Landscape Message: March 22, 2024

UMass Extension's Landscape Message is an educational newsletter intended to inform and guide Massachusetts land care 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 2024 growing season, and Happy Spring! This is the first Landscape Message of 2024.  The next message will be published in two weeks, on April 5.  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, scroll down to see the different section headings. The collapsible headings are unavailable while we undergo a software upgrade.

---

Scouting Information by Region

Environmental Data

The following data was collected on or about March 20, 2024. Total accumulated growing degree days (GDD) represent the heating units above a 50ºF baseline temperature collected via regional NEWA stations (http://newa.cornell.edu) for the 2024 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.

	GDD		SOIL TEMP		PRECIP		TIME/DATE OF READINGS
	2023 Total	Current 2024	Sun	Shade	Since 1/1	Since 3/1
CAPE	2850	1	44	40	13.08	3.41	10:00 AM 3/20
SOUTHEAST	2894	4	51	42	14.80	5.10	3:00 PM 3/20
NORTH SHORE	2603	0	41	37	12.82	3.72	10:00 AM 3/20
EAST	2996	2	43	39	9.93	3.20	4:00 PM 3/20
METRO	2725	2	39	37	9.91	3.96	6:45 AM 3/20
CENTRAL	2790	1	41	40	13.46	5.90	1:00 PM 3/20
PIONEER VALLEY	2855	3	44	42	16.11	6.83	11:00 AM 3/20
BERKSHIRES	2327	0	41	37	10.47	3.75	8:00 AM 3/20
AVERAGE	2755	2	43	39	12.57	4.48	-

 

US Drought Monitor:  In Massachusetts, only Nantucket island has an official drought designation at this time, classified as D1 (Moderate Drought).  State map as of Thursday 3/21: https://droughtmonitor.unl.edu/CurrentMap/StateDroughtMonitor.aspx?MA

Phenology

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.
Cornus mas (Cornelian cherry dogwood)	*	Begin	Begin	Begin	Begin	Begin	Begin/Full	Begin
Acer rubrum (red maple)	*	Begin	Begin	Begin	Begin	Begin	Full	Begin
Acer saccharinum (silver maple)	Begin/Full	*	Full	Full	Full	Begin/Full	Full	Begin
Hamamelis x intermedia (witch hazel hybrids)	Full/End	*	Full	Full	Full/End	Full	Full/End	Full
Hamamelis mollis (Chinese witch hazel)	Full/End	Full	Full	Full	Full/End	Full/End	Full/End	Full
* = no activity to report/information not available

Regional Notes

Cape Cod Region (Barnstable)

General Conditions:

Overall, the winter has been mild. Average temperatures for the months of December, January, February and March have been above freezing with extreme lows in December, January, and February in the mid-teens and extreme highs near 60º F each month. The ground did not freeze at a depth of 4” all winter; shallow freezing occurred off and on in January and February. Precipitation has been plentiful.

Month	Average	Low	High	Precip.
Dec	42º F	19º F 12/23	61º F 12/10	4.42”
Jan	34º F	15º F 1/20	56º F 1/13	7.36”
Feb	35º F	16º F 2/21	58º F 2/27	2.31”

 

There was only one significant snow event (February 13), resulting in 6-10 inches of snow. The snow in the upper Cape remained for about a week. There were numerous high wind/Northeaster type weather events, resulting in a near constant cleaning up of dead and broken limbs. Soil moisture is adequate at this time; but has been excessive for much of the winter.

The mild conditions have resulted in earlier than normal plant development in some species. Crocuses and snowdrops were first seen in bloom in mid/late Feb. Other plants seen in bloom include winter aconite (Eranthis hyemalis), hellebores (Helleborus orientalis), Siberian squill (Scilla siberica), and daffodils (Narcissus spp.). Woody plants seen in bloom include Japanese andromeda (Pieris japonica), slippery elm (Ulmus rubra), and random cherry and Forsythia flowers can be seen.

Pests/Problems: Plant development is advancing rapidly with the mild conditions; many species are tolerant of the ups and downs of late winter/early spring. However, bud development in big leaf hydrangea is occurring rapidly and is susceptible to freezing temperatures possible for many more weeks.

The abundant soil moisture in Dec. and Jan. will likely contribute to some poor performance of plants that don’t like wet feet. There is not much to report on insect activity. The mild conditions have resulted in some fungi remaining active nearly all winter; red thread is one that could be seen active in turf nearly all winter.

