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Landscape Message: Apr 3, 2015

Apr 3, 2015
Issue: 
3

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 10. To receive immediate notification when the next Landscape Message update is posted, be sure to join our e-mail list.

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Scouting Information by Region

Regional Notes

Cape Cod Region (Barnstable):

General Conditions: The past week has overall been cloudy, chilly and damp. When it wasn't raining, it was overcast and somewhat below average in temperature. Soils remain frozen at a depth of 4", although the top ½" is becoming defrosted. Plant development hasn't progressed much. Helleborus hybrids are in bud but not yet in bloom. Snow drops and crocus are up and open when the sun is out. Lawns haven't begun to green up yet. Pests/Problems: Snow mold has been observed on lawns when the snow cover has melted. Winter desiccation is evident on some broadleaf evergreens such as Blue holly. Foliage that was above the snow line is damaged, while those leaves that were below the snow are fine. Winter desiccation has also been observed on hemlock, while roadside evergreens, especially white pine, are showing salt damage.

Southeast Region (Hanson)

No report available this week.

North Shore Region (Beverly)

General Conditions: Most of the landscape is still covered under compact snow pack, but snow continues to melt slowly when temperatures are above freezing. Approximately 0.89 inches of precipitation (rain/snow mix) fell in Beverly over the past week. Temperatures ranged from a low of 21 degrees Fahrenheit on March 25 and a high of 52 degrees on March 26. High temperatures were in the low 40s and low temperatures ranged from the high 20s to low 30s. The wind speeds were in single digits over the past week. Where the snow has melted, especially on the south side of buildings and at the base of some trees, snowdrops (Galanthus sp.) and crocus (Crocus sp.) have emerged and are in full bloom. Chinese witchhazel (Hamamelis mollis) is also in full bloom. Vernal Witchhazel (Hamamelis vernalis) and goat willow (Salix caprea) are beginning to bloom. Pests/Problems: Marginal browning of leaves due to winter damage is showing on some rhododendrons. Some rhododendrons are also showing leaf spots possibly caused by Cercospora fungi. As the snow begins to melt above the shrubs it is revealing a lot of damage (limb breakage) on boxwood (Buxus sp.) shrubs.

East Region (Boston)

General Conditions: We are experiencing an unusually late start to spring. The average daily high for the past seven days was 46.5º F and the low was 35.5º F, well below historic averages. We received precipitation on four days ranging from snow and sleet to rain. This resulted in a total of 1.18 inches for the week including 2 inches of snow which fell on the 28th. While this snow did not accumulate on roads or walkways, it did accumulate on the existing snow pack. For the month of March, we accumulated a total of 3.03" of precipitation equivalence including 6 inches of snow. The average low for the month was 24º F and the high 42º F, compared to the respective historical averages of 32º F and 46º F.  Temperatures were far below average, with high temperatures falling below average for 22 days. Color in the landscape continues to be extremely limited; several witch hazels (Hamamelis x intermedia) cultivars are in full bloom. Snowdrops are almost in full flower in areas where the snow has melted. There are signs of daffodil leaves peeking through the soil. A sure sign of spring, the male red-winged blackbirds (Agelaius phoeniceus) have returned to stake out their territory.  Pests/Problems: Not much has changed since last week: Allium vineale (wild garlic) is visible in some areas and Ranunculus ficaria (lesser celandine) continues to emerge. The snow is slowly melting, at approximately an inch per day, creating wet spots in low lying areas due to the impermeable frozen ground beneath. This melting snow has exposed mole and vole damage to turf.  Winter's wind damage is especially visible on the evergreen Magnolia virginiana (sweetbay magnolia), many Ilex (holly), Mahonia (Oregon grape), and Pyracantha (firethorn).

