UMass Extension's Landscape Message is an educational newsletter intended to inform and guide Green Industry professionals in the management of our collective landscape. Scouts compile and record environmental and phenological data for locations throughout Massachusetts to aid in the monitoring of plant and pest development, the planning of management strategies, and the creation of site-specific records for future reference. Detailed reports from Extension specialists on growing conditions, pest activity, and cultural practices for the management of woody ornamentals, trees, and turf are regular features. UMass Extension has updated the following issue to provide timely management information and the latest regional news and environmental data.
The Landscape Message will be updated weekly April through June. The next message will be available on April 29. To receive immediate notification when the next Landscape Message update is posted, be sure to join our e-mail list.
NEW! To read individual sections of the message, click on the section headings below to expand the content:
Scouting Information by Region
Environmental Data
The following growing-degree-day (GDD) and precipitation data was collected for an approximately one week period, April 14 through April 20. Soil temperatures and phenological indicators were observed on or about April 20. Total accumulated growing degree days (GDD) represent the heating units above a 50° F baseline temperature collected via our instruments for the 2016 calendar year. This information is intended for use as a guide for monitoring the developmental stages of pests in your location and planning management strategies accordingly.
|
Region/Location |
GDD |
Soil Temp |
Precipitation |
Time/Date of Readings |
||
|
1-Week Gain |
2016 Total |
Sun |
Shade |
|||
|
Cape Cod |
2 |
55 |
54 |
45 |
0.02 |
1:30 PM 4/20 |
|
Southeast |
6 |
60 |
56 |
50 |
0.07 |
2:00 PM 4/20 |
|
North Shore |
2 |
50 |
46 |
41 |
0.02 |
10:15 AM 4/20 |
|
East |
3 |
61 |
57 |
52 |
0.02 |
3:30 PM 4/20 |
|
Metro West |
8.5 |
47 |
46 |
44 |
0.00 |
5:45 AM 4/20 |
|
Central |
19 |
77 |
56 |
43 |
0.06 |
9:00 AM 4/20 |
|
Pioneer Valley |
18 |
59 |
53 |
49 |
0.00 |
11:00 AM 4/20 |
|
Berkshires |
13 |
50 |
51 |
46 |
0.00 |
9:40AM 4/20 |
|
AVERAGE |
9 |
57 |
52 |
46 |
0.02 |
- |
|
n/a = information not available |
||||||
Phenology
Phenological indicators are a visual tool for correlating plant development with pest development. The following are indicator plants and the stages of bloom observed for this period:
| Indicator Plants - Stages of Flowering (BEGIN, BEGIN/FULL, FULL, FULL/END, END) | ||||||||
|---|---|---|---|---|---|---|---|---|
| PLANT NAME (Botanic/ Common) | CAPE | S.E. | N.S. | EAST | METRO W. | CENT. | P.V. | BERK. |
| Cercis canadensis (Redbud) | * | * | * | * | Begin | * | Begin | * |
| Amelanchier spp. (Shadbush, Serviceberry) | * | * | Begin | Begin | * | * | Begin/Full | Begin |
| Pyrus calleryana (Callery Pear) | * | Begin | Begin/Full | * | Begin | Begin | Begin/Full | * |
| Chaenomeles speciosa (Common Flowering quince) | Begin | Full | * | Begin | Begin | * | Begin | Begin |
| Magnolia soulangiana (Saucer Magnolia) | Begin | * | Full | * | Full | Begin | Full | * |
| Rhododendron 'P. J. M.' | Begin |
Begin/Full |
Begin/Full | Begin/Full | Begin/Full | Begin | Begin | * |
| Prunus serrulata (Japanese Flowering Cherry) | Full | Full | Full | * | Begin/Full | Begin | Begin | * |
| Forsythia x intermedia (Border Forsythia) | Full | Full | Full/End | Full/End | Full/End | Full/End | Full/End | Full |
| Rhododendron mucronulatum (Korean Rhododendron) | Begin/full | * | * | * | End | * | * | * |
| Magnolia stellata (Star Magnolia) | Full | Full | Full/End | * | Full/End | Full | Full/End | * |
| Pieris japonica (Japanese Pieris) | Full | Full | Full | Full | Full | Full | Full | Full |
| * = no activity to report/information not available | ||||||||
Regional Notes
Cape Cod Region (Barnstable)
General Conditions: It has been a cool and windy week on Cape Cod. Daytime temperatures have stayed mostly in the upper 40s to low 50s, with almost constant winds off the water making working outdoors less than ideal. Saturday the 16th had a high temperature of 44° F with gale force winds and a wind chill of 32°! Temperatures improved greatly on Sunday and Monday, when the wind died down and temperatures made to the low 60s, but temperatures went down on the 19th and the wind off the water returned. At least it has been bright and sunny for the most part. Lungwort (Pulmonaria spp.), Pansies (Viola spp.), and Daffodils are all in bloom.
