Landscape Message: June 7, 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 Landscape Message #9 for the 2024 growing season.  The next message will be published in one week, on June 14.  To receive immediate notification when the next Landscape Message update is posted, be sure to join our e-mail list 

Click on the headings below to jump to that section of the message.

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In This Issue

Scouting Information by Region

Environmental Data

Phenology

Regional Notes

Woody Ornamentals

Diseases

Insects and Other Arthropods

Landscape Weeds

Additional Resources

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Scouting Information by Region

Environmental Data

The following data was collected on or about June 5, 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.

MA Region/Location	2024 Growing Degree Days		Soil Temp (°F at 4" depth)		Precipitation (Gain in inches since last report)	Time/Date of Readings
	Gain since last report	2024 total	Sun	Shade
CAPE	91	322	68	62	0.32	12:00 PM 6/5/2024
SOUTHEAST	101	440	76	64	0.86	3:00 PM 6/5/2024
NORTH SHORE	89	348	65	57	0.73	10:00 AM 6/5/2024
EAST	106	459	78	69	1.03	4:00 PM 6/5/2024
METRO	105	452	65	59	0.00	5:30 AM 6/5/2024
CENTRAL	109	464	72	68	1.37	2:00 PM 6/5/2024
PIONEER VALLEY	98	504	71	64	1.21	1:00 PM 6/5/2024
BERKSHIRES	92	433	68	62	0.62	8:00 AM 6/5/2024
AVERAGE	99	428	70	63	0.77	-
n/a = information not available

 

US Drought Monitor:  Once again, no change from last week... at this time, no area of Massachusetts is under official drought status. State map as of Thursday 6/6: 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.
Catalpa speciosa (Northern catalpa)	*	*	*	*	Begin	*	Begin	*
Sambucus canadensis (American elderberry)	*	Begin	Begin	Begin	Begin	Begin	Full	Begin
Kalmia latifolia (mountain laurel)	Begin	Begin/Full	Begin	Begin/Full	Full	Begin	Full	Begin
Cotinus coggygria (common smokebush)	Begin	Full	Full	Full	Full	Full	Full	Full
Weigela florida (old fashioned weigela)	Full	Full	Full	Full	Full	Full	Full/End	Full
Robinia pseudoacacia (black locust)	Begin/Full	Full/End	Full	Full	Full/End	Full	End	Full/End
Syringa meyeri (Meyer lilac)	Full	Full/End	End	Full/End	Full/End	End	End	Full/End
Deutzia spp. (deutzia species)	Full	End	Full/End	Full/End	*	Full/End	Full/End	Full
* = no activity to report/information not available

Regional Notes

Cape Cod Region (Barnstable)

General Conditions:

The average temperature for the period from May 29 through June 5 was 63ºF, with a high of 79ºF on June 2 and a low of 45ºF on May 3. Highs have been mainly in the 70s, with lows in the 50s and mostly sunny days. About a third of an inch of precipitation fell on May 30. Evapotranspiration outpaced precipitation, but soil moisture remains adequate.

Herbaceous plants seen in bloom include peony (Paeonia spp.), iris (Iris x germanica), foxglove (Digitalis purpurea), blood red geranium (Geranium sangiumeun), columbine (Aquilegia spp.), and lupine (Lupinus spp). Woody plants seen in bloom include azaleas and rhododendrons (Rhododendrons spp.), many viburnums (Viburnum spp.), many dogwoods (Cornus spp.), and black cherry (Prunus serotina). Pollen is abundant.

Pests/Problems:

Box tree moth was discovered in several towns of the upper Cape last season. This insect is capable of defoliating boxwood if left unmanaged. Box tree moth is active and should be scouted for.

Lots happening on oak at this time; some heavy feeding from fall cankerworm was observed near the mid-Cape, possibly mixed with a little winter moth, though both are or are just about done feeding. Keep an eye out for spongy moth (Lymantria dispar), which has been seen on the lower and outer Cape. Oak shothole leafminer damage has been seen in several locations, though this damage is variable from tree to tree. Other insect pests seen on oak include lecanium scale, sawfly, and leaf rollers.

Other insects or insect injury observed during the period include dogwood sawfly on alternate leaf dogwood, viburnum leaf beetle on arrowwood, columbine leafminer on columbine, daylily leafminer on daylily, black turpentine beetle on pitch pine, hemlock woolly adelgid and hemlock elongate scale on hemlock, hydrangea leaf tier on smooth hydrangea, and plant bug damage on viburnum.

Disease symptoms or signs observed during the period include spotty but heavy needlecast on both pitch pine and white pine, lots of brown rot on both Kanzan and weeping cherries, beech leaf disease on European and American beech, maple antracnose, oak anthracnose, sycamore anthracnose, and leaf spot on river birch.

Invasive plants seen in bloom during the period include scotch broom (Cytisus scoparius), multiflora rose (Rosa multiflora), winged euonymus (Euonymus alatus), and buckthorn (Rhamnus cathartica). Other weeds seen in bloom include white clover (Trifolium repens), black medic (Medicago lupulina), and hawkweed (Hieracium pratense).

Rabbits, snails & slugs remain active.

Southeast Region (Dighton)

General Conditions:

Over the past week, since May 29^th we’ve had some lovely weather. The highest temperature was 82ºF on Monday, June 3^rd. The coolest temperature was a refreshing 52ºF on the night of Thursday, May 30^th. The average temperature was a pleasant 66ºF while the average humidity was around 66%. We had rain on the morning of May 30^th, totaling about 0.86 inches. The week experienced its windiest day on Tuesday, June 4^th, with gusts reaching up to 14 mph from the south-southeast. The soil temperatures were 75ºF in full sun and 64ºF in shade on June 5th at 3 pm.

