Did you miss the live broadcasts of UMass Extension’s Invasive Insect Webinar Series? No problem! View the archived recordings of all seven webinars here: https://ag.umass.edu/landscape/education-events/invasive-insect-webinars
Interesting Insects Reported or Seen Since the Last Landscape Message:
- Three-lined Potato Beetle: Lema daturaphila was spotted defoliating ornamental Nicotiana spp. on 7/11/2020 in Plymouth County, MA. Nicotiana as a genus includes not only smoking tobacco, but also ornamental flowering tobacco. This ornamental is planted as an annual with showy flowers available in many colors, with smaller leaves. Other relatives found in the nightshade family (Solanaceae) include petunias, tomatoes, peppers, eggplants, and potatoes. The three-lined potato beetle is a pest of potato (uncommon) and tomato (rare) and some of their relatives. This insect is most commonly found on tomatillo (Physalis ixocarpa). Adults are ¼ inch in length, orange-yellow in color, with three lengthwise black stripes on their elytra (hardened wing covers). Females will lay orange-yellow eggs in groups on the undersides of leaves. Larvae hatch in late June or July and have black heads. Larvae feed in groups, and like some other Chrysomelidae (leaf beetles), they cover themselves with their own excrement. In the Northeast, a second generation is possible in August. Both the larvae and the adults feed on foliage. Injury is minor on tomato and potato, but can be severe on tomatillo. These insects are likely to overwinter in New England in the soil in the pupal stage. In the case of three-lined potato beetle on ornamental flowering tobacco, hand-picking to remove adults and larvae should be acceptable for managing this insect.
- “Smokey Winged Beetle Bandit”: Cerceris fumipennis is a native, ground-nesting wasp that is excellent at finding buprestid beetles, or the jewel beetles, including our own native species as well as the invasive emerald ash borer. The female wasps will collect these jewel beetles and provision their own individual (although aggregated) subterranean nests with paralyzed beetles on which they will lay an egg. Although these wasps are not able to decrease the emerald ash borer population in the state, they can be used as a monitoring tool with a technique known as biosurveillance. These wasps nest in hard-packed, sandy soils in full sunlight, such as those found in baseball diamonds and along dirt roads. These wasps, although large, are incapable of stinging people. They can be distinguished from other ground-nesting wasps that might offer a painful sting by their black body with a single yellow band on the abdomen and yellow spots on the head (3 on the females, 2 on the males) and their blue-black iridescent wings. The openings to their nests are about the thickness of a pencil and often have a buildup of sand in a mound around them, known as a tumulus. Sometimes jewel beetles (including the emerald ash borer) can be found on the ground, scattered between the groups of nests. If you find these wasps nesting in a ballfield or other such area, there is no need to remove them or kill them (no one will get stung). So please, help preserve this wonderful native insect!
For more information, visit: http://www.emeraldashborer.info/documents/CFIA-CercerisBook_r06.pdf
Insects and Other Arthropods of Public Health Concern:
For current information, including searchable risk maps for both EEE and WNV in Massachusetts, visit: https://www.mass.gov/info-details/massachusetts-arbovirus-update
According to the Massachusetts Bureau of Infectious Disease and Laboratory Science and the Department of Public Health, there are at least 51 different species of mosquito found in Massachusetts. Mosquitoes belong to the Order Diptera (true flies) and the Family Culicidae (mosquitoes). As such, they undergo complete metamorphosis, and possess four major life stages: egg, larva, pupa, and adult. Adult mosquitoes are the only stage that flies and many female mosquitoes only live for 2 weeks (although the life cycle and timing will depend upon the species). Only female mosquitoes bite to take a blood meal, and this is so they can make eggs. Mosquitoes need water to lay their eggs in, so they are often found in wet or damp locations and around plants. Different species prefer different habitats. It is possible to be bitten by a mosquito at any time of the day, and again timing depends upon the species. Many are particularly active from just before dusk, through the night, and until dawn. Mosquito bites are not only itchy and annoying, but they can be associated with greater health risks. Certain mosquitoes vector pathogens that cause diseases such as West Nile virus (WNV) and eastern equine encephalitis (EEE).
For more information about mosquitoes in Massachusetts, visit: https://www.mass.gov/service-details/mosquitoes-in-massachusetts
There are ways to protect yourself against mosquitoes, including wearing long-sleeved shirts and long pants, keeping mosquitoes outside by using tight-fitting window and door screens, and using insect repellents as directed. Products containing the active ingredients DEET, permethrin, IR3535, picaridin, and oil of lemon eucalyptus provide protection against mosquitoes.
For more information about mosquito repellents, visit: https://www.mass.gov/service-details/mosquito-repellents https://www.cdc.gov/features/stopmosquitoes .