P.J.M Rhododendrons and Norway maple are also beginning to bloom. Vinca is in full bloom. Lawns have greened up and mowing season is well under way.
Pests/Problems: Damage to plants from the freezing temperatures two weeks ago continues to show up. Foliage of daylilies is discolored, distorted, and appears water soaked as a result. The annual spring “streaking” of daylilies is also beginning to show up. Winter moth hatch continues; silken strands can be observed on trees and shrubs. Lily leaf beetle is active and feeding on emerging true lily foliage. Cutworms are active, as are Tent caterpillars and carpenter bees. Monitor Canadian hemlock for Hemlock Wooly Adelgid. Adult deer ticks are active. White cabbage butterfly is actively seeking host plants. Dandelions and Bittercress are blooming.
The Cape is a bit on the dry side, especially with all the wind. The last decent rainfall was on April 7thh; since then the Cape has received less than 0.5”. Be sure to water newly planted trees, shrubs, and perennials.
Southeast Region (Hanson)
General Conditions: Hanson received 0.7 inches of rain this past week and soils are dry. Weather was sunny, windy and on the cool side (50’s daytime). Cooler weather has slowed plant development, so plants like Magnolia stellata, Magnolia kobus var. loebneri 'Leonard Messel, Magnolia 'Wada's Memory’ and Lonicera fragrantissima (winter honeysuckle) remain in bloom. After the initial freeze a few weeks ago which damaged some of the emerging magnolia buds, in many areas the remaining undamaged buds were plentiful enough to open and continue to provide color and interest. Depending on location, PJM Rhododendrons are in full bloom, or not, depending on bud damage due to the previous cold weather in February and April. On many plants, bud damage was severe and flowering is “hit or miss”. Sugar maple, Norway maple, Prunus sp. (cherries), Lindera benzoin (Common Spicebush), Chaenomeles speciosa (Common Floweringquince), Vaccinium corymbosum (highbush blueberry), Forsythia, Pieris japonica, Pieris floribunda, Pieris 'Brouwer's Beauty', Spiraea thunbergii 'Ogon', Anemones, Primula, daffodils, hyacinths, Chionodoxa luciliae, Dicentra cucullaria (Dutchman's Breeches), Pachysandra terminalis, Pachysandra procumbens, Helleborus foetidus, H. x hybridus, Corydalis solida, Trillium, Phlox subulata, Ranunculus ficaria and Vinca minor are in full bloom. Epimedium sp., Lamium, Lunaria sp., Lathyrus vernus, Pulmonaria, Epimedium sp., Brunnera macrophylla and Ajuga are beginning to bloom and Petasites japonicus (Japanese butterbur) is ending bloom.