Among the many plants in flower are: Cotinus coggygria (American smokebush), Cornus kousa (Kousa dogwood), Chionanthus virginicus (fringe tree), Kalmia latifolia (mountain-laurel), Kolkwitzia amabilis (beautybush), Rhododendron catawbiense (Catawba rhododendron), Robinia pseudoacacia (black locust), Sambucus canadensis (American elderberry), Syringa meyeri (Meyer lilac), and Weigela florida (old fashioned weigela)

Pests/Problems

White pine pollen has been so heavy this year it has made national news, coating everything with yellow dust while contributing to itching eyes and sneezing.

Ash rust continues to desolate already heavily impacted whte ash, producing leaf litter.

Mosquito numbers are beginning to build and bite.

North Shore (Beverly)

General Conditions:

This was a week of mostly dry weather with clear sunny skies, except for Thursday May 30^th when a storm came through and brought some much-needed rain. Approximately 0.73 inch of rainfall was recorded at Long Hill during this rain event. Temperatures were variable, with daytime temperatures ranging from 60ºF to 85ºF and nighttime temperatures from 46ºF to 59ºF. The average daily temperature was 63ºF, with the highest temperature of 85ºF recorded on June 5 and the lowest temperature of 46ºF recorded on May 30. The weather was very pleasant and comfortable for outdoor work.

Because of the rain showers on June 5 and cool weather at night, grass is looking good on lawns. Woody plants seen in bloom include arrowwood viburnum (Viburnum dentatum), fringe tree (Chionanthus virginicus), mock orange (Philadelphus spp.), beautybush (Linnaea amabilis), mountain laurel (Kalmia latifolia), weigela (Weigela florida), Korean dogwood (Cornus coreana), maple leaf viburnum (Viburnum acerifolium), deutzia (Deutzia crenata), Chinese neillia (Neillia sinensis), and ninebark (Physocarpus opulifolius). Non-woody plants seen in bloom include: scotch rose (Rosa spinosissima), red leaf rose (Rosa glauca), cranesbill (Geranium spp.), bleeding heart (Dicentra spectabilis), catmint (Nepeta spp.), salvia (Salvia spp), foam flower (Tiarella cordifolia), leopard's bane (Doronicum spp.), goat’s beard (Aruncus dioicus), fetterbush (Leucothoe fontanesiana), peony (Paeonia sp.), amsonia (Amsonia hubrichtii), and annuals such as petunia and million bells.

Pests/Problems:

Boxwood psyllid (Psylla buxi) was observed on some boxwoods. Boxwood psyllid feeding injury produces cupping and curling of the leaves, enclosing several nymphs in the leaf pockets. The nymphs also produce white, fluffy secretions. Prune out and dispose of infested branch tips. Boxwood psyllid nymphs can be controlled with horticultural oil or insecticidal soap. Multiflora rose (Rosa multiflora) and wild raspberry (Rubus rosifolius) weeds are in full bloom and are easy to identify. Mosquitoes and ticks are very active. Protect yourself with a repellent when working outdoors

East (Boston)

General Conditions:

Meteorological summer began June 1^st. We have had consistant warm, sunny days. Daytime temperatures averaged 76ºF. We had a low daytime high of 64ºF on May 30^th, when we received 1.03 inches of precipitation. This was the only precipitation recorded over the past seven days. We have reached 435 growing degree days (base 50). Favorable growing conditions have resulted in lush plant growth. Some plants in bloom include; Baptisia australis (false indigo), Kalmia latifolia 'Polypetela’ (Polypetela mountain laurel), Rosa spp. (landscape roses), Styrax japonicus (Japanese snowbell), and Symphytum officinale (common comfrey). Two additional noteworthy plants include: Clematis ‘Doctor Rupple’ (Doctor Rupple clematis), a low maintenance, durable, rambling, large-flowered clematis with prolific blooms, and Salix integra ‘Hakuro Nishiki’ (dappled willow), with its striking white and pink tinged emerging foliage.

Pests/Problems:

Some Ilex spp. (holly) foliage is yellowing and some is blackened. Although visually concerning, this is fairly typical as the hollies are experiencing annual leaf drop; prior year's foliage is turning yellow and being shed as they put on new growth. The black blemishes on the leaves are a result of aphids and other sap sucking insects feeding and excreting honeydew onto the foliage below. The honeydew is then infected by a black soot-like fungus, resulting in the blackened leaves. Sycamore lace bug (Corythuca ciliata) has been active on Platanus occidentalis (American sycamore). Japanese knotweed (Fallopia japonica, +Polygonum cuspidatum) is 3-4 feet tall. The invasive Rosa multiflora (multiflora rose) is in full bloom.

Metro West (Acton)

General Conditions:

Spring or early summer-like weather continued into this week’s reporting period. High temperatures were scattered and were recorded in the 60s, 70s and low 80’s all week with a high temperature of 82ºF on the 2^nd. Rainfall fell short last month of the monthly May average, but not by much. The average is 4.04” and 3.07” of rain was recorded. For the month of June, the average monthly rainfall is 3.93” and there has not been any rain recorded yet for this first partial week of the month. The landscape is lush and colorful with all that is in bloom and the following woody and herbaceous plants were observed in some stage of bloom at this time: Catalpa speciosa (northern catalpa), Chionanthus retusus (Chinese fringe tree), Geranium cantabrigiense 'Biokovo' and 'Cambridge' (hardy cranesbill), Gymnocladus dioicus (Kentucky coffeetree), Kolkwitzia amabilis (beautybush), Liriodendron tulipifera (tulip tree), Potentilla fruiticosa (potentilla), and Rosa rugosa (beach rose).

