Landscape Message: April 22, 2022

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

Happy Earth Day!  The Landscape Message will be updated once more in April, then weekly in May.  The next message will be posted on April 29. To receive immediate notification when the next Landscape Message update is posted, be sure to join our e-mail list 

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

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Scouting Information by Region

Environmental Data

The following data was collected on or about April 20, 2022. Total accumulated growing degree days (GDD) represent the heating units above a 50° F baseline temperature collected via regional NEWA stations (http://newa.cornell.edu) for the 2022 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	GDD		Soil Temp (°F at 4" depth)		Precipitation (2-Week Gain)	Time/Date of Readings
	2-Week Gain	2022 Total	Sun	Shade
CAPE	15	26	*	*	*	*
SOUTHEAST	29	57.5	60	46	1.65	3:00 PM 4/20
NORTH SHORE	23	42	46	42	1.45	10:00 AM 4/20
EAST	35	65	57	49	2.02	4:00 PM 4/20
METRO	24	41	44	43	2.51	6:00 AM 4/20
CENTRAL	20	34	51	44	2.18	4:00 PM 4/20
PIONEER VALLEY	22	31.5	50	43	4.19	1:00 PM 4/20
BERKSHIRES	18	26	44	38	4.52	8:00 AM 4/20
AVERAGE	23	40	50	44	2.65	_
* = information not available

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.
Cercis canadensis (redbud)	*	*	Begin	Begin	*	*	Begin	*
Amelanchier spp. (shadbush, serviceberry)	*	Full	Begin	Begin	Begin	Begin	Begin	*
Pyrus calleryana (Callery pear)	*	Full	Full	Full	Begin	Begin	Full	Begin
Magnolia soulangiana (saucer magnolia)	*	Full/End	Full	Full	Begin	Begin	Full	Begin
Prunus serrulata (Japanese flowering cherry)	*	*	Full	Full	Begin	Begin	Full	Begin/Full
Rhododendron 'P. J. M.'	*	Full	Begin/Full	Begin/Full	Begin/Full	Begin	Begin/Full	*
Rhododendron mucronulatum (Korean rhododendron)	*	*	Begin	Full	Full	Full	Full	Begin
Magnolia stellata (star magnolia)	*	End	Full	Full	Full	Full	Full	Full
Forsythia x intermedia (border Forsythia)	*	Full/End	Full	Full	Full	Full	Full	Full
Pieris japonica (Japanese pieris)	*	Full	Full	Full	Full	Full	Full	Begin/Full
* = no activity to report/information not available

Regional Notes

Cape Cod Region (Barnstable)

There is no report this week.

Southeast Region (Dighton)

General Conditions: The weather has been pleasant with day temperatures above freezing and frequent rain showers. Lawns are green and growing. Honey bees, bumble bees, cabbage white butterflies, flies, blackflies, slugs, and centipedes were observed. Plants seen in flower include: Acer platanoides (Norway maple), Acer rubrum (swamp red maple), Amelanchier canadensis (shadblow, serviceberry), Cydonia oblonga (quince), Forsythia x intermedia (border forsythia), Lindera benzoin (spicebush), Leucojum aestivum (snowflake), Lunaria annua (honesty), Magnolia soulangeana (saucer magnolia), M. stellata (star magnolia), Muscari sp. (grape hyacinth), Narcissus spp. (daffodils), Pieris japonica (Japanese andromeda), Prunus persica (peach), P. cerasifera (plum), P. x subhirtella (Higan cherry), Pulmonaria officinalis (lungwort), Pyrus calleryana (Callery pear), Rhododendron 'PJM', Trillium grandifolia (white trillium), Tulipa (tulip), Viburnum carlesii (Korean allspice viburnum), Viola sororia (common violet) and V. tricolor (annual pansy).

Pests/Problems: Weeds that are blooming include: Alliaria petiolata (garlic mustard), Glechoma hedera (ground ivy), Lamium amplexicaule (henbit), Stellaria media (chickweed), and Taraxacum officinale (dandelion).

North Shore (Beverly)

General Conditions: The weather pattern in the last two weeks has been variable but on the cooler side, fluctuating from overcast and rainy days to clear sky and sunny days. There were also a lot of temperature fluctuations, ranging from low 30s to low 70s. The average daily temperature in the last two weeks was 48˚F with a minimum of 33˚F and maximum of 71˚F. Winds have been very strong on some of the days making it feel much colder. Approximately 1.45 inches of rain were received at Long Hill during this period with most of the rainfall occurring on Tuesday, April 19. Soils are moist and turf grass is greening up, growing fast and almost reaching mowing height. Woody plants seen in bloom include: Merrill magnolia (Magnolia x loebneri ‘Merrill’), Japanese pieris (Pieris japonica), weeping higan cherry (Prunus subhirtella), star magnolia (Magnolia stellata), cylindrical magnolia (Magnolia cylindrica), Sargent cherry (Prunus sargentii), Giraldi forsythia (Forsythia giraldii) and mountain pieris (Pieris floribunda). Spring flowering herbaceous plants in full bloom include: daffodils (Narcissus spp.), bloodroot (Sanguinaria canadensis), hellebores (Helleborus orientalis), and vinca (Vinca minor).

Pests/Problems: Annual weed seeds continue to germinate. Yellow buttercup weed (Ranunculus ficaria) has started to form masses of green carpets and is in bloom. Garlic mustard (Alliaria petiolata) is beginning to bloom. Norway maple (Acer platanoides) which is classified as an invasive plant is also in full bloom. No major pest activity was observed but ticks are active. It is important to protect yourself when working outdoors with a repellent such as DEET.

East Region (Boston)

General Conditions: Over the past two weeks, daytime temperatures averaged 60ᐤF while overnight lows averaged 41ᐤF. We had a daytime high of 73ᐤF on April 13th and an extreme low of 33ᐤF overnight on the 17th. Saturday April 9 was an unusual weather day; we had sun, two separate pea-sized hail events, clouds, thunder, wind, more sun and a rainbow over Franklin Park. We received a total of 2.02 inches of precipitation over the two week period for a total of 2.61 inches for April. Turf continues to green up. Forsythia spp., early Magnolia spp., early Prunus spp. (cherry), Pieris japonica (Japanese andromeda) and PJM rhododendrons continue to add color to the landscape. Also in bloom are Corylopsis spp. (winter hazel), Lindera benzoin (spicebush, see Plant of the Week below) and Rhododendron praevernum (February rhododendron). Take a closer look at Acer japonica spp. (Japanese maple) - many are in flower. Cercis chinensis (Chinese redbud) is in full bloom. It’s native to central and southern China, similar to our native Cercis canadensis (redbud), but more heat and drought tolerant with profuse showy clusters of darker pink flowers.

Pests/Problems: Temperature fluctuations continue to keep a big burst of spring at bay. Most plants are slowly coming along unscathed by the drastic overnight lows with minimal damage to new growth. Winter annuals continue to thrive. Cardamine hirsuta (hairy bittercress) is in flower and producing seed and garlic mustard (Alliaria petiolata) second year rosettes are fully developed. Ficaria verna (lesser celandine) has emerged and is flowering in sunny locations. The red shoots of Japanese knotweed (Polygonum cuspidata) have emerged and range from one to six inches tall. The recognizable chartreuse foliage of the invasive Norway maple (Acer platanoides) can be seen emerging throughout the canopy even as last year’s seed bank seedlings are emerging below.

