please contact us|
|Rhabdocline and Swiss Needle
Casts of Douglas Fir
|Plant trees at wide spacings and keep weed growth mowed. Rogue severely affected trees.||Chlorothalonil (Bravo, Daconil) when about 10 percent of trees have broken buds, and twice again at two week intervals.|
|Viburnum Leaf Beetle||Prune off twigs with egg pockets on them before May 1st.||Treat infested shrubs early (before the end of May) with acephate (Orthene) carbaryl (Sevin), chlorpyrifos or methoxychlor.|
|*Yellowheaded Spruce Sawfly||In some cases, infested branches can be removed before damage occurs.||Watch for adults around foliage in late May and early June. Look for developing larvae in June and be prepared to treat with carbaryl or chlorpyrifos if populations warrant.|
|Yellow Witches' Broom of Balsam Fir||Prune brooms from Christmas trees, taking care to make pruning cuts below galls at the bases of brooms.|
*uBrowntail Moth (Euproctis chrysorrhoea) - Larvae of this species are now actively feeding in infested areas around Casco Bay. The infested area appears to be expanding inland and east along the coast. State supervised control operations are now underway in Brunswick, Freeport and Yarmouth. Mowing or raking lawns and leaves in infested areas should only be done carefully and with adequate protection to avoid contact with the toxic caterpillar hairs. Control is difficult especially around water, and anyone needing advice should contact the I&DM Lab.
*uGypsy Moth (Lymantria dispar) - Gypsy moth defoliation was heavy and widespread covering roughly 30,000 acres in southwestern Maine in 2001. Populations are expected to be even higher, causing more widespread defoliation this season even though disease struck down some populations in 2001. Only one private control operation has so far been planned and this is in Auburn. No state projects are planned.
Egg hatch was first observed in South Berwick on May 7th and should be widespread by now. Tiny larvae commonly drift around so that defoliation can occur in stands with few or no egg masses. This pest bears watching.
*uHemlock Looper (Lambdina fiscellaria) - Nearly 200,000 acres of defoliation by this pest was mapped in 2001 in Hancock, Washington and York counties. Roughly 27,000 acres fell in the heavy category. While populations are expected to be heavy again this season in some areas, they are expected to drop in others. Several hundred acres in the West Grand Lake area of Washington County, which were heavily defoliated in 2001, will be treated this season by private contractors. Anyone wishing to assess potential populations should do so in early June using information from our fact sheet.
The *hemlock borer is causing increased mortality in association with looper and drought.
*uHemlock Woolly Adelgid (Adelges tsugae) - The Maine Forest Service continues to look for hemlock woolly adelgid, Adelges tsugae (HWA) on planted hemlock nursery stock and recently completed the annual inspection of 50 out planting sites with hemlock trees from a 1999 tree shipment containing infested trees. HWA was found on a total of 6 planted hemlocks at 3 sites in the Camden and Rockland area. The pest was also recently found on 4 planted hemlocks at a site with trees planted in 1998. All landscape sites with infested trees are being treated and the infested trees will be removed and destroyed. All trees are from shipments received from other states. To date hemlock woolly adelgid has only been on landscape trees and has not been found in native forest stands in Maine. If you wish to report to an infestation of HWA you should contact Don Ouellette, Insect & Disease Laboratory, 50 Hospital Street, Augusta, ME 04330, Telephone (207) 287-2431 or e-mail firstname.lastname@example.org
*Pear Thrips (Taeniothrips inconsequens) - Pear thrips populations are low again in all areas checked.
*uPine Shoot Beetle (Tomicus piniperda) - A state quarantine is now in effect in Maine for preventing the spread of the pine shoot beetle (PSB), Tomicus piniperda, an introduced bark beetle that has been found north of the Appalachian Trail in Oxford and Franklin counties. This new bark beetle primarily attacks and injures hard pines (Scots, red and jack pines) but it can also breed in eastern white pine. A trapping survey is being conducted at this time for this beetle to determine if it has spread. Single catches of this beetle were made in Adamstown during 2000 and 2001 and in Rangeley in 2001. The catches resulted in designating the northern portion of Oxford county north of the Appalachian Trail (AT) as a PSB regulated area. The Maine Department of Agriculture is in the process of amending the quarantine to include the northern portion of Franklin county. The Maine quarantine may also have to be amended again later in 2002 to parallel a federal PSB quarantine which is not yet finalized.
The PSB quarantine requires businesses in uninfested areas of Maine to have a compliance agreement with the Maine Forest Service if they receive pine logs or unprocessed pine bark (sawmill residue) from the regulated area north of the AT in Maine or from regulated areas in other states that include Coos county in NH and Essex, Orleans or Calledonia counties in VT. It is also imperative to note that we are currently in the high risk period - April 1 through June 30 - when adult PSB bark beetles emerge and disperse from logs. During this time - pine logs and unprocessed bark can not be moved from the regulated zone (quarantine or infested areas) to areas outside the quarantine. To request a compliance agreement or to find out more about the PSB quarantine please contact Don Ouellette, Insect & Disease Laboratory, 50 Hospital Street, Augusta, ME 04330, Tel. 207 287-2431 or e-mail email@example.com.
