Landscape Message: May 1, 2026

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 plants in the landscape are regular features. The following issue has been updated to provide timely management information and the latest regional news and environmental data. 

This is the 4th Landscape Message of 2026. The next message will be published in one week, on May 8.  

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In This Issue

Regional Scouting Observations

Environmental Data

Plant Phenology

Regional Notes 

     Cape Cod Region (Barnstable)

     Southeast Region (Plymouth)

     North Shore (Beverly)

     East (Boston)

              Metro West (Acton)

              Central Region (Boylston)

              Pioneer Valley (Amherst)

              Berkshire Region (West Stockbridge)

Landscape Pest Reports

Diseases

Insects and Other Arthropods

Weeds

Additional Resources

Regional Scouting Observations

Environmental Data

The following data was collected on or about April 29, 2026. Total accumulated growing degree days (GDD) represent the heating units above a 50ºF baseline temperature collected via regional NEWA stations for the 2026 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.

US Drought Monitor:  At this time, about 88% of the land area of Massachusetts is classified as at least D0 (Abnormally Dry).  Of this, 37% is classified as at least D1 (Moderate Drought). State map as of Thursday, April 30. 

Plant Phenology

The basis of plant phenology is that specific environmental conditions such as temperature, daylength, and precipitation directly influence plant development at a given location. The development of other organisms of interest, such as insects, are also subject to the same factors, and this natural synchrony can aid in decision making that is free of the limitations of calendar dates. The bloom stage of plants can be an especially visible and useful tool for optimizing planting schedules, better timing of cultural activities such as pruning, fertilization, and pest management, or simply taking note of seasonal progress.

Note also that the following is presented as a list of commonly observed indicator species and is not intended as a list of recommended plants, per se.  Plants denoted with # are officially classified as invasive in MA, and plants denoted with + often exhibit invasive or aggressive tendencies.

If you enjoy this publication or depend on it as a resource, consider contributing what you can to support its ongoing success. Click here to donate to UMass Extension!

Regional Notes

Cape Cod Region (Barnstable)

General Conditions:

The average temperature for the period from April 22 through April 29 was 45°F with a high of 60°F on April 23 and a low of 29°F on April 24, and there were more sunny days than cloudy. There was no significant precipitation during the period. Soil moisture is short and disturbed/tilled soils are drying quickly.

Woody plants observed in bloom include border forsythia (Forysthia x intermedia), flowering quince (Chaenomeles speciosa), skimmia (Skimmia japonica), and paperbush (Edgeworthia chrysantha).

Herbaceous plants seen in bloom include Siberian bugloss (Brunnera macrophylla), lungwort (Pulmonaria officinalis), barrenwort (Epimedium grandiflorum), and moss phlox (Phlox subulata).

Pests/Problems:

Winter injury can be observed on boxwood (Buxus spp.), cherry laurel (Prunus laurocerasus), inkberry (Ilex glabra), and arborvitae (Thuja spp.).

Deer, rabbit, and vole damage is widespread on woody trees and shrubs with thin bark. Rabbit damage to emerging plants is also being observed. A combination of winter injury and cicada damage on rhododendrons can be seen in the upper Cape.

Several pests of pitch pine (Pinus rigida) have been observed during the period including needle cast, black turpentine beetle (Dendroctonus terebrans), southern pine beetle (Dendroctonus frontalis), and veiled polypore (Cryptoporus volvatus). Needle cast has been seen on many random trees in the upper Cape region causing the entire crown to show symptoms. Damage from southern pine beetle has been recently observed. Fortunately, southern pine beetle populations have likely been knocked back by winter temperatures but will rebound quickly.

Winter moth (Operophtera brumata) has hatched and small caterpillars about 5mm long can be found feeding in buds of various trees and shrubs. Winter moth no longer causes widespread defoliation and does warrant management in ornamentals; however, populations may still be large enough to damage fruit producing apples and blueberries. In recent years minor defoliation, likely from a combination of winter moth and fall cankerworm, has been observed in isolated areas of Barnstable, Falmouth, Harwich, Mashpee and Sandwich.

Box tree moth (Cydalima perspectalis) is active and can be found feeding on boxwood (Buxus spp.). It has continued to spread and can be found in most of the upper, mid and lower Cape. Box tree moth overwinters as early instar caterpillar and begins feeding around forsythia bloom (now). Boxwood leafminer (Monarthropalpus flavus) and volutella blight (Volutella buxi) have also been observed during the period on boxwood.

Other insect or disease issues observed during the period include black knot (Apiosporina morbosa) on black cherry (Prunus serotina), holly leafminer (Phytomyza ilicicola) on holly (Ilex opaca), and red lily leaf beetle (Lilioceris lilii) feeding on Asiatic lily.

Invasive plants in bloom include lesser celandine (Ficaria verna) and garlic mustard (Alliaria petiolata).