Pests/Problems: Although we had a warm winter and thought, perhaps, that winter moth would complete hatch earlier than usual, in fact the cold in April pushed-back winter moth development, resulting in a hatch that began April 1st in Hanson, MA and is concluding just now, April 20th. Base 40 growing degree days are at 290. There are still a few eggs hatching, but for the most part, winter moth eggs have just about finished hatching. Most of the caterpillars are 1stt instar but some are 2nd instar. Caterpillars were found in the developing buds of: blueberry, crabapple, apple, European beech, maples (Japanese, red, Norway) and feeding on the flower buds of lilac ‘James MacFarlane’. The most winter moth caterpillars I observed today were in Japanese maples. Staff at Dr. Elkinton’s lab has seen high numbers of caterpillars on buds sampled in West Bridgewater and report that for now it seems that the “cold snap may have had no impact” on winter moth numbers. However, as usual, that could change as the season progresses. Stay tuned, as we continue to get updates from Dr. Elkinton’s lab. For now, continue to monitor for winter moth caterpillars on susceptible species, especially in those areas with a heavy winter moth flight last fall and manage early to avoid extensive damage .(See Tawny Simisky’s Insect Section of the Landscape Message). Snowball aphids are active now on viburnum; their feeding causes the foliage to twist and curl, but does no significant damage. Monitor for the bright red lily leaf beetle and manage when seen. This pest of true lilies can destroy the plants unless managed. Monitor for eastern tent caterpillar on crabapples, apples and wild cherry. Monitor for spruce spider mite on spruce, fir, hemlock, arborvitae, etc. Although there was high mortality of hemlock woolly adelgid (HWA) this past winter, continue to monitor hemlocks for this pest and manage if needed. Black flies, carpenter bees, bumblebees, honeybees, solitary bees and deer ticks are active. Ground ivy is starting to bloom and violets, dandelions and chickweed are in full bloom. Bittercress continues to form seed heads. Rabbits and turkeys continue to browse. Vole damage to Hosta, Epimedium and other perennials continues to show up. White cabbage butterflies and blue, azurea butterflies were observed this week flitting about the gardens. Nice.
North Shore Region (Beverly)
General Conditions: In the past week we had pleasant spring weather. Day temperatures were in the mid 50s except on Monday, April 18th when the temperature climbed to 64 degrees. Night temperatures were on the cooler side, mainly in the mid 30s. This past week we gained only 2 growing degree days at Long Hill. There was very little precipitation during the past week and relative humidity was very low. Woody plants seen in bloom include: Anise Magnolia (Magnolia salicifolia), Cylindrica Magnolia (Magnolia cylindrica), Leonard Messel Magnolia (Magnolia x loebneri), Merrill Magnolia (Magnolia x loebneri ‘Merrill’), Sargent Cherry (Prunus sargentii), Star magnolia (Magnolia stellata), Beatrix Farrand forsythia (Forsythia ‘Beatrix Farrand’) and Border forsythia (Forsythia suspensa var. sieboldii). Non-woody plants seen in bloom include: Bloodroot (Sanguinaria canadensis), Glory of the snow (Chionodoxa sp.), Vinca vine (Vinca minor), Daffodil (Narcissus spp.) and Hellebores (Helleborus orientalis).
Pests/Problems: Because of very low relative humidity, the conditions are ideal for brush fires. Fire weather warnings have been issued for several days. Everyone should be careful when working outdoors. Ticks are active and people should be careful to protect themselves when working outdoors. Some weeds seen in bloom include: Dandelion (Taraxacum officinale), Fig buttercup (Ranunculus ficaria), Ground Ivy (Glechoma hederacea) and Purple Deadnettle(Lamium purpureum). Norway maple (Acer platanoides) which is classified as an invasive plant is also in full bloom. Try to control them before they go into seed. Also seen in the landscape are fungal leaf spots of mountain laurel. They seem to be severe under shaded areas. Rake and remove fallen leaves from the vicinity of the shrubs in the fall to reduce the number of spores available to infect in the spring.
East Region (Boston)
General Conditions: Cool spring temperatures continue, a light frost was visible on turf on the morning of the 13th and 14th. Low temperatures over the last week were consistently in the 30’s until the 19th, when the low reached 44° F. Highs averaged 55.9° F over the last week, peaking at 67° F on the 18th. We gained 3.0 GDDs on April 18th bringing us up to 61.0 for the year. The week has been dry, a brief shower on the morning of the 19th delivered 0.02 inches of rain. Turfgrass has completely greened up and Prunus species (flowering cherries) continue to come into bloom adding color to the landscape. Additional plants in bloom include: Acer platanoides (Norway maple), Amelanchier arborea (downy serviceberry), Lindera benzoin (spicebush), Muscari sp. (grape hyacinth), Phlox stolonifera (creeping phlox), Rhus aromatica (fragrant sumac), Ribes fasciculatum (winterberry currant), Sanguinaria canadensis (bloodroot), and Tulipa sp. (tulip).