Invasive plants that bud out before many other species are doing so; growth on privet (Ligustrum spp.), multiflora rose (Rosa multiflora) and honeysuckle (Lonicera spp.) can be observed. Weedy plants such as hairy bittercress (Cardamine hirsuta), fig buttercup (Ficaria verna), and chickweed (Stellaria media) are in bloom.

Seeing a lot of rabbits before dawn and after dusk.

Southeast Region (Dighton)

General Conditions:

The winter of 2023-2024 was quite mild in Bristol County, with little snow cover and few storms needing plowing. Since the last landscape message on November 19th, there was a total of 1.5 inches of precipitation for the remainder of November. The high temperature for the month after the 19th was 59°F on the 22nd, with a low of 22°F on the 26th. The maximum sustained wind speed was 22 mph on the 27th.

In December, there was a significant increase in precipitation, with a total of 5.3 inches. The high temperature for the month was 64°F on the 10th, 11th, and 18th. The low temperature for December was 17°F on the 23rd. The peak wind speed for the month was 32 mph on the 18th.

January brought a total of 7.2 inches of precipitation. The high temperature for the month was 59°F on the 13th, while the low temperature was 17°F on the 22nd. The maximum wind speed for January was 28 mph.

February was drier than the previous two months, with only 2.5 inches of precipitation. The high temperature for the month was 61°F on the 27th, with a low of 16°F on the 21st. The peak wind speed for February was 24 mph.

Finally, in March, leading up to the arrival of Spring, we had 5.1 inches of precipitation. The high so far for the month has been 64°F, with a low temperature of 22°F on the 1st. The peak wind speed for March was 25 mph on the 11th.

With all the precipitation we had over the winter, water tables are quite high. Vernal pools and streams are all full. The Spring peeper chorus can be heard on warmer days. Redwing blackbirds have arrived and are still flocked up. Robins are patrolling lawns and have begun squabbling over the best territories. The warmer winter temperatures seemed to have resulted in early blooms. Winter aconite has already set seed. Snowdrops are fading. Crocus are still going off while daffodils are just beginning to flower. American elm, silver maple, swamp red maple (Acer rubrum), Cornelian cherry dogwood (Cornus mas), weeping willow, Japanese black pussy willow, Japanese andromeda, and Chinese witchhazel (Hamamelis mollis) are all in flower.

Pests/Problems:

Annual weeds have begun germinating. I've found a single adult rose chafer although that seems an anomaly. Ticks are very active and have survived the winter in large numbers. Be sure to take appropriate precautions.

North Shore (Beverly)

General Conditions:

This writing is on the first day of spring. The winter was very mild with limited snowfall at Long Hill and less than average for the region, and there was only one major snowfall during the winter season. 12.82 inches of precipitation has been recorded at Long Hill since January 1. The average daily air temperature was above the freezing point on most days this winter. Temperatures below 20ºF were recorded on only 14 days during this winter. The lowest temperature of 11ºF was recorded on both January 9 and January 20. Signs of spring are evident with some plants starting to bloom. Early spring flowering plants seen in bloom include winter aconite (Eranthis hyemalis), glory-of-the-snow (Chinodoxa forbesii), Siberiam squill (Scila siberica), snowdrops (Galanthus nivalis) and Hellebore (Helleborus spp.). Blooming trees include: ‘Arnold Promise' witchhazel (Hamamelis x intermedia), Chinese witchhazel (Hamamelis mollis), pussy willow (Salix caprea), winter honeysuckle (Lonicera x purpusii), Farrer viburnum (Viburnum farreri), and silver maple (Acer saccharinum). Cornelian cherry dogwood (Cornus mas) is beginning to bloom but the buds are not yet open. Some homeowners and landscapers are already starting to do spring cleanups as weather permits.

Pests/Problems:

Deer browsing has been observed with some plants showing serious damage. Vole feeding activity has also been observed on apple trees. Vole tunnels were also observed in a perennial garden.

East (Boston)

General Conditions:

Happy spring! We had a mild winter with minimal snow cover. January daytime temperatures averaged 38ºF with overnight lows averaging 26ºF. We received 3.2 inches of snow on January 6^th and 7^th, a high temperature of 60ºF on the 13^th and another 3.5 inches of snow on 16^th. The two snow events were followed by our only extended cold snap of the season. We had a daytime high of 25ºF on the 17^th with five consecutive days not going above 30ºF. Overnight lows averaged 15ºF during this period. Total rainfall equivalent precipitation for January was 6 inches.