The next live webinar will be held on August 12, 2020: Extinction of Deer Ticks in North America - Speaker: Dr. Stephen Rich, Professor of Microbiology, University of Massachusetts Amherst; Director the Laboratory of Medical Zoology
Dr. Stephen Rich will discuss a recent publication in Nature (June 2020) from the Laboratory of Medical Zoology that provides insight to the evolutionary and ecological origin of the primary Lyme disease vectors in North America. To register for the next TickTalk, visit: https://ag.umass.edu/landscape/education-events/ticktalk-with-tickreport-webinars
Ixodes scapularis nymphs (immatures) are active, and may be encountered at this time, through August. Nymphs will have already taken a blood meal, and therefore can be infected with disease causing pathogens. It is important to protect yourself against ticks and be especially vigilant for tiny, difficult to see nymphs. For images of all deer tick life stages, along with an outline of the diseases they carry, visit: http://www.tickencounter.org/tick_identification/deer_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: http://www.tickencounter.org/prevention/protect_yourself .
Have you just removed an attached tick from yourself or a loved one with a pair of tweezers? If so, consider sending the tick to the UMass Laboratory of Medical Zoology to be tested for disease causing pathogens. To submit a tick to be tested, visit: https://www.tickreport.com/ and click on the blue “Order a TickReport” button. Results are typically available within 3 business days, or less. By the time you make an appointment with your physician following the tick attachment, you may have the results back from TickReport to bring to your physician to aid in a conversation about risk.
The UMass Laboratory of Medical Zoology does not give medical advice, nor are the results of their tests diagnostic of human disease. Transmission of a pathogen from the tick to you is dependent upon how long the tick had been feeding, and each pathogen has its own transmission time. TickReport is an excellent measure of exposure risk for the tick (or ticks) that you send in to be tested. Feel free to print out and share your TickReport with your healthcare provider.
- Wasps/Hornets: Many wasps are predators of other arthropods, including pest insects such as certain caterpillars that feed on trees and shrubs. Adult wasps hunt prey and bring it back to their nest where young are being reared, as food for the immature wasps. A common such example are the paper wasps (Polistes spp.) who rear their young on chewed up insects. They may be seen searching plants for caterpillars and other soft-bodied larvae to feed their young. Paper wasps can sting, and will defend their nests, which are open-celled paper nests that are not covered with a papery “envelope”. These open-celled nests may be seen hanging from eaves or other outdoor building structures. Aerial yellow jackets and hornets create large aerial nests that are covered with a papery shell or “envelope”. Common yellow jacket species include those in the genus Vespula. Dolichovespula maculata is commonly known as the baldfaced hornet, although it is not a true hornet. The European hornet (Vespa crabro) is three times the size of a yellow jacket and may be confused for the Asian giant hornet (Vespa mandarinia). The European hornet is known to Massachusetts, but the Asian giant hornet is not. If you are concerned that you have found or photographed an Asian giant hornet, please report it here: https://massnrc.org/pests/report.aspx . A helpful ID tool, although developed for Texas by the USDA, depicts common look-a-like species that we also have in MA that can be confused for the Asian giant hornet and is found here: https://agrilife.org/lubbock/files/2020/05/Asian_Giant_Hornet_Look-alikes_101_Xanthe_Shirley.pdf .
Paper wasps and aerial yellowjackets overwinter as fertilized females (queens) and a single female produces a new nest annually in the late spring. Nests are abandoned at the end of the season. Annually, queens start new nests, laying eggs, and rearing new wasps to assist in colony/nest development. Some people are allergic to stinging insects, so care should be taken around wasp/hornet nests. Unlike the European honeybee (Apis mellifera), wasps and hornets do not have barbed stingers, and therefore can sting repeatedly when defending their nests. It is best to avoid their nests, and if that cannot be done and assistance is needed to remove them, consult a professional.
Woody ornamental insect and non-insect arthropod pests to consider, a selected few:
- Asian Longhorned Beetle: (Anoplophora glabripennis, ALB) was detected for the first time in South Carolina in 2020. Asian longhorned beetle eradication programs currently exist in Massachusetts, New York, and Ohio. A homeowner is responsible for finding, reporting, and making officials aware of the infestation in South Carolina. Great job!
The U.S. Department of Agriculture’s (USDA) Animal and Plant Health Inspection Service (APHIS) and the Clemson University’s Department of Plant Industry (DPI) are inspecting trees in Hollywood, South Carolina following the detection and identification of the Asian longhorned beetle (ALB).
On May 29, a homeowner in Hollywood, South Carolina contacted DPI to report they found a dead beetle on their property and suspected it was ALB. A DPI employee collected the insect the same day and conducted a preliminary survey of the trees on the property. Clemson’s Plant and Pest Diagnostic Clinic provided an initial identification of ALB, and on June 4, APHIS’ National Identification Services confirmed the insect. On June 11, APHIS and DPI inspectors confirmed that one tree on the property is infested, and a second infested tree was found on an adjacent property. For more information, visit: https://www.aphis.usda.gov/aphis/newsroom/stakeholder-info/sa_by_date/sa-2020/sa-06/alb-sc .