Pests/Problems: Aphids have been spotted on many Rosaceae (Rose family) plants including Malus sp. (crabapple and apple), Prunus sp. (apricot, cherry, plum), and Sorbus sp. (mountain ash); the damaged curled leaves of new growth is easily visible. Winter moth caterpillars continue to actively feed inside the buds. Ficaria verna (lesser celandine or fig buttercup) is lush and flowering throughout the landscape. Dandelion (Taraxacum officinale), ground ivy (Glechoma hederacea), purple deadnettle(Lamium purpureum), and violets (Viola sp.) are flowering in unmanaged turf. Basal rosettes of Alliaria petiolata (garlic mustard) are getting bigger every day and are becoming an eyesore in mulched beds.
Metro West (Acton)
General Conditions: Spring is exploding with the recent spell of summer like temperatures. Despite the warm daytime temperatures, the evening and early morning temps have been cool and enough so that I have had to remove the frost from my car windows on the mornings of the 13th, 14th and 15th. There has not been any precipitation recorded for this area in the past eight days, since April 13th. Much is in bloom for this time of the year, including the following woody plants: Cercis canadensis (Redbud), Chaenomeles speciosa (Common Flowering Quince), Erica sp. (Heath), Forsythia spp. (Forsythia), Lindera benzoin (Common Spicebush), Magnolia x loebneri 'Merrill', M. x soulangeana (Saucer Magnolia), Pieris japonica (Japanese Pieris), Prunus spp. (Cherry), Pyrus spp. (Pear),and Rhododendron 'P. J. M.' (PJM Rhododendron). Contributing even more color and interest to the landscape are some flowering herbaceous plants and spring ephemerals including: Anemone nemorosa (Wood Anemone), Asarum europaeum (European Ginger), Aurinia saxatilis (Basket of Gold), Caltha palustris (Marsh Marigold), Chionodoxa luciliae (Glory of the Snow), Claytonia virginica (Virginia Spring Beauty), Dicentra cucullaria (Dutchman's Breeches), Erythronium americanum (Yellow Trout-Lily), Helleborus niger (Christmas Rose), Hyacinthus spp. (Hyacinth), Mertensia virginica (Virginia Bluebells), Muscari sp. (Grape Hyacinth), Narcissus spp. (Daffodil), Omphalodes verna (Blue-eyed Mary), Pachysandra procumbens (Allegheny Spurge), P. terminalis (Japanese Pachysandra), Phlox subulata (Moss Phlox), Primula spp. (Primrose), Pulmonaria longifolia (Lungwort), P. rubra (Salmon colored Lungwort), Puschkinia libanotica (Striped Squill), Sanguinaria canadensis (Bloodroot), S. canadensis 'Multiplex' (Double Bloodroot), Scilla siberica (Siberian Squill), Trillium erectum (Red Flowering Trillium), T. sessile (Toadshade), Tulipa spp. (Tulip), Vinca minor (Periwinkle) and Viola spp. (Violet).
Pests/Problems: April showers bring May flowers, right? Well it has been eight days without any precipitation and there is not any rain in the forecast until the end of the weekend. Let’s hope that the forecast is correct! Acer platanoides (Norway Maple) is in full bloom. This invasive tree is hard to miss now that it is in bloom and its flowers are yellowish-green and it is found growing most everywhere. Ticks are active so continue to monitor yourself and others for these parasites. Wear light color clothes to make the job easier on you. Also, seen flourishing everywhere is the basal foliage of Alliaria petiolata (Garlic Mustard). Other weeds seen in bloom but without the invasive tendency of the previous two mentioned are: Draba verna (Spring Whitlow Grass), Glechoma hederacea (Ground Ivy) and Lamium purpureum (Purple Deadnettle), Stellaria media (Common Chickweed), and Taraxacum officinale (Dandelion).