Pests/Problems:

Rosa multiflora, an aggressive and invasive shrub, is just coming into bloom and is very easy to detect with its abundant white flowers. It is seen growing in and amongst and over other trees and shrubs in the planted and/or wild landscape.

Central Region (Boylston)

General Conditions:

A hot and summer-like week, there was less rain except for a large amount of precipitation mid-week. Max precipitation was 1.37 inches on the 30th, averaging 7.25 inches for May. Temperatures ranged from the 70s to the 80s; the highest recorded was 85.9ºF on the June 5th. It has been dry and windy, creating poor air quality along with the amount of pollen dusted around. Some woody plants that can be seen blooming currently are fringe tree (Chionanthus spp.), sweetshrub (Calycanthus spp), mountain laurel (Kalmia latifolia), maple-leaf viburnum (Viburnum acerfolium), and ninebark (Physocarpus opulifolius). Some herbaceous material that can also be seen blooming is: Eastern bluestar (Amsonia tabernaemontana), peony (Peaonia spp.), foam flower (Tiarella cordifolia), and bleeding heart (Dicentra eximia).

Pests/Problems:

As stated in the general conditions, the pollen levels have been what seems record breaking, sending puffs of yellow smoke into the air and covering all foliage in a yellow film. Some pests/problems spotted in the garden are plume moth caterpillar, azalea gall, and Phyllosticta leaf blotch. The plume moth caterpillar was spotted on some Joe-pye weed (Eutrochium spp.), eating away at the leaves. Azalea gall was spotted on Pinxterbloom azalea (Rhododendron periclymenoides). Lastly, Phyllosticta leaf blotch was spotted on witchhazel (Hamamelis x intermedia) and has been present for a season or two. Usually this pathogen thrives in damp/wet conditions and is more commonly found on hydrangea, holly, rhododendron, and Kalmia. Signs of this can be spotting on the leaves, browning them completely, and then defoliation. Though not detrimental to the tree, fungicide applications can be helpful, along with pruning the infected branches.

Pioneer Valley (Amherst)

General Conditions:

June has arrived, and this month is all about celebrating the sun. As we approach the solstice, this is a good time to assess exactly how much direct sunlight trees and shrubs in the landscape are receiving. Plants that once received full sun may be receiving far less as a landscape matures and neighboring canopies encroach and converge. Insufficient sunlight is a chronic stress that can contribute to a thinning canopy or increase in disease issues.

It’s been a warm and dry week, but the long-term forecast calls for cooler temperatures and scattered showers. Eastern white pine (Pinus strobus), the Commonwealth’s most abundant tree species, is shedding huge volumes of pollen at this time. Like most forest trees in New England, white pines are monoecious (male and female reproductive parts on the same plant). However, the male flowers (strobili) that disperse pollen tend to occur at the base of new shoots on older lateral branches in the lower canopy. The female flowers (which develop into cones) occur in the upper canopy towards the ends of larger branches. It takes over a year for cones to fully mature, typically late summer to early autumn of the second year.

Crickets and grasshoppers have joined the summer soundscape and lightning bugs are visible at night. Lady beetle larvae are abundant and typically bear little resemblance to the adults. Educate clients on their appearance so they aren’t inadvertently killed under the assumption they are plant pests.

Pests/Problems:

Needle blight symptoms on eastern white pine are on full display right now. Older, diseased needles are yellow to brown and prematurely shedding from the canopy. Several native fungal pathogens are responsible, but the two most prominent are Septorioides and Lecanosticta. The combined appearance of the older diseased needles, numerous, brown-colored male flowers, and partially developed new needles can give white pines a sickly brown appearance. Once the older needles and male flowers are shed and the current season’s needles fully elongate later this month, these trees will appear much healthier.

Anthracnose symptoms on oak, beech, and maple, among many other tree species, are starting to appear. However, symptoms are generally minor and many sycamores in the valley appear relatively healthy right now, indicating this is a low severity year for sycamore anthracnose.

Berkshire Region (West Stockbridge)

General Conditions:

After a cool end of May when low temperatures were 42ºF in Richmond, 40ºF in North Adams, and 41ºF in Pittsfield on May 31^st, a heat wave has moved in. Temperatures at all three NEWA sites in Berkshire County rose into the 80s, with the highest temperatures over the latest scouting period rising to highs of 86ºF at both the Richmond and North Adams weather recording sites on June 4^th. Pittsfield recorded a high of 83ºF on that day. The heat has hastened the drying of soils, though most still retain moisture below the top inch or two of soil. Those soils high in clay content and low in organic matter are somewhat crusty, and require some tillage to break the crust when one is attempting to sow seeds or transplant annuals. Still, growth of plants seems not affected by any lack of moisture yet. That is especially true of the growth of weeds. Landscapes, both natural and managed, are still quite colorful as flowering plants abound. Roses have come into bloom, including the invasive Rosa multiflora. Among other plants now in flower are foxglove (Digitalis purpurea), peonies (Paeonia spp.), alliums (Allium spp.), and perennial bachelor's button (Centaurea montana).

