Scouting Re-Cap from the Landscape Pests and Problems Walkabout on 6/6/2018:
- For those of you who were not able to attend the Landscape Pests and Problems Walkabout focusing on insects and cultural problems, I will provide here a quick recap of the insect pests I discussed at this educational program. This “walkabout” was held at the beautiful Heritage Museums and Gardens in Sandwich, MA. It was a real treat for me to visit this location for the first time. I had the pleasure of meeting many of the Garden’s dedicated staff as well as some enthusiastic interns. The grounds are wonderful and the location is clearly a treasure for both tourists and locals alike.
I worked with Russ Norton, Horticulture and Agriculture Educator with Cape Cod Cooperative Extension, to co-lead this educational event. Like with the Heritage Museums and Gardens, Barnstable County is lucky to have Russ Norton. He is a great local resource and he discussed on our walk a variety of cultural, disease, and insect problems. For the purposes of this quick recap, I will not go over his topics. Russ and I were joined by an excellent, attentive group of professionals and landscape practitioners who, as always, make these programs a joy to hold.
While the Heritage Gardens are superb and clearly cared for, no location is 100% devoid of insect pests. If it were, our walkabout would certainly have been boring! In some cases, the insects we discussed were not present- but a host plant was that sparked the conversation. One example of this was with Chionanthus virginicus, or the white fringetree. It was noted that researchers have recently discovered that the emerald ash borer (EAB; Agrilus planipennis) can complete its life cycle in white fringetree. This was the first non-Fraxinus spp. host noted for EAB. No evidence of EAB infested white fringetrees in Massachusetts landscapes have yet been discovered, however this was a nice opportunity to recap the 8 confirmed counties in MA that have known EAB populations in ash. We also discussed the northerly expansion of the range of the southern pine beetle (Dendroctonus frontalis) and the threat that insect poses to our pitch pines. (Southern pine beetle has been detected in MA in traps only; no infested trees have been discovered to date.) We saw other commonly seen invasive insects, the hemlock woolly adelgid (Adelges tsugae) as well as the elongate hemlock scale (Fiorinia externa) on hemlock, although we ran out of time to discuss the latter in detail. Lily leaf beetle (Lilioceris lilii) adults and larvae were present on our garden tour, and I also passed around some imported willow leaf beetle (Plagiodera versicolora) adults and larvae (in a closed container). A pignut hickory’s leaves were being munched on by a gypsy moth caterpillar (Lymantria dispar), but more prevalent on this tree were the caterpillars of the fall cankerworm (Alsophila pometaria). The green color form of this insect was present, sporting 3 pairs of prolegs (that some describe as 2 and ½ due to the short length of the 3rd pair). The fall cankerworm is of course a common name that refers to the time the adults are active and laying eggs (late November/early December). This insect often co-occurs with the spring cankerworm (Paleacrita vernata) in mixed caterpillar populations. Both of these inchworm species can have a green and dark color form. They will soon drop to the soil to pupate. Winter moth (Operophtera brumata) caterpillar feeding damage was observed on crabapples and we discussed the recent data detailing the successes of the Cyzenis albicans biological control effort from the Elkinton Lab. Larval viburnum leaf beetles (Pyrrhalta viburni) were found feeding and skeletonizing leaves. Finally, rounded and brown soft scale insects were seen on oak twigs. The likely culprits are in the genus Parthenolecanium, perhaps P. quercifex (oak lecanium scale) or P. corni (European fruit lecanium). Both species look very similar to one another in the field, both are found on Quercus spp. and both have been recorded in Massachusetts.
If you are interested in attending such an educational opportunity, where you can see pests and problems up close and in person, another opportunity to join UMass Extension for a walkabout is coming up in July: https://ag.umass.edu/landscape/events/landscape-pests-problems-walkabout-insects-cultural-problems-0 .
Do not wait too long to sign up – space is limited and these walkabouts fill up fast!
