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Landscape Message: March 17, 2017

March 17, 2017
Issue: 
1

UMass Extension's Landscape Message is an educational newsletter intended to inform and guide Massachusetts Green Industry professionals in the management of our collective landscape. Detailed reports from scouts and Extension specialists on growing conditions, pest activity, and cultural practices for the management of woody ornamentals, trees, and turf are regular features. The following issue has been updated to provide timely management information and the latest regional news and environmental data.

Welcome to the first Landscape Message of the 2017 season! The Landscape Message will be updated bi-weekly in March, and weekly April through June. The next message will be available on March 31. To receive immediate notification when the next Landscape Message update is posted, be sure to join our e-mail list.

To read individual sections of the message, click on the section headings below to expand the content:


Scouting Information by Region

Environmental Data

The following data was collected on or about March 15. Total accumulated growing degree days (GDD) represent the heating units above a 50° F baseline temperature collected via our instruments for the 2017 calendar year. This information is intended for use as a guide for monitoring the developmental stages of pests in your location and planning management strategies accordingly.

Region/Location

GDD

Soil Temp
(°F at 4" depth)

Precipitation
(inches, rainfall equivalent)

Time/Date of Readings
2016 Total 2017 Current   Sun Shade Since 1/1 Since 3/1

Cape Cod

2908 16 37 34 8.80 2.00 12:00 PM 3/15

Southeast

2725 18 - - 9.61 0.77 4:30 PM 3/15

North Shore

2969 28 - - 5.25 1.07 9:30 AM 3/16

East

3165 34 34 31 8.97 1.80 4:30 PM 3/15

Metro West

2745.5 22.5 - - 2.86 0.73 5:15 AM 3/15

Central

2961 22 - - n/a 1.83 1:15 PM 3/16

Pioneer Valley

3032 16 - - 4.99 3.17 12:10 PM 3/16

Berkshires

2590 10 - - 5.49 1.04 1:00 PM 3/15

AVERAGE

2887

21

- - 6.57 1.55 -

n/a = information not available

Drought Conditions Update: Greater than 99% of Massachusetts is currently under official drought status, of that approximately 97% of the Commonwealth is classified as at least 'Moderate Drought', 37% is classified as 'Severe Drought', and approximately 41% is classified as 'Extreme Drought'.  For more information see http://droughtmonitor.unl.edu/Home/StateDroughtMonitor.aspx?MA.

Phenology

Phenological indicators are a visual tool for correlating plant development with pest development. The following are indicator plants and the stages of bloom observed for this period:

Indicator Plants - Stages of Flowering (BEGIN, BEGIN/FULL, FULL, FULL/END, END)
PLANT NAME (Botanic/ Common) CAPE S.E. N.S. EAST METRO W. CENT. P.V. BERK.
Hamamelis x intermedia (Witchhazel hybrids) Full Full/End Full Full Full Full Full/End Fill
Hamamelis mollis (Chinese Witchazel) Full/End Full Full End Full Full Full/End Full

Regional Notes

Cape Cod Region (Barnstable)

General Conditions: Overall weather conditions have been mild this winter. January had an average temp. of 36° F with a low of 6° F on January 9 and a high of 55° F on January 12. Approximately 4.8 inches of precipitation fell in January. February averaged 37° F with a low of 10° F on February 10 and a high of 68° F on February 24. The period from February 22-25 was unseasonably mild. Approximately 2.0 inches of precipitation fell in February. March has been up and down so far with an average of 32.5° F and a low of 10° F on March 12 and a high of 58° F on March 9. The March 14th storm started as snow in most locations however quickly turning to rain and melting most of the previous storm’s snow. The ground has been bare for much of the winter except for short periods with snow cover. Numerous storms with high winds and snow have caused damage to woody plants.

Pests/Problems: There is some concern as to whether the mild conditions in late February followed by cold temperatures in early March may have resulted in damage to plants. I have seen little evidence of widespread damage except to Crocuses that were in full bloom prior to the cold snap. Chickweed, Stellaria media and bittercress, Cardamine spp. were in bloom in late February. Some predation of gypsy moth egg masses has been observed but will not make a dent in the population. Damage to rhododendron in unirrigated landscapes is widespread as a result of the previous season’s drought and very noticeable at this time.

Southeast Region (Hanson)

General Conditions: It seems that from January, until now, we have experienced warm weather one day and cold the next, although the weather on March 14, and the memories of the winter of 2015, keeps us all on our toes and checking the weather forecast. However, overall not a bad winter, with a warm January and February, even with some really cold days. Hanson received approximately 20.5 inches of snow and 3.00 inches of rain from in January. January saw the most snow with 17 inches falling overnight on the 7-8th. Many of the towns in Plymouth County had similar totals, although some were higher with Bridgewater receiving 23”. In February, Hanson received approximately 12.20 inches of snow and 2 inches of rain. From March 1 - March 15th, Hanson received approximately 10 inches of snow and 0.77 inches of rain. Most of the snow (6 inches) in March fell during the storm on March 14th, which also produced high winds and gusts and several area power outages. The snow was followed by rain.

