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Landscape Message: Jul 10, 2015

Jul 10, 2015
Issue: 
16

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 bi-weekly July-September. The next message will be available on July 24.  To receive immediate notification when the next Landscape Message update is posted, be sure to join our e-mail list.

Scouting Information by Region

Regional Notes

Cape Cod Region (Barnstable)

General Conditions:  The two weeks of this reporting period have seen widely fluctuating weather, going from cool to warm, nice to stormy. On June 28, the Cape had a real soaker of a rain storm. A total of 1.46" was recorded in the rain gauge in Marstons Mills and high temperatures were only in the low 60s F. Day long sustained winds in the 40+ MPH range hitting fully leafed out canopies brought down some limbs. A gust of 57 MPH was recorded in Falmouth, where trees came down on power lines. On July 1st, a line of thunderstorms that swept through the Cape and Islands generated a Tornado Warning, something that rarely occurs in this area. There were no sightings of funnel clouds but the thunder and lightning were quite enough! Straight line winds were strong, again causing some tree damage and the heavy downpours caused street flooding. In Marstons Mills, 1.7” was recorded in the rain gauge while 2.25” was recorded in Harwich. The Cape has almost received more rain in the past two weeks than it received in May and June, certainly alleviating the moderate drought. Landscapes are looking quite green now, with many flowering shrubs and perennials in bloom. Bigleaf hydrangea is flowering, although some only have flowers where the buds were protected underneath the winter snow cover! Daylilies, Shasta daisies, Asiatic lilies, and coreopsis are all blooming in the perennial border.  Pests/Problems: Gypsy moth caterpillars have pretty much finished feeding for this year. Dennis, Brewster, and Harwich saw very large populations with widespread defoliation. In many areas of Brewster, caterpillars appeared to be dying on the trunks from Entomophaga maimaiga, helped in part by the return of rain and moisture. Trees are beginning to re-leaf. The best practice for defoliated trees is to keep them irrigated if there is no regular rainfall. Do not fertilize defoliated trees. Japanese beetles, Oriental beetles, and Asiatic garden beetles are all active. Lily leaf beetle larvae are beginning to go into the ground to pupate. Hibiscus sawfly is still active. Leafhoppers, spittle bugs, and mites are active. Golden tortoise beetles can be found on ornamental sweet potato vines. Cottony taxus scale crawlers are active.  Black spot of rose is active, as is apple scab and cedar apple rust on susceptible crabapples. Red thread is active on turf. Powdery mildew can be observed on Phlox, Lilac, and Beebalm

Southeast Region (Hanson)