February was mild and dry. Daytime temperatures averaged 43ºF with a high of 60ºF on the 10^th. Overnight lows averaged 27ºF with a low of 14ºF on the 25^th. We received no measurable snow and a total of 0.73 inches of precipitation. By February 19^th a significant number of Galanthus nivalis (common snow drop), Eranthus hyemalis (winter aconite), and Helleborus spp. (hellebores) were flowering throughout the landscape.

March to this point has had daytime highs consistently in the 40’s and 50’s, averaging 50ºF with a high of 60ºF on the 17^th. Overnight lows have averaged 36ºF with only one extreme of 20ºF on March 1^st. We had one high wind/rain event on the 7^th delivering 1.03 inches of precipitation. We have accumulated 3.20 inches through March 20. Many Hamamelis x intermedia (witchhazel hybrids) ‘Arnold Promise’, ‘Diane’ and ‘Jelena’ have been flowering for several weeks. Cornus mas (Cornelian cherry dogwood) has just begun to bloom. For extended winter interest, the fragrant Lonicera x purpusii (winter honeysuckle) has been in bloom since mid-February.

Pests/Problems:

Entering spring, there do not appear to be any visible weather-related concerns. Despite the dry February, most soils are now adequately moist. Winter annuals in bloom include: Capsella bursa-pastoris (shepards purse), Cardamine hirsuta (hairy bittercress), and Stellaria media (common chickweed). First year rosettes of the invasive biennial Alliaria petiolata (garlic mustard) are visible along roadsides and forest edges.

Metro West (Acton)

General Conditions:

Welcome back and to Spring! The season officially began this past Tuesday on the 19^th and we already have been treated to some spring-like weather with temperatures rising to the low 60’s earlier this month. For the most part, this past winter was fairly mild with limited snowfall and with not one subzero temperature recorded.  Only once did the temperature fall into single digits and that was on January 22^nd when 8° F recorded. Doesn’t it just figure that as I am writing this message, it is snowing outside?

Pests/Problems:

Water levels are high with the recent rain. Average monthly rainfall for March is 4.62”. 3.96" has been recorded so far with much of that rain, 1.29” and 0.9” respectively, on the 7^th and 10^th.

Central Region (Boylston)

General Conditions:

Happy Spring! A very mild winter has passed with very few snow events (of course this morning we had some nice flurries with no accumulation). Including warmer days so far this month, there were a few occasions of hitting warmer than usual temperatures both in January (56.7ºF) and February (60.8ºF), which caused major melt of any snow accumulation present at the time. The lowest temperature was recorded on only a couple of occasions in January, barely dipping below 10ºF. Definitely a wet season; just at the start of this month we’ve had 5.9 inches of precipitation. Many bulbs, shrubs, and trees are in full bloom or starting to bloom, including Hamamelis vernalis, Hamamelis x intermedia, Hamamelis mollis, Lonicera x purpusii, and even Rhododendron dauricum (Dahurian azalea) has been observed starting to bloom. Only a few larger Acer rubrum are starting to bloom just at the top of the canopy, but are sure to pop more later this month.

Pests/Problems:

Being an unusually warm and wet season, the soil seemed to not freeze as much and created a lot of flooded areas. Knowing this, a lot of plant material is blooming earlier than previously recorded. This could be potentially troubling, especially if a hard frost rolls through. With the soil being so workable, a lot of vole/mole activity has been seen and plants have been uprooted some.

Pioneer Valley (Amherst)

General Conditions:

Welcome back for another season of the Landscape Message. Spring has already taken hold across the Pioneer Valley as last fall’s prediction of a warm and wet El Niño winter held true. The tri-counties saw only limited snowfall and we had just one significant storm in early January, when ~7–9” of snow accumulated and then quickly melted. In addition, the region experienced only a brief stretch of very cold temperatures, from January 18–22, when lows hovered in the single digits. February, typically the snowiest month of winter in recent years, was sunny, mild and dry. Witchhazels and snow drops started flowering early and by the beginning of March, high temperatures were consistently hitting the lower to upper 50s. A brief stretch in the upper 60s (to even 70°F) on March 13 & 14 really pushed plants along. Flowering cherry, viburnum, clematis, honeysuckle and multiflora rose have all started leafing out while elm, silver maple and red maple are in full flower. Peach, Forsythia, andromeda, and azalea have started flowering (some are full flower) and numerous other plants have swollen buds, including yew, pine, and Japanese maple. Right now, there are major differences in plant phenology between warm, south-facing microclimates and north-facing, shaded landscapes. Ah, but the meteorological start of spring has brought a return to winter. At the time of writing, the forecast calls for a low near 20°F on 3/21 and the possibility of sleet and snow over the weekend. Hopefully this doesn’t damage flower buds and newly developing leaves.