Metro West (Acton)

General Conditions: Happy Earth Day! This year marks its 52nd anniversary. The landscape is filled with activity and color. Lawns are greening up and leaf and flower buds are expanding and opening. Daytime temperatures are climbing, a high of 74°F was recorded on the 13th, and evening temperatures continue to fall below freezing. Frost and a thin layer of ice were found on my car windshield and bird bath on the morning of the 18th. As of the 19th, some amount of precipitation has been recorded for every day but 4 for the month of April. On the 9th, not only was there 0.38” of rain recorded but also pea sized hail accompanied with thunder and lightning was noted. On the 19th, 1.02” of rain was recorded as well as wind gusts up to 31 mph. The driving rain and strong winds woke me and others at 4am that morning. The average rainfall total for the month of April is 4.16” and I have recorded a total of 2.94” of rain in this area for this month so far. The landscape is lit up with color and in some stage of bloom at this time are the following woody plants: Magnolia x loebneri 'Merrill', (Merrill magnolia), M. x soulangeana (saucer magnolia), Prunus spp. (cherry), Pyrus spp. (pear), and Rhododendron 'P. J. M.' (PJM rhododendron). Contributing even more color and interest to the landscape are some flowering herbaceous plants and spring ephemerals including: Anemone nemorosa (wood anemone), Asarum europaeum (European ginger), Chionodoxa luciliae (glory of the snow), Crocus spp. (crocus), Helleborus niger (Christmas rose), Hepatica spp. (liver leaf), Hyacinthus spp. (hyacinth), Mertensia virginica (Virginia bluebells), Muscari sp. (grape hyacinth), Narcissus spp. (daffodil), Omphalodes verna (blue-eyed Mary), Pachysandra procumbens (Allegheny spurge), Petasites japonicus (Japanese butterbur), Primula spp. (primrose), Pulmonaria longifolia (lungwort), P. rubra (salmon colored lungwort), Puschkinia libanotica (striped squill), Sanguinaria canadensis (bloodroot), Scilla siberica (Siberian squill), Symplocarpus foetidus (skunk cabbage), Vinca minor (periwinkle) and Viola spp. (violet).

Pests/Problems: Acer platanoides (Norway maple) is in full bloom. This invasive tree is hard to miss now that it is in bloom and its flowers are a bright yellowish-green and are easily seen on a tree found growing almost everywhere. Another problem plant seen flourishing is the basal foliage of Alliaria petiolata (garlic mustard). Other weeds seen in bloom but without the invasive tendency of the previous two mentioned are: Draba verna (spring whitlow grass), Glechoma hederacea (ground ivy), Lamium purpureum (purple deadnettle), Stellaria media (common chickweed), and Taraxacum officinale (dandelion).

Central Region (Boylston)

General Conditions: This reporting period gave us the typical highs and lows associated with mid-April in New England. Cooler temperatures have been persistent, especially overnight; high temperatures reached the low-70’s, and precipitation was average for the period. Much has come into bloom over the last two weeks, including many native and non-native species of rhododendron, flowering cherries like Prunus subhirtella ‘Autumnalis’, and early-blooming woodland perennials like wood poppy (Stylophorum diphyllum). Rainfall during the period came in both bursts of heavy precipitation and long, slow soaking drizzle, making soils adequately moist.

Pests/Problems: Generally, very few pest problems have been observed so far this spring. Winter damage to evergreen trees and shrubs is now quite apparent. Ticks, slugs, and mosquitoes are all active.

Pioneer Valley Region (Amherst)

General Conditions: Spring is charging forward in the Pioneer Valley, despite the recent plunge in temperatures. We had an incredible stretch of warm weather from 4/12 through 4/15, with high temperatures in the upper 60s to low 70s and vivid sunshine. Soil temperatures responded to the warm weather, illustrated by readings taken on the afternoon of 4/14 (shade = 49°F and full sun = 57°F). The warm-up pushed a lot of plants into either flowering, new growth or bud swelling. Then a persistent cold front descended upon the region and temperatures plummeted well below average. Scattered snow flurries and gusty winds dominated during Easter Sunday and the low temperature on the morning of 4/18 cratered at 28°F in Easthampton, but most blooms appear to have weathered the freeze and continue to shine. Cool temperatures during the spring flowering period do prolong the display. We had two major rain events over this past reporting period. The first was a four-day stretch (4/6–4/9) of scattered showers that deposited >2” of precipitation. A late season nor’easter on 4/18–19 spared the valley of snow and the damaging winds but we recorded well over 1” of rain. Soils remain wet and have cooled off dramatically since the mid-month warmup. Nurseries are fully stocked and the planting season is well underway. Despite the high soil moisture, this is a good time to get plants into the ground while the soils are still cool and new growth has yet to emerge. Turfgrass is greening and growing in sunny and shaded sites now. We are entering the time to treat lawns and landscape beds for grubs.

Pests/Problems: Evidence of winter injury is very clear at this time. A number of rhododendrons, both established and recently planted, have been observed with moderate to serious damage. Other plants in the landscape with visible winter injury include: American holly (Ilex opaca), Andromeda (Pieris japonica), azalea (Rhododendron spp.), boxwood (Buxus spp.), false-cypress (Chamaecyparis spp.), dwarf Alberta spruce (Picea glauca ‘Conica’) and emerald green arborvitae (Thuja occidentalis 'Smaragd’). Snowball aphid (Neoceruraphis viburnicola) activity has begun on emerging foliage of various viburnum species. Insecticidal soap or horticultural oil can be used to control the aphids at this time. Overall, this early season pest does not leave any lasting injury but can reduce their aesthetic value. Cankering fungi can be active anytime temperatures are warm enough for growth and spread. Continue to identify and prune out dead stems and branches in trees and shrubs. For thin-barked trees, such as beech, Japanese maple, dogwood, and Japanese snowbell, reducing inoculum in the canopy is important to maintain low disease levels. Japanese maples are starting to leaf out and new shoot production will soon follow. Mosquitoes emerged during the warm conditions last week but have since retreated with the onset of below-average temperatures. Ticks remain a serious problem in the valley and getting into the regular habit of checking yourself, kids and pets for ticks can help to catch these parasites.

Berkshire Region (Great Barrington)

General Conditions: The weather pattern over the past 2 weeks has been one characterized by dramatic changes. The temperature on April 14 reached a high of 74ᐤF as recorded at the Pittsfield Airport. On the 17th, a light frost occurred as temperatures dropped to an overnight low of 32ᐤF. On the following day, the low was 29ᐤF. Snow flurries occurred on and off throughout the day on April 17, 18 and 19th. Most melted when hitting the ground. However, snow did accumulate up to 3 inches or more at the higher elevations and in the northern part of the county. Some precipitation occurred on 10 of the 14 days from April 6-20. Of course, soils are quite moist and saturated in some areas. This was particularly evident on lawns with slight depressions. Turfgrass growth now is rapid and has reached mowing height in most managed landscapes. Most spring flowering bulbs are displaying their colorful bloom.

Pests/Problems: Other than black-legged ticks, there is little or no pest insect activity currently. The most prominent problems in the landscape are “winter burn” or browning of foliage on needled and broadleaf evergreens, and damage from persistent winds. Fallen tree limbs and downed trees have been common throughout the winter and now in spring. Weed growth has accelerated. One prominent weed, especially in woodlots and in shaded areas of managed landscapes is garlic mustard (Alliaria petiolata). The seeds of this biennial germinate in late winter (February-early March). The second-year plants will be coming into bloom soon if they have not already flowered. 