Woody ornamental insect and non-insect arthropod pests to consider, a selected few:
- Gypsy Moth:(Lymantria dispar) host plants include but are certainly not limited to oak (favored), maple, birch, poplar, and many others. Gypsy moth caterpillars continue to feed and grow in size. Caterpillars observed on 6/7/18 in Amherst, MA are approximately 1 inch in length. Many are in the 3rd and 4th instars. (See Regional Reports above.) Caterpillars pictured in this week’s report have developed the red and blue pairs of warts or raised bumps recognizable in older gypsy moth caterpillars. They also have yellow coloration to their head capsule. Historically, gypsy moth caterpillars that have developed the yellow coloration on their head and those that are greater than ¾ inch in length are not as responsive to Btk (Bacillus thuringiensis Kurstaki) applications. (So the time for using that active ingredient has likely run out and professionals may need to start considering other options, such as spinosad.)
On 5/23/18 in Amherst, MA gypsy moth caterpillars were observed feeding on bur oak, elm, Norway maple, crabapple, fernleaf beech (Fagus sylvatica ‘Asplenifolia’), European linden, Rosa rugosa, and apple. Feeding damage from gypsy moth is becoming more apparent, and dark colored and hairy caterpillars can be seen on leaf undersides as well as leaf surfaces.
Despite the fungal outbreak that swept through the 2017 caterpillar population, some lucky caterpillars survived to pupation and emerged as adult moths. (However, adults were present in 2017 in far fewer numbers than would have existed without the fungus.) While it is very difficult to predict how much defoliation Massachusetts will see in 2018 due to gypsy moth caterpillar feeding, we can be certain that in areas where many egg masses were seen overwintering, pockets of defoliation could still occur in certain areas of the state this year. Thanks to the gypsy moth caterpillar-killing fungus, however, the population should be on the decline, but we cannot expect the caterpillars to disappear completely from Massachusetts landscapes this season.
- Winter Moth: (Operophtera brumata) caterpillars have pupated for the 2018 season. (See Regional Reports above.) Therefore, winter moth caterpillars will no longer be causing feeding damage in 2018 and they cannot be managed with chemical options at this time. Do not confuse the green color form of fall cankerworm (Alsophila pometaria) caterpillars for lingering winter moth caterpillars. Fall cankerworm caterpillars have three pairs of prolegs (one is shorter in length than the others are) while winter moth caterpillars have two pairs.
- 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. Adult insects of this species will not be present at this time of year.
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 .
- 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, and 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. 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 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.
- Eastern Tent Caterpillar: Malacosoma americanum tents are large and so are the eastern tent caterpillars. Tents may become vacant at this time as caterpillars wander away. Eastern tent caterpillars continue to be observed wandering on paved and dirt roads in Chesterfield, MA on 6/5/18, yet the number of wandering caterpillars has decreased in this location. Others are still reporting active caterpillars in other locations of the state (See Regional Reports above). Eastern tent caterpillars have likely begun to pupate in sheltered areas they locate, although not all individuals will do so at exactly the same time. Pupation for the species reportedly lasts around three weeks, and adult moths historically emerge between late June and early July.
- Elongate Hemlock Scale: Fiorinia externa is found on eastern, Carolina, and Japanese hemlock, as well as yew, spruce, and fir. Crawlers will be present this month and throughout the growing season and the overlap of many developmental stages at any given time can be observed. Treatments (active ingredients effective through contact) for the crawler, or mobile, stage of this insect may be made in late May through mid-June, or between 360-700 GDD’s, base 50°F. (Systemic options can be made at other times, such as the spring and fall.)
- Emerald Ash Borer: (Agrilus planipennis, EAB) 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). Adult emerald ash borers will be emerging from their hosts (ash) in locations that have reached roughly between 450 – 550 GDD’s, base 50°F. At this time, this includes areas in the North Shore, East, Metro West, Pioneer Valley, and Berkshires (see Environmental Data above). This is important to note, as anyone using traps and lures to detect the presence of EAB in their community should have their traps hung at this time. Signs of an EAB infested tree may include 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. As of 5/23/18 and continuing through 5/30/18, euonymus caterpillars are present, feeding, and creating an ample amount of webbing at a location in Amherst, MA. The caterpillars are present by the thousands in an understory, forested area. At this location, they have eaten nearly all euonymus leaves in sight. Caterpillars were very active the morning of 5/23/18, feeding in large groups and dangling from host plant branches on webbing.
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, and the plants at this location in Amherst are nearly defoliated. Management of young, actively feeding caterpillars with Bacillus thuringiensis is possible if deemed necessary, however many species of Euonymus are considered invasive themselves.