Pests/Problems:

Beech leaf disease is certain to be more widespread throughout the tri-counties this year with higher levels of disease severity. While scientists continue to learn more about the nematode and disease development, management efforts remain limited. This upcoming season should prove helpful in determining which treatments are effective. The threat of frost and freeze can last well into early May in southern New England (and some years even later based on last year’s frost event on May 18). Therefore, when plants start flushing new growth in mid-March, some level of frost injury is a serious concern. Winter burn on rhododendron, azalea, andromeda, mountain laurel, and holly appear to be minimal this spring due to the mild winter, but exceptions always exist. The foliar blight and premature leaf shedding late last summer on lilacs caused many plants to flush scattered new growth and blooms last fall. Some buds that broke last fall on these plants are now burned and desiccated. Saturation and flooding in heavy, poorly drained soils could be an issue for plants that don’t tolerate wet feet (boxwood, yew, and rhododendron). The resulting condition, known as edema, is likely to be a problem as the season begins. Symptoms include chlorotic areas of the upper leaf surface and dark-colored, callus-like blisters on the underside of the foliage. White pine weevil is active early in the growing season, feeding on the terminal shoot of eastern white pine and Norway spruce, among others. Spruce spider mite is active during mild periods of spring, so scouting and treatment of this pest should commence soon once the weather warms. Ticks have been very active this spring season so pay extra attention to these nefarious pests. Light-colored pants and permethrin applications to footwear can be very helpful.

Berkshire Region (West Stockbridge)

General Conditions:

This has been another odd winter with unusual warm periods. Earlier this month, there were record high temperatures recorded at Pittsfield airport of 65ºF on March 13 and 63ºF on March 14. Perhaps most unusual has been the lack of significant snowfall this past winter. The total for the season was only 28 inches, compared with the normal of 54.1 inches. Nevertheless, the precipitation total from January 1 to March 19 was 9.67 inches. That’s 2.57 inches above normal. As such, soil moisture is moderate to high. Yet, it is not frozen, and this is a good time for digging and planting dormant trees and shrubs. The biggest concern this winter has been high wind events which brought down many trees or caused considerable damage to limbs.

Turfgrass is just beginning to show signs of a bit of growth. Given the high soil moisture levels, it is best to avoid repeatedly traversing the same path across turf as this will cause soil compaction. Early season bulbs are in full bloom. These include crocus (Crocus spp.), snowdrops (Galanthus spp.), scilla (Scilla lucilia), and dwarf iris (Iris danfordiae, Iris reticulata). Another herbaceous plant now in bloom is winter aconite (Eranthis hyemalis).

Pests/Problems:

Pest activity at this time is limited to blacklegged (a.k.a. deer) ticks (Ixodes scapularis). These have been active for much of the year and the usual precautions should be taken when performing outdoor work. Voles have been very active this winter and their tunnels and trails are prominent. Some damage to roots and crowns of herbaceous perennial plants in plant borders has been observed.

Regional Scouting Credits

• CAPE COD REGION - Russell Norton, Horticulture and Agriculture Educator with Cape Cod Cooperative Extension, reporting from Barnstable.
• SOUTHEAST REGION - Brian McMahon, Arborist, reporting from the Dighton area.
• 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 Boston area.
• METRO WEST REGION – Julie Coop, Forester, Massachusetts Department of Conservation & Recreation, reporting from Acton.
• CENTRAL REGION - Mark Richardson, Director of Horticulture, and Anna Petrie, reporting from New England Botanic Garden at Tower Hill, Boylston.
• PIONEER VALLEY REGION - Nick Brazee, Plant Pathologist, UMass Extension Plant Diagnostic Lab, reporting from Amherst.
• BERKSHIRE REGION - Ron Kujawski, Horticultural Consultant, reporting from Great Barrington.