Pests/Problems:

Wooly beech aphids remain active on copper beech. Aphids were found on a variety of herbaceous perennials as well as some shrubs and trees, including on paper birch (Betula papyrifera). Cutworms have been gnawing on the stems of some recently planted annuals. Magnolia scale (Neolecanium cornuparvum) was observed on a magnolia in southern Berkshire County. Boxwood leafminer is now in the adult stage. Some crabapple trees have already experienced a bit of defoliation due to infections of cedar apple rust and apple scab.

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:

Needle blight of pitch pine (Pinus rigida) caused by Ploioderma lethale. The tree is roughly 50 to 60 years old and resides in an open, full sun landscape with no surrounding plants in sandy, moderately well-drained soils. Symptoms of needle blight developed throughout the lower canopy in recent years. The root flare was excavated using an airspade, there’s a mulched ring around the base, and the discarded needles were removed. Despite what appears to be an ideal setting for a hard pine (open setting with full sun in sandy soils), mature conifers often have shaded interior canopies where needle blight outbreaks can develop. Ploioderma is a common pathogen on pitch pine in southern New England and is capable of causing serious injury in some cases. This pathogen has a broad host range among two- and three-needle pines but is not known to occur on five-needle pines.

Foliar anthracnose on red oak (Quercus rubra) caused by Apiognomonia errabunda. The tree is young, approximately 10 to 12 years old, and has been present at the site for several years. It resides in 4’ wide strip or turfgrass adjacent to a street. The tree experiences part sun in compacted, well drained soils. In mid-May, a marginal leaf scorch and coalescing leaf spots appeared. The symptoms have been present in previous years. The tree received a phosphite bark drench in early May and a foliar application of metconazole in late May. The submitted sample exhibited foliar symptoms along with a shoot tip blight. After a brief incubation, the anthracnose pathogen was abundant from the symptomatic tissues. Anthracnose fungi can be persistent and challenging to control on oak.

Severe canopy dieback of Chinese wisteria (Wisteria sinensis) due (in part) to stem and branch cankering caused by Phomopsis, Neofusicoccum, and Fusarium. This large plant is around 25 years old and has been trained to a wooden arbor in full sun over a brick driveway. The soil is described as loam-based with good drainage. The wisteria flowered well in 2023 and appeared relatively healthy. However, after flowering this spring, a significant percentage of the canopy wilted and has died. There are likely several interacting stresses present here but based on the submitted branch segments, three cankering pathogens are partly responsible. What other stresses may be contributing remains unknown, but the abundant rainfall last season may have contributed to the cankering outbreak. Each of these fungi can cause dieback on a stressed and weakened host, and the occurrence of all three is unusual.

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

• Box Tree Moth has been detected in the following Massachusetts communities: Bourne, Sandwich, and Barnstable. A map of these locations is available at MDAR’s Invasive Pest Dashboard. If you believe you have found this insect, please take a photo, note your location, and report it immediately to the MA Department of Agricultural Resources using their Report a Pest Form. Box tree moth caterpillars were reported to be active at certain locations on Cape Cod, MA as of the week of April 19th. For updates this week, see the Cape Cod Region Report. 

The USDA APHIS has announced a new quarantine for box tree moth in Massachusetts and Ohio, and has expanded existing quarantines in Michigan and New York. This includes conditions for interstate movement of regulated Buxus species. This quarantine includes the entire Commonwealth of Massachusetts. The federal order states:

“Boxwood plants may only be moved interstate from a quarantined area from an establishment operating under a compliance agreement, and only if accompanied by a certificate issued by a State Agricultural Authority certifying that the requirements of this Federal Order and the compliance agreement have been met. These requirements will prevent producers and distributors of boxwood from moving infested plants interstate. State Agricultural Authorities may prescribe additional safeguards and protocols.

All other regulated articles of boxwood, including plant parts, pieces, cuttings, clippings, debris, and any portion of the plant, alive or dead, except for decorative purposes, are prohibited from movement.”

MDAR has recently sent a notice to boxwood growers in Massachusetts of the following:

"Effective May 22, 2024, the USDA has issued a Federal Order establishing a quarantine for the entire state of Massachusetts. In an effort to restrict the movement of box tree moth, boxwoods (Buxus spp.) may no longer be exported from Massachusetts except by an establishment operating under a compliance agreement (CA) to be issued by MDAR. Anyone wishing to register for a CA must go to the Massachusetts Department of Agricultural Resources box tree moth page and click on the EXPORTS link, and fill out the form. An MDAR staff person will follow up within one week. Please note that the quarantine does NOT restrict in-state sales, movement within the state, or import of boxwoods into Massachusetts. If you have any further questions, please feel free to contact either MDAR (taryn.lascola@mass.gov) or USDA (203-741-5641)."

To read the full announcement of the box tree moth quarantine for Massachusetts from MDAR, please visit the Massachusetts Introduced Pests Outreach Blog.

Need information about monitoring and trapping box tree moth? Check out this newly available Box Tree Moth Monitoring & Trapping fact sheet from UMass Extension. 

•  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 using MA DCR’s Massachusetts Elm Zigzag Sawfly Reporting Form. Felicia Hubacz, MA DCR, reports elm zigzag sawfly larvae actively feeding in the Becket, MA population as of 5/28/2024. UMass Extension observed tiny elm zigzag sawfly feeding in the Windsor, MA population on 5/31/2024 (see photos).

Now is the time to search for elm zigzag sawfly larvae actively feeding on their host plants! Please report any suspicious defoliation of elm to the previous reporting link.