This is a good reminder for us to remain vigilant, and report any suspicious beetles or damage to trees, especially maples. Asian longhorned beetle infests 12 genera of trees, however maples are preferred hosts.
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 .
More information can be found in the “Trouble Maker of the Month” section of July’s edition of Hort Notes: https://ag.umass.edu/landscape/newsletters/hort-notes/hort-notes-2020-vol-315
- White Spotted Pine Sawyer (WSPS): Monochamus scutellatus adults can emerge in late May throughout July, depending on local temperatures. The Asian Longhorned Beetle Eradication Program reports that white spotted pine sawyer adult beetle activity is starting to decrease for the season. This is a native insect in Massachusetts and is usually not a pest. Larvae develop in weakened or recently dead conifers, particularly eastern white pine (Pinus strobus). However, the white spotted pine sawyer looks very similar to the invasive Asian Longhorned Beetle, Anoplophora glabripennis, ALB. ALB adults can be present in Massachusetts in July and August. Look for the key difference between WSPS and ALB adults, which is a white spot in the top center of the wing covers (the scutellum) on the back of the beetle. White spotted pine sawyer will have this white spot, whereas Asian longhorned beetle will not. Both insects can have other white spots on the rest of their wing covers; however, the difference in the color of the scutellum is a key characteristic. See the Asian longhorned beetle entry above for more information about that non-native insect.
- Arborvitae Leafminer: In New England and eastern Canada, four species of leafminers are known to infest arborvitae. These include Argyresthia thuiella, A. freyella, A. aureoargentella, and Coleotechnites thujaella. The arborvitae leafminer, A. thuiella, is the most abundant of these and has the greatest known range when compared to the others. (It is also found in the Mid-Atlantic States and as far west as Missouri). Moths of this species appear from mid-June to mid-July and lay their eggs. The damage caused by all of these species is nearly identical. Trees, however, have been reported to lose up to 80% of their foliage due to arborvitae leafminer and still survive. At least 27 species of parasites have been reported as natural enemies of arborvitae leafminers, the most significant of which may be a parasitic wasp (Pentacnemus bucculatricis). Arborvitae leafminer damage causes the tips of shoots and foliage to turn yellow and brown. If infestations are light, prune out infested tips.
- Asiatic Garden Beetle: Maladera castanea adults are active and are typically most abundant in July and August. These rusty-red colored beetles are bullet-shaped and active at night. They are often attracted to porch lights. They feed on a number of ornamental plants, defoliating leaves by giving the edges a ragged appearance and also feeding on blossoms. Butterfly bush, rose, dahlia, aster, and chrysanthemum can be favored hosts.
- Azalea Bark Scale: Eriococcus azaleae was discovered in CT in 1917 and has since been reported in other states. It is found on the bark of twigs and stems and commonly settles in branch crotches. It has been reported on azalea, rhododendron, andromeda, and others. Female scales are approximately 2-3 mm. in length and covered in a white, waxy coating. The females are purple in color and may resemble a mealybug, although they are a soft or felt scale. These females have overwintered and are going to lay eggs which will hatch into crawlers toward the end of June through mid-July. Crawlers will settle into branch crotches, bark crevices, or on the axils of leaves. There is a parasitic wasp that will attack these insects. When high in number, these scales can cause yellowing of the foliage and their sugary excrement can lead to the promotion of sooty mold. Because these are soft scales, they may be targeted with horticultural oils or insecticidal soaps while observing label instructions to prevent phytotoxicity.
- Azalea Sawflies: There are a few species of sawflies that impact azaleas. Johnson and Lyon's Insects that Feed on Trees and Shrubs mentions three of them. Amauronematus azaleae was first reported in New Hampshire in 1895 and is likely found in most of New England. Adults of this species are black with some white markings and wasp-like. Generally green larvae feed mostly on mollis hybrid azaleas. Remember, sawfly caterpillars have at least enough abdominal prolegs to spell “sawfly” (so 6 or more prolegs). Adults are present in May, and females lay their eggs and then larvae hatch and feed through the end of June. There is one generation per year. Nematus lipovskyi has been reared from swamp azalea (Rhododendron viscosum). Adults of that species have been collected in April (in states to the south) and May (in New England) and larval feeding is predominantly in late April and May in Virginia and June in New England. One generation of this species occurs per year, and most mollis hybrid azaleas can be impacted. A third species, Arge clavicornis, is found as an adult in July and lays its eggs in leaf edges in rows. Larvae are present in August and September. Remember, Bacillus thuringiensis Kurstaki does not manage sawflies.