Woody Ornamentals

Diseases

Recent pests, pathogens, or problems of interest seen in the UMass Extension Plant Diagnostic Lab, a select few:

Root rot of true fir (Abies) at a Christmas tree farm caused by Phytophthora and Armillaria. The trees were seven-years-old and well-spaced, growing in full sun with loam-based soils that can be wet and poorly drained. Last summer, needles on the lower canopy branches became pale green to pale brown while the upper canopy developed a chlorotic appearance. Two entire trees were submitted, and dissection of the roots detected two common and destructive root rot pathogens. Roots infected with Phytophthora had a brown to blue-gray discoloration of the vascular tissue and were easily pulled apart. Infection by Armillaria resulted in roots that were spongy, with bleached and stringy wood tissue. The abundant rainfall last summer, especially in July, likely facilitated disease development for Phytophthora.

Needle blight of lodgepole pine (Pinus contorta var. latifolia) caused by Septorioides strobi. The tree is 40-years-old and has been present at the site for more than 35 years. It resides on a slope in full sun with dry, gravelly, compacted soil. For multiple years, the tree has had a sparse canopy and needle discoloration. The submitted shoots had needles with brown tips and black-colored fruiting bodies rupturing from the blighted tissue. Septorioides needle blight is a common disease on an array of native and non-native pines in the region, acting as a chronic stress that can weaken trees and predispose them to other stresses, such as drought.

Poor root development and stunted growth on Norway spruce (Picea abies) due to transplant shock and poor site conditions. Several trees that are approximately 15-years-old were transplanted last year to a site with full sun and no supplemental irrigation. The clay soils are compacted and wet and the mulch ring surrounding the trees is limited. Erosion on the downhill side of the trees has exposed the root ball and there is no root expansion past the dripline. The submitted branch segments showed last year’s growth (2023) was severely stunted but generally had good color. The roots showed no sign of disease and aside from some scattered eastern spruce gall adelgid, the samples were free of insect pests.

Canopy dieback of recently transplanted hollies (Ilex ×'Nellie R. Stevens') due to transplant shock and two fungal pathogens (Botryosphaeria and Pestalotiopsis). The trees are roughly seven-years-old and were transplanted (from ball and burlap) in November. Over the next several weeks into December, the foliage became brown to black but remained attached throughout the canopies. Samples from three separate trees all had blackened shoots, which is typical of fungal cankering, and, after a brief incubation, Botryosphaeria emerged. This pathogen is especially common in stressed and weakened hollies. The foliage was pale green to brown with darker, scattered blotches. Pestalotiopsis was present from the foliar tissue and this pathogen occurs regularly on broadleaved evergreens. The trees were diseased prior to planting and became visibly symptomatic shortly after installation.

Decline and death of privet (Ligustrum) in an established hedge due to root rot caused by Armillaria. A dense, double row of privet was established 10 years ago in a residential setting. It receives full sun and supplemental water from lawn sprinklers. To maintain their height and shape, the plants are pruned three times per growing season. The loam-based soils have good drainage. In spring of ’23, decline was noted in several plants that did not leaf out properly. The dieback has worsened with the death of some plants. The submitted branches and stems were harboring a cankering pathogen (Phomopsis) but root disease was suspected. A subsequent submission of the base and roots of a recently dead plant revealed a well-established infection by Armillaria.

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

Insects and Other Arthropods

Invasive Updates:

• Asian Longhorned Beetle is still present in Worcester, Shrewsbury, Boylston, West Boylston, and parts of Holden and Auburn, MA. If you suspect you’ve found this insect or the damage it causes, please report it to the Asian Longhorned Beetle Eradication Program office in Worcester, MA at 508-852-8090 or toll free at 1-866-702-9938.

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

• Box Tree Moth has been detected in the following Massachusetts communities: Bourne, Sandwich, and Barnstable. A map of these locations is available here. If you believe you have found this insect, please take a photo, note your location, and report it immediately here.
• Elm Zigzag Sawfly has been detected in the following Massachusetts communities: Becket, Chester, Windsor, and Williamstown. If you believe you have found this insect, please take a photo, note your location, and report it immediately here or email Danielle Johnson at Danielle.j.johnson@mass.gov .
• Emerald Ash Borer is well established across most of Massachusetts. A map of these locations from the MA Department of Conservation and Recreation is available.
• Jumping Worms are non-native earthworms that impact natural ecosystems. Available resources include a fact sheet about earthworms in Massachusetts and jumping worm FAQ’s.
• Spotted Lanternfly now has established populations in the following locations in Massachusetts: Holyoke, Springfield, West Springfield, Agawam, Fitchburg, Worcester, Shrewsbury, Southborough, Ashland, Wellesley, Weston, and Chelmsford. If you believe you have found this insect, please take a photo, note your location, and report it immediately here. Available resources include a map of spotted lanternfly locations in Massachusetts from the MA Department of Agricultural Resources, MDAR’s spotted lanternfly fact sheet, UMass Extension’s Spotted Lanternfly Management Guide, and an SLF InsectXaminer episode.