• 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.
• Hammerhead Worms: Also known as flatworms or land planarians, belong to Phylum Platyhelminthes (flat worms) rather than Arthropoda (arthropods) which makes them different from insects and their relatives. Class Insecta is the taxonomic classification of the Insects, whereas hammerhead worms belong to Class Turbellaria. A few common species of non-native hammerhead worms noted in New England include but are not limited to: Bipalium kewense, Bipalium adventitium, and Bipalium pensylvanicum. For more information, see this article in Hort Notes on Hammerhead Worms in New England.
  
  Sightings of these organisms have increased in recent years, possibly due to warming winters and wet summers. Hammerhead worms are predators that prefer to feed on earthworms; however, depending upon the species involved, they may not be an effective predator of certain species of jumping worms. Again in 2024, reports of hammerhead worms have come from parts of Massachusetts (in this case, Martha’s Vineyard; see photos) with questions about safety. Hammerhead worms are known to produce a neurotoxin (tetrodotoxin) which they use in self-defense and to subdue prey. Luckily, hammerhead worms do not produce enough tetrodotoxin to be lethal to humans, but if the neurotoxin comes into contact with exposed skin, irritation may occur. It is advised that handling hammerhead worms should be avoided, and hands or exposed skin be washed with soap and water following any accidental contact.
• 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. The MA Department of Agricultural Resources reports that spotted lanternfly egg hatch has begun in Holyoke and Springfield, MA as of 5/14/2024. Now is the time to monitor egg masses and areas nearby for emerging early instar nymphs (immatures). If you believe you have found this insect, please take a photo, note your location, and report it immediately using the Spotted Lanternfly Report Form. 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. Encounters with deer ticks can increase in New England in April, October, and November; however, precautions should be taken year-round to prevent tick bite exposure. 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, Massachusetts risk maps will be available.
• Wasps/Hornets: Many wasps are predators of other arthropods, including pest insects such as certain caterpillars that feed on trees and shrubs. Adult wasps hunt prey and bring it back to their nest where young are being reared as food for the immature wasps. A common such example are the paper wasps (Polistes spp.) who rear their young on chewed up insects. Paper wasps can sting, and will defend their nests, which are open-celled paper nests that are not covered with a papery “envelope”. These open-celled nests may be seen hanging from eaves or other outdoor building structures. Aerial yellow jackets and hornets create large aerial nests that are covered with a papery shell or “envelope”. Common yellow jacket species include those in the genus Vespula. Dolichovespula maculata is commonly known as the baldfaced hornet, although it is not a true hornet. The European hornet (Vespa crabro) is three times the size of a yellow jacket and may be confused for the northern giant hornet (Vespa mandarinia). The European hornet is known to Massachusetts, but the northern giant hornet is not. If you are concerned that you have found or photographed a northern giant hornet, please report it using the MA Department of Agricultural Resources Report Pest Sightings page. Some people are allergic to stinging insects, so care should be taken around wasp/hornet nests. Unlike the European honeybee (Apis mellifera), wasps and hornets do not have barbed stingers and therefore can sting repeatedly when defending their nests. It is best to avoid them and, if that cannot be done and assistance is needed to remove them, consult a professional.

Tree & Shrub Insect & Mite Pest Suggested Scouting:

• Andromeda Lace Bug is most commonly encountered on Japanese andromeda, however other host plants may be impacted. Most activity from this insect occurs between late May through September, with several generations occurring per year. Both nymphs and adults feed on host plant leaf undersides and cause white/yellow-colored spots or chlorosis to occur on host plant leaf surfaces. This image from 5/9/2024 (Boston, MA) shows Pieris japonica ‘Cavatine’ with old andromeda lace bug feeding damage from 2023 and possible winter injury. Samples were submitted to the UMass Extension Plant Diagnostic Lab. As of now, the new growth is starting to show damage as well, after developing without it. Boston, MA was at 132 GDD’s on 5/12/2024 and andromeda lace bug is known to begin activity by 120 GDD’s. (Image courtesy of Susan Shafer.)
• Arborvitae Leafminer moths appear from mid-June to mid-July and lay their eggs. Eggs hatch and larvae enter the leaves where they feed, often unnoticed until January or February when browned leaf tips become more apparent. Feeding from this insect is sometimes confused for winter injury, and vice versa.
• Azalea Lace Bug is a pest of both deciduous and evergreen azaleas (Rhododendron spp.), however resistance has been reported in Rhododendron atlanticum, R. arborescens, R. canescens, R. periclymenoides, and R. prunifolium. The insects feed on host plant leaf undersides, and cause chlorosis on leaf surfaces. Azalea lace bugs are active from 120+ GDD’s throughout the summer.
• Azalea Sawflies is a common name that might refer to three different species of sawflies that feed on azaleas. Adults of Amauronematus azaleae are often present in May and laying eggs which hatch into larvae that typically mature by July 1st. At that time, they finish feeding and drop to the soil to pupate. These green larvae feed on the edges of host plant leaves and may defoliate the plant.
• 
  Bagworm is overwintering on Juniperus spp., Thuja spp., Quercus spp., Platanus spp., and others as 500-1000 eggs can be found in the bags of last season’s deceased females. Warmer areas of Massachusetts that are approaching or at 600 GDD's should be monitoring for bagworm egg hatch NOW! Look for the very small, young caterpillars who nearly immediately begin creating "bags" over themselves tied together with silk and bits of their host plants (leaves, bark, etc.). Early instar caterpillars (below 2/3 inch in length) are very susceptible to Btk (Bacillus thuringiensis Kurstaki). Apply to actively feeding, young caterpillars once all eggs have hatched, but before caterpillars exceed 2/3 inch in length. For great photos of early-instar bagworms, visit The Ohio State University Extension's Buckeye Yard & Garden onLine (BYGL).
   
