Wishing everyone a happy holiday season!
This is the last woody ornamental insects report for the Landscape Message for 2021! The next reports will begin again in March/April of the New Year. Thank you to those of you who read these messages, and we hope that this information has been useful to you again this year. The winter is a great time to reflect on the insect pest problems you encountered during the last growing season, monitor and detect and mechanically remove overwintering pest insect life stages on high value host plants, and plan for reduced risk management options starting in the spring of 2022 as necessary. It is also a great time to plan for pollinator gardens or think about plants that you might install in 2022 to support native insect diversity and natural enemies (naturally occurring insects which help regulate pest insect populations).
We hope you have a restful winter season enjoyed with family and friends!
Do You Have Questions about Jumping Worms? If So, This Announcement is for You!
Join UMass Extension’s Jumping Worm Conference on January 26 & 27, 2022 from 9:00 AM – 11:45 AM. Registration is available: https://ag.umass.edu/landscape/events/jumping-worm-conference .
Are you a land manager and have been receiving requests for more information about so-called "jumping/snake worms"? Are you a homeowner who is looking to learn more, ask questions, or perhaps you just found jumping worms on your property in 2021? No matter who you are, if you are curious or concerned about jumping worms, this conference is for you!
Join UMass Extension as we welcome scientists who specialize in jumping worm research to discuss the latest understanding of these earthworms. How to identify jumping worms, what their potential impacts are, and the latest research into how we might manage them to be discussed. These LIVE virtual presentations will also give you the chance to get your questions answered following each speaker's presentation. So, bring your questions!
For the full agenda, visit the link above.
Winter Flights of Moths:
- Bruce Spanworm: Operophtera bruceata is a native moth that occurs from New England to the Great Lakes whose caterpillars are periodic defoliators of hosts such as maple, especially sugar maple, beech, birch, cherry, willow, and others. Frequent readers of the Landscape Message might recognize the genus of this insect – Operophtera as it is the same as a well-known, invasive defoliator in eastern Massachusetts – the winter moth, or O. brumata. In fact, the two species are extremely difficult to differentiate, and identification must be done by an entomologist (looking at adult moth genitalia) or through DNA sequencing. Both species are also known to be able to hybridize, and the Elkinton Lab at UMass Amherst reports that they do that with some frequency in parts of central Massachusetts. Bruce spanworm (O. bruceata) has a history of occasional outbreaks that are sometimes widespread geographically in localized patches, and can last 3-5 years. However, in the 1990’s and until recently, the majority of the outbreaks in eastern Massachusetts and coastal New England have been attributed to the non-native winter moth.
Female Bruce spanworm moths are wingless and brown/white spotted in color. They emerge in October and November, at which time the females crawl to their host plants, mate with winged males (males do fly), and deposit green eggs in cracks and crevices of bark or beneath lichens. Bruce spanworm eggs then turn bright orange prior to overwintering and egg hatch occurs at the time of budbreak in the spring. One might look for tiny orange overwintering eggs with a hand lens, however (much like winter moth), finding Bruce spanworm eggs on host plants is difficult. The feeding habits of Bruce spanworm caterpillars are very similar to those of winter moth. Full grown Bruce spanworm caterpillars are approximately 1 inch in length, and typically bright green although some individuals are very dark green-black in color with longitudinal (lengthwise) white to yellow-white lines. Peak feeding by this species (defoliation) can occur by the beginning of June, but this varies season-to-season. By late June, Bruce spanworm drops to the ground to pupate in the leaf litter or soil (similar to winter moth). Bruce spanworm moths are sometimes referred to as “hunter’s moths” as they are one of the few species active in the fall.
Bruce spanworm caterpillars do not typically require management, unless a localized outbreak is occurring. As a native insect, natural enemies such as predators, parasites, and pathogens regulate Bruce spanworm populations.
- Fall Cankerworm: Alsophila pometaria is a native species of inchworm known as the fall cankerworm. Host plants for this species include ash, beech, cherry, red maple, sugar maple, red oak, white oak, and many other hardwoods. As the common name suggests, the adults of this species are active in the late fall. Fall cankerworms usually cause some defoliation in our forests year-to-year, and on occasion localized outbreaks occur. Fall cankerworm adult moths (particularly the males that can fly) may be seen in late fall/early winter and often stand out as one of the few moths that are active at this time of year.