General Conditions: Cooler weather in June gave way to humid warm weather in July. June was not only cooler than May, and but also wetter and Hanson received 7.16 inches of rain in June. July started off with 0.85 inches of rain and soils are moist. Stewartia pseudocamellia (Japanese Stewartia), Catalpa bignonioides (Southern Catalpa), Catalpa ovata (Chinese catalpa)and Rhododendron maximum have been in bloom over the past two weeks and there are some Kousa dogwoods remaining in full bloom, although most are past bloom. The following plants are in full bloom: Amorpha canescens (Leadplant), Weston hybrid azaleas, Indigofera sp., Clematis, Roses, Spiraea sp., Hydrangea arborescens (Smooth Hydrangea), Hydrangea quercifolia (Oakleaf hydrangea), Hydrangea macrophylla, Hydrangea paniculata ‘Praecox’, Rubus odoratus, Ilex verticillata, Ilex pedunculosa, Campanula sp., Geranium sp., Persicaria polymorpha, Astrantia major, Achillea, Alchemilla mollis, Lamium, Foxgloves, Asiatic lilies, Heliopsis sp., Platycodon grandiflorus, Asclepias tuberosa, Shasta daisies, Deinanthe caerulea, Perovskia atriplicifolia, Yucca filamentosa, Astilbe, Liatris, Corydalis lutea, daylilies, Hosta, Coreopsis sp., Kniphofia sp., and Spigelia marilandica (Indian Pink). Echinacea sp. are in full bloom and are attracting numerous pollinators including fritillary butterflies. Cotinus obovatus (American Smoketree) and Cotinus coggygria (European Smokebush) continue decorate the landscape with their colorful “smoke”. Staghorn sumac fruit is red. Lysimachia clethroides, Actaea pachypoda (Doll's-eyes, White baneberry), Filipendula venusta, Lysimachia ciliata and Monarda didyma (Beebalm) are beginning bloom.  Pests/Problems: Gypsy moths pupated in late June – early July, and around that same time, many Southeast MA areas received rain between June 27 and July 2. That rain combined with previous rain was just what “the doctor ordered”. With sufficient moisture, the insect-attacking fungus, Entomophaga maimaiga, became active and reports have come in from around southeast MA, that numerous gypsy moth caterpillars were observed dead from the fungus. The Entomophaga maimaiga resting spores, produced in the dead bodies of those late-stage caterpillars, can remain in the soil litter for many years and hopefully will be active next spring to help keep gypsy moth populations in check. Many crabapple, cherry, and oak trees have yet to start leafing out after being defoliated. Japanese beetles emerged in early July and were observed feeding on roses, along with Oriental beetles, Asiatic beetles and Rose curculio weevils; unfortunate for the roses. White-spotted Pine Sawyer and Graphisurus fasciatus (Longhorned Beetle), another Asian longhorned beetle look-alike, are active. The sunflower moth caterpillar (Homoeosoma electellum) was found in Coreopsis. Monitor Echinacea, Bidens, marigolds, Heliopsis and other composites for this pest. Flowers simply look ragged or weather damaged. Dissect the dying flower and look for a small caterpillar inside the seed receptacle. Monitor white pine, Mugo pines etc. for the Introduced Pine Sawfly (black head, black body with white and yellow spots) on pines. Also monitor 2 and 3-needled pines for the Redheaded Pine Sawfly (rusty-red head, yellow-white body, black spots). These sawflies can cause much damage if not managed. Monitor or inspect the interior foliage of Junipers for Juniper webworm caterpillars. The Sharpshooter leafhopper or red-banded leafhopper is active. This insect reportedly favors the new foliage produced by Rhododendron maximum and R. catawbiense, as well as the foliage of roses and raspberries. Hibiscus sawfly larvae continue to be active, and unmanaged Hibiscus foliage looks like Swiss cheese. Bt does not work on sawfly larvae. Four-lined plant bugs continue to be active and their damage is widespread and evident on the foliage of several plant species. Monitor Azaleas for Azalea bark scale, eggs and crawlers. The following insects are also active: lily leaf beetle adults, Taxus mealybug, earwigs, golden tortoise beetle on sweet potato vines, azalea and Andromeda (Pieris) lacebugs, aphids, slugs, snails, stink bugs, leafhoppers, wasps, pine spittlebugs, hornets, deer flies, black flies, horse flies, deer and dog ticks. Powdery mildew is evident on Cornus florida and Phlox paniculata. The following weeds are in bloom: Lonicera japonica (invasive), Oxalis, Polygonum persicaria (Smartweed), oxeye daisy, Linaria vulgaris (Yellow toadflax), Phytolacca americana (Pokeweed), milkweed, Achillea, and oxeye daisy. On lawns, sod webworm moths remain active.

North Shore Region (Beverly)

General Conditions: This reporting period saw the end of June and beginning of July. June ended relatively cool and wet. Temperatures during this reporting period at Long Hill were in the high 70s during the day and high 60s during the night. Long Hill gained 233 growing degree days (GDD) during this period, and approximately 0.59 inches of rainfall were received. Most of the rainfall was received on Wednesday July 1 and the rest on Sunday (July 5) and Tuesday (July 7). Because of the rains and ideal temperatures turf on lawns is growing fast requiring regular mowing. Woody plants seen in bloom include: Virginia sweetspire (Itea virginica), Summer blooming azaleas, Smoke bush (Cotinus coggygria), Sweet azalea (Rhododendron arborescens), Indigofera (Indigofera amblyantha), Oakleaf hydrangea (Hydrangea quercifolia), Big leaf hydrangea (Hydrangea macrophylla), Staghorn sumac (Rhus typhina), Tree false spirea (Sorbaria arborea), Winterthur Smooth witherod (Viburnum nudum), American elderberry (Sambucus canadensis), Littleleaf Linden (Tilia cordata). Herbaceous plants seen in bloom include: Summer flowering roses (Rosa sp.), Clematis vines (Clematis paniculata), Spiderwort (Tradescantia sp.), Bush cinquefoil (Potentilla fruticosa), Persicaria (Persicaria polymorpha), Water lily (Nymphaea odorata), Hardy cranesbill (Geranium sp.), and Ox-eye daisy (Leucanthemum vulgare), Japanese hydrangea vine (Schizophragma hydrangeoides), Daylilies (Hemerocallis sp.), Hostas and Astilbes (Astilbe sp.). Adding even more color in the landscapes are an assortment of annuals.  Pests/Problems: Marginal leaf scorch was observed on Japanese stewartia. Hemlock woolly adelgid is thriving on some affected trees. Cedar-apple rust was observed on some crab apple trees. Also observed was powdery mildew on lilac. If you have infected trees apply a registered fungicide. Weeds are thriving due to moist soil and some are in bloom. Poison ivy is also thriving so take caution when walking or working in the woods. Remember also that ticks and mosquitoes are still very active. Take measures to protect yourself while working outdoors, especially at dawn or at dusk.