The coldest temperatures were three days in January (8, 9, and 10) with a low of 2 degrees F. overnight on the 9th. Temperatures really warmed up on Feb 23, 24, and 25 with balmy temperatures (64, 71, 70 degrees respectfully); it was the warmest February 23rd on record. Like last winter, the warm temperatures in January and February accelerated plant development and buds on plants like Hydrangea macrophylla. Time will tell whether the buds were killed or not. Hanson has 18 GDD, Base 50 and 171 GDD, Base 40.

Winter Jasmine (Jasminum nudiflorum) started to bloom in January and is still in bloom (covered by snow). Hamamelis x intermedia ‘Jelena’ began to bloom the 3rd week of January and just ended bloom. Hamamelis mollis 'Pallida' and Hamamelis x intermedia 'Arnold Promise' began bloom mid-February and remain in bloom. Honeybees were observed on the witchhazel flowers in February and on warm days have been observed on other flowers, like hellebores, etc. Lonicera fragrantissima (Winter honeysuckle) is in bloom. Snow drops and Eranthis hyemalis (Winter aconite) began bloom in mid-February and have ended bloom, however, Helleborus xhybridus ‘Jacob’ also began bloom in mid-February and remains in bloom. Other Helleborus xhybridus are beginning to bloom along with Helleborus foetidus. In Halifax, MA, Adonis vernalis and some crocus began bloom in early February, however, only recently,in Hanson, the crocus started to bloom and some daffodils were budding up, and they are now covered with snow. Silver maples were in bloom March 8, and Abeliophyllum distichum (White forsythia) is beginning bloom along with Daphne mezereum (February Daphne), Cornus mas and Cornus officinalis. Red-winged blackbirds and grackles are back, and some peepers started peeping on March 1st. All signs that spring is slowly but surely coming!

Pests/Problems: Winter moth caterpillar numbers may be down this year, according to staff at Dr. Elkinton’s UMass lab. In Hanson, MA, the number of winter moth eggs observed on the banded tree are far fewer in number than in previous years. Although the caterpillars may be fewer in numbers, they still can do damage to plants, especially the flowers (which produce fruit) on apples and blueberries. In early April, monitor susceptible trees for winter moth caterpillars, which usually hatch early-mid-April. If you do have clients that are growing apples or blueberries, they may want to consider protecting the plants and flower buds just as the buds are swelling, by applying a well-timed dormant oil spray when the weather conditions are optimum: temperatures above 45 degrees F and to avoid applying oil when temperatures may dip below freezing for 24 - 48 hours after application. For more information see Tawny Simisky’s Insect Section of the Landscape Message and also check out the UMass Winter Moth ID & Management fact sheet: http://ag.umass.edu/landscape/fact-sheets/winter-moth-identification-management

Monitor Pieris, evergreen azaleas and rhododendrons for signs of last year’s damage, from last year’s lacebugs, which is very apparent now. The top of the foliage will appear stippled like tiny grains of salt and pepper. If seen, make plans to monitor those plants later in the season for lacebugs and manage accordingly. Lacebugs can cause significant damage and subsequent decline to the plants they attack.

Monitor hemlocks, especially the outer branch tips for the tiny, white, cotton-ball-like egg masses of Hemlock Wooly Adelgid and if found, manage early, weather permitting.

Deer ticks may once again enjoy a banner year with the mild winter we had. Also, if there is an abundance of white footed mice that too would add to seeing more ticks, according to a recent report on National Public Radio (NPR): http://www.npr.org/sections/goatsandsoda/2017/03/06/518219485/forbidding-forecast-for-lyme-disease-in-the-northeast

Remember to conduct tick checks frequently and use repellants any time the weather is above freezing and especially during landscape cleanups. For tick information go to: https://ag.umass.edu/services/tick-borne-disease-diagnostics

Voles have been and continue to be present in the landscape as evidenced by the vole runs seen after the snow has receded and also by the number of hosta crowns devoured in overwintering pots. Deer have been browsing all winter, and turkeys are active.

Although the winter saw few major storm events, there was significant wind in many areas over the past three months and tree debris and broken branches are evident in many of those areas.

It appears that even with some snow and rain this winter, that most of Massachusetts remains dry with the southeast at the ‘moderate drought level’. http://droughtmonitor.unl.edu/Home/StateDroughtMonitor.aspx?MA

http://www.mass.gov/eea/agencies/dcr/water-res-protection/water-data-tracking/drought-status.html

We need rain this coming season!

North Shore Region (Beverly)

General Conditions: The year started off very mild. January was unseasonably mild with temperatures going below freezing for only 12 days in the month. Temperatures below 20° F occurred only for two days in January when a cold front passed through pushing down the temperatures to 15° F and 12° F on January 8 and 9. Snowfall was experienced only for a few days in January. February was colder than January, but it was still milder than expected. The last week of the month was unseasonably warm with temperatures climbing to the 50s and lower 60s. There were significant amounts of snow for a few days in the first half of the month. Notable amounts of snowfall occurred on the 7th through the 9th and on the 16th of the month. The start of the month of March was mild and and uneventful but this changed on the 13th through the 14thwhen a blizzard moved through and brought in a significant amount of snow. Some plants were in bloom before the snowstorm but are now under the snow. Early spring flowering bulbs seen in bloom before the snowfall include Winter aconite (Eranthis hyemalis) and Snowdrops (Galanthus nivalis). Hellebores (Helleborus orientalis) are also in bloom. Trees seen in bloom include: Arnold promise witchhazel (Hamamelis x intermedia). Cornelian cherry dogwood (Cornus mas) and Goat willow (Salix caprea) are just starting to flower.