• Boxwood Leafminer adult emergence occurs by mid-May, with pupal cases left behind clinging to leaves. Boxwood leafminer pupae were found in boxwood leaves in Berkshire County (Dalton, MA) on 5/11/2024. Shake bushes to detect flying adults. Resistant varieties of boxwood are available; see preceding link.
  
  
  
   
• 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. Boxwood psyllids are actively feeding in Berkshire County (Dalton, MA) as seen on 5/11/2024. White, waxy wool created by the insects can be seen in new growth that has already cupped around the insects.

Boxwood psyllid activity may be very noticeable at this time if the population is large enough. Leaves may appear covered in "sticky snow". See photo by JoAnne Palmer taken on 5/23/2024 in Holyoke, MA.

• 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 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 is a species of clearwing moth whose larvae bore not only into dogwood (Cornus), but hosts also include flowering cherry, chestnut, apple, mountain ash, hickory, pecan, willow, birch, bayberry, oak, hazel, myrtle, and others. Kousa dogwood appears to be resistant to this species. Signs include the sloughing of loose bark, brown frass, particularly near bark cracks and wounds, dead branches, and adventitious growth. The timing of adult emergence can be expected when dogwood flower petals are dropping and weigela begins to bloom. Adult moth flights continue from then until September.
• Dogwood Sawfly eggs have hatched and young sawflies are munching their way through dogwood leaves. See photos taken on 5/28/2024 in Chesterfield, MA. Dogwood sawflies are not susceptible to Btk (Bacillus thuringiensis Kurstaki) however, spinosad should be effective on young dogwood sawfly larvae.
• Eastern Tent Caterpillar overwintering eggs hatch in the spring and caterpillars emerge as cherry leaves begin to open. Anecdotally, eastern tent caterpillar activity has been more noticeable in Massachusetts in 2024. Tents and caterpillars in warm locations are large at this time. Many eastern tent caterpillars may have already pupated, however some can still be seen wandering through the landscape as of 5/30/2024.
• 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. Treatments for the crawler, or mobile, stage of this insect may be made in late May through mid-June, or between 360-700 GDD's, base 50F. Nitrogen fertilizer applications may make elongate hemlock scale infestations worse.

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 eggshells 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. By late June, euonymus caterpillars will pupate and the majority of their feeding for the 2024 growing season will be complete.
• 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 Elm Scale is a non-native scale that is widespread in North America on native and European elms, in addition to hackberry and Zelkova. Adult females are black with a ring of white fibers around their bodies and may be found in branch forks or rough/creviced areas of the bark. By the end of June, females will produce eggs that hatch into crawlers. Crawlers will disperse to the underside of elm leaves and leaf midveins to feed.
• European Pine Sawfly eggs have overwintered in slits in last year’s needles. Egg hatch begins in approximately late-April and early May. Young European pine sawfly caterpillars were seen feeding in Berkshire County (Dalton, MA) on 5/11/2024. Look for tiny, gray-green larvae with black heads feeding on favored host plants such as Jack, Japanese red, Mugo, red, Scots, or Table Mountain pine. Sawfly larvae will feed until roughly early June, at which time they drop to the ground to pupate.
• Fletcher Scale is a soft scale pest of yew, juniper, and arborvitae. Feeding scales, especially on yew, result in honeydew and sooty mold, needle yellowing, and at times, premature needle drop. There is one generation per year. Nymphs develop and adult females lay eggs (on average 500-600) in May that hatch by June. Dead females conceal egg masses beneath. Crawlers migrate short distances to branches and may be concentrated on certain branches of a particular plant.  
• 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. In warmer locations of Massachusetts, forest tent caterpillars are large and may be reaching maturity. On 5/21/2024 in Chesterfield, MA, a group of much smaller, younger instar forest tent caterpillars was observed.
  
  
  
  
   