Volutella leaf blight, caused by the fungus Volutella pachysandrae, was observed on Pachysandra. Prompt removal of diseased Pachysandra plants is advised to prevent spread of the disease. Some rodent damage to young trees has been observed. This occurs mostly where grass or other herbaceous vegetation grows right around the trunk of a tree. This is a reminder to protect young trees with tree guards and to maintain vegetation-free zones around trees in lawns and other landscape settings.

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 reporting from Tower Hill Botanic Garden, 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

Upcoming workshop: White Pine Health and the Impacts on Lumber Workshop

Friday June 3rd, 2022: 1–4 pm at the UNH Sawmill in Durham, NH ($20 registration required)

Join in for a unique examination of white pine from stump to board at the UNH Sawmill. Presenters will walk you through assessing white pine health and defects in the forest, examining logs on the landing, and sawing lumber at the sawmill to see the impacts white pine disease, pests and defects have on lumber.

This event is co-sponsored by the Eastern White Pine Management Institute, a collaborative effort between the University of New Hampshire Cooperative Extension, University of Maine, and University of Massachusetts to expand existing knowledge on Eastern white pine management and make available training to natural resource professionals.

 

Recent pests and pathogens of interest seen in the UMass Extension Plant Diagnostic Lab, a select few.  http://ag.umass.edu/diagnostics

• Edema will likely be a problem for certain evergreen trees and shrubs this growing season. From April through October 2021, the Commonwealth recorded 41.7” of rain (statewide average), a new record amount for this seven month period. Yew (Taxus), boxwood (Buxus), rhododendron (Rhododendron), among other evergreens can be sensitive to excess soil moisture. Many landscapers are well aware of which plants don’t tolerate “wet feet''. Edema develops when moisture is taken up by the roots at a rate faster than what the canopy can use during transpiration and respiration. If conditions are hot, then a great deal of the water is used for cooling during transpiration. But as temperatures cool in the fall, transpirational water loss decreases. In an attempt to expel this excess water, brown-colored, corky growths can appear on leaves (typically the underside) and stems. Chlorosis, canopy thinning and dieback can also develop. If yews, boxwoods and rhododendrons appear unthrifty, check for symptoms of edema and consider soil drainage in that particular location. Also ensure that irrigation systems are not running during periods of high rainfall. When edema is caused by overwatering, this can be corrected. But when plants are irrigated during naturally wet periods, this amplifies the problem and can significantly contribute to decline and death.
• Death of a Split Rock Hinoki false-cypress (Chamaecyparis obtusa ‘Split Rock’) due to winter injury, deep planting and poor root form. The tree was approximately 20-years-old and has been present at the site (zone 6A) for at least 10 years. In February, the homeowner noticed the needles appeared desiccated and felt dry to the touch. During the month of March, the canopy became tan to brown in color, indicating the tree was dead. Despite being established for over a decade, the tree was very easy to remove. Examination of the roots confirmed the tree was planted several inches too deep and the roots were not properly distressed and reoriented at the time of planting. The record-setting rainfall during the ’21 growing season may have been stressful, as C. obtusa doesn’t tolerate wet soils very well (in most cases). The tree had been thriving and this was an inglorious end for a remarkable ornamental conifer. A nearby C. obtusa ‘Gemstone’, planted in October of ’21, also died over the winter. However, four other C. obtusa on the property (‘Sunny Swirl’, ‘Gracilis’, ‘Nana Lutea’ and ‘Tetragona Aurea’) exhibited no symptoms of winter injury this spring.
• Armillaria root rot of a mature rhododendron (Rhododendron sp.). The plant is one of several in a very old group, established at the property for roughly 40 years. The site includes filtered sunlight and well-drained soils. The plants had been doing well for many years, prior to 2020 when decline symptoms developed. Leaf wilting/browning and canopy dieback has intensified since that time. A section of the main stem was submitted and there was significant white rot at the base with rhizomorphs present. Stems and small branches submitted were harboring opportunistic cankering fungi common on rhododendron (Phomopsis and Pestalotiopsis). Armillaria has an extremely broad host range and is capable of attacking nearly all woody plants.
• Isolated lower canopy dieback of red spruce (Picea rubens) due to needle cast caused by Rhizosphaera kalkhoffii and Septorioides strobi. There was also a minor eastern spruce gall adelgid infestation causing some shoot tip dieback. The tree is believed to be 12-years-old and has been present at the site for five years. It was planted as an understory tree where it receives about six hours of filtered sun in well-drained, sandy loam soils. Symptoms of needle blight developed in the lower canopy of the northeast side of the tree last growing season. Only ~5% of the canopy is symptomatic at this time. While Rhizosphaera is common on a variety of landscape spruce, Septorioides is primarily found on pines, but can attack other members of the Pinaceae. An uncommon ornamental, red spruce can survive in heavy shade but like many spruce species, requires full sun to perform its best.
• Needle tip browning and scattered shoot dieback within an arborvitae (Thuja occidentalis) hedge caused by an infestation of the arborvitae leafminer (Argyresthia thuiella; ALM) and secondary needle/stem blight by Pestalotiopsis. The plants are approximately 30-years-old and the hedge has been established for 20 years. The trees receive full sun in a landscaped bed with moderately well-drained soils. However, the side facing the adjacent residential property was aggressively sheared by a neighbor. The submitted sample showed a serious infestation of the ALM with an abundance of blighted needle tips with exit holes where the adult moths emerged. Typically, when ALM infestations are significant, there is subsequent needle and stem blight by fungal pathogens like Pestalotiopsis. The home has not been a primary residence since the pandemic began and the problem was not detected until the infestation was unmistakable.
• Severe needle loss of blue spruce (Picea pungens) caused by Rhizosphaera kalkhoffii. The tree is around 20-years-old and has been present at the site for >15 years. The tree receives significant sun in loamy-clay soils. It has several neighboring plants, including a sugar maple on the south side. The submitted shoots had needles with brown tips that when incubated, prompted Rhizosphaera to sporulate from the infected needles.

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

Insects

An Update about Neonicotinoid Use in Massachusetts:

Beginning July 1, 2022 systemic insecticide active ingredients known as neonicotinoids will become state restricted use for tree and shrub uses in Massachusetts. If an individual works in the commercial industry (landscapers, arborists, etc.), then a Commercial Certification License is needed. (Example: Category 36 Commercial Certification License, Shade Trees & Ornamentals.) Someone can use a state or federal restricted use pesticide if they have a Commercial Applicators License as long as they are working under the direct supervision of someone with a Commercial Certification. Unlicensed or uncertified individuals will no longer be able to apply neonicotinoids to manage insect pests of trees and shrubs in Massachusetts.