Central Region (Boylston)
General Conditions: Sunny days and spring warmth has brought more plants to the brink of bloom. For woody plants Magnolia 'Merrill' is in full bloom though petals are showing damage from the early april cold. Magnolia soulangiana is beginning to bloom and showing similar damage. Lindera benzoin is in full bloom, as is Lonicera x purpusii. Daffodils are blooming along with Scilla siberica, Chionodoxa forbesii, Puschkinia libanotica and Muscari aremeniaca. Vinca minor is in full bloom, Cherries are begining to bloom. Spring ephemerals like Corydalis solida, Sanguinaria canadensis, and Anemone blanda are in full bloom. Mertensia virginica is beginning to bloom. Phlox subulata is in full bloom. Turf is lush and green in spite of the somewhat dry conditions and our first mow was last week.
Pests/Problems: Ticks continue to be a problem, and now black flies are active.
Pioneer Valley Region (Amherst)
General Conditions: Spring is rapidly progressing in the Connecticut River Valley thanks to the warm weather over this past reporting period. Daily high temperatures progressively increased from 4/13 to 4/18, starting in middle 50s and peaking in the upper 70s on Patriot’s Day (4/18). Winds have been subdued a bit compared to earlier this month but repeated red flag warnings have been issued due to the high risk of wildfire in the region. Nighttime temperatures remain cool, mostly settling in the middle to upper 30s each night with exceptions. Sugar/red/Japanese maples, Red/pin/bur oaks, paper birch, Japanese stewartia, horsechestnut, Washington elm and serviceberry are just some of the trees and shrubs observed on the UMass campus flushing new foliage. For conifers, larch is producing new needles and white pine candles are elongating but all others are still dormant. Soil temperatures have increased significantly in both exposed and shaded settings, increasing ~10 °F in less than a week. According to the Northeast Regional Climate Center, the first half of April was considerably cooler than average throughout the northeast. In the Pioneer Valley, conditions were 2–6 °F below average (http://www.nrcc.cornell.edu). Total precipitation to date this month (4/1 – 4/20) is just 1.35″ with minor accumulations forecasted over the next week. The warm days, low humidity and spring winds have dried the soil surface. Overall, soils remain moist but newly planted trees and shrubs in exposed settings should be monitored closely to avoid early season drought stress.
Pests/Problems: Based on samples submitted to the UMass Extension Plant Diagnostic Lab and scouting in the Amherst area, the Norway spruce gall midge is very abundant on landscape Norway spruce. For many trees, the damage is minor and easily overlooked. However, on some trees the damage is significant, leading to needle loss and canopy dieback. Scout Norway spruce for distorted shoot tips, premature needle shedding on 2015 shoots or shoots with brown, desiccated needles that may mimic salt injury on conifers. Distorted shoots may be abnormally swollen and may have exit holes at the base where the galls typically occur. Warm and prolonged dry weather create ideal conditions for spider mites. While not yet active, the spruce spider mite can be a highly destructive pest on arborvitae, spruce, hemlock, true fir, among others. Scout with a hand lens for egg masses and previous year’s damage (flecking and off-color needles, especially on branches closer to the main trunk). Eastern tent caterpillar tents have been observed on crabapple. Scout this host and cherries for tents and larvae and remove or treat. Now that sugar maple is leafing out, the young, succulent foliage is highly susceptible to maple anthracnose. The dry weather helps to suppress anthracnose fungi but these pathogens can respond quickly to any rainfall we will receive over the next few weeks. Spruce needle rust pustules on blue spruce are still not yet swollen and remain somewhat cryptic without careful inspection. Use a hand lens to scout green blue spruce needles for the needle cast pathogen Stigmina. It will appear as a fine, black dust emerging from the stomata. This pathogen has been abundant on recent samples submitted to the diagnostic laboratory.