• Grape Plume Moth caterpillars were seen webbing terminal wild grape leaves together as they feed on 5/28/2024 in Chesterfield, MA. These caterpillars rarely occur in large enough numbers to warrant management. The adult moth is a member of Family Pterophoridae and is visually very striking.
• 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 looper caterpillars mature slowly, and may not begin pupation until late July with adults emerging by September and October.
• 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. Hemlock woolly adelgid completes most of its development from October (of the previous season) through June. During the hot summer months (beginning in July), HWA spends its time as a first instar nymph (barely visible) at the base of hemlock needles. During that time, it is in a summertime dormancy known as aestivation.
• Honeysuckle Aphid is the likely culprit causing leaf curling seen in Williamsburg, MA on honeysuckle on 5/17/2024. This European species of aphid was first detected in North America in Quebec in 1976 and Illinois in 1981. Since then, it has been detected in New England and spread rapidly elsewhere in the United States, likely anywhere bush honeysuckle is grown. Green-colored aphids may be found on the newly opened leaves of host plants in the spring. Look for stunted and curled leaves.
• Hydrangea Leaftier caterpillars use silk applied to the edges of two newly expanding hydrangea leaves to tie them together to create an envelope-like structure within which they feed. Search the tips of plant stems. Envelope or purse-like structures may be pulled apart and caterpillars detected within. Caterpillars may mature and pupate by June.
• 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.
•  Oak Shothole Leafminer activity in Massachusetts has alternated between elevated and lacking in certain areas in recent years. Evidence of springtime feeding holes created by adult flies was photographed in Chesterfield, MA on 5/28/2024 along with old, frass-filled leaf mines from the immature feeding larvae. Arborists working in Duxbury, MA also report oak shothole leafminer damage to newly planted oaks on 5/31/24. Mining is reported to occur in the second week in June in Maine, while Ohio reports blotch mine formation by mid-May. 
• Pitch Mass Borer overwinters in the pitch mass found on the host plant. This insect tunnels beneath the bark, into the cambium. It may take up to two years for the pitch mass borer to mature. Pupation typically occurs by the end of May through June, in time for adult clearwing moth emergence in July and August.   
• Privet Thrips are a non-native insect pest of privet, lilac, and ash. Thrips feed on the leaves of privet, causing them to appear gray in color made up of chlorotic spots. Immature thrips may be viewed with magnification on the undersides of host plant leaves. Several generations per year may be possible throughout the summer.
• Redheaded Flea Beetle (Systena frontalis) has been identified as a native pest of nurseries in many locations in the eastern United States. Suspected redheaded flea beetle damage was seen on Ilex crenata 'Dwarf Pagoda' (Dwarf Pagoda Japanese holly) on 3/27/2024 that was purchased in Massachusetts but may have originated in NJ. While identification of this species of insect is uncertain based on host plant damage alone, it appears to be a reasonable and educated assumption. Redheaded flea beetles are known to feed on a wide variety of host plants. These include but are not limited to: cabbage, beans, beets, blueberries, and other agricultural crops as well as Physocarpus, Weigelia, Cornus, Forsythia, Itea, Hydrangea, and Ilex. Adult beetles are active and feed from approximately late-June to mid-September on the upper and lower leaf surfaces of their hosts. This can cause damage that looks like skeletonization and eventually holes in the leaves. Leaves appear covered in brown patches as in these photos. This damage was caused last season on this evergreen plant.
• Rhododendron Borer is one of the smallest of the native clearwing moths. Adult emergence may begin in May and can last through July, depending upon local temperatures. Rhododendron are preferred host plants, with the larvae of this species boring into stems, often near the base of plants. Injured plant parts may be more attractive to these insects.
• Roseslugs is a common name for at least two species of sawflies whose larvae may be found feeding on the foliage of roses. These small larvae will skeletonize the upper leaf surface and leave a “windowpane”-like pattern behind. If present in large numbers, entire shrubs can be defoliated. Monitor for feeding larvae from the end of May through June. Roseslugs are still feeding as of 5/17/2024 in Williamsburg, MA as pictured here.
• Southern Pine Beetle has been trapped in Massachusetts since 2015. By 2022 and 2023, southern pine beetle has reached outbreak conditions in small areas of the state, killing pitch pine (Pinus rigida). (Particularly on Martha’s Vineyard and Nantucket islands in MA.) If you believe you have found infested pitch pine in Massachusetts, please report southern pine beetle using the Massachusetts Southern Pine Beetle Reporting Form from MA DCR.
• 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. In this location, they finish maturing and eggs are retained in the female spruce bud scale body cavity where, eventually, crawlers develop. These immature and mobile crawlers appear by approximately the beginning of June and may remain active through July. They then find suitable locations to settle and begin their feeding on the new growth of the plant. During this time, copious amounts of honeydew (sugary liquid excrement) may be excreted.
• 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 is commonly a pest of Taxus spp. in New England, but can also be found on dogwood, rhododendron, Prunus spp., maple, andromeda, and crabapple. First instar nymphs overwinter, and in April and May it might be difficult to find these insects. However, by mid-June the population can increase considerably. Taxus mealybug feeding can lead to sparse plants covered in honeydew (sugary liquid excrement).
• 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.
• Twospotted Spider Mite season is under way as warm termperatures rise! Populations on many different deciduous and some coniferous hosts may rise from 363-618 GDD's and again from 1300-2000 GDD's. Twospotted spider mites prefer hot, dry conditions in the summer and fall. Population increases and subsequent plant damage can occur under these conditions. Using piercing-sucking mouthparts, mites feed primarily on the underside of host plant leaves and remove fluids. This feeding causes graying or yellowing of the leaves. Necrotic spots can also occur in advanced stages of leaf damage. This may lead to a stippled/bleached appearance of leaves; on occasion, complete defoliation due to spider mite activity is possible under high populations. Twospotted spider mites also create a fine webbing which can be found on infested plants.

Magnification is needed to visually detect twospotted spider mites. At least a 10-15X hand lens is required. The undersides of host plant leaves can be examined for the mites themselves or their shed or cast skins, as well as the fine webbing left behind by spider mites. However, it may be easier to view twospotted spider mites when a branch that is suspected to be infested is shaken or struck over a white piece of paper. See previous link for more details.