- Forest Tent Caterpillar: Malacosoma disstria caterpillars are still seen in Amherst, MA on 6/7/2018 some of them are 2 inches in length. One such caterpillar was seen resting in between the cracks and crevices of ash (Fraxinus spp.) bark. A slightly smaller caterpillar (1.5 inches) was seen feeding on European linden. Forest tent caterpillars are still significantly larger than gypsy moth caterpillars in this location at this time. They are hairy with visible blue lateral stripes and white “key-hole” or “penguin”-shaped spots from head to hind end dorsally. Susceptible hosts whose leaves are fed on by this insect include oak, birch, ash, maple, elm, poplar, and basswood.
- 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. Monitor susceptible hosts for small, inch-worm like caterpillars at this time. Where populations are low, no management is necessary.
- Imported Willow Leaf Beetle: Plagiodera versicolora overwintered adults are present and continue to be active and found on willow foliage. Adult beetles will chew holes and notches in the leaves of willow. Egg laying was observed on 5/16/18, 5/23/18, and 5/30/2018 in Chesterfield, MA.Females lay yellow eggs in clusters on the undersides of leaves. As of 5/30/2018, eggs have hatched at the location in Chesterfield, MA and multitudes of small imported willow leaf beetle larvae are feeding in groups. By 6/7/2018, these larvae have grown larger in size and have skeletonized many leaves. Larvae are slug-like and bluish-green in color. They feed in clusters. 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.
- Lace Bugs: Stephanitis spp. lace bugs are active and damage is becoming more apparent. 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 and 6/7/18 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.
- Lily Leaf Beetle: Lilioceris lilii overwintering adults continue to be active in Amherst, MA on 6/7/18 and mating is still occurring at this location. Susceptible hosts include Lilium spp. (Turk’s cap, tiger, Easter, Asiatic, and Oriental lilies) and Fritillaria spp. (Note: daylilies are not hosts.) Typically, in May, mating will occur and each female will begin to lay 250-450 eggs in neat rows on the underside of the foliage. In Amherst, MA, orange lily leaf beetle eggs were observed on the underside of host plant foliage on 5/16/2018 and some of these eggs hatched by 5/23/18. Frass-covered larvae were observed feeding on 5/23/18, 5/30/18, and again on 6/7/18 in Amherst, MA. Larvae are growing ever larger and eating entire leaves. Younger groups of eggs are hatching with still tiny larvae starting to feed by skeletonizing the leaf in groups. Where adults and larvae are seen, they can be removed from host plants with a gloved hand, where practical.
- Roseslugs: Two species of sawfly can be found on the leaves of roses at this time. These small, caterpillar-like larvae will skeletonize the upper leaf surface and leave a “window-pane” like pattern behind. When present in large numbers, these insects are capable of defoliating their entire host. Management options include an insecticidal soap spray or a product containing spinosad.
- Spotted Lanternfly: (Lycorma delicatula, SLF) is not known to occur in Massachusetts. The Pennsylvania Department of Agriculture reported on 5/14/2018 that spotted lanternfly eggs had begun to hatch in Berks County, PA for the 2018 season. Small, black and white spotted nymphs (immatures) were seen in PA at that time.
This insect is a member of the Order Hemiptera (true bugs, cicadas, hoppers, aphids, and others) and the Family Fulgoridae, also known as planthoppers. This insect is a non-native species first detected in the United States in Berks County, Pennsylvania and confirmed on September 22, 2014. Until November 2017, this invasive insect was only known to Pennsylvania. It has now been reported from Delaware (November 20, 2017), New York (November 29, 2017), and most recently in Virginia (January 10, 2018). The Delaware Department of Agriculture announced the finding of a single female spotted lanternfly in New Castle County in the Wilmington, Delaware area. At this time, officials in Delaware note that it is unclear if this individual was an accidental hitchhiker, or evidence of an established population in the state. For more information about the find in Delaware, visit: https://news.delaware.gov/2017/11/20/spotted-lanternfly-confirmed-delaware/ . The New York State Department of Agriculture and Markets reported on November 29, 2017 the finding of a single dead individual spotted lanternfly in the state from earlier in the month. A single dead specimen was confirmed at a facility in Delaware County, New York, which is located south-west of Albany. The NYS Dept. of Agriculture and Markets states that this dead individual may have come in on an interstate shipment. For more information about the find in New York, visit: https://www.agriculture.ny.gov/AD/release.asp?ReleaseID=3637 . Most recently, Virginia Cooperative Extension announced the finding of a spotted lanternfly population in Frederick County, Virginia, on January 10, 2018. It was noted that at the location in Virginia, numerous adult lanternflies and egg masses were discovered, in addition to more at another site approximately 400 yards away. For more information about the find in Virginia, visit: https://ext.vt.edu/agriculture/commercial-horticulture/spotted-lanternfly.html .