Metro West (Acton)

General Conditions: In like a lion, out like a lamb? I'm not so sure if that saying applies to this past March especially since twice this week, we experienced snow. Albeit, only dustings but adding to the already existing snow that covers the ground that is up to a foot in some areas. Snowmelt is happening but not as quickly as one would think it would happen for this time of year. Still, lower limbs on some trees and shrubs remain weighted down by the snow. Spring clean ups in the landscape will be well delayed. The historical amount of precipitation on record for the month of March is 4.83"; the historical average high temperature is 46º and the historical low temp is 27º. Weather tracked for this month in the Metro area did not come close to these numbers. Recorded for this month was 2.64" for the total precipitation, 41º for the average high and 21º for the average low temperature. A couple more numbers for you, the highest temperature of 58º was recorded for the month on the 11th and the lowest temp of -3º was recorded on the 1st. Pests/Problems: As the snow continues to melt, more damage in the landscape as a result of the record amount of snow and the ensuing snow removal operations, including ice melt damage on conifers seen growing along roadways and broken and split branches on trees and shrubs from the weight of the snow continues to reveal itself.

Central Region (Boylston)

General Conditions: 50% of the landscape is still covered in a slowly dwindling snow pack. Where the snow has receded Tulips, Narcissus, Crocus, snowdrops and other minor bulbs are emerging, in fact, snowdrops (Galanthus sp.) and Crocus species are beginning to bloom. The early Adonis (A. amurensis 'Fukujukai') is above ground and showing specks of color. Pests/Problems: Deer are ravenous and continue to seek out conifers, broadleaf evergreens and apple buds. Black bear have emerged and are marauding birdfeeders. As the snow recedes more and more damage to trees and shrubs from the snow load and snow removal efforts is apparent

Pioneer Valley Region (Amherst)

General Conditions: Conditions continue to be cool and breezy around the valley. Snow melt carries on, and most areas exposed to direct sunlight exhibit bare ground. Shaded areas with northerly aspects are likely see lingering snow for several more weeks. In these exposed settings that receive full sunlight, the soil has thawed to a depth of at least four inches, possibly more. Settings that receive only partial sun are still frozen. High temperatures mostly hovered in the mid- to upper-40s over this past reporting period with lows ranging from the teens to upper 20s. Average maximum wind gusts have lessened since mid-March and ranged from 10-22 mph at Barnes Airport in Westfield. A rainstorm on 3/26-27 resulted in over 0.5" accumulation in most areas of the valley, accelerating snow melt on large piles. The Connecticut River and its main tributaries continue to flow at levels well below flood stage. Saturday, 3/28 was anything but spring-like. Snow flurries fell all day across the Pioneer Valley, but mercifully none accumulated in the valley bottom. It was a cloudy, dreary end to an unspectacular March. The majority of the valley witnessed only two days with high temperatures in the 50s, which came and went over three weeks ago now. Pests/Problems: Winter injury is more apparent now as snow continues to recede. Several conifer species have experienced cold injury as result of the harsh conditions. Specifically, blue atlas cedar (Cedrus atlantica 'Glauca'), dwarf Alberta spruce (Picea glauca 'Conica') and even eastern hemlock (Tsuga canadensis) are exhibiting a "burned" appearance that includes browning and chlorotic needles. Broken branches on trees and shrubs are visible with an early season snowstorm to blame in many cases. Heavy, wet snow from a December storm led to widespread limb and branch failure in the valley. This downed material was then covered by heavy snow in mid-January and is only now reappearing.