• Viburnum Leaf Beetle larvae may be found anywhere on the leaves and usually in groups. When young, larvae feed on the undersides of the leaves. As they grow larger, they may feed on the upper surface. Larval development may take approximately 8-10 weeks to complete and 3 larval instars are reported. Pupae are yellowish and are found in the soil beneath the host plant. Adults emerge around the middle of July and are brown, smaller than the largest larvae (approximately ¼ inch), and will also feed on the leaves. Adults are present in the landscape until the first hard frost.
• White Pine Aphid is a large, black, long-legged aphid found on twigs and small branches of eastern white pine. Search for aphids beginning in May and June. As the season progresses, honeydew and sooty mold may coat branches and needles of the host plant.
• White Spotted Pine Sawyer is a native longhorned beetle that is often confused for the invasive Asian longhorned beetle (see entry above). White spotted pine sawyer adults emerge in late May throughout July in MA. This insect completes its life cycle in weakened or recently dead conifers, particularly eastern white pine (Pinus strobus). It is not a significant pest. However, if you are unsure of the identification of a longhorned beetle, always take a photo and report it. You can report suspicious insects at the MA Department of Agricultural Resources Introduced Species Outreach Project Report a Pest Form.
• 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 apple aphid feeding distortion was seen on new elm foliage on the UMass Amherst campus on 5/1/2024.
• Woolly Beech Leaf Aphid overwinters as eggs in host plant bark crevices near buds. At budbreak, eggs hatch and wool covered aphids begin feeding on host plant leaf undersides (Fagus spp.). Even though aphid populations may be very noticeable, they seldom require chemical management.
• Yellow Poplar Weevil is also known as the sassafrass weevil, the magnolia leafminer, or the tulip tree leafminer. This insect, as all of these common names suggest, feeds on yellow poplar (tulip tree; Liriodendron tulipifera), sassafras (Sassafras albidum), magnolia (Magnolia spp.), as well as bay laurel (Laurus nobilis). Adult beetles lay eggs in the midribs of host plant leaves by May, after which the eggs hatch and larvae feed by creating blotch mines in the leaves. Larvae can be observed in May and June, and adults emerging to feed again by August, prior to overwintering in sheltered areas.

Beneficials/Non-Pests:

• Likely Trichapion Weevil on Robinia spp. was seen in Chesterfield, MA on 5/28/2024. Possibly Trichapion nigrum, the black locust seed weevil was present in noticeable numbers on this host plant. The larval (immature) weevils mine immature seed pods of Robinia. Little attention may be otherwise paid to this insect, but others in this genus are associated with the seeds of wild indigos and false indigos. It does not appear that this insect is considered a pest. That said, some do not prefer to plant black locust to begin with, due to their tendency to spread and possession of sharp spines.

 

• Oak Timberworm Weevil adults are shaped differently than weevils in the Curculionidae (snout and bark beetles) such as species like the black vine weevil or the white pine weevil that we may be more accustomed to dealing with. Oak timberworm weevils (Arrenodes minutus) are in the Family Brentidae (the primitive weevils or straight-snouted and pear-shaped weevils). Adults are found on the bark of dead or dying trees and at lights at night in late spring and early summer. They can take two to three years to develop as larvae. This photo is from "a punky piece of oak firewood" in Swansea, MA on 6/5/2024. (Courtesy of: Jean Aguiar.) These insects do not appear to be the primary cause of decline for their host plants.

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

Landscape Weeds

For information about identification of weeds noted below, check out UMass Extension's Weed Herbarium.

Garlic mustard (Alliaria petiolata): This biennial weed is considered invasive in Massachusetts and other northeast states. Second year plants have completed their flowering period and seedpods are still green. Green seedpods contain seeds that are not mature and lack reproductive ability. An herbicide application now will control the second-year plants before they produce viable seed as well as the first-year seeding plants that are germinating below the canopy of the second-year plants.

Japanese knotweed (Fallopia japonica): Do not attempt to control Japanese knotweed at this time, as herbicide applications are not effective in this early part of the growing season. In preparation for a late season herbicide application, cut or mow stands of knotweed to the ground in late May and early June. This practice is done to facilitate later herbicide application by removing the dried stems from the previous year’s growth and will control plant height to make herbicide treatment easier in late summer. There is also some indication that the plant’s carbohydrate reserves may be reduced with this early season mowing.

Ground ivy (Glechoma hederacea) in turf and landscape: This often “tough-to-manage” weed is currently in full flower or just past full flower. Management of ground ivy is usually not effective during the early part of the growing season. The best control of ground ivy is achieved with an application of a broadleaf turf herbicide product that contains triclopyr in September and October. Ground ivy in landscape beds can be controlled now with a direct-spray application of glyphosate or glufosinate.

Scout for annual weeds in ornamental beds: Recent rainfall and warm weather has pushed summer annual weed germination and establishment along. If a preemergence herbicide was applied earlier in the season, now is a good time to begin determining if the application provided effective control. Treat these weeds before they get too large. Spot spraying with a non-selective herbicide (glyphosate or glufosinate) is usually a better strategy than hand-weeding as it does not break the mulch barrier.

Crabgrass (and other annual grassy weed) management in turf: Monitor turf areas for the emergence of crabgrass and other annual grassy weeds. Routine monitoring should be conducted on all turf areas regardless of whether they received a preemergence herbicide application. After crabgrass has germinated, it can be controlled with several postemergence herbicides. Postemergence herbicides vary in their ability to control crabgrass at different stages of growth (see table below). Determination of the predominant growth stage will dictate the herbicide selection.

Postemergence herbicides for crabgrass control
Postemergence Herbicide	Crabgrass Growth Stage LF = leaf, TL = tiller
	1- to 5-LF	1-TL	2-TL	3-TL	4-TL	5-TL & up
dithiopyr	YES	YES	YES	YES	NO	NO
mesotrione	YES	YES	YES	YES	NO	NO
quinclorac	YES	YES	NO	NO	NO	YES
fenoxaprop	YES	YES	NO	NO	NO	NO

Report by Randy Prostak, Weed Specialist, UMass Extension Landscape, Nursery, and 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, 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.

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