- 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. Remove and destroy overwintering bags before June. In certain areas across MA in 2019, increased populations of bagworms were observed and reported. At this time, bagworm caterpillars are large (hidden within their bags made of chewed leaves and other debris) and capable of completely defoliating young trees. Bagworm caterpillars were reported feeding on honeylocust in Holyoke, MA on 7/22/20. See photos of bagworms at the base of a defoliated tree, as reported by Sarah Greenleaf, MA DCR Urban Forester. More information can be found here: https://ag.umass.edu/landscape/fact-sheets/bagworm
- Cottony Taxus Scale: Pulvinaria floccifera, also referred to as the cottony camellia scale, utilizes such hosts as taxus, camellia, holly, hydrangea, Japanese maple, euonymus, magnolia, and jasmine, among others. Females have laid the long, narrow, white and fluted egg sac that makes them much more noticeable. Eggs will hatch over an extended period of 6 weeks and crawlers may be treated between 802-1388 GDD’s. This insect can cause the host to appear off-color. They also produce honeydew which promotes sooty mold growth. Dieback is not common with this insect. Target the underside of the foliage. Horticultural oil, neem oil, and insecticidal soaps may be used to manage these soft scales. Reduced risk options help preserve natural enemies.
- Dogwood Borer: Synanthedon scitula is a species of clearwing moth whose larvae bore not only into dogwood (Cornus), but hosts also include flowering cherry, chestnut, apple, mountain ash, hickory, pecan, willow, birch, bayberry, oak, hazel, myrtle, and others. Kousa dogwood appear to be resistant to this species. Signs include the sloughing of loose bark, brown frass, particularly near bark cracks and wounds, dead branches, and adventitious growth. The timing of adult emergence can be expected when dogwood flower petals are dropping and weigela begins to bloom. Adult moth flights continue from then until September. Emergence in some hosts (ex. apple) appears to be delayed, but this differs depending upon the location in this insect’s range. Eggs are laid singly, or in small groups, on smooth and rough bark. Female moths preferentially lay eggs near wounded bark. After hatch, larvae wander until they find a suitable entrance point into the bark. This includes wounds, scars, or branch crotches. This insect may also be found in twig galls caused by other insects or fungi. Larvae feed on phloem and cambium. Fully grown larvae are white with a light brown head and approx. ½ inch long. Pheromone traps and lures are useful for determining the timing of adult moth emergence and subsequent management.
- Dogwood Sawfly: Macremphytus tarsatus larvae are commonly seen feeding on dogwoods, especially gray dogwood (Cornus racemosa). One generation occurs per year. The larvae of the dogwood sawfly overwinter in decaying wood and occasionally (rarely) 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 from late May through July. 100+ eggs are laid in groups on the underside of leaves. Eggs hatch and the larvae feed gregariously, initially skeletonizing the leaves. As the caterpillars grow in size, they are capable of eating the entire leaf, leaving only midveins behind. Larval appearance varies greatly throughout instars. Early instars are translucent and yellow, but as the caterpillars grow, they develop black spots (over the 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. Sawfly caterpillars can be collected from plants and dropped into a can of soapy water.
- Emerald Ash Borer: (Agrilus planipennis, EAB) As of March 2020, the Massachusetts Department of Conservation and Recreation has confirmed a total of at least 116 communities in Massachusetts that have known populations of emerald ash borer. A map of these locations 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). Adult insects of this species will not be present at this time of year. Signs of an EAB infested tree may include (at this time) D-shaped exit holes in the bark (from adult emergence in previous years), “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. Positive identification of an EAB-infested tree may not be possible with these signs individually on their own.
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: http://massnrc.org/pests/pestreports.htm .
- Euonymus Caterpillar: Yponomeuta cagnagella is of European origin and widespread in distribution throughout Europe. It was first reported in North America in Ontario in 1967. The euonymus caterpillars (larvae) feed in groups and envelop the foliage of the host plant in webs as they feed. Hosts include: Euonymus europaeus (tree form), E. kiautschovicus, E. alatus, and E. japonicus. Mature caterpillars are just under an inch in length, creamy yellow-gray in color with black spots and a black head capsule. By late June, these larvae pupate in white, oval-shaped cocoons which are typically oriented together vertically either on host plants or non-hosts in the area. Cocoons can be found in cracks and crevices, or webbed together leaves. The adult moth emerges in late June in most locations. The adult female secretes a gummy substance over her eggs which will harden, making them even more difficult to see. Eggs hatch by mid-August, at which time the tiny larvae prepare to overwinter beneath their eggshell-like covering. These larvae are inactive until the following year, when caterpillars group together to feed on newly emerging leaves, creating a mess of webs as they feed. There is one generation per year. Plants may be partially or entirely defoliated. Management of young, actively feeding caterpillars with Bacillus thuringiensis is possible if deemed necessary, however many species of Euonymus are considered invasive themselves.