Weeds seen in bloom include mouse ear cress (Arabidopsis thaliana), hairy bittercress (Cardamine hirsuta), dandelion (Taraxacum officinale), purple deadnettle (Lamium purpureum), common violet (Viola sororia), and common groundsel (Senecio vulgaris).

Russell Norton, Horticulture and Agriculture Educator with Cape Cod Cooperative Extension, reporting from Barnstable.

Southeast Region (Plymouth)

General Conditions: 

The past period was characterized by mostly cooler days. We had one warm day (April 23) reaching 64°F, but most days only reached to about the mid-50’s during the day. Night temperatures dropped low into the 30’s or below.

Very light precipitation happened sporadically and did not amount to any noticeable accumulation. As of April 23, the southern portion of the region has fallen back into either D0 (abnormally dry) and D1 (moderate drought) status.

Despite the cool weather, spring continues to be underway.

Still blooming since the last message are forsythia (Forsythia spp.), willow (Salix spp.), magnolia (Magnolia spp.), cherries (Prunus spp.), greater periwinkle (Vinca major), daffodils (Narcissus spp.), violets (Viola spp.), and rhododendrons (Rhododendron spp.).

Adding to the mix, tulips (Tulipa spp.), bleeding heart (Lamprocapnos spectabilis), wood anemone (Anemone quinquefolia), phlox (Phlox spp.), northern spicebush (Lindera benzoin), and leatherleaf (Chamaedaphne calyculata) have begun blooming.

Pests/Problems:

Despite low total accumulation, the cool and wet weather has been affecting plants in the area. Many fungal and bacterial diseases thrive under these conditions.

Deer and rabbit browsing remain prevalent on small shrubs.

Common weedy plants, such as hairy bittercress (Cardamine hirsuta), mouse-ear cress (Arabidopsis thaliana), common chickweed (Stellaria media), common whitlowgrass (Draba varna), red deadnettle (Lamium purpureum), sheep sorrel (Rumex acetosella), grape hyacinth (Muscari botryoides), and dandelions (Taraxacum spp.) are blooming.

Invasive callery pear (Pyrus calleryana) and Norway maple (Acer platanoides) are also blooming.

Be on the lookout for paper wasps (Polistes spp.) and yellowjackets (Vespula spp. and Dolichovespula spp.). They will start building nests soon. They tend to prefer shaded areas, such as eaves of houses or shrubs.

Chinese mantis (Tenodera sinensis) ootheca (egg cases) have been spotted in numerous locations, but they have not hatched yet. Now is a good time to decide on removal (or not). A wasp (Podagrion mantis) in the region has been observed parasitizing these cocoons.

Eastern tent caterpillars (Malacosoma americanum) are hatching. They live communally within webs built at the crotches of trees and shrubs, preferring black cherry (Prunus serotina). They are native caterpillars and not invasive.

Deer ticks (Ixodes scapularis) and American dog ticks (Dermacentor variabilis) can be active any time temperatures are above freezing. Despite the cool weather, adult and nymphal ticks have been observed questing throughout the region.

Blake Dinius, Entomologist with Plymouth County Extension, reporting from the Plymouth area.

North Shore (Beverly)

General Conditions: 

Below normal temperatures persisted during this reporting period. Day temperatures were in the low to mid 50s most days except on Monday, April 27, when temperatures went up to 63˚F. Night temperatures were mostly in the low 30s to low 40s. The average daily temperature was 46˚F, with a minimum temperature of 28˚F recorded on April 25 and that maximum temperature of 63˚F also recorded on April 27.

No rainfall was recorded at Long Hill during this one-week reporting period. Soils are still a bit moist and suitable for planting.

The low temperatures during this period have slowed down bloom of some plants and enabling the flowers of those already in bloom to persist for a longer time. Woody plants in bloom include mountain pieris (Pieris floribunda), large fothergilla (Fothergilla major), early azeleas (Rhododendron spp.), Japanese pieris (Pieris japonica), and serviceberry (Amelanchier canadensis).

Non-woody plants seen in bloom include hellebores (Helleborus orientalis), daffodil (Narcissus spp.), forget-me-not (Myosotis sylvatica), tulips (Tulipa spp.), bleeding heart (Lamprocapnos spectabilis), vinca vine (Vinca minor), hyacinth (Hyacinthus orientalis), primrose (Primula vulgaris), yellow corydalis (Corydalis lutea), and tiny bluets (Houstonia pusilla).

Pests/Problems:

Invasive garlic mustard (Alliaria petiolata) is thriving in the landscape. Other weeds observed and in bloom include common blue violet (Viola papilionacea), dandelion (Taraxacum officinale), and lesser celandine (Ranunculus ficaria).

Symptoms likely to be volutella blight (Pseudonectria pachysandricola) were observed on a small patch of pachysandra.