Medically Important Pests:

• Ticks are a serious public health concern and may be active in managed landscapes any time temperatures are above freezing. Available resources include tick information from Cape Cod Cooperative Extension, personal protective measures, and a list of potential tick testing resources. The New England Center of Excellence in Vector-Borne Diseases (NEWVEC) also provides the latest tick information and resources.
• Mosquitoes and the diseases they vector are also a serious public health concern in Massachusetts by summer. Available resources include Mosquito Repellents from the Department of Public Health and Prevent Mosquito Bites from the Centers for Disease Control and Prevention. The Massachusetts Department of Public Health tests for Eastern Equine Encephalitis (EEE) and West Nile Virus (WNV) from June to October. Beginning in June, risk maps will be available here.

Tree & Shrub Insect & Mite Pest Suggested Scouting:

• Bagworm is overwintering on Juniperus spp., Thuja spp., Quercus spp., Platanus spp., and others as 500-1000 eggs found in the bags of last season’s deceased females. Now is the time to remove and destroy overwintering bags of eggs prior to egg hatch at approximately 600 GDD’s (approx. mid-June).
• Balsam Twig Aphid overwinters as eggs on host plant bark, trunks, and branches (primarily Abies and Picea spp.). Eggs hatch roughly between 30-120 GDD’s, approximately April-May. Nymphs quickly mature into stem mothers, which produce 20-40 young (each) without laying eggs. These young feed on buds and tender needles, and cause most of their feeding damage during that time. Scout now for curled or stunted needles from feeding in prior years.
• Boxwood Leafminer is overwintering as a partially developed larva within Buxus spp. leaves. Larvae will become active as temperatures warm, with pupae present by late April. Adult emergence occurs by mid-May, with pupal cases left behind clinging to leaves. Shake bushes in late April to detect flying adults. Resistant varieties of boxwood are available; see previous link.
• Boxwood Mite feeds on upper and lower leaf surfaces of Buxus spp. hosts. Overwintered eggs hatch into larvae in the spring, which mature into nymphs and eventually adults. The entire life cycle takes approximately 18-21 days. Most feeding injury occurs in the spring and hosts may appear off-color.
• Boxwood Psyllid nymphs have overwintered within eggshells inserted between bud scales last summer. As soon as buds expand, nymphs will emerge and begin feeding on Buxus spp. developing buds and leaves. Upward cupping and yellowing of leaves can be a sign of previous or current season’s damage. Dormant season horticultural oil applications may be made in the spring, as temperatures and weather conditions allow.
• Cankerworms can be found feeding on similar host plants in the spring, despite fall and spring cankerworm being different species of insects. Spring cankerworm adult moths are active in February and March, laying masses of 100 or so eggs in the rough bark of larger branches or the trunk of the host plant. Fall cankerworm adults have already laid their masses of eggs on host plant branches and twigs, back in late November and early December of last year (sometimes the current year’s January). Egg hatch of both species will occur by approximately mid-May, with caterpillar feeding through roughly the end of June.
• Cooley Spruce Gall Adelgid typically overwinters as an immature female near spruce twig terminals. By early spring, this female matures into a stem mother which will lay hundreds of eggs on lateral terminals. Following egg hatch, nymphal feeding induces gall formation on spruce hosts. Green galls on spruce may be removed and destroyed. On Douglas fir, the Cooley spruce gall adelgid’s alternate host, look for woolly masses in the spring and distorted or crooked needles. Do not plant spruce and Douglas fir close together when possible.
• Eastern Spruce Gall Adelgid overwinters as a partially grown female, maturing into a stem mother by early spring. Stem mothers lay 100-200 eggs by budbreak. Eggs hatch and nymphs feed on the needles of their Picea spp. hosts. As green galls develop, prune out and destroy when possible.
• Eastern Tent Caterpillar overwintering eggs hatch in the spring and caterpillars emerge as cherry leaves begin to open. Look for groups of caterpillars feeding in silken tents at that time.
• Elongate Hemlock Scale is primarily a pest of hemlock and fir. Overwintered fertilized females or their eggs will become active with warming temperatures, with egg hatch generally occurring by the end of May or the beginning of June. At that time, crawlers will be present before they settle to feed on a needle. Colletotrichum fioriniae was observed on elongate hemlock scales in Lynnfield, MA on 2/23/2024 and again in Manchester, MA on 3/19/2024 by Richard Grant (see photos). C. fioriniae is an endophytic fungus that lives within the needles of hemlock. Up to 90% mortality can occur in elongate hemlock scale if this fungus invades the insect. Scales appear coated in a black material, looking similar to sooty mold (it is not sooty mold). This fungus was reported as active in elongate hemlock scale populations in western MA in 2023 as well.
• Euonymus Caterpillar tiny, overwintered larvae have spent their time beneath egg shells from last year. As temperatures increase in the spring, groups of caterpillars will begin feeding on newly emerging Euonymus spp. leaves. Additional resources include an InsectXaminer episode about euonymus caterpillar.
• Euonymus Scale overwinters as a fertilized female. Eggs are laid beneath dark brown female scale covers in the early spring. Egg hatch occurs over a 2-3 week period, with crawlers present by early June. While Euonymus spp. host plants are preferred, additional host plants have been reported.