Want to see euonymus caterpillars in action?! I bet you’ve never seen so many of these caterpillars in one place! Check out Episode 3 of InsectXaminer: https://ag.umass.edu/landscape/education-events/insectxaminer
- Fall Webworm: Hyphantria cunea is native to North America and Mexico. It is now considered a world-wide pest, as it has spread throughout much of Europe and Asia. (For example, it was introduced accidentally into Hungary from North America in the 1940’s.) Hosts include nearly all shade, fruit, and ornamental trees except conifers. In the USA, at least 88 species of trees are hosts for these insects, while in Europe at least 230 species are impacted. In the past history of this pest, it was once thought that the fall webworm was a two-species complex. It is now thought that H. cunea has two color morphs – one black headed and one red headed. These two color forms differ not only in the coloration of the caterpillars and the adults, but also in their behaviors. Caterpillars may go through at least 11 molts, each stage occurring within a silken web they produce over the host. When alarmed, all caterpillars in the group will move in unison in jerking motions that may be a mechanism for self-defense. Depending upon the location and climate, 1-4 generations of fall webworm can occur per year. Fall webworm adult moths lay eggs on the underside of the leaves of host plants in the spring. These eggs hatch in late June or early July depending on climate. Fall webworm caterpillars were observed feeding on foliage coated in webbing on 7/8/2020 and 7/21/2020 in Chesterfield, MA. Branches fed upon by this insect have web-coated leaves that have now turned brown. Young larvae feed together in groups on the undersides of leaves, first skeletonizing the leaf and then enveloping other leaves and eventually entire branches within their webs. Webs are typically found on the terminal ends of branches. All caterpillar activity occurs within this tent, which becomes filled with leaf fragments, cast skins, and frass. Fully grown larvae then wander from the webs and pupate in protected areas such as the leaf litter where they will remain for the winter. Adult fall webworm moths emerge the following spring/early summer to start the cycle over again. 50+ species of parasites and 36+ species of predators are known to attack fall webworm in North America. Fall webworms typically do not cause extensive damage to their hosts. Nests may be an aesthetic issue for some. If in reach, small fall webworm webs may be pruned out of trees and shrubs and destroyed. Do not set fire to H. cunea webs when they are still attached to the host plant.
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.
- Hibiscus Sawfly: The larvae of the hibiscus (mallow) sawfly, likely Atomacera decepta, may be observed feeding on hibiscus hosts at this time. Sawfly larvae develop into wasp-like adults (Order: Hymenoptera) and therefore these “caterpillars” will not be managed by Bacillus thuringiensis var. kurstaki which is specific to the Lepidoptera (caterpillars that develop into moths or butterflies as adults). Reduced risk active ingredients such as spinosad are labelled for use against sawfly larvae. However, given that hibiscus are very attractive to pollinators, non-chemical management options such as hand picking and disposing of larvae, when possible, are best. Spinosad is toxic to pollinators until it dries. For more information about the risks of insecticide active ingredients to pollinators, visit: https://ag.umass.edu/landscape/fact-sheets/tree-shrub-insecticide-active-ingredients-risks-to-pollinators-other-non
The hibiscus (mallow) sawfly adult female uses her ovipositor to cut slits into leaf surfaces to deposit her eggs. Larvae emerge from these eggs and begin by first feeding on leaf undersides when small, and then move to feed on leaf surfaces as they grow in size. Only large leaf veins may be left behind if the population is large enough. Larvae have been observed moving to the base of the plant to pupate. Adults emerge and in some locations in the US, multiple generations have been recorded per year. This insect is known in the mid-Atlantic and Midwest states, but was reported feeding on Hibiscus spp. in Connecticut in 2004 and 2005 and has previously been reported in Massachusetts. The timing of the life cycle of this insect, as well as how many generations occur per year in Massachusetts, however, is not fully understood. Some research has shown that Hibiscus acetosella, H. aculeatus, and H. grandiflora seem to either exhibit some resistance to or tolerance of hibiscus sawfly feeding. In one study, all three had few if any eggs or larvae and were given the lowest damage rating among the species evaluated. This insect also does not feed on Rose of Sharon or H. rosasinensis. It has, however, been reported to “voraciously” feed on H. moscheutos, H. palustris, H. militaris, and H. lasiocarpus.
- 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 the feeding from this insect, and foliage will appear brown. Repeated yearly feeding can be an issue, in which case management of the young larvae may be necessary. Take care with treatment in areas near water. Imported willow leaf beetle may have 2 generations per year in New England (4 generations per year are possible in the warmer locations of its introduced range).
Want to see the imported willow leaf beetle in action? Check out the NEW short (2 min 53 sec) InsectXaminer video now available here: https://ag.umass.edu/landscape/education-events/insectxaminer
- Lacebugs: Stephanitis spp. lacebugs such as S. pyriodes can cause severe injury to azalea foliage. S. rhododendri can be common on rhododendron and mountain laurel. S. takeyai has been found developing on Japanese andromeda, leucothoe, styrax, and willow. Stephanitis spp. lace bug activity should be monitored through September. Before populations become too large, treat with a summer rate horticultural oil spray as needed. Be sure to target the undersides of the foliage in order to get proper coverage of the insects. Certain azalea and andromeda cultivars may be less preferred by lace bugs.