Rounded galls of cedar-apple rust caused by fungal pathogen (Gymnosporangium juniperi-virginianae) were observed on infected twigs of juniper, with gelatinous tendrils (telia) starting to develop. To prevent the disease from spreading to apple and crabapple trees, prune off the galls before they develop orange-colored spore tendrils.

Geoffrey Njue, Green Industry Specialist, UMass Extension, reporting from the Long Hill Reservation, Beverly.

East (Boston)

General Conditions: 

We had an average April week with no extreme temperature fluctuations or weather events. Daytime temperatures averaged 55°F, while overnight lows averaged 37°F.

We received zero precipitation over the previous seven days. Rain is in the forecast.

Turf is slowly greening up.

Several plants in bloom include serviceberry (Amelanchier canadensis), redbud (Cercis canadensis), bishop’s hat (Epimedium x rubrum), trout lily (Erythronium ‘Pagoda’), kerria (Kerria japonica), summer snowflake (Leucojum aestivum), Virginia bluebells (Mertensia virginica), and Koreanspice viburnum (Viburnum carlesii).

Persian lily (Fritillaria persica) is also in flower. This is a reliable bulb that is deer and rabbit resistant and will also naturalize.

Other underutilized plants coming into bloom are the woodland peonies (Paeonia japonica and P. obovata). They are not as showy as the commonly grown herbaceous peony hybrids. Woodland peonies prefer shade, ideally under deciduous trees; they benefit from spring sunshine and summer shade. They also provide three seasons of interest; the flowers develop into large seed capsules, opening in early fall to a display of glossy black seeds laid out on the red interior of the seed capsule.

Red-throated hummingbirds (Archilocus calobrus) have returned to the area and are visiting feeders.

Pests/Problems:

Soils are dry. We have not received adequate April showers. Total rainfall for April is 1.24” through April 28. Containers and recent transplants require supplemental irrigation.

Norway maples are nearing the end of flowering, last year's prolific seed bank is germinating everywhere.

Pine bark adelgid (Pineus strobe) is active on white pines (Pinus strobus) and its cultivars. Adelgids are aphid-like insects. This one is quite small and dark; they cover themselves with white waxy strands and can be seen at the base of the needles. Small infestations on healthy trees tend not to be a concern. This adelgid is regarded as an aesthetic issue on smaller trees where they are visible and potentially alarming. Effective control for large infestations is said to be horticultural soap or horticultural oil.

Kit Ganshaw & Sue Pfeiffer, Horticulturists, reporting from the Boston area.

Metro West (Acton)

General Conditions: 

The outdoors is full of vibrant colors, including the grass, spring ephemerals, perennials, shrubs, trees, and birds.

Outside temperatures continue to greatly fluctuate and thankfully have been more spring-like than summer-like. A high temperature of 66°F was recorded on April 27 and a low temperature of 28°F was recorded on April 25.

The average rainfall total for the month of April is 4.16” and I have recorded 1.54” for this month so far. Unfortunately, that is the same amount as last week.

Pests/Problems:

April showers were non-existent during this past week’s reporting period. There was not a trace of precipitation recorded. Precipitation totals for this area continue to fall below the monthly averages. No surprise, that according to both the current MA Drought and the U.S. Drought Monitor maps that this area continues to remain in a drought. Some of the potential impacts of this drought might include stressed trees, shrubs and perennials, water sources below capacity, the decline in honey production, and the increase in wildfires.

Continuing to flourish everywhere in the landscape is garlic mustard (Alliaria petiolata). It is just beginning to flower.

Julie Coop, Forester, Massachusetts Department of Conservation & Recreation, reporting from Acton.

Central Region (Boylston)

General Conditions: 

The landscape has no shortage of blooms or emerging green foliage as we enter our 6th week of spring. Since the last report, temperatures averaged around 60.5°F, the lowest night temperature being 31.3°F on April 25.

There has been no recorded precipitation within this reporting period, creating an average precipitation amount of 1.12’ for the month of April. April of last year averaged 5.50’.

Foliage continues to emerge, such as maple (Acer spp.), willows (Salix spp.), and the whimsical fronds of ferns (Matteuccia spp. and Osmunda spp.).

Herbaceous material that can be seen in bloom are barren strawberry (Waldsteinia fragarioides), purple bergenia (Bergenia purpurascens), trillium (Trillium spp.), violets (Viola spp.), fawn lily (Erythronium spp.), bishop's-cap (Mitella diphylla), Dutchman's-breeches (Dicentra cucullaria), wood poppy (Stylophorum diphyllum), bellwort (Uvularia grandiflora), sharp-lobed hepatica (Anemone acutiloba), eastern bluebells (Mertensia virginica), marsh-marigold (Caltha palustris), and bishop's hat (Epimedium spp.).