Mature fall cankerworm larvae are approximately an inch in length and also vary in color from light green to dark green/brown. Both color forms have varied light or dark longitudinal lines/stripes. The larvae also have three pairs of hardened thoracic legs and three pairs of fleshy prolegs on their abdomen, yet one of those pairs is much shorter than the others. (Sometimes referred to as “two and a half pairs” of prolegs.) Eggs hatch in the spring just as host plant leaves begin to emerge. Larvae feed and mature in 5-6 weeks. This insect also pupates at the soil surface, after larvae drop to the ground, and adult moths emerge that are brown in color with winged males that fly, and wingless females that cannot. Adult emergence may be seen after late October to early December. The eggs of fall cankerworm are tiny and often laid in clusters on host plant twigs. They appear vase-shaped with a dark colored ring and central spot on the top of the egg. Each female can lay approximately 100 eggs, which overwinter.
Like Bruce spanworm caterpillars, fall cankerworm does not always require management, unless a localized outbreak is occurring. As a native insect, natural enemies such as predators, parasites, and pathogens and even seasonal fluctuations in abiotic conditions (ex. cool, wet spring weather) can help regulate fall cankerworm populations. That said, some years and in certain locations noticeable fall (and spring) cankerworm populations may be seen that do require some attention in managed landscapes. In recent years, fall and spring cankerworm caterpillar populations have been noticed in parts of coastal Massachusetts, including Cape Cod. It is important to monitor specimen trees and shrubs next spring for these caterpillar populations, particularly after budbreak.
- Winter Moth: Operophtera brumata is a non-native insect that was identified in Massachusetts for the first time in 2003 following persistent reports of defoliation in eastern areas of the state such as Cape Anne and on the North Shore near Cohasset, Hingham, and Rockland on the South Shore in the late 1990’s. For more information about the life cycle and management of winter moth, please visit thisfact sheet: Winter Moth Identification and Management . For more detailed information about the history of this insect pest in North America and Massachusetts, please visit this fact sheet: Winter Moth in Massachusetts: History and Biological Control .
Similar to both Bruce spanworm and fall cankerworm, winter moth adult males tend to emerge and are seen flying in mid to late November, typically right around Thanksgiving. Winter moth male flights may continue into January any time temperatures are above freezing. As with the other two native inchworm species, winter moth females are nearly wingless and do not fly. Males mate with females, who lay eggs on host tree bark, which overwinter and give rise to caterpillar populations in the early spring, just as host plant buds are beginning to open. The life cycle of winter moth is described in the identification and management fact sheet above, but is similar to those of Bruce spanworm and fall cankerworm. Landscape message scouts report seeing possible winter moth adult male flights in Dighton and Boston, MA and professionals living and working in Middleborough and Rehoboth, and Cotuit, MA also report possible adult male winter moth flights. Beginning the week prior to Thanksgiving, small brown moths were seen flying in car headlights and attracted to outdoor lights at night in these areas. It is possible that these moths are mixed populations of winter moth, Bruce spanworm, and/or fall cankerworm, however the timing is typical for winter moth male flights. Due to the success of the biological control of winter moth in recent years, we do not anticipate populations will be high or particularly damaging next spring, yet we cannot say anything with absolute certainty for all locations year to year. However – moth flights this time of year always remind us that it is a good idea to plan to monitor for these springtime defoliating inchworm caterpillars next season!
Insects and Other Arthropods of Medical Importance:
- Deer Tick/Blacklegged Tick: Ixodes scapularis – Adult male and female deer ticks are active any time temperatures are above freezing from October through next May. So do not let your guard down, even though colder temperatures are upon us! For images of all deer tick life stages, along with an outline of the diseases they carry, and their timing of activity, visit: https://web.uri.edu/tickencounter/species/blacklegged-tick/ .
Anyone working in the yard and garden 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/ . Check out the archived TickTalk with TickReport webinars available here: https://ag.umass.edu/landscape/education-events/webinars .
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 .
*Note that deer ticks (Ixodes scapularis) are not the only disease-causing tick species found in Massachusetts. The American dog tick (Dermacentor variabilis) and the lone star tick (Amblyomma americanum) are also found throughout MA. Each can carry their own complement of diseases, including others not mentioned above. Anyone working or playing in tick habitats (wood-line areas, forested areas, and landscaped areas with ground cover) should check themselves regularly for ticks while practicing preventative measures.