East Region (Boston)

General Conditions: Over the last two weeks, we received 2.35 inches of rain; we received significant rain on two occasions, the weekend of June 27/28th saw 1.7 inches of precipitation and on July 1st a fast moving thunderstorm dropped 0.45 inches over an hour in the morning and an additional 0.19 inches over a 15 minute period in the evening. High temperatures averaged 78º F and low temperatures averaged 58º F; June 28th saw unseasonably cool temperatures as the high temperature for the day only reached 59º F. We gained 277 GDDs, bringing us up to 1082 GDDs on the year. The month of June was plenty moist, as we received 5.71 inches of rain; the average high was 73.9º F while the average low was 55.5º F. Herbaceous plants in bloom include: Allium sphaerocephalon (drumstick), Angelica gigas (giant angelica), Asclepias incarnata (swamp milkweed), Asclepias syriaca (common milkweed), Asclepias tuberosa (butterflyweed), Clematis ‘Roguchi’ (clematis), Hemerocallis fulva (tawny daylily), Lysimachia clethroides (gooseneck loosestrife), Platycodon grandiflorus (balloon flower), Pontederia cordata (pickerelweed), Thalictrum sp. (meadowrue), and Typha latifolia (common cattail). Woody plants in bloom: Aesculus parviflora (bottlebrush buckeye), Albizia julibrissin (pink silk tree), Castanea mollissima (Chinese chestnut), Hydrangea quercifolia (oakleaf hydrangea), Hydrangea arborescens (smooth hydrangea), Hydrangea macrophylla ssp. serrata ‘Blue Billow’ (bigleaf hydrangea), Hypericum kalmianum ‘Ames’ (St. Johnswort), Ilex verticillata (common winterberry), Perovskia atriplicifolia (Russian sage), Potentilla fruticosa (bush cinquefoil), and the native Spiraea virginiana (Virginia spirea).  Pests/Problems: The warm weather has brought a plethora of weeds into bloom: annual fleabane (Erigeron annuus), birdsfoot trefoil (Lotus corniculatus), bird vetch (Vicia cracca), bittersweet nightshade (Solanum dulcamara), black medic (Medicago lupulina), black swallowwort (Cynanchum louisae), broadleaf plantain (Plantago major), Carolina horsenettle (Solanum carolinense), carpetweed (Mollugo verticillata), chicory (Cichorium intybus), common mullein (Verbascum thapsus), enchanter’s nightshade (Circaea lutetiana ssp. canadensis), healall (Prunella vulgaris), hedge bindweed (Calystegia sepium), Queen Anne’s lace (Daucus carota), rhombic copperleaf (Acalypha rhomboidae), stinging nettle (Urtica dioica), Virginia pepperweed (Lepidium virginicum), water hemlock (Cicuta sp.), white avens (Geum canadense), yarrow (Achillea millifolium), yellow toadflax (Linaria vulgaris), and yellow woodsorrel (Oxalis stricta). Weeds in seed include: bittersweet nightshade (Solanum dulcamara), black swallowwort (Cynanchum louisae), catchweed bedstraw (Galium aparine), curly dock (Rumex crispus), and enchanter’s nightshade (Circaea lutetiana ssp. canadensis). The parasitic plant dodder (Cuscuta sp.) is wrapping itself around its host plants in meadow areas. The noxious water chestnut (Trapa natans), a floating annual weed, has been spotted in fresh water settings. Clematis has begun to show signs of clematis wilt. Lacebug on Amelanchier is noticeable. Evidence of shoot borer beetle is visible on pine (Pinus sp.) and spruce (Abies sp.) as the growing tips are turning brown. Abbott's sphinx (Sphecodina abbottii) caterpillars were spotted feeding on grapevines.

Metro West (Acton)