Some woody material that is also blooming is fothergilla (Fothergilla spp.), spirea (Spiraea thunbergii 'Ogon'), American plum (Prunus americana), hobblebush (Viburnum lantanoides), and spicebush (Lindera benzoin).

Pests/Problems:

We’re not completely out of the clear for potential frost, which delays some planting and poses threats to flowering material.

With no precipitation accumulation, conditions have been very dry, and the central region is still within level 1 mild drought status.

With new green shoots of foliage, what we deem as pests have already found a way to reduce material. Willow leaf beetle (Plagiodera versicolora) can be seen on willows, more specifically pussy willows (Salix discolor) and have started skeletonizing the new leaves.

Rabbits have also been seen browsing on all types of herbaceous material, creating potential stress on emerging plants.

Anna Petrie, Plant Recorder, and Steven Conaway, Director of Horticulture, reporting from New England Botanic Garden at Tower Hill, Boylston.

Pioneer Valley (Amherst)

General Conditions: 

April is wrapping up, and we’re settling into the heart of spring here in the Pioneer Valley. The UMass campus is humming with activity as classes wind down and graduation approaches. After the unseasonably warm stretch in mid-April, the pace of new plant growth has slowed down significantly with a return to more seasonable conditions. This past week has provided some peak spring weather with bright sun and high temperatures in the 60s to 70s, but low temperatures continue to bottom out in the 30s.

Many redbuds and cherries are still in full flower and the mobs of bees attracted to their canopies are one of the sights of spring. Native wildflowers like red trillium (Trillium erectum), wild ginger (Asarum canadense), bloodroot (Sanguinaria canadensis), violets (Viola), and Anenome are in bloom.

Precipitation was minimal over this past week and with the bright sun, low humidity, and lack of shade, the uppermost soil layer may be dry. However, deeper horizons still have good moisture, so spot watering is all that’s currently required. Mass DEP will update outdoor water use restrictions on May 1.

During the winter, mulch and organic matter may build up over the root flare of smaller trees and shrubs. Ensure the root flare is exposed to avoid the development of girdling roots.

Pollen levels are building now that oak catkins are fully developed.

Pests/Problems:

As feared, the freeze on April 21 was very damaging to certain plants with tender new growth. The injury is highly scattered across the landscape, and it appears that most woody and non-woody plants fared well despite temperatures plunging into the lower and middle 20s. Regrettably, damage to Japanese maple (Acer palmatum), fragrant snowbell (Styrax obassia), Hick’s yew (Taxus × media), spirea (Spirea), katsura (Cercidiphyllum japonicum), and numerous herbaceous perennials and annuals (e.g. toad lily) has been observed. The UMass fruit team reports minor to serious freeze injury on apples (Malus domestica) at the Cold Spring Orchard. The damage varied by elevation and stage of development, with bud mortality ranging from 10% to possibly 90%.

Pine candles are elongating, and this remains a good time to scout for white pine weevil (Pissodes strobi) and the European pine sawfly (Neodiprion sertifer). Larvae of the sawfly can be highly camouflaged against the dark green needles of two- and three-needle pines. Recent scouting on Japanese white pines (Pinus parviflora) revealed an adult white pine weevil on the terminal shoot and larvae of some type of pine shoot moth (possibly Rhyacionia buoliana) inside developing candles that were distorted and growing at an odd angle.

Scout deciduous hardwoods like cherry (Prunus), and apple/crabapple (Malus) for eastern tent caterpillars (Malacosoma americanum). This native pest is capable of significant early season defoliation on infested trees.

Voles (Microtus spp.) can be a destructive nuisance in the garden but poisoning these rodents can kill wildlife and pets higher on the food chain. Instead, use castor oil pellets or granules to drive them away. When applied thoroughly to an area, inside their tunnels and the surrounding area, they can be very effective.

Nick Brazee, Plant Pathologist, UMass Extension Plant Diagnostic Lab, reporting from Amherst.

Berkshire Region (West Stockbridge)

General Conditions: 

Although we have had no rainfall in the last week, there still seems to be ample moisture in the soil and spring is exploding in bloom and chartreuse green foliage throughout the Berkshire hills.

Perennials currently blooming in the garden include wake-robin (Trillium erectum), marsh marigold (Caltha palustris), a variety of primrose (Primula spp.), myrtle spurge (Euphorbia myrsinites), American globeflower (Trollius laxus), violets (Viola spp.), barren strawberry (Waldsteinia fragaroides).

Later blooming narcissus are still putting on an impressive show along with other bulbs including grape hyacinths (Muscari spp.), Grecian windflower (Anemone blanda), trout lily (Erythronium spp.).

Woodies currently in bloom include shadblow (Amelanchier canadensis), northern spicebush (Lindera benzoin), redbud (Cercis canadensis) flowering quince (Chaenomeles spp.)

Pests/Problems: 
Deer, rabbit and vole damage continue to be a problem.