Pests/Problems: Very little deer browsing was observed due to lack of snow and relatively warm winter temperatures. Deer had sufficient plants to browse in the woods. Some vole tunneling was observed on lawns.

East Region (Boston)

General Conditions: January temperatures were unseasonably warm, temperatures averaging 4.5° warmer than usual. Lows averaged 26.5°F (ranging from 4.7°F to 42.9°F) while highs averaged 41.0°F (ranging from 19.7°F to 61.8°F). A cold front on the 8th and 9th saw lows in the single digits before a warm spell came through on the 11th to the 13th, as temperatures reached into the 60’s. We received 9.25 inches of snow for the month, most of it falling on the 7th, with a total precipitation of 4.45 inches, well above the January average of 3.35 inches.

February was also milder than usual, averaging 4.0° warmer than normal. Lows averaged 27.1°F (ranging from 9.1°F to 48.5°F) while highs averaged 45.4°F (ranging from 25.3°F to 74.2°F). A warm spell from the 23rd to the 25th saw temperatures soar into the 70’s, resulting in a gain of 24.5 GDDs – each of the three days setting new records (69°F, 74°F, and 72°F). We reached 74°F on the 24th, the highest February temperature ever recorded in Boston since record keeping began in 1872. We received one significant snow event on the 11th into the 12th as a system dropped one foot of snow. A total of 21.5 inches of snow fell during the month with total precipitation of 2.72 inches, half an inch below the February average. The record-setting warm temperatures and lack of snow cover late in the month caused early spring blooming of Acer rubum (red maple), Acer saccharinum (silver maple), Alnus sp. (alder), Corylus sp. (hazel), Galanthus nivalis (snowdrops), Hamamelis x intermedia cultivars ‘Arnold Promise’, ‘Diane’, and ‘Jelena’, Hellebore sp. and cultivars (lenten rose), Salix gracilistyla (rose-gold pussy willow), and some Scilla siberica (‎Siberian squill).

So far during March, temperatures have been chilly, much cooler than February. Lows average 22.2°F (ranging from 7.8°F to 48.2°F) while highs average 40.5°F (ranging from 19.6°F to 63.0°F). Over the last two weeks, we dipped down to lows in the single digits on three occasions. We received a total of 8.5 inches of snow, with a total precipitation of 1.8 inches. On the 14th, a blizzard brought high winds and blowing snow; snowfall totaled 6.5 inches followed by heavy rain, a total of 1.53 inches of precipitation fell. We lost one Prunus armeniaca (apricot) and one Salix sp. (willow). Temperatures dropped well below freezing overnight turning the landscape, roads and sidewalks in a skating rink on the morning of the 15th. Just beginning to flower are Cornus mas (Cornelian cherry), Crocus sp. (crocus), Lonicera sp. (honeysuckle), and Salix melanostachys (black pussy willow).

Pests/Problems: February’s warm conditions resulted in significant emergence of biennials, perennials and spring ephemerals: Alliaria petiolata (garlic mustard), Allium vineale (wild garlic), Chelidonium majus (greater celandine), Ficaria verna (lesser celandine), Symplocarpus foetidus (skunk cabbage), and Urtica dioica (stinging nettle). Winter annuals have germinated and have been flowering since February. Buds began swelling in early March, specifically on: Chaenomeles sp. (flowering quince), Prunus sp. (cherry), and Syringa sp. (lilac).

Metro West (Acton)

General Conditions: In like a lion, out like a lamb? That remains to be seen. As I write this report, I am watching the snow fall and listening to the weather forecasters predict 12” to 18” of snow for this area; warn against occasional wind gusts up to 50 mph and forewarn us all for the potential for power outages. My snowdrops that emerged and flowered with the warm temperatures in late February and into early March are now buried in the snow and my Hamamelis x intermedia “Diane” (Witch Hazel), which is in full bloom, is now blanketed in snow.

It was just over two weeks ago when five growing degree days were recorded and just and a bit longer than that when an additional sixteen GDD were picked up when the record high temperatures were recorded on February 24, 24 and 25 with 69°,74°, and 69° recorded for this area. On the flip side, there were three days in January when sub-zero temps were recorded on the 8th, 9th and 10th with temperatures of -0.5°, -4°, and -1.6°. Some additional numbers to share with you, the average high temperature for March is 46°; the low is 27° and the average precipitation is 4.83”.

Spring is less than a week away. I sure hope that we see more signs of spring in the landscape next week!

Pests/Problems: A drought advisory for this area remains in effect and was issued on March 1st as a result of a recommendation from the Drought Management Task Force. Despite recent precipitation, this drought status has not changed from the month of February and will remain in effect until water levels return to normal in this region. Let’s hope that this late season blizzard will have a positive impact on this area’s drought status and downgrade this area to normal!