More information is available, here: https://www.mass.gov/service-details/pesticide-newsupdates

Interesting Insects Reported Recently:

• Katydid Eggs: insects in the family Tettigoniidae are referred to as katydids, due to the sounds certain species make when communicating. (Each species has their own unique way of communicating, and not all katydids sound like they are saying “Katy did, Katy didn’t!” on repeat.) They are closely related to the crickets and grasshoppers, and as such another common name for these insects are bush crickets. Many species are green and well camouflaged to hide nearby plants and are seldom seen and more often heard. (They are typically found in trees and not on the ground.) On occasion, a pink katydid is seen with much excitement. Katydid females will lay eggs on the soil, plant stems, or on tree bark. The egg stage overwinters. Katydid eggs were recently observed in Norfolk County, MA and reported on April 11, 2022. Eggs hatch and nymphs emerge, which eventually develop into adults. (Katydids have incomplete metamorphosis, so no pupal stage occurs.) Most katydids feed on plant material, but rarely cause any notable or noticeable damage to their host plants. As such, these insects should be preserved in our landscapes.

Insects and Other Arthropods

• Deer Tick/Blacklegged Tick: Ixodes scapularis adults have been active all winter, as they typically are from October through May, and “quest” or search for hosts at any point when daytime temperatures are above freezing. Engorged females survive the winter and will lay 1,500+ eggs in the forest leaf litter beginning around Memorial Day (late May). For images of all deer tick life stages, along with an outline of the diseases they carry, visit: https://web.uri.edu/tickencounter/species/blacklegged-tick/ .

Anyone working in the yard and garden on springtime cleanup and planting should be aware that there is the potential to encounter deer ticks. The deer tick or blacklegged tick can transmit Lyme disease, human babesiosis, human anaplasmosis, and other diseases. Preventative activities, such as daily tick checks, wearing appropriate clothing, and permethrin treatments for clothing (according to label instructions) can aid in reducing the risk that a tick will become attached to your body. If a tick cannot attach and feed, it will not transmit disease. For more information about personal protective measures, visit: https://web.uri.edu/tickencounter/prevention/protect-yourself/

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

 

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

Invasive Insects & Other Organisms Update:

• Spotted Lanternfly: (Lycorma delicatula, SLF) is a non-native, invasive insect that feeds on over 103 species of plants, including many trees and shrubs that are important in our landscapes. It overwinters as an egg mass, which the adult female insect lays on just about any flat surface. Pictures of egg masses can be seen here: https://massnrc.org/pests/linkeddocuments/SLFChecklistForResidents.pdf .

The MA Department of Agricultural Resources (MDAR) recently released the following “Notice to Nursery and Landscape Industry” regarding spotted lanternfly, an excerpt of which is included here:

Last year, the Massachusetts Department of Agricultural Resources (“MDAR”) detected populations of the invasive pest known as spotted lanternfly (Lycorma delicatula) in multiple locations throughout the state. Since this is the time of year that nurseries are receiving shipments of stock for the spring planting season, we are sending this notice to remind growers and landscapers to inspect any plant material coming from states where SLF has been found, to ensure it does not harbor SLF egg masses, and to report any finds to MDAR. This reminder is especially important as MDAR has recently received several reports that nursery stock from SLF-infested areas was sent to Massachusetts growers.

To read the FULL NOTICE, visit: https://massnrc.org/pests/blog/?p=2933 .

Currently, the only established populations of spotted lanternfly in Massachusetts are in a small area in both Fitchburg and Shrewsbury, MA. Therefore, there is no reason to be preemptively treating for this insect in other areas of Massachusetts. If you suspect you have found spotted lanternfly in additional locations, please report it immediately to MDAR here: https://massnrc.org/pests/slfreport.aspx . If you are living and working in the Fitchburg and Shrewsbury areas, please be vigilant and continue to report anything suspicious.

For More Information:

From UMass Extension:

Check out the InsectXaminer Episode about spotted lanternfly adults and egg masses! Available here: https://ag.umass.edu/landscape/education-events/insectxaminer

Fact Sheet: https://ag.umass.edu/landscape/fact-sheets/spotted-lanternfly

From the MA Department of Agricultural Resources:

Fact Sheet and Map of Locations in MA: https://massnrc.org/pests/pestFAQsheets/spottedlanternfly.html

• Asian Longhorned Beetle: (Anoplophora glabripennis, ALB) Look for signs of an ALB infestation which include perfectly round exit holes (about the size of a dime), shallow oval or round scars in the bark where a female has chewed an egg site, or sawdust-like frass (excrement) on the ground nearby host trees or caught in between branches. Be advised that other, native insects may create perfectly round exit holes or sawdust-like frass, which can be confused with signs of ALB activity.

The regulated area for Asian longhorned beetle is 110 square miles encompassing Worcester, Shrewsbury, Boylston, West Boylston, and parts of Holden and Auburn. If you believe you have seen damage caused by this insect, such as exit holes or egg sites, on susceptible host trees like maple, please call the Asian Longhorned Beetle Eradication Program office in Worcester, MA at 508-852-8090 or toll free at 1-866-702-9938.

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

• Browntail Moth: Euproctis chrysorrhoea is an invasive insect originating from Europe and first detected in the US in Somerville, MA in 1897. Currently, browntail moth is limited to a small portion of eastern Massachusetts, particularly areas near the coast. Scout for the tightly wrapped winter webs which have overwintering caterpillars within by looking at the tips of host plant branches. Report suspected browntail moth webs here: https://massnrc.org/pests/pestreports.htm . Due to a persistent outbreak of this insect in Maine since approximately 2016, it is a good idea for us to again familiarize ourselves with this pest. (For more information and the latest updates about the status of this insect in Maine, visit: https://www.maine.gov/dacf/mfs/forest_health/invasive_threats/browntail_moth_info.htm .)

Caution: hairs found on the caterpillar and pupal life stages of this insect can cause a rash similar to poison ivy. Some individuals are very sensitive to browntail moth hairs and may also experience allergic reaction. The chance of interacting with browntail moth hairs increases between May and July, although they could be a problem at any time of year.

The larval or caterpillar stage of this insect is present from August until the following June (spending the winter in webs they create on the tips of host plant twigs). In the fall, groups of caterpillars are found creating webs around a tightly wrapped leaf (covered in bright white silk) where they will overwinter in groups of 25-400. These 2-4 inch long webs can be found on the ends of branches often on apple or red oak. As soon as leaves begin to open in the spring (usually by April), the caterpillars will crawl from their webs to feed on the new leaves. Caterpillars are fully grown around June and spin cocoons in which they pupate. These cocoons are also full of the irritating hairs and should be dealt with extreme caution. Adult moths emerge in July and females lay eggs on the undersides of leaves in masses of 200-400, covering them with hairs from their bodies. (Adults do not typically cause skin rashes.) Eggs hatch around August and September and larvae feed shortly before forming their overwintering webs.

The primary concern with this insect are the poisonous hairs found on the caterpillars. Contact with the caterpillar or its hairs can cause a rash similar to poison ivy in susceptible individuals. If hairs break off and blow around in the wind, they can cause difficulty breathing and headaches. While this insect can act as a defoliator in the larval stage, feeding on the leaves of many deciduous trees and shrubs, this activity may be secondary to concerns about public health risks. Care should be taken to avoid places infested with these caterpillars, exposed skin or clothing should be washed, and the appropriate PPE should be worn if working with these insects. Consult your physician if you have a reaction to the browntail moth.

• Emerald Ash Borer: (Agrilus planipennis, EAB) has been detected in at least 11 out of the 14 counties in Massachusetts. A map of these locations across the state may be found here: https://ag.umass.edu/fact-sheets/emerald-ash-borer . Additional information about this insect is provided by the MA Department of Conservation and Recreation, here: https://storymaps.arcgis.com/stories/b60f63199fa14805a8b9f7c82447a25b .

