Recent insect-related submissions to the UMass Plant Diagnostic Laboratory:
Granulate ambrosia beetle: (Xylosandrus crassiusculus) A sample of Ilex opaca (American holly) was submitted to the UMass Plant Diagnostics Laboratory after collection on 7/6/2018. The host plant was one of multiple 7 ft. plants purchased from an out-of-state nursery. Adult, immature insects, and eggs were present in the sample material submitted.
- Status: Non-native, invasive ambrosia beetle from tropical and subtropical Asia; has been widely introduced elsewhere, including into the United States.
- Occurrence in USA: Alabama, Arkansas, Connecticut, Delaware, Florida, Georgia, Illinois, Indiana, Kansas, Kentucky, Louisiana, Maryland, Massachusetts (detected in traps in Bristol County in 2010), Michigan, Mississippi, Missouri, Nebraska, New Jersey, New York, North Carolina, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Carolina, Tennessee, Texas, Virginia, and West Virginia.
- Host Plants: Many, including but not limited to: aspen, beech, cherry, Chinese elm, crape myrtle, dogwood, golden rain tree, hickory, holly, Japanese snowbell, locust, Magnolia, maples, mimosa, oaks, peach, persimmon, redbud, sweet gum, tulip poplar, and walnut.
- Damaged Caused: includes visible symptoms such as wilted foliage, and "toothpick-like" wood shavings extending outside of entrance holes which are tiny and round. Branch die back and eventual death of the host plant is possible. The granulate ambrosia beetle tends to be a bit more aggressive than other closely related Xylosandrus spp. beetles, according to reports.
- Life Cycle: These tiny ambrosia beetles (females are 2.1-2.9 mm long and males are 1.5 mm long) bore into twigs, branches, or small trunks of susceptible woody plants. The females excavate a system of tunnels in the wood or pith and into these tunnels they introduce a symbiotic ambrosial fungus. Within the tunnels, the females produce young (a brood). Their young feed on the introduced fungi, not the wood or pith of the host. So the wood shavings produced by these insects are from tunneling activities and are not frass (excrement) produced through feeding. Eggs, larvae, and pupae are all found within the tunnels created by the females. This species does not make individual egg niches, larval tunnels, or pupal chambers. This species most commonly utilizes small diameter branches and stems. Males are rare.
- Hawthorn leafminer: (Profenusa canadensis) A sample of Crataegus spp. (hawthorn) was submitted to the UMass Plant Diagnostic Laboratory after collection on 7/10/2018. These are established trees in a landscape.
- Status: Native insect with at least two known wasp parasites (Aptesis segnis and Trichogramma minutum) which are often capable of managing populations.
- Occurrence in USA: Found in the Northeast, west to Iowa, Missouri, and Arkansas.
- Host Plants: This insect is commonly found on Crataegus crus-galli, C. persimillis, and C. erecta. C. mollis may be less commonly mined. This wasp-like sawfly was also first described as a pest of sour cherries, Prunus cerasus.
- Damaged Caused: Freshly hatched larvae begin to feed in the space between leaf surfaces. This feeding creates mines that eventually coalesce into blotches. These blotches become brown in color and may take up most of the leaf. By mid-June, the larvae drop from the leaves and much black colored, pellet-like frass (excrement) is left behind within the mines.
- Life Cycle: The sawfly is found in the pupal stage in the ground at the start of the growing season. When host plant leaves begin to unfold and blossom buds begin to open, the adult sawflies emerge. Female sawflies will lay their eggs singly in the upper epidermis at the base of the leaf. Freshly hatched larvae begin to feed in the space between leaf surfaces. Several larvae can be found in a single leaf. The larvae will mine together, eventually causing large blotches to form which can cover 1/2 the leaf. The larvae are flattened in shape and grow up to 7 mm. in length when fully grown. By mid-June, the larvae leave the foliage and drop to the ground to make cells in the soil within which to overwinter. From a distance, heavily infested trees look like they have been singed by fire due to the brownish cast of the leaves. Injury to the tree is not permanent, especially in years when new leaves develop rapidly.
Magnolia and Tuliptree scales: The soft scale insects included in the sample material submitted (Magnolia spp.) are either the Magnolia scale (Neolecanium cornuparvum) or the tuliptree scale (Toumeyella liriodendri). The sample, from an established tree in the landscape, was collected on 7/17/18 and sent to the UMass Plant Diagnostics Laboratory.
- Status: 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.
- Occurrence in USA: 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.
- Host Plants: 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. *On Magnolia, it is very difficult to distinguish between the two species of soft scale.
- Damaged Caused: 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.
- Life Cycle: 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.
Woody ornamental insect and non-insect arthropod pests to consider, a selected few:
- 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. Adult insects may be seen beginning in July in the regulated area in Massachusetts. 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, or believe you have captured or taken a photo of an adult insect, 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 .
- 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. When levels of damage reach a management threshold, pyrethroid- based insecticides may be necessary. Read and follow label instructions and avoid harming non-target organisms. Certain neem oil products are also labelled for use against adult beetles. Observe label instructions to minimize the potential for leaf injury.