Winter damage to evergreens, particularly boxwood has been noticed. The boxwood has also been damaged by boxwood leafminer (Monarthropalpus flavus). Hopefully a hard pruning will help with both issues.

Deer ticks (Ixodes scapularis) are active. Mosquitoes have started to torment. The Eastern tent caterpillar (Malacosoma americanum) has been spotted on flowering quince (Chaenomeles spp.)

Eric Ruquist, Director of Horticulture, reporting from Berkshire Botanical Garden, Stockbridge.

Landscape Pest Reports

Diseases

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

Insects and Other Arthropods

Are you a professional (landscaper, arborist, municipal employee, tree warden, pest management professional, etc.) managing insect & mite pests of trees & shrubs in Massachusetts? Please consider joining our Tree & Shrub Insect & Mite Pests of Massachusetts Collection Project on iNaturalist! 

Here's how to participate:

• Use your existing iNaturalist account or create a new iNat account using a valid e-mail address, creating a unique username & password.
• Visit the Tree & Shrub Insect & Mite Pests of Massachusetts Collection Project and navigate either to the "join" or "join this project" area. Further instruction on how to join an existing project are explained on iNatHelp.
• Take up-close & in-focus photos of insect & mite pests on trees & shrubs you are currently managing (as a regular part of your monitoring activities). You can take multiple photos of the same observation - including images of any life stages that are present as well as the feeding damage seen on the tree or shrub. A smart phone works just fine to make and upload observations. (Mites may require magnification.)
• Start uploading your observations of insect & mite pests on trees & shrubs in Massachusetts. At this time, the project should automatically collect & include your observations, as long as you start identifying what you've found and note your location in MA. (See the project description for more information on obscuring location data for privacy, while still being able to participate.)

Please upload any monitoring data you collect throughout the 2026 growing season. This information may help us to identify native pest outbreaks on trees and shrubs, non-native pests on trees & shrubs, increase stakeholder engagement, and inform the creation of pertinent educational materials. We hope to see you on iNat!

The Professional Insect and Mite Management Guide for Woody Plants is freely available. The online, searchable guide is for professionals managing the health of trees and shrubs in Massachusetts, although the insect and mite species mentioned within may be applicable to much of New England. Search for information about over 200 pest species, native and introduced, using common and scientific names, host plants, and growing degree days. Information about pest identification and life cycles as well as integrated pest management options are included.

Please let me know how it works or isn’t working for you using this feedback form. Your response is valuable, and I cannot wait to hear from you!

2026 Updated Resources:

• Monthly Insect Almanacs: Track pest insect activity on trees and shrubs in Massachusetts seasonally with monthly insect almanacs. Pest life cycles vary throughout the growing season and so do professional options for management. Consider this pest itinerary when planning. It is a new resource within the Professional Insect and Mite Management Guide for Woody Plants. It is not meant to replace site-specific monitoring or growing degree day tracking.
• Insects Added to the Professional Insect & Mite Guide:
  • Imported Longhorned Weevil
  • Gouty Oak Gall Wasp
  • Horned Oak Gall Wasp

Introduced (Invasive) Species Updates:

• Asian Longhorned Beetle is still a concern in Worcester, Shrewsbury, Boylston, West Boylston, and parts of Auburn, MA. The 12.3 square miles of Holden, MA that were originally part of the regulated area for ALB has been removed as of 2025.

  If you suspect you’ve found this insect or the damage it causes, particularly on maple, there are many ways to report it depending on your location:

  1. If in Massachusetts: please report suspicious insects or damage to host plants to the Asian Longhorned Beetle Eradication Program office in Worcester, MA at 508-852-8090 or visit the Massachusetts Introduced Pests Outreach Project.
  2. All US states outside of MA: please visit the USDA APHIS Asian Longhorned Beetle page.

• Box Tree Moth has been detected in some communities in Barnstable County, MA as well as Norfolk County, MA in the community of Brookline. A map of these locations is available courtesy of the MA Department of Agricultural Resources. If you believe you have found this insect, please take a photo, note your location, and report it to the Massachusetts Introduced Pests Outreach Project. *MDAR has an excellent new box tree moth short video alert available.

• Elm Zigzag Sawfly has been detected in various communities in Massachusetts. A map of where elm zigzag sawfly has been confirmed in MA is available. If you believe you have found this insect, please take a photo, note your location, and report it immediately using the Massachusetts Elm Zigzag Sawfly Reporting Form.

• Spotted Lanternfly now has established populations in multiple communities in Massachusetts. If you believe you have found this insect, please take a photo, note your location, and report it immediately to the Massachusetts Introduced Pests Outreach Project. 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:

• Mosquitos and the diseases they vector are also a serious public health concern in Massachusetts by summer. Available resources include Mosquito Repellents from the Massachusetts Department of Public Health and Preventing 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 with details about mosquito activity will be available through the MA Department of Public Health. 