Central Region (Boylston)

General Conditions: The year is off to a mild start with warmer than usual temperatures throughout January and February. The weather was most unusual for February – temperatures ranged from a daytime low of 4 degrees on February 10th to a high of 69 degrees on the February 24th. Periods of snow were interspersed among the warmth with accumulating snow on February 9th (8”), 11th (4”), and 12th (7”). Temperatures were above historic averages 17 out of 28 days. The last two weeks of the month brought 8 days with temperatures 55 degrees or over, with three days well into the 60’s. Though it is not unusual to see some Witch-hazel (Hamamelis x intermedia cultivars), Snowdrop (Galanthus nivalis and G. elwesii), and Winter Jasmine (Jasminum nudiflorum) blossoms in January and February they were unusually prolific and showy in the extraordinary warmth. The warmth in February brought Eranthis hyemalis and Adonis amurensis into bloom, as well as Helleborus niger and H. foetidus, and Salix chaenomeloides ‘Mt. Aso’ and Salix gracilistyla ‘Melanostachys’. In early March the buds of Cornus officinalis cracked open and flowers to emerge by March 13th. Some damage to early crocus was observed in the cold temperatures in early March. March has been exceedingly windy causing limb breakage and downed trees throughout the region. Winter storm Stella moved into the region in the early hours of March 14th and dropped 12-14” of drifting snow of the course of the day and early evening. High winds accompanied the storm and added to the tree damage throughout the region.

Pests/Problems: Deer continue to feed. Turkeys and other birds have all but stripped the berries of the red Winterberry (Ilex verticillata) cultivars - yellow and orange cultivars still retain their fruit. Ticks have been active on warmer days.

Pioneer Valley Region (Amherst)

General Conditions: Spring is on hold as the Connecticut Valley digs out from winter storm Stella, a large nor’easter that dumped over a foot of snow in most areas of the tri-county region. Westover Air Reserve Base in Chicopee recorded nearly 22″ of snow (with a liquid equivalent of 2.9″) from the 3/14 storm. Just three weeks ago, it appeared we would have an early spring, thanks to unseasonably warm late February weather that brought temperatures into the upper 60s to lower 70s across the northeast. From 2/19 through 3/2, high temperatures >60°F were recorded on 8/12 days with a peak of 73°F on 2/24. The abnormally warm weather contributed to the development of a tornado in western Hampshire County on Saturday, 2/25. It was the first tornado recorded in the Commonwealth during the month of February since record keeping began in 1950. The EF1 storm with winds over 100 mph damaged homes, businesses and numerous trees in Conway with minor damage reported in Goshen (see photos below). Thankfully there were no reported injuries or deaths from the storm. Spring-flowering witchhazels put on their typical show, starting in early February, which is always beautiful and a sign that spring is approaching. But the sustained warm weather and increasing intensity of the sun resulted in greening of turfgrasses (and noticeable growth on the UMass campus) and an early break of dormancy for many landscape trees and shrubs. Elms and many silver maples in the valley have already bloomed, red maple buds are swollen and ready to break, and serviceberry and blueberry buds have been observed in various stages of bud break. As the calendar flipped into March, the spring roller coaster continued with brief glimpses of spring (61°F on 3/8) followed by a return to the depths of winter (high of 22°F with wind gusts over 45 mph at Barnes Airport on 3/11). The long-term forecast calls for highs in the 30s and 40s, with low temperatures consistently below freezing. Additional snowfall may also develop, suggesting it could be April before this latest snow is melted. The U.S. Drought Monitor shows that all of Massachusetts is still suffering through lingering drought conditions. On a positive note, this winter’s rain and snow have improved the situation dramatically and the seasonal forecast from the National Weather Service predicts that drought conditions will improve. However, we are likely to see drought classifications persist throughout this upcoming growing season unless we experience abnormally high rainfall (i.e. amounts at least twice the monthly average). Most of the valley is still classified as D2, or severe drought (http://droughtmonitor.unl.edu/Home/StateDroughtMonitor.aspx?MA). While this late winter snowstorm was most unwelcome, the resulting snowpack will help to saturate soils as the growing season approaches. The abundant snowfall the region experienced in early February melted so quickly there was concern prior to the nor’easter that soils could dry out if we didn’t receive average rainfall in March. At present, it appears soils will be wet heading into April.

February 26, 2017 Conway-Goshen tornado damage (photo by T. Simisky) February 26, 2017 Conway-Goshen tornado damage (photo by T. Simisky)

Pests/Problems: Disease-causing fungi and bacteria won’t be actively growing for several weeks, making this a good time to prune cankered branches and blighted stems without fear of spreading pathogens. Once the snow is melted, remove oak leaves that did not abscise in the fall. The foliage can harbor fungi responsible for oak anthracnose and tubakia leaf blotch. Now is a good time to prepare treatment plans for pervasive landscape pests like lace bugs on rhododendron, azalea and andromeda, spider mites on conifers and armored scales like the elongate hemlock scale. Spruce spider mites were widely abundant in 2016, especially on Norway spruce, thanks to the drought. Unlike most spider mites, the spruce spider mite thrives during cooler temperatures. Scout trees for damage and prepare to treat early in the growing season if necessary. The detection of the oak wilt pathogen, Ceratocystis fagacearum, at several locations in southern New York has arborists fearful that this destructive vascular wilt pathogen may finally take up residence in New England. To date, oak wilt has never been confirmed in New England, but with multiple detections on Long Island, it may only be a matter of time. In areas where oak wilt is abundant, pruning of oaks is only performed during the dormant period from November to March. Pruning from April through June results in sap flow from the wounds that can attract the sap feeding beetles responsible for vectoring the fungal pathogen. Symptoms of infection include marginal leaf browning that develops mid-season and a general wilt of foliage and branches.