• European Pine Sawfly eggs have overwintered in slits in last year’s needles. Egg hatch begins in approximately late-April and early May.
• Forest Tent Caterpillar egg masses overwinter and will hatch as leaves expand in the spring. Small caterpillars will search for expanding flower and leaf buds to begin feeding on.
• Hemlock Looper collectively refers to two species of geometrid (inchworm; looper) caterpillars. Overwintered eggs hatch by late May or early June, at which time young larvae begin their messy feeding on host plant needles. Hemlock and balsam fir are preferred hosts.
• Hemlock Woolly Adelgid has been favored this winter by the mild temperatures we’ve experienced in Massachusetts, according to the MA Department of Conservation and Recreation. Very little overwintering mortality has been measured at sites sampled across the state. Overwintered sistens generation females produce viable eggs in February and March.
• Imported Willow Leaf Beetle adults overwinter in loose bark or other sheltered areas near susceptible Salix and Populus spp. host plants. Once the host plant leaves emerge in the spring, adults will begin to feed and lay tiny, yellow eggs in clusters on leaf undersides. Additional resources include an InsectXaminer episode about imported willow leaf beetle.
• Lecanium Scales, including most notably in Massachusetts, the oak lecanium, are soft scales that overwinter on host plant twigs as second instar immatures. In the spring, these immatures begin feeding and mature into hemispherical shaped adult females who lay their eggs by late May and into June. Between April and May, much honeydew (sugary excrement) may be produced by the active adult females.
• Lily Leaf Beetle, while not a pest of trees and shrubs, can be an important insect found in ornamental landscapes. As soon as lilies break through the ground in the spring, bright red overwintered adult beetles begin feeding on the foliage. This typically occurs in April, with adults mating and laying eggs by May. 250-450 eggs may be laid per female. Additional resources include an InsectXaminer episode about lily leaf beetle.
• Magnolia Scale overwinters as nymphs (immatures) found on 1 and 2-year old twigs of the host plant. Nymphs begin feeding as temperatures warm in the spring, molting once by late April or May and again by early June.
• Pine Bark Adelgid overwinters in an immature life form which begins feeding again as springtime temperatures increase. This is the time when the insects begin secreting a white, waxy layer over their bodies. High populations can make the trunks of eastern white pine appear as if coated in snow. Typically, management is not necessary. Syringing (washing adelgids off the trunk of larger trees with a strong jet of water) is an option.
• Snowball Aphid overwinters as an egg on the twigs and buds of Viburnum spp. hosts. Egg hatch occurs at the same time host plant buds are opening in the spring. Newly hatched aphids will begin to feed on and distort the newly developing leaves of their hosts. Aphids may be protected from contact insecticides within curled leaves.
• Spruce Bud Scale overwinters as an immature scale on the undersides of host plant needles. Once spring temperatures warm, the dormant scales become active by late March and in April female spruce bud scales move to host plant twigs. Adult females are reddish-brown and round, and usually found at the base of new twig growth.
• Spruce Spider Mite is a cool season mite which causes most of its feeding damage on coniferous hosts in the spring and fall. Monitor for discolored needles and the mites themselves. Monitoring for spruce spider mite can be done by shaking 3-4 branches over a white piece of paper and viewing mites with a hand lens.
• Tuliptree Scale is a soft scale pest of Liriodendron and Magnolia spp. among others. Second instar nymphs overwinter, begin feeding as temperatures warm in the spring, and mature into adults by the late spring/early summer.
• Viburnum Leaf Beetle overwinters on susceptible viburnum as eggs laid in pits chewed near the ends of twigs last season. These egg laying locations are covered with an oval-round cap. Prune out and destroy infested twigs prior to egg hatch in May.
• White Pine Aphid eggs overwinter in rows on the needles of their host plants. Egg hatch will occur as spring temperatures begin to warm. Aphids may feed on the needles, twigs, and small branches of their host plants.
• White Pine Weevil overwinters as an adult in the leaf litter in sheltered areas near host plants. As spring temperatures warm, adults fly to the leaders of Pinus and Picea spp. hosts where they mate, dig round holes in the bark, and deposit 1-5 tiny eggs in the cavity. Eggs hatch and the larvae tunnel as they feed, killing the previous season’s leader. Adult white pine weevils are active in March (through May), as soon as 7 GDD’s are reached.
• Woolly Apple Aphid overwinters as eggs in the cracks and crevices of Ulmus spp. host plants. As spring temperatures warm, these eggs hatch and stem mothers begin feeding on developing elm leaves. Their feeding and the feeding of the wingless nymphs they produce causes leaf distortion and a rosette to form on elm. If no elm is present, the aphids will complete their life cycle on apple year-round.
• Woolly Beech Leaf Aphid overwinters as eggs in host plant bark crevices near buds. At budbreak, eggs will hatch and wool covered aphids will begin feeding on host plant leaf undersides (Fagus spp.). Even though aphid populations may be very noticeable, they seldom require chemical management.
• Woolly Elm Aphid overwinters as eggs hidden in cracks and crevices of elm bark. As leaves unfold in the spring, eggs hatch and young aphids feed on the underside of elm leaf tissue. These aphids mature and give birth to hundreds of additional females. Feeding causes leaves to curl around the aphids. Curled leaves may also turn reddish brown.