This wood-boring beetle readily attacks ash (Fraxinus spp.) including white, green, and black ash and has also been found developing in white fringe tree (Chionanthus virginicus) and has been reported in cultivated olive (Olea europaea). Signs of an EAB infested tree may include D-shaped exit holes in the bark (from adult emergence), “blonding” or lighter coloration of the ash bark from woodpecker feeding (chipping away of the bark as they search for larvae beneath), and serpentine galleries visible through splits in the bark, from larval feeding beneath. It is interesting to note that woodpeckers are capable of eating 30-95% of the emerald ash borer larvae found in a single tree (Murphy et al. 2018). Unfortunately, despite high predation rates, EAB populations continue to grow. However, there is hope that biological control efforts will eventually catch up with the emerald ash borer population and preserve some of our native ash tree species for the future. For an update about the progress of the biological control of emerald ash borer, visit Dr. Joseph Elkinton’s archived 2022 webinar now available here: https://ag.umass.edu/landscape/education-events/invasive-insect-webinars .

• Spongy Moth: Lymantria dispar egg masses will be seen overwintering on just about any flat surface, including host plants such as oak, but also fencing, buildings, steps, outdoor furniture, and more. The end of winter and start of spring is a good time to scout properties, particularly in areas of Berkshire County, MA that experienced elevated L. dispar populations in 2021. If large numbers of egg masses are seen, plan to monitor them between 90-100 growing degree days (roughly the first week in May, but this varies) to better time egg hatch and caterpillar emergence. If egg masses are plentiful near high-value specimen trees in Berkshire County in 2022, consider applying the reduced risk insecticide Bacillus thuringiensis Kurstaki (Btk) to host plant leaves before caterpillars are over ¾ inch in length.

Why did the common name for Lymantria dispar change recently? More information is available here: https://entsoc.org/news/press-releases/spongy-moth-approved-new-common-name-lymantria-dispar .

• Winter Moth: (Operophtera brumata) data since 2017 has indicated that the winter moth population in eastern Massachusetts has been on the decline while the percent of winter moth pupae parasitized by Cyzenis albicans has increased! Dr. Joseph Elkinton’s laboratory at UMass Amherst has released this biological control of winter moth since 2005 and conducted the rigorous sampling required to determine where the insect has established and what its impact on the winter moth population has been at multiple sites in eastern MA. More information about the Elkinton Lab’s research and the biological control of winter moth can be found here: https://www.fs.fed.us/foresthealth/technology/pdfs/FHAAST-2018-03_Biology_Control_Winter-Moth.pdf .

The take-home point? Do not worry about winter moth this spring! In fact, management of this insect in landscaped settings will likely not be necessary in most locations. Blueberry and apple growers may still, on the other hand, be interested in scouting and continuing to monitor for this insect, as only very low numbers of winter moth caterpillars might be tolerated in those systems. For an April 16, 2022 (NEW since the previous Landscape Message) update about winter moth in blueberry and apple production from Heather Faubert, University of Rhode Island, visit: https://web.uri.edu/ipm/2022/04/2667/ .

In recent years, it is worthwhile to note that some areas on the Cape and other locations in eastern MA have reported noticeable cankerworm populations in the spring, which are often confused for winter moth. Read more about cankerworms in the spring scouting list below.

• Jumping Worms: Amynthas spp. earthworms, collectively referred to as “jumping or crazy or snake” worms, overwinter as eggs in tiny, mustard-seed sized cocoons found in the soil or other substrate (ex. compost). The tiny, impossible to remove cocoons will overwinter and provide a population of these earthworms in the 2022 season.

For More Information:

UMass Extension Fact Sheets:

Earthworms in Massachusetts – History, Concerns, and Benefits: https://ag.umass.edu/landscape/fact-sheets/earthworms-in-massachusetts-history-concerns-benefits

Jumping/Crazy/Snake Worms – Amynthas spp.:

https://ag.umass.edu/landscape/fact-sheets/jumpingcrazysnake-worms-amynthas-spp

A Summary of the Information Shared at UMass Extension’s Jumping Worm Conference in January 2022:

https://ag.umass.edu/news-events/highlights/jumping-worms-conference

 

Spring Scouting Suggestions & Preparation for Upcoming Tree & Shrub Insects:

• Bagworm: Thyridopteryx ephemeraeformis is a native species of moth whose larvae construct bag-like coverings over themselves with host plant leaves and twigs. This insect overwinters in the egg stage, within the bags of deceased females from last season. Eggs may hatch and young larvae are observed feeding around mid-June, or roughly between 600-900 GDD’s. Now is the time to scout for and remove and destroy overwintering bags. More information can be found here: https://ag.umass.edu/landscape/fact-sheets/bagworm

• Balsam Twig Aphid: Mindarus abietinus overwinters as a silvery colored egg on host plant twigs. Eggs hatch just prior to budbreak and nymphs feed for a period of time on the undersides of last season’s needles before molting into a wingless stem mother. Stem mothers move to buds just as they open and give “live birth” to second generation nymphs. These second generation nymphs are the most damaging, feeding on new needles as they elongate, causing distortion and stunting. Excessive amounts of honeydew may be produced and cause needles to stick together. Foliar applications, if needed, may be made between 30-100 GDD’s, base 50°F on warm days before budcaps loosen. Inspect the twigs, near the base of needles of Balsam fir, Fraser fir, and other true firs for overwintering eggs and eventually the needles for feeding nymphs. This insect may be most problematic in Christmas tree production. In landscapes, many natural enemies can provide adequate management of this insect.

• Black Turpentine Beetle: Dendroctonus terebrans adults may begin to be active between mid-April to mid-May. Host plants include: black pine (Pinus thunbergiana), eastern white pine (Pinus strobus), Japanese black pine (Pinus thunbergii), loblolly pine (Pinus taeda), pitch pine (Pinus rigida), red spruce (Picea rubens), Scots pine (Pinus sylvestris), and slash pine (Pinus elliottii).

This is one of the largest native North American bark beetles. In the northern parts of its extensive range, the black turpentine beetle overwinters as an adult in the bark of its hosts. In the southern portions of its range, all life stages may be present throughout the year. Egg laying and feeding is usually kept to the basal 6 feet of the host plant. Mated pairs of adult beetles work to excavate galleries that may be 9.8 inches wide and 11.8 inches long. 100-200 eggs may be laid on one side of the gallery. Once hatched, larvae feed in groups on the inner bark. Fully grown larvae are legless, white, and almost 1/2 inch in length. Pupation occurs and adults eventually emerge from the bark to re-infest the same tree, or disperse to another susceptible host.

Stumps and buttress roots of freshly cut trees are favored by this insect. Attacked trees may exhibit browning of needles and oozing of large masses of pitch. Masses of pitch (pitch tubes) may cover holes in the trunk and may be considerably larger than those of southern pine beetle. Pitch hardens and is first white but may turn red as it ages. Pitch is irregular in shape and up to 1.6 inches in diameter. Pitch tubes are not visible when the area below the soil line is attacked. Healthy trees are usually not attacked, however it has been reported on occasion.

Check drought-stressed or otherwise stressed trees for needles turning light green to rust color. Check the lower 6 feet, particularly the lower 18 inches of the trunk for 1.6 inch in diameter pitch tubes or small entrance holes from the adults. Reddish-brown boring dust may be found near the base of the tree as well.