Berkshire Region (Great Barrington)

General Conditions: For the most part, this winter has been a roller coaster ride with dramatic temperature changes since the first of the year. February, saw a range of temperatures for the month from a low of 6° F on February 6th to a record high (for the date) of 73° F on February 24th. During that last full week of February, witch hazels (Hamamelis x intermedia and H. mollis) came into bloom along with snowdrops (Galanthus). Just before the “Blizzard of 2017), winter aconite (Eranthus hyemalis) could also be seen in bloom. The storm on the 14th of February left 15.5 inches of snow at this reporting station.

Pests/Problems: During the warm spell in February, ticks were quite active and were found attached to hikers in woodlands and to pet animals.

Regional Scouting Credits

  • CAPE COD REGION - Russell Norton, Horticulture and Agriculture Educator with Cape Cod Cooperative Extension, reporting from Barnstable.
  • SOUTHEAST REGION - Deborah Swanson, UMass Extension Horticulturist for Plymouth County - Retired, reporting from Hanson.
  • NORTH SHORE REGION - Geoffrey Njue, Green Industry Specialist, UMass Extension, reporting from the Long Hill Reservation, Beverly.
  • EAST REGION - Kit Ganshaw & Sue Pfeiffer, Horticulturists, reporting from the Arnold Arboretum, Jamaica Plain.
  • METRO WEST REGION – Julie Coop, Forester, Massachusetts Department of Conservation & Recreation, reporting from Acton.
  • CENTRAL REGION  -  Joann Vieira, Superintendent of Horticulture, reporting from the Tower Hill Botanic Garden, Boylston.
  • PIONEER VALLEY REGION - Nick Brazee, Plant Pathologist, UMass Extension Plant Diagnostic Lab, reporting from UMass Amherst.
  • BERKSHIRE REGION - Ron Kujawski, Horticultural Consultant, reporting from Great Barrington.

Woody Ornamentals

Diseases

Recent pests and pathogens of interest seen in the UMass Extension Plant Diagnostic Lab:

Armored scale infestation, caused by Lepidosaphes sp., on umbrella pine (Sciadopitys verticillata). Host trees range from young and recently transplanted (<10-years-old) to the state champion specimen on the UMass campus (>125-years-old). This oystershell-like armored scale is found in clusters at the base of umbrella pine needles, partially obscured by the remnants of the bud sheath. Several samples submitted to the diagnostic lab were positive for this insect pest in 2016 and while many trees exhibited needle browning and dieback, it’s unclear what role the scale plays in decline. Additional scouting for this pest during this past winter has shown it is widely abundant on umbrella pines in landscape settings.

Needle tip browning of eastern white pine (Pinus strobus) and limber pine (P. flexis) caused by Septerioides strobi. The white pine is approximately 10-years-old and resides in sandy soils in a landscape setting with partial sun at the edge of the wooded area. Needle tip browning was observed this winter but was not noticed in 2016 or previous years. The shade for significant portions of the day is likely a predisposing stress. The limber pine is young, less than 20’ tall, and resides on the UMass campus in a sunny and windy location along a road where a large amount of deicing salts are applied. Neither tree is provided with supplemental irrigation. Septorioides has been frequently associated with needle tip blight of eastern white pine since 2015, although much remains to be learned about its pathogenicity on this host.

Trunk rot of European beech (Fagus sylvatica) caused by Ganoderma applanatum (artist’s conk). Tree is approximately 80-years-old and, like many landscape beeches, has been desecrated with countless carvings of initials and names into the bark. Two perennial conks were observed, one close to the soil line and another approximately 3-4’ high. Significant canopy dieback has developed in recent years, likely due to colonization of the outer sapwood and phloem, especially in the area of the trunk where the conks are present.

Suspected drought-induced mortality of Fraser fir (Abies fraseri). Young trees (up to six-years-old) at two Christmas trees in eastern Massachusetts. Symptoms range from top dieback, undersized 2016 needles, needle browning, curling of shoots and outright mortality. The season-long drought affected many young firs in landscape and Christmas tree farm settings. While firs are adaptable to many locations, at this latitude these trees are native to cool, high-elevation forests where soils are thin and moist. Additionally, fog is common in these settings, which reduces drought stress during prolonged dry periods.

Phomopsis stem galls on forsythia (Forsythia x ‘Meadowlark’). The shrub is approximately 18-years-old and has numerous stem galls in the canopy, mostly on older canes (see Figure 1). Little remains known about Phomopsis species that produce stem galls on trees and shrubs but the condition is fairly common on older forsythia shrubs. The galls can lead to stem dieback but in many cases, the plant appears healthy overall.