Berkshire Region (Great Barrington)
General Conditions: Average daily temperatures for the week were above normal for this time of year, with a high temperature of 76° F in April 18. There was one report of 82° F on that date in the West Stockbridge. The combination of sun, wind, low humidity, and zero precipitation has depleted much moisture from soils, leaving the top 1-2 inches of soil in most locations quite dry. Since April 18, Berkshire County has been under a daily Red Flag Warning to date (4/20). As such outdoor burning is prohibited. During such weather conditions, outdoor workers should keep track of such warnings. The warm weather has pushed plant development along but many plants are a little behind in their development for this time of year. Among the plants in bloom now are Pulmonaria, Caltha palustris (Marsh Marigold), Vinca minor, Petasites japonica (Japanese butterbur), Scilla siberica, Primula spp., Narcissus spp., Chionodoxa spp. Helleborus spp. and Anemone blanda. Dandelions have come into bloom and garlic mustard (Alliaria petiolata) has set flower buds but they are yet open.
Pests/Problems: More of the damage to plants from low temperatures of mid-February and early April are becoming apparent. The foliage of crabapple and many viburnums is either severely damaged or showing considerable marginal leaf necrosis. Rhododendrons in open areas are also showing much foliar desiccation. Flower buds on many Magnolia stellata, M. soulangiana, and early blooming magnolia hybrids are dead in the Housatonic River Valley of Berkshire County, but I have received reports that these same species are flowering in the southern most parts of the County and in the higher elevations where late flowering is normal. Pest activity is low. Deer ticks are active as is Hemlock eriophyid mite. Animal damage to emerging vegetation is increasing with deer, woodchucks, rabbits, and voles being the primary perpetrators.
Regional Scouting Credits
- CAPE COD REGION - Roberta Clark, UMass Extension Horticulturist for Barnstable County - Retired, reporting from Barnstable.
- SOUTHEAST REGION - Deborah Swanson, UMass Extension Horticulturist for Plymouth County - Retired, reporting from Hanson.
- NORTH SHORE REGION - Geoffrey Njue, Green Industry Specialist, UMass Extension, reporting from the Long Hill Reservation, Beverly.
- EAST REGION - Kit Ganshaw & Sue Pfeiffer, Horticulturists, reporting from the Arnold Arboretum, Jamaica Plain.
- METRO WEST REGION – Julie Coop, Forester, Massachusetts Department of Conservation & Recreation, reporting from Acton.
- CENTRAL REGION - Joann Vieira, Superintendent of Horticulture, reporting from the Tower Hill Botanic Garden, Boylston.
- PIONEER VALLEY REGION - Nick Brazee, Plant Pathologist, UMass Extension Plant Diagnostic Lab, reporting from UMass Amherst.
- BERKSHIRE REGION - Ron Kujawski, Horticultural Consultant, reporting from Great Barrington.
Woody Ornamentals
Diseases
Recent pathogens of interest seen in the UMass Extension Plant Diagnostic Lab:
Stem cankering on weeping blue Atlas cedar (Cedrus atlantica ‘Glauca Pendula’) caused by Sirococcus and Botryosphaeria. Tree is 30-years-old and has been present at the site nearly as long. Approximately four years ago, stem and branch dieback was first observed and the condition has since worsened. Sirococcus can be found attacking many different conifers but is most often present in coastal locations where fog and humidity are higher compared to inland sites.
Cyclaneusma needle cast of Scots pine (Pinus sylvestris). Tree is 10-years-old and has been present at the site for five years. Earlier this year, needles began to brown but lacked noticeable symptoms of needle cast disease (e.g. banding on the needles). Cyclaneusma attacks various pine species but is most common in this region on Scots pine sheared for Christmas tree production. When established, it can lead to significant needle loss, leaving only the current year’s growth in the canopy.
Needle tip blight of arborvitae (Thuja occidentalis) caused by Pestalotiopsis and spruce spider mite (Oligonychus unuguis). Trees of unknown age planted in 2010 at a sunny, lakeside home. During the summer of 2015, needle tips turned brown throughout the canopy on most of the trees and one is near death. Trees are irrigated and soils are not excessively drained.