• Boxwood Leafminer: Monarthropalpus flavus partly grown fly larvae overwinter in the leaves of susceptible boxwood. Yellowish mines may be noticeable on the undersides of leaves. This insect grows rapidly in the spring, transforming into an orange-colored pupa. After pupation, adults will emerge and white colored pupal cases may hang down from the underside of leaves where adults have emerged. Adults may be observed swarming hosts between 300-650 GDD’s, or roughly the end of May through June. Most cultivars of Buxus sempervirens and B. microphylla are thought to be susceptible. If installing new boxwoods this spring, resistant cultivars such as ‘Vardar Valley’ and ‘Handsworthiensis’ are good choices at sites where this insect has been a problem.

• Boxwood Mite: Eurytetranychus buxi overwinter as tiny eggs on boxwood leaves and hatch mid-spring. These mites are tiny (about the size of a period) and difficult to detect. Feeding may cause plants to appear off-color. If management is deemed necessary, the timing for treatment may be between 245-600 GDD’s or roughly the beginning of May.

• Boxwood Psyllid: Psylla buxi feeding can cause cupping of susceptible boxwood leaves. Leaf symptoms/damage may remain on plants for up to two years. English boxwood may be less severely impacted by this pest. Eggs overwinter, buried in budscales, and hatch around budbreak of boxwood. Eggs may hatch around 80 GDD’s. While foliar applications may be made between 290-440 GDD’s, the damage caused by this insect is mostly aesthetic. Therefore, typically, management is not necessary.

• Cankerworms: Alsophila pometaria (fall cankerworm) and Paleacrita vernata (spring cankerworm) are often confused for winter moth (Operophtera brumata). Cankerworm populations in eastern MA, particularly on areas of Cape Cod, were confused for winter moth in 2019. Spring cankerworm adults are active in February and March, and fall cankerworm adults are active in late November into early December. During these times, both species lay eggs. These native insects most commonly utilize elm, apple, oak, linden, and beech. Eggs of both species hatch as soon as buds begin to open in the spring. Caterpillars occur in mixed populations and are often noticeable by mid-May in MA. Young larvae will feed on buds and unfolding leaves. There are two color forms (light green and dark) for caterpillars of both species. Like winter moth, they will drop to the soil to pupate. This usually occurs in June. Fall cankerworm larvae have three pairs of prolegs (one of which is small so it is sometimes referred to as ½) and spring cankerworm have two pairs. (Winter moth caterpillars also have 2 pairs of prolegs.) If populations are large and damage is noticeable on hosts, reduced risk insecticides such as Bacillus thuringiensis Kurstaki or spinosad may target larvae between approximately 148-290 GDD’s.

• Cooley Spruce Gall Adelgid: Adelges cooleyi is a native insect that has a complex life cycle. It has at least five different morphological forms, and requires 2 years and two hosts to complete its normal life cycle. Galls (pineapple shaped/cone-like and at the tips of twigs) are produced on Colorado blue spruce, Engelmann, Sitka, and Oriental spruce and cause needle injury (yellow spots and distortion) to Douglas-fir. Immature females overwinter on spruce near twig terminals. In the early spring, females mature into stem mothers and lay hundreds of eggs on lateral terminals. Upon egg hatch, nymphs migrate to new spring growth and feed at the base of growing needles. Immatures can be targeted on spruce between 22-81 GDD’s (mid-late April). On Douglas-fir, dormant oil applications should be made immediately before budbreak to avoid phytotoxicity. Follow all label instructions.

• Dogwood Sawfly: Macremphytus tarsatus has one generation per year. The larvae of the dogwood sawfly overwinter in decaying wood and occasionally compromised structural timber. An overwintering "cell" is created in this soft wood. Pupation occurs in the springtime and adults can take a lengthy time to emerge, roughly between late May and July. 100+ eggs are laid in groups on the underside of leaves. Eggs hatch and the larvae feed gregariously, initially skeletonizing leaves. As the caterpillars grow in size, they are capable of eating the entire leaf with the exception of the midvein. Larval appearance varies greatly throughout instars, so much so that one might mistake them for multiple species. Early instars are translucent and yellow, but as the caterpillars grow they develop black spots (over yellow) and become covered in a white powder-like material. Larvae and their shed skins may resemble bird droppings. Full grown larvae begin to wander in search of a suitable overwintering location. Rotting wood lying on the ground is preferred for this. Foliage of dogwood, especially gray dogwood (Cornus racemosa) may be impacted. Skeletonizes leaves at first, then eats all but the midvein.

• Eastern Spruce Gall Adelgid: Adelges abietis is a pest of Norway spruce primarily, but occasionally damages other spruce species such as Colorado blue, white, and red spruce. This adelgid overwinters as a partially grown female, often referred to as a stem mother. This overwintering individual matures around bud break and lays 100-200 eggs. The eastern spruce gall adelgid may be targeted for management between 22-170 GDD’s, base 50°F (mid-April to early-May). This insect is non-native, and was introduced into the United States from Europe before 1900. Galls are small, sometimes pineapple shaped/variable, but produced on the basal portion of the shoots, such that the twig extends beyond the gall. Twig dieback may occur.

• Eastern Tent Caterpillar: Malacosoma americanum eggs overwinter on host plant twigs. Egg hatch typically occurs when wild cherry leaves begin to unfold and young caterpillars may emerge by late-April through the first two weeks in May (90-190 GDD’s). Susceptible hosts include cherry and crabapple. Other host plants whose leaves are fed upon by this native insect can include apple, ash, birch, willow, maple, oak, poplar, and witch-hazel. Prune off and remove egg masses from ornamental host plants by early spring. Eastern tent caterpillars are native to Massachusetts and have many associated natural enemies (parasites and predators) that help regulate populations. Unless these caterpillars are actively defoliating specimen trees in a landscaped setting, we can coexist with this particular herbivore native to our forests.

• Elm Leaf Beetle: Xanthogaleruca (formerly Pyrrhalta) luteola is found on American elm (Ulmus americana; not preferred), Chinese Elm (Ulmus parvifolia; not preferred), English Elm (Ulmus procera; preferred host), Japanese Zelkova (Zelkova serrata), and Siberian Elm (Ulmus pumila; preferred host).

This species was accidentally introduced into the eastern United States early in the 1800's. Since then, it has been found throughout the USA anywhere elms are located. It also occurs in eastern Canada. The adult elm leaf beetle overwinters in protected areas, such as the loose bark of trees, but can also be a nuisance when it tries to invade homes in search of overwintering protection. Beetles will try to enter houses or sheds in the fall.

In the spring, the adult beetles will fly back to the host plant and chew small, semi-circular holes in the leaves. The adult female can lay 600-800 yellow eggs in her life. Eggs are laid in clusters on the leaves and resemble pointy footballs. Larvae are tiny, black, and grub-like when they hatch from the egg. Young larvae will skeletonize the undersides of leaves. As they grow in size, the larvae become yellow-green with rows of black projections. Oldest larvae may appear to have two black stripes along their sides, made from the black projections. There are 3 larval instars. Mature larvae will wander down the trunk of the host tree and pupate in the open on the ground at the tree base or in cracks and crevices in the trunk or larger limbs. They spend approximately 10 or so days as a pupa, and then the adults emerge. Those adults will fly to the foliage of the same host plant or other adjacent potential hosts in the area, where they will lay eggs. In the fall, the adults will leave the host plant in search of overwintering shelter. In most locations in the USA, two generations of this insect are possible per year. In warmer locations, 3-4 generations per year are possible.