Fig. 1: Stem galls on Forsythia produced by Phomopsis.  Fig. 2: Feeding damage by lace bugs (Stephanitis) on Rhododendron.

Report by Nick Brazee, Plant Pathologist, UMass Extension Plant Diagnostic Lab, UMass Amherst.

Insects

Woody ornamental insect and non-insect arthropod pests to consider, a selected few:

  • Winter Moth: Operophtera brumata. The eggs of this insect, laid by the females who emerged in November of 2016 and were active through the winter months (mainly November through December when temperatures are above freezing) are currently present in the landscape and hidden in cracks and crevices of bark or beneath lichen on host plants such as oak, maple, apple, blueberry, crabapple, etc. Eggs are tiny and green when first laid, but quickly turn a red-orange color soon after. At this time, anyone monitoring winter moth eggs will most likely see that they are orange in color. As the egg develops, it will turn a bright blue color, shortly prior to egg hatch. For more information about the life cycle and management of winter moth, please visit this newly updated (March, 2017) fact sheet: Winter Moth Identification and Management (https://ag.umass.edu/landscape/fact-sheets/winter-moth-identification-management).

According to reports, winter moth eggs in Rhode Island (Heather Faubert, University of Rhode Island) and eastern Massachusetts (Dr. Joseph Elkinton, University of Massachusetts) are still orange at this time. As of 3/16/2017, egg color change indicating winter moth egg hatch and caterpillar arrival has not yet been observed. While some areas in eastern Massachusetts, where winter moth is problematic, may have accumulated enough growing degree days to indicate the possibility of winter moth egg hatch, using that method to predict this particular insect’s development is complicated. As one could imagine, although we recently experienced record-breaking, above average temperatures, were winter moth eggs to hatch at this time, they would not arrive in the most favorable of conditions thanks to our recent snowfall. For more information about using growing degree days to predict insect development, please visit: https://ag.umass.edu/landscape/fact-sheets/growing-degree-days-for-management-of-insect-pests-in-landscape.

Continued monitoring of winter moth egg development is needed at this time, especially for blueberry and apple growers looking to manage winter moth caterpillars early before damage to the buds can occur. For individuals managing winter moth in ornamental plants, depending on the active ingredient being used, waiting until host plant leaves open completely may be important for management, particularly if Bacillus thuringiensis Kurstaki (Btk) is the active ingredient of choice. Btk must be ingested by actively feeding, young caterpillars to be effective. Applying Btk to closed buds for winter moth management will not have the desired effect. The Elkinton Lab has reported that the number of pupating winter moth in 2016 (at their study sites) was much lower than what has been observed in previous years. Reports from Hanson, MA (see Southeast Region report) indicate fewer winter moth eggs are present on monitored trees than in previous years. Hopefully this will translate into fewer caterpillars at least for some areas in Massachusetts this year, however one should not expect them (or the damage they cause) to completely disappear in 2017.

Winter moth is a non-native insect that was identified in Massachusetts for the first time in 2003 following persistent reports of defoliation in eastern areas of the state such as Cape Anne and on the North Shore near Cohasset, Hingham, and Rockland on the South Shore in the late 1990’s. For more detailed information about the history of this insect pest in North America and Massachusetts, please visit the newly updated (March, 2017) fact sheet: Winter Moth in Massachusetts: History and Biological Control (https://ag.umass.edu/landscape/fact-sheets/winter-moth-in-massachusetts-history-biological-control).

This fact sheet also includes updates regarding the progress of the work of Dr. Joseph Elkinton’s laboratory group at the University of Massachusetts and their efforts towards the biological control of winter moth using Cyzenis albicans, a tachinid fly. The fly parasitizes the caterpillars of winter moth specifically. In other areas, such as Nova Scotia where winter moth was also problematic, this fly used for biological control has been successful in reducing winter moth to a non-pest. C. albicans has been released across 41 sites in Massachusetts and has been established in at least 17 of those sites as evidenced through the recovery of flies in winter moth in subsequent years. In one site in Wellesley, these flies have been observed to be spreading from the initial release location and their populations have increased alongside an observed decrease in the winter moth population there. For more information, please visit the above mentioned fact sheet.

  • Gypsy Moth: Lymantria dispar egg masses laid by female moths in 2016 can be seen at this time. This is the stage of the insect that overwinters. Egg masses are “fuzzy” or hairy and brownish-tan in color. Each egg mass can hold up to 500-1000 eggs. These masses may be found on host plant trunks and branches such as oak (favored), maple, birch, poplar, and many others, but are also laid on inanimate objects including the surfaces of homes, outdoor furniture, camping equipment, firewood piles, etc. This may make the accidental movement of gypsy moth egg masses possible.