• Stinging Insects such as bees and wasps are awakening from their overwintering shelters on mild, sunny spring days!

• 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.

Tree & Shrub Insect & Mite Pest Suggested Scouting:

• Andromeda Lace Bug is most commonly encountered on Japanese Andromeda. Eggs are tiny and inserted into the midveins on the lower surface of the leaf and covered with a coating that hardens into a protective covering. 5 nymphal stages are reported. Nymphs are different in appearance from adults, often covered with spiky protrusions. 3-4 generations per year have been observed in New England, with most activity seen between late-May into September.

• Arborvitae Leafminer mature caterpillars are found roughly from April to June and fully grown caterpillars overwinter in mined host plant leaves. Pupation occurs the following spring and adults emerge, and females lay eggs.

• Ash Plant Bug eggs are laid in cracks and crevices of host bark in the fall, where they overwinter. Eggs hatch in mid-May. Nymphs crawl to the undersides of the leaves where they will feed. Adults of the first generation will lay eggs on the midveins of the leaves in the summer (July) and eventually hatch to produce the second generation of nymphs. Second generation plant bugs will feed on the underside of leaves until killed by the frost, laying the eggs that overwinter on host bark.

• Azalea Lace Bug native to Japan, deposits tiny eggs on the midveins on leaf undersides. Look for dark, black tar-like spots of excrement deposited by immature and adult lace bugs on the underside of susceptible host plant leaves, especially on leaves with white-yellow stippling visible on the upper surface. If lace bugs are not already known to the location, check susceptible hosts located in full sun first. Monitor plants for lace bug feeding from late April through the summer.

• 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).

• 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 yellow 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.

• Dogwood Borer feeds as a larva on the phloem and cambium of their host plants. When dogwood flowers begin to drop, adult dogwood borer moths begin to emerge. Moth flight and activity can last through September. That being said, it is best to combine phenological indicators, growing degree day tracking, and pheromone trapping to accurately monitor this insect and time treatments. Research has suggested that emergence times for dogwood borer adult moths differ regionally and by host plant.

• 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 eggs have hatched and young caterpillars have begun to feed on expanding cherry foliage. Look for ever growing silken tents around groups of feeding caterpillars as the season continues. Tents are often placed where branches join.

• European Pine Sawfly eggs have overwintered in slits in last year’s needles. Egg hatch begins in approximately late-April and early May, with larvae feeding on previous year's needles until approximately late-May or early June, at which time they drop to the ground to pupate.

• European Pine Shoot Moth may refer to at least three species of native moths in the Northeast. The yellowing of the tips of twigs or the clear deposits of pitch between new bud clusters may be early signs of activity of this insect on Pinus spp. hosts. Mined needles will die and turn brown in color, which can be noticed in the summer. Initial areas of wounding are covered with resin-coated webbing. By the middle of the summer, the larvae move to the buds and burrow into them. Scaring is often caused. In August, feeding stops and tiny, black caterpillars overwinter in this area covered by the resin-coated webs.

• Fletcher Scale is a pest of arborvitae, juniper, yew and others. Second instar nymphs (immatures) overwinter. They begin to mature in May and females will lay (500-600; but up to 1000) eggs beneath their bulbous bodies by late May and early June. During this time of development in the spring, plant damage and honeydew may become especially obvious, particularly on yew. Sooty mold may grow on the honeydew. 

• Forest Tent Caterpillars will feed together in groups when caterpillars are still small but may wander individually as they mature. Caterpillars may reach up to 2 inches in length and are blue and gray with oval white spots down the back that are sometimes described as "key holes" or "tiny penguins". They do not create tents, unlike the common name suggests.

• Four-Lined Plant Bug feeds on over 250 plant species, many of which are herbaceous. The four-lined plant bug overwinters as eggs which are inserted into the tender shoots or water sprouts of certain host plants. Females use their ovipositor to cut a slit in the tissue of the plant, into which the eggs are inserted. Egg hatch may occur in late April or May in Massachusetts. Nymphs develop over the course of approximately 30 days. Feeding injury from both the nymphs and adults causes black or brown disease-like spots to form on the foliage of numerous hosts. The injured areas may turn black or appear translucent. After a few weeks, the necrotic tissue may drop from the plant leaving small holes behind.

• Fruitworms is a complex of at least 10 species that are sometimes collectively referred to as "fruitworms" or "green fruitworms". These are native insects that feed on similar hosts at the same time and cause similar feeding damage. Eggs hatch and young larvae crawl to the opening buds of their host plants and begin to feed, usually beginning around April or May in Massachusetts. Caterpillars mature as the leaves of their host plants mature. Fruitworm caterpillars may be observed feeding on their hosts until approximately the end of June.