- 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.
- Lilac Borer: Podosesia syringae is a clearwing moth pest of lilac, privet, fringetree, and ash. (It is also known as the ash borer, not to be confused with the emerald ash borer.) Adults mimic paper wasps. Larvae are wood-boring, and signs and symptoms include branch dieback, holes, and occasionally, sawdust-like frass accumulated on bark. Larvae bore into stems, trunks, and branches, chewing an irregularly shaped entrance hole. Peak adult moth flights may occur in the northern portion of this insect’s range in June and is usually over by August 1st. Pheromone traps can be used to time adult emergence. Adult females lay flattened, oval, and tan eggs that are deposited singly or in clusters on bark crevices, ridges, and sometimes smooth bark; but usually laid in or near wounds in the bark. On average, 395 eggs are laid by each female. After hatch, larvae chew into the bark and feed laterally and then vertically in phloem tissue. Larvae overwinter in tunnels in the final instar and resume feeding in the spring. Adults emerge through a round exit hole (4-5 mm. in diameter). This insectmay be targeted between 200-299 GDD’s, base 50°F.
- Magnolia and Tuliptree Scales: The soft scale insects known as the magnolia scale (Neolecanium cornuparvum) and the tuliptree scale (Toumeyella liriodendri) can be difficult to differentiate in the field, depending upon the host they are found on. (On Magnolia, it is very difficult to distinguish between the two species of soft scale.) As two native scale insects in North America, the magnolia and tuliptree scales are hosts themselves for natural enemies that can impact their populations. Solitary parasitoid larvae have been collected from Magnolia scales and have been identified as a syrphid fly species, Ocyptamus costatus. The natural enemies of the tuliptree scale have been studied to a greater degree and include certain lady beetle species [Hyperaspis signata, Adalia (formerly Hyperaspis) bipunctata, and Chilocorus stigma] which feed on nymphal scales, a number of parasitic wasps, and even an insect feeding moth caterpillar (Laetilia coccidivora). This particular moth species, also referred to as a type of snout moth, will consume the tuliptree scale underneath the protection of a silken web it spins over them! (The specific epithet coccidivora can be translated as “ones that eat soft scales” or Coccidae.) Unfortunately, in a landscape setting, it often seems that although these natural enemies may be common within the scale populations, they are seldom able to reduce the scale insect numbers below damaging levels. That being said, our management options should still seek to preserve these natural enemies.
The magnolia scale is distributed throughout the eastern United States. The tuliptree scale is found east of the Mississippi River from Michigan to Alabama and from New York and Connecticut to Florida. It is also reported to be found in ornamental tuliptrees and magnolias in California and could be found wherever these trees are grown. Magnolia scale host plants include: Magnolia stellata (star Magnolia), M. acuminata (cucumber Magnolia), M. lilliflora ‘Nigra’ (lily Magnolia; formerly M. quinquepeta), and M. soulangeana (Chinese Magnolia). Other species may be hosts for this scale, but attacked to a lesser degree. M. grandiflora (southern Magnolia) may be such an example. Tuliptree scale host plants include: Liriodendron tulipifera (tuliptree or yellow poplar), Magnolia stellata (star Magnolia), and M. soulangeana (Chinese Magnolia). This insect has also been recorded on M. grandiflora (southern Magnolia) and Tilia spp. (linden). The tuliptree scale has also, to a lesser extent, been reported on other ornamental trees and shrubs.
Mature individuals settle on a location on branches and twigs, then insert piercing-sucking mouthparts to feed. The insects feed on plant fluids and excrete large amounts of a sugary substance known as honeydew. Sooty mold, often black in color, will then grow on the honeydew that has coated branches and leaves. Repeated, heavy infestations can result in branch dieback and at times, death of the plant. Honeydew may also be very attractive to ants, wasps, and hornets. The life cycle of both of these species is similar and may have similar timing during the year, however subtle differences exist. The life cycle of the magnolia scale is as follows: This scale overwinters as a young nymph (immature stage) which is elliptical in shape, mostly a dark-slate gray, except for a median ridge that is red/brown in color. These overwintering nymphs may be found on the undersides of 1st and 2nd year old twigs. The first molt (shedding of the exoskeleton to allow growth) can occur by late April or May in parts of this insect’s range and the second molt will occur in early June. At that time, the immature scales have turned a deep purple color. Stems of the host plant may appear purple in color and thickened – but this is a coating of nymphal Magnolia scales, not the stem itself. Eventually, these immature scales secrete a white layer of wax over their bodies, looking as if they have been rolled in powdered sugar. By August, the adult female scale is fully developed, elliptical and convex in shape and ranging from a pinkish-orange to a dark brown color. Adult females may also be covered in a white, waxy coating. By that time, the females produce nymphs (living young; eggs are not “laid”) that wander the host before settling on the newest twigs to overwinter. In the Northeastern United States, this scale insect has a single generation per year.