Leaves are skeletonized by the larvae. Skeletonization may cause the leaf to turn brown or whitish. Adults are capable of chewing through the leaf, often in a shothole pattern. When in very large populations, they are capable of completely defoliating plants. Populations of this insect can fluctuate from year to year, and often management is not necessary if populations are low. However, defoliation for consecutive seasons may lead to branch dieback or death of the entire tree.

• Elongate Hemlock Scale: Fiorinia externa is found on eastern, Carolina, and Japanese hemlock, as well as yew, spruce, and fir. The elongate hemlock scale may overwinter in various life stages, and overlap of many developmental stages at any given time can be observed throughout much of the season. Dormant oil applications for this pest can occur according to label instructions in April, roughly between 7-120 GDD’s. 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 50°F. Nitrogen fertilizer applications may make elongate hemlock scale infestations worse.

• Euonymus Scale: Unaspis euonymi is an armored scale that can be found on euonymus, holly, bittersweet, and pachysandra. This insect can cause yellow spotting on leaves, dieback, and distorted bark. Dormant oil applications can be made between 35-120 GDD’s or roughly from mid-April to early-May. For crawlers, early June timing is suggested between 533-820 GDD’s. (Eggs begin to hatch in early June.)

• European Pine Sawfly: Neodiprion sertifer overwinters in the egg stage. Eggs are laid by females the previous season by cutting slits in needles using their ovipositors and depositing 6-8 eggs in each of 10-12 needles. Egg hatch occurs from late-April to mid-May and caterpillars become active roughly between 78-220 GDD, base 50°F. The primary host in MA is Mugo pine but it can be found on Scots, red, jack, and Japanese red pine. It is also found on white, Austrian, ponderosa, shortleaf, and pitch pine when planted near the aforementioned species. This dark colored caterpillar feeds in tight groups and small numbers can be pruned or plucked out of host plants and destroyed. Spinosad products can be used whenever the caterpillars are actively feeding, usually by mid-May and when caterpillars are still small. Bacillus thuringiensis kurstaki is not effective against sawflies.

• Forest Tent Caterpillar: Malacosoma disstria egg hatch occurs between 192-363 GDD’s, base 50°F, by mid-late May and caterpillars may be active for at least 5-6 weeks following. Susceptible hosts whose leaves are fed on by this insect include oak, birch, ash, maple, elm, poplar, and basswood. This native insect has many natural enemies, including some very effective pathogens that typically regulate populations. However, outbreaks of this insect can occur on occasion.

• Hemlock Looper: Two species of geometrid moths in the genus Lambdina are native insects capable of defoliating eastern hemlock, balsam fir, and white spruce. Adult moths lay their eggs on the trunk and limbs of hosts in September and October, and eggs will hatch by late May or early June. (L. fiscellaria caterpillars may be active between 448-707 GDD’s.) Monitor susceptible hosts for small, inch-worm like caterpillars. Where populations are low, no management is necessary. Hemlock loopers have several effective natural enemies.

• Hemlock Woolly Adelgid: Adelges tsugae is present on eastern and Carolina hemlock. The overwintering hemlock woolly adelgid generation (sistens) is present through mid-spring and produces the spring generation (progrediens) which will be present from early spring through mid-summer. HWA, unlike many other insects, does most of its feeding over the winter. Eggs may be found in woolly masses at the base of hemlock needles beginning in mid-March. Each woolly mass is created by a female who may then lay 50-300 eggs. Hemlock woolly adelgid eggs were observed in samples collected in Amherst, MA on April 13, 2022. Eggs hatch and crawlers may be found from mid-March through mid-July. Infested trees may be treated with foliar sprays in late April to early May, using Japanese quince as a phenological indicator. Systemic* applications may be made in the spring and fall, or when soil conditions are favorable for translocation to foliage. Nitrogen fertilizer applications may make hemlock woolly adelgid infestations worse.

*Note: beginning July 1, 2022 systemic insecticides known as neonicotinoids (including imidacloprid) will become state restricted use for tree and shrub uses in Massachusetts. More information is available, here: https://www.mass.gov/service-details/pesticide-newsupdates

• Imported Willow Leaf Beetle: Plagiodera versicolora adult beetles overwinter near susceptible hosts. Adult beetles will chew holes and notches in the leaves of willow once they become available. Females lay yellow eggs in clusters on the undersides of leaves. Larvae are slug-like and bluish-green in color. They will feed in clusters and skeletonize the leaves. Most plants can tolerate multiple years of feeding from this insect, and foliage will appear brown. Repeated yearly feeding can occasionally be an issue, in which case management of the young larvae may be necessary. Take care with treatment in areas near water.

Check out Episode 4 of InsectXaminer to see the imported willow leaf beetle in action: https://ag.umass.edu/landscape/education-events/insectxaminer

• Lecanium Scales (Oak): Parthenolecanium quercifex overwinters as a second instar nymph on oak twigs. Females will begin feeding and mature in the spring, from mid-April to early May and eggs may be laid between late May and into June. Eggs hatch in June or early July and crawlers migrate to host plant leaves where they spend the summer and migrate as second instars back to host plant twigs in the fall. Mid-April to early-May (35-145 GDD’s) for dormant oil applications.

• Lily Leaf Beetle: Lilioceris lilii adults overwinter in sheltered places. As soon as susceptible hosts such as Lilium spp. (Turk’s cap, tiger, Easter, Asiatic, and Oriental lilies) and Fritillaria spp. break through the ground, the adult lily leaf beetles are known to feed on the new foliage. (Note: daylilies are not hosts.) Typically, in May, mating will occur and each female will begin to lay 250-450 eggs in neat rows on the underside of the foliage. If there are only a few plants in the garden, hand picking and destroying overwintering adults can help reduce local garden-level populations at that time.

Check out Episode 3 of InsectXaminer to see the lily leaf beetle in action: https://ag.umass.edu/landscape/education-events/insectxaminer

• Magnolia Scale: Neolecanium cornuparvum overwinters as first instar nymphs which are elliptical, and dark slate gray in color and can usually be found on the undersides of 1 and 2 year old twigs. Nymphs may molt by late April or May and again by early June at which time the scales may be purple in color. Eventually nymphs secrete a white powdery layer of wax over their bodies. Dormant oils can be applied between 7-35 GDD’s targeting the overwintering nymphs. Avoid applications to opening buds or blooms.

• Pine Bark Adelgid: Pineus strobi overwinters as an immature which begins feeding during the first days of warm weather in the spring and begins secreting white wax over itself, which can eventually coat the entire trunk of infested trees. The white wax from pine bark adelgids was observed on eastern white pine in Amherst, MA on April 13, 2022. Egg laying may begin in April. This insect can be found on the trunk, branches, twigs, and the base of needles on new shoots. Spruce is a secondary host but this adelgid can repeatedly reproduce itself on pine. Wash off bark with a strong jet of water. If necessary, dormant oil applications can be made in mid-late April between 22-58 GDDs. Hosts include eastern white, Scots, and Austrian pines. This insect does little damage to healthy trees and can often be tolerated.