• Hackberry Psyllid may refer to at least 10 species of psyllid in the genus Pachypsylla that are reported on hackberry. When new hackberry leaves begin to unfold from the buds, mating and egg laying by these species will occur over the next few weeks. Eggs hatch in approximately 10 days and the nymphs (immatures) will begin to feed on the leaves. Depending on the species, a blister or a nipple gall is formed on the leaf in response to the insect's feeding. 

• 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 Rust Mite feeds on the needles of its hosts by removing fluids from the needles. When mite populations are high, foliage may appear blue-ish in color and turn yellow before dropping from the plant. The hemlock rust mite causes most of its damage in the spring and may be a pest in nurseries. Damage by this eriophyid mite is most noticeable by mid-summer, but by that time the populations typically die off.

• Honeylocust Plantbug is one of the most impactful (of at least 7 species of) plant bugs on this tree species. There is one generation per year and this insect overwinters as eggs laid just beneath the bark surface of 2 and 3 year old twigs. Eggs hatch once the buds of honeylocust begin to open. Young nymphs will move to the freshly opening leaves and begin to feed. Nymphs (immatures) are pale green with short wing buds that do not extend to the end of the abdomen. The majority of the feeding damage from this insect occurs at this time, while leaves are still very small and the insect is well hidden. 

• 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.

• Juniper Scale is native to Europe and is now found throughout the United States. The overwintering life stage are adult females, which can be found on the needles of the host plant, filled with yellow eggs. By late May or early June (in Connecticut, New Jersey, and Ohio) crawlers appear. Monitor susceptible host plants for off-color foliage. Examine needles using magnification (10X hand lens) for tiny, circular, white female scale covers. Observe scale covers for the evidence of natural enemy activity (ex. exit holes from parasitoids).

• Larch Casebearer is an introduced species from Europe. The insect overwinters as a larva in its case, firmly attached to a branch or near the base of a bud. Feeding by the larvae begins again in the spring. This begins as soon as foliage begins to appear. Fully grown larvae are approximately 6 mm in length. By late May or June, larvae complete their feeding and pupate within their case. Adults emerge by June and early July and are winged to disperse.

• 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 will 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.

• Oak Leaftier caterpillars hatch from eggs in approximately mid-April to early May. The earliest hatched caterpillars are capable of entering the buds of their host plants even prior to their expansion. Any leaves that survive often expand with holes created before they even opened.

• Oystershell Scale eggs hatch from early May to mid-June. Second instar crawlers (immatures) are found from mid-June to late July. Adults from early August to late September.

• Pales Weevil overwintering life stage are the adults who hide at the soil surface or in the leaf litter. Activity resumes in the spring with warming temperatures, typically by late April and early June (in warmer climates, adult activity can occur year-round). Adult beetles are particularly attracted to freshly cut stumps, where egg laying will preferentially occur on the roots.

• 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.

• Pine Spittle Bugs feed on a variety of coniferous and other host plants. "Spittlebug" refers to the habit of the nymphs of these species, which produce frothy liquid around themselves to keep moist and protected from natural enemies. Eggs overwinter. In the spring, the nymphs hatch and begin feeding on host plant twigs. With piercing-sucking mouthparts, the nymphs feed on sap from host plant phloem. Sap is partially digested, whipped into a spittle-like foam, and several nymphs may be found in a single spittle mass. 

• 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.

• Taxus Mealybug first instar nymphs are reported as the overwintering life stage in New Jersey. They may be found in bark crevices on the host plant. In April and May few live mealybugs are found. However, by mid-June the population may increase considerably. Adult female taxus mealybugs are present from June to August and give birth to live young in the early summer. Nymphs and adults have been reported in Massachusetts in June, but no eggs or young nymphs were seen at that time in prior studies.

• 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 Weevil adults have already been active at this time, anywhere GDD’s are above 58 accumulated heat units. Any insecticide applications for adult white pine weevils need to have already occurred, as most locations are above the growing degree day range for the adult springtime activity. Before June, remove and destroy flagging or crooked leaders on small trees. Affected trees can be pruned and staked to regain single leader dominance. Trees in sunny locations are more apt to be attacked.

• White Prunicola Scale (Pseudaulacaspis prunicola) is a temperate species of armored scale. It is so very closely related to and easily confused with the white peach scale (P. pentagona) that for a very long time, scientists thought each was a single species. Mated adult females are the overwintering life stage. In northeastern Pennsylvania, egg laying began in mid-May, and again in late-July, with crawlers shortly thereafter. Each female laid approximately 27-78 eggs. In points north of Pennsylvania, there are typically 2 generations per year, occurring approximately in early June and early August in central New England.