The lifecycle of the tuliptree scale is as follows: The mature female tuliptree scale is hemispherical in shape. The color of the mature female varies in this species as well - a grayish-green to pink-orange insect mottled with black. Adult males emerge sometime in June and mate with the females. Like the Magnolia scale, eggs develop within the body of the female tuliptree scale, leading to the “live birth” of immatures (crawlers) in late August and September. In the Northeast, one generation of tuliptree scales occurs per year. (However, in the southern-most portions of its range, this insect has been found in all stages of development during the winter, suggesting multiple generations per year.) A single female tuliptree scale may produce 3,000+ crawlers in one season. These crawlers are tiny (approximately the size of the head of a pin) and settle on host plant twigs in September. Past studies have shown that in addition to moving on their own with fully functional legs, the crawlers can be blown to new hosts on the wind, up to 100 feet away. (Being wind-blown to a new host, however, is a haphazard method of travel through which some less than 20% of these crawlers successfully make contact with a host plant, and fewer still attach to a suitable site on the plant.) The immature, crawler stage molts once prior to overwintering.
- Rhododendron Borer: Synanthedon rhododendri is one of the smallest of the native clearwing moths. Rhododendrons are preferred hosts, although mountain laurel, and deciduous azaleas can be heavily infested, especially if they are planted in close proximity to rhododendrons. Injury may be first noticed in the fall (leaves lose their sheen, then become pale green, then olive, then chlorotic) and can look similar to drought stress. On branches that seem to be stunted, look at limb crotches, scars, and other irregularities for sawdust stuck on bark or on the ground beneath these areas. In late May and early June, holes may contain pupal shed skins extending halfway out. Moth emergence occurs in the late-spring, early-summer. After mating, female moths seek out suitable egg laying locations (preferring wounded areas or limb crotches). The female lays her eggs and dies. Eggs hatch and larvae tunnel into the inner bark where they feed in tunnels that become packed with reddish frass pellets. By late fall, larvae move to the sapwood where they overwinter and resume feeding by mid-March. Pupation occurs in the spring and there is one generation per year.
- Spotted Lanternfly: (Lycorma delicatula, SLF) is not known to occur in Massachusetts landscapes (no established populations are known in MA at this time). However, due to the great ability of this insect to hitchhike using human-aided movement, it is important that we remain vigilant in Massachusetts and report any suspicious findings. Spotted lanternfly reports can be sent here: https://massnrc.org/pests/slfreport.aspx
For a map of known, established populations of SLF as well as detections outside of these areas where individual finds of spotted lanternfly have occurred (but no infestations are present), visit: https://nysipm.cornell.edu/environment/invasive-species-exotic-pests/spotted-lanternfly/ This map depicts an individual find of spotted lanternfly at a private residence in Boston, MA that was reported by the MA Department of Agricultural Resources on February 21, 2019. More information about this detection in Boston, where no established infestation was found, is provided here: https://www.mass.gov/news/state-agricultural-officials-urge-residents-to-check-plants-for-spotted-lanternfly
This insect is a member of the Order Hemiptera (true bugs, cicadas, hoppers, aphids, and others) and the Family Fulgoridae, also known as planthoppers. The spotted lanternfly is a non-native species first detected in the United States in Berks County, Pennsylvania and confirmed on September 22, 2014.
The spotted lanternfly is considered native to China, India, and Vietnam. It has been introduced as a non-native insect to South Korea and Japan, prior to its detection in the United States. In South Korea, it is considered invasive and a pest of grapes and peaches. The spotted lanternfly has been reported from over 70 species of plants, including the following: tree of heaven (Ailanthus altissima) (preferred host), apple (Malus spp.), plum, cherry, peach, apricot (Prunus spp.), grape (Vitis spp.), pine (Pinus spp.), pignut hickory (Carya glabra), sassafras (Sassafras albidum), serviceberry (Amelanchier spp.), slippery elm (Ulmus rubra), tulip poplar (Liriodendron tulipifera), white ash (Fraxinus americana), willow (Salix spp.), American beech (Fagus grandifolia), American linden (Tilia americana), American sycamore (Platanus occidentalis), big-toothed aspen (Populus grandidentata), black birch (Betula lenta), black cherry (Prunus serotina), black gum (Nyssa sylvatica), black walnut (Juglans nigra), dogwood (Cornus spp.), Japanese snowbell (Styrax japonicus), maple (Acer spp.), oak (Quercus spp.), and paper birch (Betula papyrifera).
The adults and immatures of this species damage host plants by feeding on sap from stems, leaves, and the trunks of trees. In the springtime in Pennsylvania (late April - mid-May) nymphs (immatures) are found on smaller plants and vines and new growth of trees and shrubs. Third and fourth instar nymphs migrate to the tree of heaven and are observed feeding on trunks and branches. Trees may be found with sap weeping from the wounds caused by the insect’s feeding. The sugary secretions (excrement) created by this insect may coat the host plant, later leading to the growth of sooty mold. Insects such as wasps, hornets, bees, and ants may also be attracted to the sugary waste created by the lanternflies, or sap weeping from open wounds in the host plant. Host plants have been described as giving off a fermented odor when this insect is present.