- Deer Tick/Blacklegged Tick: Ixodes scapularis adult females, following a blood meal, can lay a single egg mass (up to 1500 – 2000 eggs) in mid-late May, then the female deer tick perishes. Larvae emerge from the eggs later in the summer. Larvae are tiny and six-legged. Prior to feeding, they are not known to be able to transmit disease. After feeding, the larvae drop from their host and molt, re-emerging the following spring as nymphs. Nymphs (from last year’s overwintering cohort) are active from May-August. Nymphs are eight-legged and about the size of the head of a pin. These tiny nymphs typically attach to small mammal hosts; however, they will readily feed on people and pets. Nymphs are capable of carrying Lyme disease, human Babesiosis, human Anaplasmosis, and deer tick virus. 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. 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 red “Test A Tick” 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.
You can also follow TickReport on Twitter @TickReport for timely updates from the Laboratory of Medical Zoology, including the latest tick and tick-borne disease related research.
- Emerald Ash Borer: (Agrilus planipennis, EAB) New community and county detections have been made in Massachusetts since the last Landscape Message was published. New community detections were made in Hampden and Berkshire Counties and EAB was detected for the first time in Bristol County, MA. All new detections were confirmed by the MA Department of Conservation and Recreation. 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 most recently, 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. 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 .
- 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 July depending on climate. Fall webworm caterpillars were reported for 2018 previously in the Pioneer Valley Region report and expanding webs were seen the week of 7/4/18 in Chesterfield, MA. 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.
- Lace Bugs: Corythucha spp. and Stephanitis spp. lace bugs are active. Corythucha spp. utilize many hosts such as hawthorn, cotoneaster, Amelanchier, quince, Pyracantha, various oaks, birch, maple, mountain ash, sycamore, hackberry, elm, walnut, butternut, basswood, etc. Corythucha spp. adult lace bugs were seen feeding on bur oak on 6/13/2018 in Amherst, MA. Many adult lace bugs were seen on leaf undersides, along with groups of tiny, black eggs. These groups of lace bug eggs were seen on nearly every leaf examined within reach on this tree. Egg are so small, they may look like fungal spores without magnification. Corythucha spp. adult and nymphal lace bugs were seen feeding on sycamore on 7/9/18 in Amherst, MA. The species that is most commonly found on sycamore is Corythucha ciliata, or the sycamore lace bug. This insect is found throughout the United States and parts of Canada. This lace bug, like most, can be found feeding on leaf undersides, initially causing a white stippling that can sometimes progress to chlorotic or bronzed foliage and may (when severe) lead to premature leaf drop.
Stephanitis spp. lace bugs are active. Yellow stippling on leaf surfaces, black colored tar-like spots on leaf undersides, and lace bug nymphs (immatures) were seen on leaf undersides on 5/30/18, 6/7/18, and 6/13/18 in Amherst, MA on Rhododendron spp. foliage. 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. Fall or early spring soil treatment with imidacloprid has been effective, but be aware of the implications this may have on pollinators attracted to these flowering plants when making management decisions. Certain azalea and Andromeda cultivars may be less preferred by lace bugs.
- Tuliptree Aphid: Illinoia liriodendri is a species of aphid associated with the tuliptree wherever it is grown. (They may at times also feed on magnolia, according to reports.) The tuliptree aphid was seen feeding on the undersides of leaves on 7/9/18 in Amherst, MA. 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 brown 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. If management is deemed necessary, select options that will preserve natural enemies, as ladybeetles and other beneficial insects are often associated with the tuliptree aphid.
- 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.
- 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 egg hatch was observed in Boston, MA on 5/4/2018. By early to mid-June, Viburnum leaf beetle larvae will crawl down the host plant, enter the soil surface, and pupate. This typically occurs when the larvae are just under ½ inch in length. After pupation, by early-July, adult beetleswill emerge from the soil and begin feeding on Viburnum foliageagain prior to mating and laying eggs. 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. Larvae, where they are present, may be treated with a product containing spinosad. 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 Spotted Pine Sawyer (WSPS): Monochamus scutellatus adults can emerge in late May throughout July, depending on local temperatures. The first report of a white spotted pine sawyer adult came from the Asian Longhorned Beetle Eradication Program in Worcester, MA. A concerned citizen in Hampshire County, MA reported (with a photo) a white spotted pine sawyer adult on 5/22/2018. A second report of 3 white spotted pine sawyers came to UMass Extension from a concerned citizen in Hampden County, MA on 6/8/2018. The report was given with photos that clearly allowed for the insect to be identified. This report was shared with the ALB Eradication Program. 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 adult white spotted pine sawyer looks very similar to the invasive Asian Longhorned Beetle, Anoplophora glabripennis, ALB. ALB adults do not typically emerge in Massachusetts until July and August. Now is the time to 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. (And where to go to report anything suspicious.)
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 red Test a Tick button for more information.
Reported by Tawny Simisky, Extension Entomologist, UMass Extension Landscape, Nursery, & Urban Forestry Program