Woody ornamental insect and non-insect arthropod pests to consider, a selected few:
Invasive Insects & Other Organisms Update:
- Spotted Lanternfly: (Lycorma delicatula, SLF) The MA Department of Agricultural Resources (MDAR) announced on September 28, 2021 that a small, established, and breeding population of the invasive spotted lanternfly (Lycorma delicatula) was detected in Worcester County, MA in the city of Fitchburg. This finding was confirmed by state officials.
For further details regarding what is currently known about the population in Fitchburg, MA and MDAR’s response, visit the press release: https://www.mass.gov/news/state-agricultural-officials-discover-invasive-spotted-lanternfly-population-in-worcester-county .
Residents and professionals living and working across the Commonwealth should learn the life stages of the spotted lanternfly and be able to identify their eggs, immatures, and adults. At this time, it is particularly valuable to learn how to ID spotted lanternfly egg masses, because the eggs are the life stage that overwinters. If any life stages of this insect are found in Massachusetts, report them immediately here: https://massnrc.org/pests/slfreport.aspx .
Currently, the only established (breeding) population of spotted lanternfly in Massachusetts is in a small area of Fitchburg, 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 at the link provided above. If you are living and working in the Fitchburg area, please be vigilant and continue to report anything suspicious.
For More Information:
From UMass Extension:
*Check out the new InsectXaminer Episode about spotted lanternfly adults and egg masses! Available here: https://ag.umass.edu/landscape/education-events/insectxaminer .
From the MA Department of Agricultural Resources:
Nursery Best Management Practices (January 2021)
Best Practices for Businesses
Checklist for Residents in or near Infested Areas
Driver’s Checklist in English or Spanish (September 2021)
Moving Industry Checklist (February 2021)
- Emerald Ash Borer: (Agrilus planipennis, EAB) in 2021 alone, the Massachusetts Department of Conservation and Recreation has confirmed at least 28 new community detections of emerald ash borer in Massachusetts. To date, 11 out of the 14 counties in Massachusetts have confirmed emerald ash borer. (The remaining counties where EAB has yet to be detected are Barnstable, Dukes, and Nantucket counties.)A map of these locations and others previously known across the state may be found here: https://ag.umass.edu/fact-sheets/emerald-ash-borer .
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.
For further information about this insect, please visit: https://ag.umass.edu/fact-sheets/emerald-ash-borer . If you believe you have located EAB-infested ash trees, particularly in an area of Massachusetts not identified on the map provided, please report here: https://massnrc.org/pests/eabreport.htm .
- 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 miles2 encompassing Worcester, Shrewsbury, Boylston, West Boylston, and parts of Holden and Auburn. If you believe you have seen damage caused by this insect, such as exit holes or egg sites, on susceptible host trees like maple, please call the Asian Longhorned Beetle Eradication Program office in Worcester, MA at 508-852-8090 or toll free at 1-866-702-9938.
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 .
- 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 next season.
Don’t miss UMass Extension’s Jumping Worm Conference on January 26 and 27th! Register now: https://ag.umass.edu/landscape/events/jumping-worm-conference .
For more information, listen to Dr. Olga Kostromytska’s presentation here: https://ag.umass.edu/landscape/education-events/invasive-insect-webinars .
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.:
Suggested reading includes Dr. Kostromytska’s recent “Hot Topics” article in Hort Notes (including an identification guide), here: https://ag.umass.edu/landscape/newsletters/hort-notes/hort-notes-2021-vol-323
Additional resources can also be found here:
University of Minnesota Extension: https://extension.umn.edu/identify-invasive-species/jumping-worms
Cornell Cooperative Extension: http://ulster.cce.cornell.edu/environment/invasive-pests/jumping-worm
UNH Extension: https://extension.unh.edu/blog/invasive-spotlight-jumping-worms
Tree & Shrub Insects & Mites:
*Note: The timing for chemical management options for insect pests of trees and shrubs has passed for this season. The following notes are seasonally appropriate, and many provide scouting tips for the winter in preparation for management options for next (2022) spring.
- Bagworm: Thyridopteryx ephemeraeformis is a native species of moth whose larvae construct bag-like coverings over themselves with host plant leaves and twigs as they feed on plant foliage. Bagworm eggs overwinter in the bags created by the females of this season. A great mechanical management option for this insect over the winter is to remove/prune out any egg-containing bags from infested host plants. This will help reduce the number of bagworms present on the plant next season.