Adults are present by the middle of July in Pennsylvania and begin laying eggs by late September and continue laying eggs through late November and even early December in that state. Adults may be found on the trunks of trees such as the tree of heaven or other host plants growing in close proximity to them. Egg masses of this insect are gray in color and look similar in some ways to gypsy moth egg masses.
Host plants, bricks, stone, lawn furniture, recreational vehicles, and other smooth surfaces can be inspected for egg masses. Egg masses laid on outdoor residential items such as those listed above may pose the greatest threat for spreading this insect via human aided movement.
For more information about the spotted lanternfly, visit this fact sheet: https://ag.umass.edu/landscape/fact-sheets/spotted-lanternfly .
- Taxus Mealybug: Dysmicoccus wistariae will produce honeydew and lead to sooty mold growth, yellowing of needles, and sparsely foliated plants. Eventual dieback may be possible. This species is commonly associated with taxus in New England, but can be occasionally found on dogwood, rhododendron, Prunus spp., maple, andromeda, and crabapple. These mealybugs are found on stems and branches and particularly like to congregate at branch crotches. Taxus mealybug feeds in the inner bark tissue of the trunk and branches. Adult females are present from June to August and give birth to living young in the summer. Immatures overwinter. A single generation may occur per year in New England, but areas to the south can have multiple generations of this insect. Management may be targeted between 246-618 GDD’s, base 50°F. Horticultural oil and neem oil may be used.
- Tuliptree Aphid: Illinoia liriodendri is a species of aphid associated with the tuliptree, wherever it is grown. Depending upon local temperatures, these aphids may be present from mid-June through early fall. Large populations can develop by late summer. Some leaves, especially those in the outer canopy, may turn brown or yellow and drop from infested trees prematurely. The most significant impact these aphids can have is typically the resulting honeydew, or sugary excrement, which may be present in excessive amounts and coat leaves and branches, leading to sooty mold growth. This honeydew may also make a mess of anything beneath the tree. Wingless adults are approximately 1/8 inch in length, oval, and can range in color from pale green to yellow. There are several generations per year. This is a native insect. Management is typically not necessary, as this insect does not significantly impact the overall health of its host. Tuliptree aphids also have plenty of natural enemies, such as ladybeetles and parasites.
- Twolined Chestnut Borer: Agrilus bilineatus is a native jewel beetle (also known as a flatheaded borer) in the Family Buprestidae. This insect is also in the same genus as the invasive emerald ash borer. The twolined chestnut borer is native to Massachusetts, much of New England, and the eastern United States. This species has one generation per year and adults are typically active from April – August, depending upon location and temperature. Adults will conduct some maturation feeding on oak prior to mating. Females will lay clusters of tiny eggs in the cracks and crevices of bark. Larvae hatch from the eggs in 1-2 weeks and burrow through the bark into the cambium, where they feed in a similar manner to the emerald ash borer, creating meandering galleries as they feed. (The galleries of the twolined chestnut borer can be straight in very stressed trees.) Larvae typically mature by August – October and burrow to the outer bark where they create a chamber in which they overwinter. Pupation occurs the following spring and adults emerge through D-shaped exit holes that are approximately 1/5 inch wide. In the northern extent of this insect’s range, they can take 2 years to complete their life cycle. Larvae of this insect have been recorded from eastern white oak, common post oak, burr oak, scarlet oak, northern red oak, and eastern black oak. Adults have been recorded on fir and pin oak. These insects are attracted to stressed host plants and typically become a secondary factor in the decline of the tree.
- Two-Spotted Spider Mite: Tetranychus urticae is a “warm-season” mite that loves hot and dry weather, which may favor the quick reproduction and build-up of this pest. Management should seek to preserve beneficial predatory mites. Monitor susceptible hosts (elm, maple, redbud, ash, black locust, tuliptree, and many deciduous shrubs) for increasing numbers of these mites until mid-August. Mites will be found on the undersides of leaves and cause stippling of the foliage.
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 .
A note about Tick Awareness: deer ticks (Ixodes scapularis), the American dog tick (Dermacentor variabilis), and the lone star tick (Amblyomma americanum) are all found throughout Massachusetts. Each can carry their own complement of diseases. Anyone working in tick habitats (wood-line areas, forested areas, and landscaped areas with ground cover) should check themselves regularly for ticks while practicing preventative measures. Have a tick and need it tested? Visit the web page of the UMass Laboratory of Medical Zoology (https://www.tickreport.com/ ) and click on the blue Order a TickReport button for more information.
Reported by Tawny Simisky, Extension Entomologist, UMass Extension Landscape, Nursery, & Urban Forestry Program