Egg hatch for this insect is also not yet upon us, and occurs after winter moth egg hatch. (Note: winter moth and gypsy moth share some common host plants. Therefore, where populations of these two insects overlap in Massachusetts, the same tree may be defoliated by winter moth and then again by gypsy moth following in the same season.) Gypsy moth egg hatch typically occurs between 90-100 growing degree days, using a base of 50°F, average temperatures, and a March 1st start date. This is usually around the first week in May in Massachusetts, but variations in temperature may lead to early egg hatch in the last week in April. This can also coincide with serviceberry (Amelanchier) bloom. After egg hatch occurs, groups of tiny gypsy moth caterpillars may remain on their egg mass just before crawling to the canopy of their host plant, where they can disperse using a technique known as “ballooning”. Ballooning occurs when very young caterpillars spin a silken thread and catch the wind to blow onto a new host plant once the thread breaks. This method of dispersal can lead to host plants becoming defoliated that previously did not have egg masses directly on them, however egg masses may be present on nearby oaks, for example, and provide a local population of caterpillars.

Patchy areas across mostly central and eastern Massachusetts experienced elevated populations of gypsy moth and significant amounts of defoliation in 2016 (see the Insects section of the archived 2016 Landscape Messages between April 29 and July 29). The Massachusetts Department of Conservation and Recreation aerially mapped approximately 350,000 acres of defoliation across Massachusetts last year, attributed to gypsy moth. State officials warn the public about another year of defoliation from gypsy moth as predicted for 2017: http://www.mass.gov/eea/agencies/dcr/pr-2017/another-year-of-defoliation-from-gypsy-moth-in-2017.html. That web page also links to a map of the 2016 defoliation from gypsy moth, which may provide a reference regarding areas that may be impacted by this insect again in 2017. To prepare for this insect, now (before the last week in April) is a great time to scout the landscape and count the number of gypsy moth egg masses present not only on valuable landscape specimens that are hosts for this insect, but on nearby forested hosts such as oak which might provide sources of ballooning caterpillars. Egg mass counts can help us make decisions regarding whether or not to manage for this insect. Some individuals also use this opportunity to scrape egg masses into a container of soapy water, although this is time consuming and some egg masses will be missed.

We can hope for elevated rainfall in the months of May and June, which helps facilitate the successful infection of younger gypsy moth caterpillars with the insect-killing fungus Entomophaga maimaiga. This fungus is currently overwintering in the soil litter in tough, protected asexual resting spores, which can survive in this state for years. Having lacked much precipitation most recently during the springs of 2015 and 2016, it is thought that our current expanding populations of gypsy moth are at least in part a result of a lack of infection in the caterpillar population by this fungus. Hopefully Massachusetts will see more normal rainfall amounts this season. Only time will tell.

We can also hope areas in Massachusetts that do not have large numbers of gypsy moth egg masses present at this time and did not experience much gypsy moth defoliation last year (areas such as most of Berkshire County) will be mostly spared in 2017 in comparison to those areas who suffered last year in central and eastern Massachusetts. At this time, monitoring susceptible hosts for gypsy moth egg masses and educating and reminding ourselves about this invasive insect that has a long history in the state is the best way to plan for management this season. For more information about gypsy moth, please visit: http://ag.umass.edu/landscape/fact-sheets/gypsy-moth and return to the Landscape Message for timely updates about this pest and others throughout the season.

  • Asian Longhorned Beetle, Anoplophora glabripennis, ALB: Look for signs of an ALB infestation which include perfectly round exit holes (about the size of a dime), shallow oval or round scars in the bark where a female has chewed an egg site, or sawdust-like frass (excrement) on the ground nearby host trees or caught in between branches. These particular signs of damage from the beetle may be more visible at this time of year, when host trees such as maples are leafless. Be advised that other, native insects may create perfectly round exit holes or sawdust-like frass which can be confused with signs of ALB activity.

The regulated area for Asian longhorned beetle is 110 miles2 encompassing Worcester, Shrewsbury, Boylston, West Boylston, and parts of Holden and Auburn. If you believe you have seen damage caused by this insect, such as exit holes or egg sites, on susceptible host trees like maple, please call the Asian Longhorned Beetle Eradication Program office in Worcester, MA at 508-852-8090 or toll free at 1-866-702-9938. Adult insects of this species will not be present at this time of year.

To report an Asian longhorned beetle find online or compare it to common insect look-alikes, visit: http://massnrc.org/pests/albreport.aspx or https://www.aphis.usda.gov/pests-diseases/alb/report.

  • Emerald Ash Borer (EAB): Agrilus planipennis readily attacks ash (Fraxinus spp.) including white, green, and black ash and has also been found developing in white fringe tree (Chionanthus virginicus). Adult insects of this species will not be present at this time of year. Signs of an EAB infested tree may include (at this time) D-shaped exit holes in the bark (from adult emergence in previous years), “blonding” or lighter coloration of the ash bark from woodpecker feeding (chipping away of the bark as they search for larvae beneath), and serpentine galleries visible through splits in the bark, from larval feeding beneath. Positive identification of an EAB-infested tree may not be possible with these signs individually on their own.

For a map of the known locations of emerald ash borer in the state, as well as further information about this insect, please visit: https://ag.umass.edu/fact-sheets/emerald-ash-borer. If you believe you have located EAB-infested ash trees, particularly in an area of Massachusetts not identified on the map provided, please follow the instructions below.