General Conditions: The metro west area gained 242 GDD during this two-week recording period and received 1.98" of rain. The average rainfall for the month of June is 3.93" and this year 6.54" of rain was recorded for that entire month! Woody plants seen in bloom this week are Buddleia spp. (Butterfly Bush), Hydrangea arborescens (Smooth Hydrangea), H. paniculata (Panicle Hydrangea), H. quercifolia (Oakleaf Hydrangea), Ilex glabra (Inkberry), I. verticillata (Winterberry), Koelreuteria paniculata (Goldenrain Tree), Oxydendron arboreum (Sourwood), Potentilla fruiticosa (Potentilla), P. tridentata (Cinquefoil), Rhus typhina (Staghorn Sumac), Rosa rugosa (Rugosa Rose), R. 'Knockout' (The Knockout family of Roses), Rosa sp. (Rose), Rubus odoratus (Purple flowered Raspberry), Sambucus canadensis (American Elderberry), Spirea japonica 'Alpina' (Daphne Spirea), Stewartia psuedocamellia (Japanese Stewartia) and Tilia cordata (Littleleaf Linden). Woody vines in bloom are Campsis radicans (Trumpet vine) and Clematis spp. (Clematis). Contributing even more color and interest to the landscape are some flowering herbaceous plants including: Achillea millefolium (Yarrow), Alcea rosea (Hollyhocks), Alchemilla mollis (Lady's Mantle), Aruncus aethusifolius (Dwarf Goat's Beard), A. dioicus (Goat's Beard), Asclepias syriaca (Common Milkweed), A. tuberosa (Butterfly Weed), Astilbe spp. (False spirea), Campanula persicifolia (Peach-leafed Bell Flower), C. takesimana 'Elizabeth' (Bellflower), Cichorium intybus (Chicory), Coreopsis verticillata (Threadleaf Coreopsis), Daucus carota (Queen Anne's Lace), Digitalis purpurea (Foxglove), Echinacea purpurea (Coneflower), Filipendula sp. (Meadow Sweet), Gaillardia aristata (Indian Blanket Flower), Geranium sanguineum (Cranesbill Geranium), G. ‘Johnson’s Blue’ (Cranesbill), Hemerocallis 'Stella D'Oro' (Daylily), H. fulva (Orange Daylily), H. spp. (Daylily), Heuchera spp. (Coral Bells), Hosta spp. (Plantain Lily), Iris ensata (Japanese Iris), Lavendula angustifolia (Lavender), Leucanthemum sp. (Shasta Daisy), Liatris spicata (Spike Gayfeather), Lilium spp. (Lily), Lychnis coronaria (Rose Campion), Monarda didyma (Bee-Balm), Nepeta spp. (Ornamental Catmint), Oenothera macrocarpa (Ozark Sundrops), Paeonia spp. (Peony), Penstemon digitalis 'Husker Red' (Beardtongue), Perovskia atriplicifolia (Russian Sage), Platycodon grandiflorus (Balloon Flower), Salvia nemerosa (Salvia), Saponaria ocymoides (Rock Soapwort), Sedum kamschaticum (Stonecrop), Thermopsis caroliniana (Southern Lupine), Thymus praecox (Thyme), Tradescantia sp. (Spiderwort), Veronica umbrosa 'Georgia Blue' (Speedwell) and Yucca filamentosa (Yucca).  Pests/Problems: One of our most aggressive weeds, Cynachum nigrum (Black Swallowwort) is flowering and will be setting seed soon. Look hard for it growing in and amongst shrubs. It can be difficult to detect. Another weed just coming into bloom now is Lythrum salicaria (Purple Losestrife) and it can be seen growing in moist areas. Most importantly, begin to scout for the Asian Longhorned beetle! Monitor the 13 host genera: Acer (Maple), Betula (Birch), Ulmus (Elm), Salix (Willow), Aesculus (Horsechestnut), Fraxinus (Ash), Platanus (Plane Tree), Populus (Poplar), Celtis (Hackberry), Sorbus (Mountain Ash), Albizia (Mimosa), Cercidiphyllum (Katsura) and Keolreuteria (Golden Raintree) for this invasive pest. Look for oviposition sites, frass and exit holes.

Central Region (Boylston)

General Conditions: Weather has fluctuated over the reporting period bringing summer-like weather punctuated by periods of rain and some cooler than normal periods. The humidity, air, and soil temperatures are on the rise and are pushing warm weather annuals and vegetables along. In bloom now are Hydrangea serrata ‘Bluebird’ and ‘Blue Billow’, Corydalis lutea, Hydrangea arborescens, Hydrangea macrophylla ‘Endless Summer’ and ‘Blushing Bride’, Hydrangea quercifolia, Indigofera amblyantha, Spiraea latifolia, Achillea millefolium cvs., Asclepia incarnata, Asclepias incarnata, Asclepias syriaca, Oenothera fruticosa, Geranium ‘Rozanne’, Phlox paniculata cultivars, Monarda didyma, Lathyrus latifolia, Lilium canadense, Nepeta ‘Walker’s Low’, Heuchera cvs., Pyrola sp., Astilbe cvs.,Thalictrum flavum, Thalictrum rochebrunianum, Nepeta subsessilis, Persicaria polymorpha, Hosta cultivars, Cynanchum ascyrifolium, Ilex verticillata, Magnolia virginiana, Oxydendrum arboreum, Rhododendron maximum, Summer-flowering Azaleas,  Pests/Problems: Hibiscus Sawfly, Golden Tortoise Beetle, Tree-Lined Potato Beetle, Japanese Beetle, and Lily Beetle are active. Weeds are germinating like gangbusters in open soils and are flourishing. Perennial weeds in flower now include Spotted Knapweed, Bird's Foot Trefoil, Crown Vetch, Cow Vetch, Enchanter’s Nightshade, Galinsoga, and Carpetweed.