Berkshire Region (Great Barrington)

General Conditions: And the beat goes on. Not much change in the weather last week as the temperature on all but one day was below normal. Counting today (April 1), it has been 97 consecutive days since the daily high temperature was 50º F or higher. That looks to change briefly as temperatures are expected reach into the 50s on April 2 and 3 before dropping to sub-normal again afterwards. Not much change in other environmental conditions as soil remains frozen and about 70-80% of ground is still snow covered. Snowdrops remain in bloom but there are no other signs of plant development except for the very tips of shoots of daffodils and crocus appearing on sites in full sun. It will be a very slow start to spring. With sub-freezing temperatures (low temperatures) expected to persist for at least another week after the two day warm up, outdoor planting will be greatly delayed. Pests/Problems: Other than browsing by deer and gnawing of bark by voles and rabbits, there is no pest activity. The biggest problem now is the abundance of twigs and branches from trees, especially white pine here in the Berkshires, strewn about home landscapes. Winter desiccation on needled and broadleaf evergreens is becoming more apparent. With significant snow cover, increasingly intense sunlight, and frozen soil, expect desiccation to get worse, helped along by sunlight reflected off the snow.

Environmental Data

The following growing-degree-day (GDD) and precipitation data was collected for an approximately one week period, March 26 through April 1. Soil temperature and phenological indicators were observed on or about April 1. Total accumulated GDDs represent the heating units above a 50° F baseline temperature collected via our instruments for the 2015 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
(1-Week Gain)

GDD
(Total 2015 Accumulation)

Soil Temp
(°F at 4" depth)

Precipitation
(1-Week Gain in inches)

Cape Cod

0

3

frozen

1.70

Southeast

n/a 1 n/a n/a

North Shore

0

0

frozen

0.89

East

0

0

frozen

1.18

Metro West

0

0

frozen

0.87

Central

0

0

frozen

0.71

Pioneer Valley

0

0

35

0.68

Berkshires

0

0

frozen

0.71

AVERAGE

0

1

frozen

0.96

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.
Cornus mas (Corneliancherry Dogwood) * * * * * * * *
Acer rubrum (Red Maple) * * * begin * * * *
Acer saccharinum (Silver Maple) begin * * begin * * * *
Hamamelis x intermedia (Witchhazel hybrids) begin/full * begin/full full full full begin/full *
* = no activity to report/information not available
  • 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 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  (Boylston)-  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

Management Practices

Spring Clean-Up

"If it blooms before June don't prune". . . Although the saying doesn't work for all plants it is a good reminder to avoid pruning plants at the wrong time. Spring pruning is fine for plants that bloom on new wood (this year's growth), but should be avoided for plants that bloom on old wood until after they have bloomed. Re-blooming plants can bloom on both old and new wood. Plants that bloom on old wood include: lilac, forsythia, azalea, rhododendron, and Hydrangea macrophylla. Clematis is a tricky plant and can bloom on either new or old growth depending on the species.

Avoid damaging the plant when pruning. Use the correct tool for the size branch you are pruning. When pruning damaged or diseases branches make sure to cut back below the damaged/diseased area whenever possible. Remember that hand pruners are fine for branches smaller in diameter than ½ inch but loppers or a hand saw should be used for branches greater than ½ inch.

Leaves and dead foliage are good insulators for plants when temperatures are still frequently below freezing. When temperatures are consistently above 40 degrees, leaves and dead foliage need to be removed as well as old mulch. This debris can contain diseased material and insects and should be properly disposed of.

Freeze-thaw events can cause pavers to become disturbed in patios and walkways. Once temperatures are consistently above freezing it is a good time to re-position these pavers. Clean up hardscape surfaces that became disturbed over the winter. It is also a good time to clean up paver or flagstone patios by adding gravel, refilling joints, or adding new sand.

Now is also a good time to start assessing drainage issues that may be becoming apparent with rain and snow melt. Ways to help prevent water getting into basements include piping downspouts underground or adding a French drain along the house or shed foundation. Rain gardens can also be installed to help in managing runoff.

Report by Mandy Bayer, Extension Assistant Professor of Sustainable Landscape Hortulculture, Stockbridge School of Agriculture, UMass Amherst.