Concerned that you may have found an invasive insect or suspicious damage caused by one? Need to report a pest sighting? If so, please visit the Massachusetts Introduced Pests Outreach Project: http://massnrc.org/pests/pestreports.htm.

A note about Tick Awareness: deer ticks (Ixodes scapularis), the American dog tick (Dermacentor variabilis), and the lone star tick (Amblyomma americanum) are all found throughout Massachusetts. Each can carry their own complement of diseases. Anyone working in tick habitats (wood-line areas, forested areas, and landscaped areas with ground cover) should check themselves regularly for ticks while practicing preventative measures. Have a tick and need it tested? Visit the web page of the UMass Laboratory of Medical Zoology (www.tickdiseases.org) and click on the red Test a Tick button for more information.

Report by Tawny Simisky, Extension Entomologist, UMass Extension Landscape, Nursery, & Urban Forestry Program

Management Practices

Plant of the week: Hamamelis x intermedia, hybrid witchhazels

One of the first signs of spring are the flowers of Hamamelis x intermedia. A hybrid of H. japonica and H. molli, H. x intermedia is a small tree or large shrub growing 15-20’ tall and wide. Plants are often multi-stemmed with an upright oval to rounded spreading form. The often fragrant flowers occur in late winter or early spring, persisting up to a month. Flowers consist of four long, narrow, strap-like twisted petals and usually occur in clusters of 2-4. Cultivars offer colors from light yellow to orange to copper or red. Leaves are dark green to blue-green, 3-6” long with yellow to orange-red fall color depending on cultivar. Plants grow best in full sun to part shade in a moist, acidic, fertile soil. Best flowering is in full sun. Cultivars are often grafted on H. vernalis or H. virginiana rootstock. Suckering from rootstock is common and suckers should be removed for best growth. Leaf scorch can occur during periods of drought. Cultivars of interest include: ‘Arnold Promise’ –bright yellow fragrant flowers that bloom later than other cultivars and has good fall color; ‘Diane’ – copper-red flowers; ‘ Jelena’ – copper to yellow flowers, horizontal habit, and good orange-red fall color; and ‘Pallida’ – early flowering form with soft yellow fragrant flowers, wide-spreading, good yellow fall color.

Hamamelis x intermedia, hybrid witchhazels Hamamelis x intermedia, hybrid witchhazels Hamamelis x intermedia, hybrid witchhazels

Report by Mandy Bayer, Extension Assistant Professor of Sustainable Landscape Horticulture, UMass Stockbridge School of Agriculture

Other Relevant News/Pest Alerts

The Massachusetts Department of Agricultural Resources (MDAR) is providing the opportunity to dispose of unwanted and/or unregistered pesticides at NO COST to licensed pesticide applicators. As a Massachusetts Pesticide Applicator you will have the opportunity to choose one of two locations to drop off your unwanted/unregistered pesticides. This is a limited opportunity and is a first come first serve basis. In order to ensure as many people as possible may participate in this program, the Department reserves the right to limit the amount of materials that can be brought in by any one participant.

In order to participate you MUST register by May 15, 2017.

This is a CONFIDENTIAL PROGRAM. Your name and the materials you bring in will be kept confidential and will not be disclosed. The goal of this program is to safely dispose of unused pesticides from licensed pesticide applicators. THIS IS NOT AN ENFORCEMENT PROGRAM.

To find out more information regarding the program and how to register you may visit the MDAR website at: http://www.mass.gov/eea/agencies/agr/about/divisions/division-of-crop-and-pest-services-generic.htm


Additional Resources

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For a complete listing of upcoming events, see our Upcoming Educational Events page.

For commercial growers of greenhouse crops and flowers - Check out the New England Greenhouse Update website

For professional turf managers - Check out Turf Management Updates

For home gardeners and garden retailers - Check out home lawn and garden resources. UMass Extension also has a Twitter feed that provides timely, daily gardening tips, sunrise and sunset times to home gardeners, see https://twitter.com/UMassGardenClip

Diagnostic Services

A UMass Laboratory Diagnoses Landscape and Turf Problems - The UMass Extension Plant Diagnostic Lab is available to serve commercial landscape contractors, turf managers, arborists, nurseries and other green industry professionals. It provides woody plant and turf disease analysis, woody plant and turf insect identification, turfgrass identification, weed identification, and offers a report of pest management strategies that are research based, economically sound and environmentally appropriate for the situation. Accurate diagnosis for a turf or landscape problem can often eliminate or reduce the need for pesticide use. For sampling procedures, detailed submission instructions and a list of fees, see Plant Diagnostics Laboratory

Soil and Plant Nutrient Testing - The University of Massachusetts Soil and Plant Nutrient Testing Laboratory is located on the campus of The University of Massachusetts at Amherst. Testing services are available to all. The function of the Soil and Plant Nutrient Testing Laboratory is to provide test results and recommendations that lead to the wise and economical use of soils and soil amendments. For complete information, visit the UMass Soil and Plant Nutrient Testing Laboratory web site. Alternatively, call the lab at (413) 545-2311.

Ticks are active whenever temperatures are above freezing! Remember to take appropriate precautions when working and playing outdoors, and conduct daily tick checks. UMass tests ticks for the presence of Lyme disease and other disease pathogens. Learn more