Pioneer Valley Region (Amherst)

General Conditions: June ended on the same wonderfully wet note that it started, by way of another soaking rainstorm on 6/27–28, with over 1.5ʺ recorded throughout the valley. For the month, we experienced four rain events with over 1ʺ of recorded precipitation and they were spaced fairly well through the month (6/1–6/2, 6/15, 6/23 and 6/27–6/28) to maintain high soil moisture for trees and shrubs. Total precipitation for the month ranged between ~6.25–8.25ʺ throughout Franklin, Hampshire and Hampden Counties. According to the Northeast Regional Climate Center, total precipitation in June was 150–200% above normal in the Pioneer Valley while the National Weather Service Eastern Region Headquarters ranked June of 2015 as one of the top ten wettest on record in the northeast. The heavy rains officially brought most of the Pioneer Valley out of any formal drought classification, according to the most recent U.S. Drought Monitor (http://droughtmonitor.unl.edu/Home/StateDroughtMonitor.aspx?MA). Conditions during this past reporting period have ranged from unseasonably cool (during the 6/28 rainstorm high temperatures reached only into the upper 50s) to warm and muggy (mid-day dew points were around 70º F on 7/7 and 7/8, pushing the heat index over 90º F). But overall conditions have been very pleasant, with high temperatures in the upper 70s to low 80s and low temperatures in the upper 50s to mid 60s. Overall, the conditions have been good for newly planted trees and shrubs, mature plants that do not receive supplemental water and evergreen shrubs recovering from winter injury. On Tuesday 7/7, a microburst was reported by the National Weather Service in South Deerfield. Wind speeds of approximately 90 mph were estimated to center on Hillside Road, on the north side of Mount Sugarloaf. The swath of damage was estimated at 2500 feet long and 1000 feet wide.  Pests/Problems: All the rain in June has had a downside, providing ideal conditions for an array of pathogens that require mild temperatures and abundant free moisture on plant surfaces for spore germination and invasion into susceptible plant tissues. Specifically, fungi that cause anthracnose, needle blight and stem cankering diseases are now abundant. Many mature trees are now harboring killed branches due, in part, to some of these fungal pathogens. The ubiquitous stem cankering fungi Phomopsis and Botryosphaeria are active on a number of hardwoods and some conifers. Increasingly, Phomopsis can be isolated from shoots of declining blue and Norway spruce. Symptoms of Dutch elm disease are now apparent on American elm and its resistant hybrids. Branch dieback (flagging), yellowing and wilting of leaves, epicormic basal sprouts and brown-colored vascular staining are all symptoms of the disease. At times, Dutch elm disease can be confused with drought stress, which causes very similar symptoms. But because of the very wet conditions in June, drought stress can be ruled out almost entirely at this point in the season. Oriental and Japanese beetles are now emerging but may be slightly delayed this year due to the cool spring. These exotic pests have very broad host ranges and can cause considerable damage to landscape trees and shrubs. Japanese beetles are especially prevalent on roses and removal of these plants can help to reduce populations along with grub control in the surrounding turf. Pheromone traps should not be used to manage Japanese beetles as they will only attract more to the property. Boxwoods continue to exhibit browning branches from their associated assemblage of pests and pathogens, which are numerous and include: Volutella leaf and stem blight, Macrophoma leaf spot, boxwood spider mite, leafminer and psyllid, among others. Overall, landscape red maples have not appeared healthy this season. There were numerous reports of abnormally high seed production this spring, with canopies full of samaras as trees were leafing out in May (a rather annoying byproduct of a heavy seed year is the constant weeding of red maple seedlings around the yard). This could simply be explained as a mast year for this tree species. But after the heavy seed production, the foliage that was produced was undersized and sparse on upper canopy shoots, giving trees a “thin” appearance. In addition, many trees have random branch dieback scattered throughout the canopy. Red maples are shallow-rooted but during the worst of this past winter (February) the roots were insulated by deep snowpack. While May was dry and hot, soil moisture was plentiful during the first half of the month due to slow soil thaw and snow melt along with average rainfall in April. Therefore, it doesn’t appear to be a root freezing issue or spring drought. The undersized foliage and heavy seed production could be the result of the dry autumn we experienced in 2014. Heavy seed production can often be a symptom of stress, as trees allocate what remaining resources they have to reproduction prior to death. But, this condition is most often observed on conifers with severe root disease issues. The abundant moisture in June and the indeterminate growth rates of red maples have allowed many trees to produce new foliage well into the growing season. But again, these leaves are mostly undersized. Red maples are notorious for developing girdling roots under nursery conditions. One has only to travel University Drive in Amherst to see dozens of mature red maples with major girdling roots. But while this is a clear issue for some trees, it likely can’t be responsible for the weak canopies on so many red maples in the area.