• Winter Moth females may produce 150-350 tiny eggs, which are very difficult to see. The adult moths then die and the eggs overwinter. Eggs are green at first, but turn red-orange soon thereafter. In March, prior to hatching, the eggs turn a bright blue and then a very dark blue-black just before hatching. Eggs hatch when temperatures average around 55º F. It is believed that egg hatch in Massachusetts occurs when 20–50 Growing Degree Days (base 50º F) have accumulated, which can be anywhere from late March into early-mid April, depending on the year and the location. While patchy and noticeable populations of winter moth may exist in eastern MA, overall, this insect is not expected to be in an outbreak status. An update about winter moth populations in Massachusetts is available from UMass Extension's Landscape, Nursery and Urban Forestry program.

• 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 are present, the aphids will complete their life cycle on apple year round.

• 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:

• Cecropia moth cocoons overwinter. As North America’s largest native moth, these ephemeral giants should be preserved wherever they are encountered. Cocoons are approximately 4-5 inches in length and may appear brown and papery. They can also be tethered tightly to branches, sometimes including desiccated leaves from the previous growing season. While the caterpillars do feed on various deciduous trees, they are not pests and should be preserved. This includes the overwintered cocoons, containing pupae that will soon develop and emerge as spectacular adults, some with over 6-inch wingspans! Take-home point: if you see a cocoon, leave it in place.

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

Weeds

Explore UMass Extension's Weed Herbarium, a definitive picture identification guide designed to aid in the management of our most common weed species. 

Garlic mustard (Alliaria petiolata): This biennial weed is considered invasive in Massachusetts and other states. Active growth is beginning for second year plants, and first-year plants will begin to germinate in the next few weeks. Delay management with herbicides until the first-year plants have germinated.

As forsythia continues to flower, it is time to apply preemergence crabgrass control products for the management of crabgrass and other summer annual grassy weeds. As the end of forsythia flowering approaches so does the application window for the effective control of annual grasses with preemergence herbicides. These preemergence herbicide products are available as on-fertilizer or sprayable formulations. These applications should be completed by the time that forsythia flowers begin to drop, and/or the first signs for green leaves arrive. The correct timing of these applications is likely to vary significantly from location to location and within a specific region of New England.

Japanese knotweed (Fallopia japonica): Do not attempt to control Japanese knotweed now, as herbicide applications are not effective in the early part of the growing season. Stay tuned to the Landscape Message for more management information as the season progresses.

Lesser celandine, also called fig buttercup, fig-crowfoot, or dusky maiden (Ficaria verna or Ranunculus ficaria), is an herbaceous invasive perennial plant found throughout New England. This species is a spring ephemeral, with shiny, dark green, kidney-shaped leaves and bright yellow, glossy flowers with 8 to 12 petals. Lesser celandine is reproduced by bulblets, tuberous roots, and seeds. As a spring ephemeral, it is only apparent in the spring and is dormant for the rest of the year, so it is often difficult to determine if an herbicide worked or the symptoms observed are just the species going dormant later in the spring. Herbicides known to effectively control lesser celandine in turf are triclopyr and dicamba. Products that contain both herbicides are the best choice. Populations of lesser celandine in landscape beds can be controlled with directed-spray applications of glyphosate. If a glyphosate product that does not have a surfactant in the formulation is selected, the addition of a non-ionic (NIS), crop oil concentrate (COC) and methylated seed oil (MSO) should be added to the spray solution. It can be difficult to achieve adequate spray coverage on the glossy leaves of lesser celandine, and a surfactant will improve leaf coverage and retention. For early occurrences of this weed in new locations consider digging plants up and disposing of them in a manner that will prevent their further spread.

A member of the lily plant family (Liliaceae), star-of-Bethlehem (Ornithogalum umbellatum), is currently apparent in some turf and landscape areas. Visit our website for photos and characteristics. Star-of Bethlehem can be difficult to control but can be managed with glyphosate. Non-chemical, burn-down herbicides (acetic acid, d-limonene, clove oil) will desiccate the leaves and repeat applications over time will weaken the bulb of this weed. Star-of Bethlehem is also very susceptible to the broadleaf turf herbicide sulfentrazone. Sulfentrazone is found in several 2-, 3- and 4-way broadleaf turf herbicide combinations and in combination with carfentrazone in the herbicide product Dismiss NXT. Sulfentrazone alone can be found in several post-patent, generic products. Consult with your distributor about the product options available.

Early season control of woody invasive plants can be very effective. Basal bark or cut-stem application of glyphosate or triclopyr can be used for the management of buckthorn, oriental bittersweet and Norway maple.

Reported by Randy Prostak, Weed Specialist, UMass Extension Landscape, Nursery, & Urban Forestry Program

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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, Total Carbon, Total Nitrogen and Soilless Media. The lab is also accepting samples for Plant Tissue analysis, including macro and micronutrients, total carbon, and total nitrogen. 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 on our website.

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
• Stakeholders like you! The Landscape Message is partially supported by educational program user fees and support from readers.