Insects

Winter Moth (Operophtera brumata): This is a new and important pest of blueberries, apples and other deciduous plants, especially in Southeastern New England. They can severely defoliate trees and bushes. Moths emerge from the soil usually in late November and may be active into January. The male moths are light brown to tan in color and all four wings are fringed with small elongate scales that give the hind margins a hairy or fringed appearance. The female is gray, almost wingless (brachypterous) and, therefore, cannot fly. Females are usually found at the base of trees or scurrying up tree trunks. Winter moth caterpillars are pale green caterpillars with a white longitudinal stripe running down both sides of the body. They are "loopers" or "inchworms" and have just 2 pairs of prolegs. At maturity, the caterpillars will be approximately one inch long, whereupon they drop to the soil for pupation. Pupation occurs from late May into early June. Winter moth caterpillars are often found in association with both the fall and spring cankerworms, which look and have similar feeding patterns to the winter moth caterpillar.

Life Cycle: After mating, the female deposits eggs loosely in bark crevices, under bark scales, under lichen, or elsewhere. The adult moths then die and the eggs over- winter. Eggs are dark-colored at first but turn orange within 3-4 weeks. In late-March or early-April, just prior to hatching, they turn red and eventually a deep, shiny blue. Eggs hatch when temperatures average around 55 ̊F. It is believed that egg hatch in Massachusetts occurs when approximately 177-239 GDD above a base of 40˚ F (starting Jan 1) have accumulated, which is historically during the second week in April but later if temperatures are atypically colder, depending. This means that egg hatch occurs just at or right before bud break of most of the host plants. After hatching, the larvae wriggle between bud scales of newly swelling buds of such hosts as: maples, oaks, ash, apples, crabapples, blueberry, cherries, etc. and begin feeding.

This year, models suggest that we will reach egg hatch after April 15, 2014.  Pinpointing a date is too risky now, but another alert will be sent out in a soon to update the forecast.

Damage: Caterpillars feed within both flower and foliar buds. Once a bud has been devoured from within, the caterpillar will migrate to other buds and repeat the process. Destruction of the flower buds leads to greatly diminished harvest on fruit crops. Older larvae feed in expanding leaf clusters and are capable of defoliating trees and other plants, when abundant.

Management: A dormant oil spray to the trunks and branches of bushes may be helpful to kill the overwintering eggs before they hatch. However, some eggs are under bark flaps and loose lichen and may be protected from oil sprays. Insecticides sprays timed to coincide with egg hatch are the most effective way of controlling this pest.  The timing is important because if the newly hatched caterpillars are allowed to crawl inside the expanding buds, they are protected from any insecticide that might be applied.  So, sprays should be applied within a day or two of egg hatch (approximately 220 GDD base 40˚F).  Caterpillars may also invade host plants by ballooning onto them after treatment has been applied. Several insecticides are labeled for use against either Winter Moth or Spanworm.

For detailed information concerning the biology and management of Winter Moth, visit the following:

Adapted from a report by Sonia Schloemann, Small Fruit Specialist, UMass Extension

Diseases

Recent pathogens and problems seen in the UMass Extension Plant Diagnostic Laboratory:

Winter injury on blue atlas cedar (Cedrus atlantica 'Glauca') (Fig. 1; photo taken on the UMass campus), dwarf Alberta spruce (Picea glauca 'Conica') and eastern hemlock (Tsuga canadensis). Multiple samples of cold injury on eastern hemlock originate from eastern Mass. A range of symptoms can appear on the same tree and include: chlorosis, browning tips, complete needle browning and premature needle shedding (Fig. 2). The trees in question had not been treated with horticultural oil, which is known to reduce cuticle thickness and predispose needles to cold injury. A possible predisposing stress that facilitated cold injury could be drought stress brought on by the dry conditions during the summer and autumn months in southeastern New England.

Report by Nick Brazee, Plant Pathologist, UMass Extension Plant Diagnostic Lab, UMass, Amherst.