Berkshire Region (Great Barrington)

General Conditions: The drought-like conditions that existed for much of March, April, and especially May are only memories as June and the beginning of July have seen considerable rain. The rain and overcast weather have also given us slightly below normal temperatures over the past two weeks. Some plant development is a little behind schedule. Rhododendron maximum has just come into bloom and is about at its peak. Many of the rain events of the past two weeks were also accompanied by high winds, which always results in broken tree limbs and a few toppled trees. As expected, soil moisture is high at this time. Turfgrass is growing very rapidly and grass can get rather tall between mowings. Avoid the tendency to reduce the cutting height of mowers in order to continue with normal mowing intervals.  Pests/Problems: All of the usual persistent pests are active, including wasps, hornets, mosquitoes, earwigs, and ticks. The wet weather has favored the buildup of a large population of slugs and snails. You could call it a “slug fest”. Damage to young annuals has been particularly severe, ruining many garden displays. Larvae of the second generation of imported willow leaf beetle are actively feeding. Oak leaf lace bug nymphs, probably the second generation, were observed. These piercing, sucking insects cause chlorosis and stippling on oak foliage, and may reduce plant vigor and cause premature leaf drop, but, for the most part, the damage is cosmetic rather than life-threatening to the tree. Adult Japanese beetles made their appearance during the past two weeks. The population of adults is not very large at the moment but should increase steadily as July marches on. Other pest observations included reddish blisters on leaves of pear caused by the pearleaf blister mite. This is usually a pest limited to unmanaged pear trees in home gardens. Applications of dormant oil at petal fall in spring are the recommended control. Another oddity was found on hickory in the form of round black galls on twigs and leaf petioles. These galls are caused by hickory leaf-stem gall aphid (Phylloxera caryaecaulis). Some twig dieback can occur as the galls girdle the twigs. Young aphids form the galls in June and when mature in July, they exit the galls. If the problem, i.e. twig girdling and dieback, becomes severe, insecticide application in early spring just as buds swell is warranted. Overall, most of the pest problems observed since the past report are occurring in vegetable gardens rather than in landscapes. Disease pressures are still lower than in past years but leaf spot diseases, mostly on trees, are on the increase of late, though no serious leaf drop or foliar distortions are occurring. Powdery mildew is on the increase, mostly on the usual hosts, i.e. ninebark, lilacs, and non-resistant phlox. Fire blight on sand cherry is still visible but has not advanced. Black spot on roses is more prevalent now. Lilac twig blight was found on several lilacs. Cedar apple rust on the leaves of crabapples has advanced to the stage where the rust is producing structures, called aecia, on the underside of leaves. These structures produce spores which are released into the air late in summer. Those spores land on the young leaves of cedar and infect the cedar.

Environmental Data

The following growing-degree-day (GDD) and precipitation data was collected for an approximately two week period, June 25 through July 8. Soil temperature and phenological indicators were observed on or about July 8. 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
(2-Week Gain)

GDD
(Total 2015 Accumulation)

Soil Temp
(°F at 4" depth)

Precipitation
(2-Week Gain in inches)

Cape Cod

236

914

70

3.17

Southeast

222

885

80

2.25

North Shore

233

928

n/a

0.59

East

277

1082

74

2.35

Metro West

242

992.5

54

1.98

Central

226

1017

70

1.80

Pioneer Valley

246

1145

75

2.83

Berkshires

190

906

70

3.58

AVERAGE

236

914

70

3.17

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.
Clethra alnifolia (Summersweet Clethra) * * begin * * * * *
Hibiscus syriacus (Rose-of-Sharon) * * * * * * begin begin
Oxydendron arboreum (Sourwood) * begin begin begin begin begin * begin
Campsis radicans (Trumpet Vine) * full full begin full * begin *
Koelreuteria paniculata (Goldenrain Tree) * * begin begin begin * begin *
Hydrangea paniculata (Panicle Hydrangea) begin begin begin/full full begin/full begin begin begin
Itea virginica (Virginia Sweetspire) begin/full full/end full end * end full/end full/end
Hydrangea macrophylla (Bigleaf Hydrangea) begin/full full full full full full full *
Tilia cordata (Littleleaf Linden) full full/end full full full * end end
Hydrangea arborescens (Smooth Hydrangea) begin/full full full full full full full full
Rhus typhina (Staghorn Sumac) full/end red (fruit) full end full/end end full/end full/end
Ligustrum spp. (Privet) * full/end * end end * end end
* = 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 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 woody ornamental problems of interest seen in the UMass Extension Plant Diagnostic Laboratory:

Tubakia leaf spot caused by Tubakia dryina and vein pocket gall of oak (Quercus; red oak group). Tree is roughly 50-years-old and 20-30% of the foliage was wilting at the time of sampling. Tubakia leaf spot is a mid- to late season disease in our region. Large, spots/blotches can consume significant portions of the foliage. The vein pocket gall has been widespread on oaks this season but is a novelty. Enlarged veins on the underside of leaves is a clear sign of insect activity.