• Snowball Aphid: Neoceruraphis viburnicola eggs overwinter on viburnum twigs and buds. Eggs hatch and this aphid becomes active on certain species of viburnum roughly between 148-298 GDD’s or around redbud bloom. This insect is particularly noticeable on V. opulus, V. prunifolium, and V. acerifolia. Stem mothers, appearing blueish-white, can be found in curled up and distorted foliage. Damage caused by this insect pest is mostly aesthetic.

• Spruce Bud Scale: Physokermes piceae is a pest of Alberta and Norway spruce, among others. Immatures overwinter on the undersides of spruce needles, dormant until late March. By April, females may move to twigs to complete the rest of their development. Dormant oil applications may be made between 22-121 GDDs. Follow all label instructions, as oil may remove the bluish color from certain conifers. Mature scales are reddish brown, globular, 3 mm. in diameter, and found in clusters of 3-8 at the base of new twig growth. They closely resemble buds and are often overlooked. Crawlers are present around June.

• Spruce Spider Mite: Oligonychus ununguis is a cool-season mite that becomes active in the spring from tiny eggs that have overwintered on host plants. Hosts include spruce, arborvitae, juniper, hemlock, pine, Douglas-fir, and occasionally other conifers. This particular species becomes active in the spring and can feed, develop, and reproduce through roughly June. When hot, dry summer conditions begin, this spider mite will enter a summer-time dormant period (aestivation) until cooler temperatures return in the fall. This particular mite may prefer older needles to newer ones for food. When damaging spruce spider mite populations are known from last season, dormant oil applications can be made (when temperatures are appropriate according to label instructions) between 7-121 GDD’s, base 50°F (April). Magnification is required to view spruce spider mite eggs. Tapping host plant branches over white paper may be a useful tool when scouting for spider mite presence. (View with a hand lens.) Spider mite damage may appear on host plant needles as yellow stippling and occasionally fine silk webbing is visible. Be sure to also scout for predatory mite adults and eggs which can help regulate spruce spider mite populations. Avoid broad spectrum chemical management options that kill predatory mite populations, often making spruce spider mite outbreaks worse.

• Viburnum Leaf Beetle: Pyrrhalta viburni is a beetle in the family Chrysomelidae that is native to Europe, but was found in Massachusetts in 2004. Viburnum leaf beetle overwinters as eggs laid in capped pits on the newest growth of susceptible viburnum branches. Scout for overwintered eggs and prune out and destroy before they hatch. Egg hatch occurs in late-April to early-May as temperatures warm and foliage becomes available. Monitor for larvae in mid-May (80-120 GDD’s). This beetle feeds exclusively on many different species of viburnum, which includes, but is not limited to, susceptible plants such as V. dentatum, V. nudum, V. opulus, V. propinquum, and V. rafinesquianum. Some viburnum have been observed to have varying levels of resistance to this insect, including but not limited to V. bodnantense, V. carlesii, V. davidii, V. plicatum, V. rhytidophyllum, V. setigerum, and V. sieboldii. More information about viburnum leaf beetle may be found at http://www.hort.cornell.edu/vlb/ .

• White Pine Weevil: Pissodes strobi adults overwinter in sheltered locations in the leaf litter and become active very early in the spring, when daytime temperatures reach 50°F and before the bloom of forsythia (between 7-58 GDDs). Hosts include eastern white pine, Norway spruce, scotch, pitch, and red pine, blue spruce, and white spruce. Adults will begin feeding on bark 7-10 inches below dormant terminal buds. Females will deposit eggs in terminal growth bark, and developing larvae will feed in leaders until they mature in July when pupation occurs in pupal chambers made of wood chips. Management in nurseries or Christmas tree production may be necessary. Target adults between 7-58 GDD’s.

• Woolly Apple Aphid: Eriosoma lanigerum may be found on apple, crabapple, hawthorn, mountain-ash, Pyracantha, and elm hosts. The primary (winter) host is elm, on which aphids infest emerging spring leaves, causing leaves to curl or close into stunted, rosette-like clusters found at twig tips. On apple and crabapple, this species of aphid colonizes roots, trunks, and branches in the summer and is commonly found near previous wounds or callous tissue. On roots, the aphids cause swelled areas which can girdle and kill roots. The aphids, when found in above ground plant parts such as elm leaves, are covered with white wax. Eggs are the overwintering stage on elm, which hatch in the spring in time for the nymphs to infest new elm foliage. Following a few generations on elm, the aphids will develop into a winged form, which will disperse and seek out apple and crabapple. Multiple generations will occur on these alternate hosts in the summer and by the fall, a winged form will return to elm and mated females will lay eggs near elm buds. These aphids are a favorite snack for insect predators such as the multicolored Asian lady beetle, Harmonia axyridis. Elm can withstand multiple years of woolly apple aphid infestation and this insect is primarily aesthetic in its impact to trees. Management may not be necessary.

• Woolly Elm Aphid: Eriosoma americanum females lay a single egg in the cracks and crevices of elm bark, where the egg overwinters. Eggs hatch on elm in the spring as leaves are unfolding. Aphids may be active from 121-246 GDD’s, base 50°F on elm. A young, wingless female hatched from the egg feeds on the underside of leaf tissue. This female aphid matures and gives birth to 200 young, all females, without mating. These aphids feed, and the elm leaf curls around them and protects them. By the end of June, winged migrants mature and find serviceberry hosts. Another set of females is produced. These new females crawl to and begin feeding on the roots of serviceberry. Multiple generations occur on the roots of serviceberry through the summer. Elm can withstand multiple years of woolly elm aphid infestation and this insect is primarily aesthetic in its impact to trees. Management may not be necessary. Lady beetle larvae and adults often feed on these insects.

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

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

Landscape Practices

Plant of the Week: Lindera benzoin

Early spring flowers, attractive fall color, and role as a larval host plant make Lindera benzoin a good addition to the landscape. Best situated in the shrub border or woodland garden, spicebush is a native, medium to large shrub growing 6-12’ tall with an irregular rounded form. The common name comes from the leaves and stems that are aromatic when bruised. Small yellow flowers line branches in early spring. Plants are dioecious with male flowers being larger and showier. Plants are non-descript through summer but shine again in the fall with bright yellow fall color. Female plants produce bright red drupes that are hidden by foliage until leaf drop. Lindera benzoin is a larval host plant for spicebush swallowtail butterfly. Its fruit is frequently eaten by birds. Spicebush does best in part shade, tolerating full shade but having better fall color with more sun. Habit is more open in shade. Lindera benzoin needs adequate moisture and does well in wet areas along streams and ponds.

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

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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 Plant Diagnostic Laboratory

Soil and Plant Nutrient Testing - The University of Massachusetts Soil and Plant Nutrient Testing Laboratory is located on the campus of The University of Massachusetts at Amherst. Testing services are available to all. The 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 new orders for Routine Soil Analysis (including optional Organic Matter, Soluble Salts, and Nitrate testing), Particle Size Analysis, Pre-Sidedress Nitrate (PSNT), and Soilless Media (no other types of soil analyses available at this time). Turnaround time: Please plan for the fact that date of receipt in the lab is affected by weekends, holidays, shipping time, and time for UMass Campus Mail to deliver samples to the lab.

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

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

• The Massachusetts Nursery and Landscape Association Fund
• The Massachusetts Department of Conservation and Recreation, Award #ISADCR28219926UMA22A
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