Figure 1: Browning needle tips resulting from winter injury on blue Atlas cedar (Cedrus atlantica 'Glauca'). This tree species is borderline hardy in our region and must be grown in protected locations to avoid injury associated with winter weather. Figure 2: Range of winter injury symptoms on eastern hemlock (Tsuga canadensis). Brown to reddish needles, blighted needle tips and premature needle shedding can be present on the same tree. Figure 3: Vole feeding on downed branches of red maple (Acer rubrum). These branches were brought down by wet, heavy snow in mid-December and provided a food source for meadow voles once they were covered with deep snow in late January. When other sources of food are scarce, voles will eat bark on a variety of landscape trees and shrubs.

Landscape Turf

Insects

Wnter Impact on Insects

Many of you have asked whether the winter we just experienced (will it ever end???) would have any impact on turf insect activity. The simple answer is, "I don't know". But here are my thoughts on the various critters we often encounter:

White grubs were probably not impacted by the cold temperatures. Each of the species we see regularly in New England is well adapted to moving downward in the soil profile during the fall, and they are able to move as deep as necessary to stay below the frost line. I suppose it is possible that there might be a little natural mortality in some locations, where frost levels exceeded four feet. Grubs that are not as tolerant of cold temperatures might have found it a challenge to move the extra several inches this year to stay below the frost line, and that might ultimately mean they are a little weaker going into the spring. Time will tell.

Chinchbugs and billbugs use the same kind of mechanism as the annual bluegrass weevils, overwintering as adults in somewhat protected locations. If any of those adults were not already beginning the process of preparing for winter by the middle of November, when we experienced sudden and severely cold temperatures throughout many parts of the Northeast, it is possible that some of them might have been killed by those cold temperatures. But if they got through November, they probably survived the rest of the winter very well.

Invasive craneflies are the big question mark for me. They are relatively new to the Northeast, and I don't have a good sense of how tolerant they are of cold temperatures. They have thrived for years in the Pacific Northwest, which is much more temperate than the Northeastern US. And this past winter seems to be the coldest one we have had in the last 10 to 15 years, so it would be the coldest one the craneflies have experienced here. It is possible that their overwintering strategy was overwhelmed by the cold temperatures. Again time will tell.

Cranefly adults of the species we are seeing in Massachusetts (Tipula oleracea) normally would be flying in mid to late April, but I assume that flight will be delayed a bit this year. Starting about two weeks from now, watch for the pupae sticking out of the ground as the telltale indicator that the adults will be emerging within the next 24 hours. And try to get a sense as to whether the density of insects is perhaps a little lower than last year. If so, that would be an indicator that the winter might have taken a toll on the cranefly larvae. (We have confirmed cranefly activity in previous years from most of Eastern Massachusetts, from Worcester east, with lots of activity in the Southeastern part of the state.)

As always, please keep me posted on what you are seeing "out there".

Report by Dr. Pat Vittum, Professor and Extension Turf Entomologist, UMass Amherst Stockbridge School of Agriculture and Interim Director, UMass Amherst Center for Agriculture, Food and the Environment.

Other Relevant News / Pest Alerts

Personnel changes at Plant Diagnostic Lab: Bess Dicklow has recently retired after a long and productive career at UMass, and Dr. Angela Madeiras has accepted an assignment to assume turf, vegetable and greenhouse/floriculture responsibilities at the lab.  Angie received her Bachelor's degree in Biology from Smith College, and completed a Master's degree in Plant Breeding at UMass in 2007. After, she conducted a two year study of fungicide resistance in Colletotrichum cereale, the causal agent of turf anthracnose, with Dr. Nathaniel Mitkowski at the University of Rhode Island. She later returned to UMass to research sooty mold and flyspeck diseases in apples, and completed her Ph.D. in 2013.  Since that time she has held a post-doc position in Dr. Rob Wick's lab, investigating genetic diversity in Peronospora belbahrii, the causal agent of basil downy mildew disease.  Angie will be working closely with Rob in the transition to her new role.  Best wishes Bess, and welcome Angie!