Severe infestation of the white prunicola scale (Pseudaulacaspis prunicola) on a weeping cherry (Prunus). Tree is approximately 15-years-old and has been present on the site for over a decade. A shaded section of the canopy began to wilt and leaves subsequently turned brown this spring/early summer. Submitted branch sections were covered with the prunicola scale, but as is often the case, were magnificently camouflaged and blended into the natural color of the bark. This insect pest can devastate Prunus in landscape and orchard settings when populations are high.

Marginal leaf scorch caused by the anthracnose pathogen Colletotrichum on European beech (Fagus sylvatica). Tree is more than 50-years-old, present on the site for several decades. Approximately four years ago, the following symptoms became apparent in the canopy: flagging of the upper canopy branches, leaf wilting and yellowing/browning of leaf margins. Colletotrichum was found causing a marginal scorch that ultimately consumed the entire leaf. No stem cankers were found and no other pathogens were present on the submitted sample.

Fire blight, caused by Erwinia amylovora, on Harvest Gold crabapple (Malus ‘Harvest Gold’). Tree is roughly 25-years-old and resides in an urban environment but receives supplemental water and regular care. Recently, sporadic tip dieback was observed on upper canopy shoots. Terminal leaves, petioles and shoot tips were blackened and curled in the “shepherd's crook” pattern that is typical of fire blight. Large volumes of bacterial streaming were observed from sections of all three plant parts.

Dutch elm disease, caused by Ophiostoma novo-ulmi, on Princeton elm (Ulmus americana ‘Princeton’). Tree is 12-years-old and has been present on the site for only three years. It was planted to replace a true American elm that succumbed to DED previously. A large branch was submitted and vascular staining was present throughout. After ~10 days of incubation, the disease was confirmed when the pathogen appeared from symptomatic shoots.

Feeding by the balsam twig aphid in the spring leads to stunted and distorted development of current season's needles. However, needles can often outgrow the damage by years end.      UMass_Washington-elm1: Significant canopy dieback as a result of Dutch elm disease on a DED-resistant Washington elm (Ulmus americana 'Washington') on the UMass campus. Wilted and yellowing/browning foliage along with vascular staining on symptomatic branches were observed.      Epicormic sprouting at the base of declining American elms is often a symptom of Dutch elm disease.

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.

Weeds

In the last week, yellow nutsedge has become apparent in the landscape beds where it resides.  Now is the time to treat yellow nutsedge.  The best product option is the translocated, non-selective herbicide glyphosate applied as a directed spray or wick application.  Applications should be completed as soon as possible.

Received two separate reports of a retail/wholesale operation selling creeping Jenny or moneywort, Lysimachia nummularia.  This plant in on the Massachusetts Prohibited Plant List and as of January 1, 2009, the importation, sale, and trade of this plant is prohibited. This ban also covers the purchase and distribution of all cultivars, varieties and hybrids of Lysimachia nummularia.   It should be noted that currently all cultivars, proposed sterile and not, of barberry, Berberis thunbergii, are also regulated.

MA prohibited plant list can be found at:  http://www.mass.gov/eea/agencies/agr/farm-products/plants/massachusetts-prohibited-plant-list.htm

Many landscape trees commonly produce vegetative suckers at their truck base.  Suckers are commonly seen on crabapples, pear, plum, linden, maple and sometimes oak.  Honeylocust will also produce vegetative sprouts along the entire length of their trunk.  If these suckes or sprouts are not controlled the landscape will be a contender for the “shabby landscape award”.  Pruning is effective but very time consuming.  Another option would be to use the product ScytheTM that contains pelargonic acid to remove these vegetative suckers and sprouts when they are very small.  Very small means less than one inch in length.  Pelargonic acid is a contact herbicide. If ScytheTM is applied to small suckers and sprouts the product will desiccate them and physical removal will not be required.  Larger growth will first need to be physically removed and then ScytheTM can be used as a maintenance program.  Products that contain glyphosate should not be used as glyphosate is a translocated herbicide.

Scout for annual weeds in ornamental beds.  Treat these weeds before they get too large.  Spot spraying with a non-selective herbicide is usually a better strategy than hand-weeding because it will not break the mulch barrier.

Look for weeds that may be creeping into landscape beds from adjacent turf areas.  Weeds with creeping growth habits such as ground ivy, sheep sorrel, white clover, old field cinquefoil and even Kentucky bluegrass are likely candidates. Use a non-selective herbicide to edge the bed.

Inspect areas of the landscape where new trees or shrubs, especially those that were field grown, have been planted in the last year.  Look for perennial weeds that may be growing from the root ball.  Canada thistle, mugwort, quackgrass, bindweed and horsenettle are some of the possible culprits.  Treat with a non-selective systemic herbicide (ex. glyphosate). Contact herbicides (SyctheTM, RewardTM) or the non-chemical burndown materials will not provide adequate control.

Poison ivy can be treated now.  Use a broadleaf brush herbicide or glyphosate-based material.  Remember that even after the plant is dead the oil that causes the rash will be active in leaves, stems and roots.