Volutella leaf and stem blight of Pachysandra. Two plantings at the same site, one in full sun and an older planting in a partial-sun setting. Zonate, marginal leaf spots, stem lesions and complete collapse of the foliage was observed (pictured below). Both plantings receive overhead irrigation, which facilitated disease development and spread.
For more detailed management information for woody plant diseases in the landscape, refer to UMass Extension's Professional Management Guide for Diseases of Trees and Shrubs.
Report by Nick Brazee, Plant Pathologist, UMass Extension Plant Diagnostic Lab, UMass Amherst.
Insects
Woody ornamental insect and non-insect arthropod pests to consider, a selected few:
- Azalea Sawfly: Amauronematus azalae will be active on deciduous azaleas as soon as new foliage emerges. Monitor for the feeding damage of this caterpillar as soon as new foliage appears and continue monitoring for 3-4 weeks after. In that amount of time, this insect could completely defoliate the plant if present in large numbers. Spinosad based products are effective on this hymenopteran pest, while Bacillus thuringiensis Kurstaki is not.
- Balsam Twig Aphid: Mindarus abietinus is active between 30-120 GDD’s, base 50° F. Inspect the needles of fir for “stem mothers” that will soon be reproducing. Young aphid feeding will lead to distorted foliage. Excessive amounts of honeydew are produced and cause needles to stick together. Monitor for the presence of reproducing females and treat with an oil application as weather permits.
- Cooley Spruce Gall Adelgid: Adelges cooleyi is active between 20-91 GDD’s, base 50°F. This insect can be found in the crevices of bark on terminal twigs and bases of buds of blue spruce, Norway spruce, and Douglas fir.
- Eastern Tent Caterpillar: (Continued monitoring) Eastern tent caterpillar larvae will have begun to hatch in areas accumulating between 50+ GDD’s, base 50°F at this time. Prune and remove any remaining egg masses that have not hatched yet and monitor host plants for any small webs found in the crotches of branches over young larvae and remove. There is still plenty of time to remove Forest Tent Caterpillar egg masses before we reach 192 GDD, base 50°F, when hatch will occur. Continue to monitor for Gypsy Moth egg hatch as we reach 90 GDD’s.
- Hemlock Eriophyid Mite: Nalepella tsugifoliae (also known as the hemlock rust mite) is currently active and should be monitored for on eastern hemlock, spruce, fir, and yew.
- Honeylocust Plantbug: Diaphnocoris chlorionis generally appears at the same time as bud-break of the host plant. It immediately begins to feed on the foliage with its piercing-sucking mouth. If numbers are low and the foliage expands quickly then damage is insignificant. Damage in this case will appear as scattered patches of fine yellow stippling on parts of the leaflets. However, if this pest is present in large numbers or foliage expands slowly, damage may warrant management. Monitor for numbers of this pest by gently shaking branches over a white piece of paper. Examine carefully with a hand lens for the tiny pale green nymphs. Young nymphs can be treated with a spray of insecticidal soap.
- Lily Leaf Beetle: Lilioceris lilii should be monitored for at this time. Management can be achieved by hand-picking and removing adults and larvae. Some chemical management options are available for this insect, but if caught early mechanical management may be effective.
- Pine Bark Adelgid: Pineus strobi has been observed in the Amherst area actively feeding at this time and secreting large amounts of waxy-white wool over their bodies (on white pine). This insect can be found on the trunk, twigs, and branches of white, Scotch, and Austrian pines. These cottony masses can even be seen on the bases of needles. On healthy trees, this insect has not warranted management as they appear unaffected by its feeding. If aesthetically unpleasant, adelgids and wool may be washed off with a strong stream of water from a garden hose on smaller plants.
- Viburnum Leaf Beetle: Pyrrhalta virburni: now is the time to inspect susceptible plants (viburnum) for over-wintering eggs on stems toward branch tips. Removal and destruction of infested stems, if small in number, can be effective. If management this way is not possible, larvae may be treated with a product containing spinosad once they appear soon after bud break.