- Cooley Spruce Gall Adelgid: Adelges cooleyi overwinters at the base of host plant needles (Colorado blue, Engelmann, and other spruces) below buds and are covered in a white-waxy material. If this life stage is seen, plan to scout for and remove green, elongated, pineapple-shaped galls from the end of new growth next spring. Plan to do this before galls turn brown and open (usually by July). Dormant oils can also be planned for the overwintering nymphs before galls form and when temperatures allow, early next spring. Follow all label instructions for safety and proper use. Note that on Douglas fir, dormant oil applications may result in yellowing of foliage. This insect does not produce galls on Douglas fir, but may result in crooked/twisted needles from adelgid feeding.
- Eastern and Forest Tent Caterpillars: Malacosoma americanum and Malacosoma disstria both overwinter as ½ to 2 inch long egg masses which encircle the twigs of their host plants (eastern tent caterpillar: wild cherry, crabapple, apple; forest tent caterpillar: oak, sugar maple, poplar, birch, etc.). These shiny, dark colored egg masses can be pruned from these host plants and destroyed over the winter, to prevent caterpillar hatch next spring.
- Eastern Spruce Gall Adelgid: Adelges abietis overwinters as white, wax-covered nymphs at the base of needles on Norway spruce, but also white, red, and blue spruce. Dormant oil applications may be made on plant terminals early next spring to kill overwintering nymphs. Follow all label instructions for safety and proper use. Plan to prune out and destroy any green, newly developing galls next spring before the insects inside emerge.
- Fall Home-Invading Insects: Various insects, such as ladybugs, boxelder bugs, seedbugs, and stink bugs have already found overwintering shelters in warm places, such as homes. While such invaders do not cause any structural damage to the home, they can become a nuisance especially when they are present in large numbers. Once they’ve entered the home, they are easy to clean up with a vacuum. Just be sure to empty the vacuum following each use. Chemical management of these insects inside the home is not recommended and is not necessary or effective in the vast majority of cases.
- Hemlock Woolly Adelgid: Adelges tsugae is a bit unique in the sense that this insect does much of its feeding on hemlock hosts over the winter, rather than during the growing season. In mid-October, hemlock woolly adelgid nymphs (which are very difficult to see at the base of hemlock needles) began feeding again. Over the winter, they will continue to feed and develop into adults, which typically produce egg masses again in March. As this development and egg laying occurs, the adelgids produce the white, waxy, woolly material around themselves which becomes easily detectible. This makes the insects look like tiny cotton balls lined up at the base of hemlock needles. While the timing for chemical management options for this insect has passed for this season, dormant oil applications can be planned, as necessary, for next March/April. Do not apply dormant oils when hemlock buds are open, or when freezing temperatures are expected. Follow all label instructions for safety and proper use.
- Honeylocust Mite: Platytetranychus multidigitali overwinters as bright orange adults that are approximately 1 mm long. These orange colored mites can be found in bud scars and cracks in the bark of their namesake host, Gleditsia triacanthos. Over the winter, host plants can be scouted using a 10X hand lens to find mites overwintering in these locations. This information can be used to plan management options for next spring, such as dormant oil applications targeting the overwintered adults. Follow all label instructions for safety and proper use.
- Lymantria dispar: formerly known as gypsy 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, etc. The winter 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, create a plan over the winter to protect susceptible specimen trees and shrubs from caterpillars next spring in the event that caterpillar activity is elevated in these areas again.
- Magnolia Scale: Neolecanium cornuparvum overwinters as immature scales that are dark in color, found on the twigs of susceptible magnolias. During the dormant winter season, scout trees that are known to have problems with this native soft scale and look at 1 to 2-year old twigs for overwintering crawlers that are approximately 1/16th of an inch in length. If found, plan for dormant oil applications next spring, targeting these locations. Follow all label instructions for safety and proper use. *Note – the winter is a good time to scout for overwintering life stages of many different scale insects on many different host plants. Be sure to bring a 10X hand lens to assist you.
- Viburnum Leaf Beetle: Pyrrhalta viburni is a beetle in the family Chrysomelidae that is native to Europe, but was found in Massachusetts in 2004. 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. Viburnum leaf beetles overwinter as eggs laid in pits chewed near the tips of twigs on susceptible hosts. A great mechanical management option for reducing next season’s viburnum leaf beetle population is to prune out over wintering egg sites and dispose of them. Do this after several hard frosts to ensure that any lingering viburnum leaf beetle adults from this season have been killed by cold temperatures. More information about viburnum leaf beetle may be found at http://www.hort.cornell.edu/vlb/ .
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