Report by Randall Prostak, Extension Weed Specialist, UMass Extension Agriculture & Landscape Program, Amherst.

Landscape Turf

Management Practices

Torrential Rain vs. Turf

After an alarmingly dry start to the growing season, the pattern has certainly shifted in favor of more regular and soaking rain events. We have had some heat, but not extreme or long-lived heat, which has kept evaporative demand reasonable. These factors, which came together just in time, have put most turf in fine shape heading into the summer. Most water-related reports as of late have concerned too much moisture, as opposed to problems caused by too little.

With our typical humid summers in the New England region comes the promise of increased thunderstorm activity. In a lot of years one might comment that any form of precipitation is welcome in July and August, but precipitation brought by thunderstorms is often less than ideal. While thunderstorms definitely have the potential to deliver large amounts of rain, the rain tends to come too hard and fast, not to mention the possibility of problems from associated phenomena like hail or high winds. The harder and faster the rain, the less likely it is that appreciable moisture will percolate into the soil to benefit turf and other plants, and the more likely that issues can arise in the form of runoff and erosion.

An immensely beneficial force in mitigating problems from torrential rainfall is dense, healthy turfgrass cover. A lot of it has to do with energy, which the rainfall in gully-washing storms has no shortage of. With a dense turf, most drops hit the canopy of leaf blades first, dissipating much of the energy before the moisture reaches the soil surface. This interception goes a long way towards mitigating what is called splash erosion. Think about a bare soil or an area of thin turf, where droplets are able smash into the surface with substantial energy. Splash erosion occurs when the force of impact from a water droplet catapults soil particles in all directions. The most visible splash erosion problem involves soil that is splattered on to buildings, fences, vehicles, etc following heavy rain (Fig. 1). Regular episodes of splash erosion on exposed soil over time can lead to formation of surface crusts which inhibit water infiltration and promote runoff.

Another key issue with regard to torrential rainfall concerns water and gravity. The movement of water down slope is desirable to some degree in managed areas to prevent pooling, ponding, and other soggy spots, but there is an optimal level in terms of the amount and speed of drainage. This is because runoff can carry soil, nutrients, pesticide residues, and other materials out of the system, robbing the system of resources and increasing the potential for negative environmental impact. The ‘army’ of turfgrass shoots in a stand of turf serve as a break or a barricade to disrupt the momentum and reduce the energy of flowing water, thereby promoting infiltration into the soil and decreasing the chance that erosion will occur or materials will be carried off site. Infiltration and percolation, of course, are vastly preferable to run off that moves quickly and directly into storm drains, surface water, and environmentally sensitive areas.

A healthy turf also provides a sort of fortification, in the form of a deep and extensive root system. When soil becomes saturated to a certain degree during a storm, the soil and water can begin to move in combination in response to gravity and momentum, carrying soil down slope and leaving channels and gullies (Fig. 2). An expansive root system serves as a structure that supports and reinforces volumes of soil, making the soil less prone to being dislodged and moving under heavy rainfall. A healthy turfgrass root system also contains microorganisms and biological compounds that function in binding soil particles together, further helping to keep sites intact.

Despite the utility of turf in mitigating runoff and erosion, it is useful to recognize that turf might not be the most appropriate or effective cover in all situations. In some extreme situations, such as below downspout outlets (Fig. 3), for example, stone, splash blocks or other manufactured materials are often a better long term option.

Fig. 1: Heavy rain hitting exposed soil can cause splash erosion, the effects of which are often visible on structures.      Fig. 2: Soil without adequate turf cover and an associated root sytem is more susceptible to erosion, especially on slopes (note manhole covers to the left and right for scale)..      Fig. 3:  Areas subject to extreme pressure from falling water might warrant non-turf solutions.

Report by Jason Lanier, Extension Educator, UMass Extension Agriculture & Landscape Program, UMass Amherst.

Other Relevant News/Pest Alerts

New Massachusetts Plant Nutrient Regulations in effect: Turf and landscape practitioners and fertilizer retailers in Massachusetts are advised to keep informed about changing plant nutrient management regulations.  The Massachusetts Department of Agricultural Resources (MDAR) has developed statewide plant nutrient regulations that went into effect on June 5, 2015.  New regulations for agricultural production will take effect on December 5, 2015.

For more information or questions about the regulations contact Hotze Wijnja at MDAR: hotze.wijnja@state.ma.us or 617-626-1771.

Sunflower Moth on Echinacea, Sunflowers and Marigolds:  The caterpillar of the sunflower moth, Homoeosoma electellum, damages the flower heads of echinacea, sunflower, marigolds cosmos, coreopsis and other composites (Asteraceae). For details: http://negreenhouseupdate.info/updates/sunflower-moth-echinaceasunflowers-and-marigolds.

Additional Resources

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For a complete listing of upcoming events, see our Upcoming Educational Events page.

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