*Satin Moth (Leucoma salicis) - Satin moth larvae should soon be active. This is the time to check white and Carolina poplar for any tiny, fuzzy, developing larvae. Check especially those trees which have been previously infested. Treatment early with a pesticide such as carbaryl (Sevin) would save a lot of headaches later. Larval activity should also be evident in 2002 in infested stands of woodland aspen north of Millinocket in central Maine where 12,900 of defoliation was mapped in 2001.
*Ticks [the American Dog Tick (Dermacentor variabilis and the Deer Tick (Ixodes scapularis)] - Tick populations are high and appeared early this season in many areas of southwestern Maine from Penobscot Bay west to the N.H. state line and north to Route 2 and locally elsewhere. Those frequenting tick infested areas should be prepared to minimize the risk, discomfort and nuisance of tick attachment. Although there are thirteen species of ticks in Maine, the two mentioned here are the most abundant. Of these two, only the deer (black-legged or lyme) tick has been associated with lyme disease transmission.
If you know that you are in "tick country" you should dress appropriately with a long sleeved shirt and long pants which are tucked in, avoid brushy areas, use repellents and check daily for ticks upon return from the field. Repellents containing DEET are most effective but should be applied as directed and not overused, especially on children. Pesticides should not be applied to the skin and only registered formulations of permethrin should be used on clothing as directed. Should you suspect that you may have been bitten by a deer tick you should carefully remove it and place it in 70% rubbing alcohol for identification. Forms to use when submitting a tick for identification, including instructions, can be obtained from the I&D lab.
*Yellowheaded Spruce Sawfly (Pikonema alaskensis) adults will soon be active around young spruce trees. They are particularly attracted to open grown white spruce under 12 feet tall. The eggs hatch in June and most people do not notice the yellow (orange)-headed, striped, green larvae until substantial amounts of foliage have already been eaten off the tree. If you have spruce that have bare lateral branches especially near the top of the tree, check for larval feeding in June. Two chemicals that will provide control are carbaryl and chlorpyrifos.Diseases and Injuries
Cones in Balsam Fir Christmas Trees - After a relative reprieve for Maine Christmas tree growers in 2001, female cones are now again becoming apparent in the tops of occasional balsam and fraser fir Christmas trees in plantations statewide. Growers may wish to take the time to remove cones from trees to be sold this year.
The two Maine Christmas Tree Association (MCTA) seed orchards were extensively harvested during the cone year of 1998 but have not been harvested since that time. Because 2002 is shaping up to be a good cone year, another good harvest is anticipated this year from MCTA orchards in Ashland and Norridgewock.
Drought - Precipitation amounts were below average throughout Maine during the 2001 growing season and drought effects were pronounced on forest and landscape trees, especially in newly established plantations. In general native species fared somewhat better than exotics, but even native species on sites which were sandy or shallow to ledge suffered greatly. And trees stressed by insect or disease factors, such as spruce affected by dwarf mistletoe, in coastal areas succumbed in significant numbers.
In the long run, drought effects will be expressed as tree dieback and increased susceptibility to insects and disease, with mortality often resulting. It may take many years of normal and timely rainfall for drought stressed trees to fully recover. And it is unclear whether last summer's drought will precipitate another round of white pine decline such as we experienced following the drought of 1995.
Porcupine Damage (caused by Erethizon dorsatum) - Damage to plantation trees, especially Christmas trees, as the result of porcupine feeding continued at significant levels overwinter. It is difficult on the basis of anecdotal evidence for us to determine whether damage statewide was greater this past winter than other recent winters, and recent surveys have been inconclusive. Trapping porcupines near dens or shooting them when encountered provides temporary relief at best. A better approach may be to defeat porcupine denning sites near trees to be protected.
Salt Damage (caused by movement of deicing salts from road surfaces to susceptible plant species) - Symptoms of salt damage to roadside vegetation were less conspicuous than usual this past winter season. A relatively mild winter resulted in reduced salt usage, and less damage to roadside vegetation.
Damage at the levels noted pose little long term threat to tree health. Symptoms will fade as new growth emerges in May and June which will mask old, browned foliage.
Winter Injury - Overall the winter of 2001-2002 was mild with regard to temperature, and many tender plants came through with "flying colors." Forsythia in much of southern Maine is flowering right to the tops of shrubs indicating low flower bud mortality. Tender ornamental evergreens such as yews, rhododendrons, and dwarf Alberta spruce also show much less winter browning than usual.Yellow Witches'-broom of Balsam Fir (caused by Melampsorella caryophyllacearum) - These perennial, bushy growths on branches of fir trees are often abundant in Christmas tree plantations, and are especially conspicuous now as their bright yellow color contrasts with the darker green normal tree foliage.
Now is the best time of year to find and destroy them. When cutting brooms from trees, be sure to sever branches an inch or so below the swollen area on the twig at the base of each broom.
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
02-1 Forest Health & Monitoring Division Augusta, Maine
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