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 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 .
- Spruce Spider Mite: Oligonychus ununguis is a cool-season mite that becomes active in the spring from tiny eggs that have overwintered on host plants. Hosts include spruce, arborvitae, juniper, hemlock, pine, Douglas-fir, and occasionally other conifers. This particular species becomes active in the spring and can feed, develop, and reproduce through roughly June. When hot, dry summer conditions begin, this spider mite will enter a summer-time dormant period (aestivation) until cooler temperatures return in the fall. This particular mite may prefer older needles to newer ones for food. Magnification is required to view spruce spider mite eggs. Tapping host plant branches over white paper may be a useful tool when scouting for spider mite presence. (View with a hand lens.) Spider mite damage may appear on host plant needles as yellow stippling and occasionally fine silk webbing is visible.
- Taxus Mealybug: Dysmicoccus wistariae was spotted on taxus in Amherst on 5/23/18, 5/30/18, and again on 6/7/18. This insect 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. Management may be targeted between 246-618 GDD’s. Horticultural oil and neem oil may be used.
- 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. In the case of this individual observed on 6/7/18 in Amherst, MA, it was lingering on an elm leaf. There are oaks nearby, so this could just be happenstance as the insect searches for a suitable host. These insects are attracted to stressed host plants and typically become a secondary factor in the decline of the tree.
- 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. Viburnum leaf beetle larvae continue to feed and grow in size. (See Regional Reports above.) As the larvae grow larger, damage to plants becomes more significant. 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 beetles will emerge from the soil and begin feeding on viburnum foliage again 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. 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 emerge in Massachusetts until July and August. Beginning in July, 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.)
- Woolly Apple Aphid: Eriosoma lanigerum may be found on apple, crabapple, hawthorn, mountain-ash, Pyracantha, and elm hosts. The primary (winter) host is elm, on which aphids infest emerging spring leaf growth, causing leaves to curl or close into stunted, rosette-like clusters found at twig tips. Woolly apple aphid was observed on elm on 5/23/2018 in Amherst, MA. On apple and crabapple, this species of aphid colonizes roots, trunks, and branches in the summer and is commonly found near previous wounds or callous tissue. On roots, the aphids cause swelled areas which can girdle and kill roots. The aphids, when found in above ground plant parts such as elm leaves are covered with white wax. Eggs are the overwintering stage on elm, which hatch in the spring in time for the nymphs to infest elm foliage. Following a few generations on elm, the aphids will develop into a winged form, which will disperse and seek out apple and crabapple. Small numbers of winged individuals were observed on elm on 5/31/2018 in Amherst, MA. These individuals were mixed with younger, non-winged aphids in their rosette-like deformed leaves. Multiple generations will occur on these alternate hosts in the summer and by the fall, a winged form will return to elm and mated females will lay eggs near elm buds.
- Woolly Elm Aphid: Eriosoma americanum females lay a single egg in the cracks and crevices of elm bark, where the egg overwinters. Eggs hatch on elm in the spring as leaves are unfolding. A young, wingless female hatched from the egg feeds on the underside of leaf tissue. This female aphid matures and gives birth to 200 young, all females, without mating. These aphids feed, and the elm leaf curls around them and protects them. Curled leaves, sheltering feeding, honeydew-producing aphids within, were observed on elm in Amherst, MA on 5/16/2018 and again on 5/23/2018. By the end of June, winged migrants mature and find serviceberry hosts. Oddly enough, on 5/31/2018 at the same location in Amherst, MA, a few winged individuals were seen within folded leaves. Most of the aphids were still wingless. Another set of females is produced. These new females crawl to and begin feeding on the roots of serviceberry. Multiple generations occur on the roots of serviceberry through the summer.
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