Winter Moth: (Continued monitoring) Operophtera brumata egg hatch is nearly complete in all locations in Massachusetts with the exception of the Cape Cod areas, lagging behind by approximately one week. The Elkinton lab reports that the cold snap experienced the week of April 8thmay have had little impact on the health and mortality of previously hatched caterpillars. For example, they observed caterpillars in 20 buds sampled from West Bridgewater and found 80 caterpillars total, most of which were healthy. The one impact the cold temperatures around April 8th may have had was to delay egg hatch for a percentage of the winter moth population. This means that we may be seeing caterpillars in different stages of their development at the same time (as mentioned in last week’s Landscape Message and can be seen in this week’s Southeast Region report). In blueberry, if buds are still tight or just beginning to open, an application of spinosad would be appropriate at this time to manage caterpillars (that is, if you are not also dealing with spotted wing drosophila, in which case you may need to reserve your spinosad applications for that insect). If plants are already flowering, do not spray. In apple, the same treatment would be appropriate if plants are still in the green tip stage or as buds open and separate. For green industry professionals looking to manage winter moth in the landscape this season, monitor for caterpillars on bud scales or wait until leaves have opened to treat with insecticides. This will not prevent the early feeding done by the smallest caterpillars in the buds, but will allow for better coverage of the leaf surface so caterpillars do not need to damage more leaf surface before ingesting the pesticide. Apples, crabapples, and other flowering plants should not be sprayed with these products while in bloom to avoid unintended impacts to pollinators.
A note about Deer 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. Adults and nymphs can be active when temperatures are above freezing and 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 Laboratory of Medical Zoology (www.tickdiseases.org) and click on the red 'Test a Tick' button for more information.
Report by Tawny Simisky, Extension Entomologist, UMass Extension Landscape, Nursery, & Urban Forestry Program
Management Practices
Plant of the Week: Amelanchier arborea
Amelanchier arborea is a native small tree or large shrub growing 15-25’ tall and wide. This early flowering tree is both a nectar and pollen source for native bees as well as honeybees. Flowers appear before leaf emergence. Fruits are also ornamental changing from green to red to purple-black at maturity, and are attractive to birds. Fall color can vary from yellow to orange to red. The bark is gray and smooth but has long fissures that can have a reddish cast. A. arborea prefers a moist well-drained acidic soil in full sun to part shade. Its natural habitat is along borders of woods, streambanks, and fence rows. Plants tend to have a natural appearance. Root suckers can be a problem and can result in a more shrubby plant if they are not kept pruned back. Cultivars can provide many variations including smaller size, richer fall color, and different forms.
Additional Resources
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For commercial growers of greenhouse crops and flowers - Check out the New England Greenhouse Update website
For professional turf managers - Check out Turf Management Updates
For home gardeners and garden retailers - Check out home lawn and garden resources. UMass Extension also has a Twitter feed that provides timely, daily gardening tips, sunrise and sunset times to home gardeners, see https://twitter.com/UMassGardenClip
Diagnostic Services
A UMass Laboratory Diagnoses Landscape and Turf Problems - The UMass Extension Plant Diagnostic Lab is available to serve commercial landscape contractors, turf managers, arborists, nurseries and other green industry professionals. It provides woody plant and turf disease analysis, woody plant and turf insect identification, turfgrass identification, weed identification, and offers a report of pest management strategies that are research based, economically sound and environmentally appropriate for the situation. Accurate diagnosis for a turf or landscape problem can often eliminate or reduce the need for pesticide use. For sampling procedures, detailed submission instructions and a list of fees, see Plant Diagnostics Laboratory
Soil and Plant Nutrient Testing - The University of Massachusetts Soil and Plant Nutrient Testing Laboratory is located on the campus of The University of Massachusetts at Amherst. Testing services are available to all. The function of the Soil and Plant Nutrient Testing Laboratory is to provide test results and recommendations that lead to the wise and economical use of soils and soil amendments. For complete information, visit the UMass Soil and Plant Nutrient Testing Laboratory web site. Alternatively, call the lab at (413) 545-2311.
Ticks are active at this time! Remember to take appropriate precautions when working and playing outdoors, and conduct daily tick checks. UMass tests ticks for the presence of Lyme disease and other disease pathogens. Learn more