Beneficials/Non-Pests:

• March Flies (Family Bibionidae) have again been spotted by homeowners in Massachusetts (first report, 3/14/2024 from Medford, MA). This time, swarms of flies were observed aggregating on the trunk of a spruce tree. While this can be a startling event that is quite noticeable, it is ephemeral and of little concern for tree or shrub health. They pose no threat to human, animal, or plant health and require no management. March fly larvae (maggots) develop in decaying organic matter, such as rotting leaf litter or wood. Adult flies may visit flowers for nectar. Following these large mating swarms, adult flies lay 200-300 eggs in the soil. The larvae will feed in this area until pupation and adult emergence occurs again the following spring. March flies may be seen emerging in March and again in April, depending on the species. Emergence may also be reported in the fall. For more information, visit: https://content.ces.ncsu.edu/march-flies. Additional photos may be found, here.

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

---

Additional Resources

To receive immediate notification when the next Landscape Message update is posted, join our e-mail list or follow us on Facebook.

For a complete listing of landscape, nursery, and urban forestry program upcoming events, see our calendar at https://ag.umass.edu/landscape/upcoming-events.

For commercial growers of greenhouse crops and flowers - Check out UMass Extension's Greenhouse Update website.

For professional turf managers - Check out our Turf Management Updates.

For home gardeners and garden retailers - Check out our home lawn and garden resources. 

Diagnostic Services

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 the Plant Diagnostic Laboratory web site.

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 lab provides test results and recommendations that lead to the wise and economical use of soils and soil amendments. For more information, including current turn-around times, visit the UMass Soil and Plant Nutrient Testing Laboratory web site. The lab is currently accepting orders for Routine Soil Analysis (including optional Organic Matter, Soluble Salts, and Nitrate testing), Particle Size Analysis, Pre-Sidedress Nitrate (PSNT), Total Sorbed Metals, and Soilless Media (no other types of soil analyses available at this time). Check for current turnaround time. Please plan for the fact that date of receipt in the lab is affected by weekends, holidays, shipping time, and time for UMass Campus Mail to deliver samples to the lab.

Tick Testing - The UMass Center for Agriculture, Food, and the Environment provides a list of potential tick identification and testing options at https://ag.umass.edu/resources/tick-testing-resources.

Acknowledgements: UMass Extension gratefully acknowledges the support of the following funding sources for the production of the Landscape Message –

• The Massachusetts Nursery and Landscape Association Fund
• The Massachusetts Department of Conservation and Recreation, Award #ISADCR28219926UMA24A
• Stakeholders like you! The Landscape Message is partially supported by educational program user fees.