Pam Bennett, Barb Bloetscher, Joe Boggs, Jim Chatfield, Erik Draper, Dave Dyke, Gary Gao, David Goerig, Tim Malinich, Amy Stone, and Curtis Young.
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May 17, 2007
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This is the Seventh 2007 edition of the Buckeye Yard and Garden Line (BYGL).
BYGL is developed from a Tuesday morning conference call of Extension
agents, specialists and other contributors in Ohio.
BYGL is also made available on the Internet from the Ohio State University
Horticulture and Crop Science (HCS) in Virtual Perspective website
(http://bygl.osu.edu). Additional fact sheet information on any of
these articles may be found through the OSU fact sheet database (http://plantfacts.osu.edu).
BYGL is a service of OSU Extension and is aided by major support
from the Ohio Nursery and Landscape Association (ONLA), with additional
funding from the Ohio Chapter of the International Society of Arboriculture
(ISA) to the OSU Extension Nursery Landscape, and Turf Team (ENLTT).
Participants in the May 15, 2007 conference included: Pam Bennett (Clark); Barb Bloetscher (Entomology/C. Wayne Ellett Plant and Pest Diagnostic Clinic (CWEPPD Clinic)); Joe Boggs (OSU Extension Center at Piketon/Hamilton-Clermont); Erik Draper (Geauga); Dave Dyke (Hamilton); Gary Gao (Delaware); David Goerig (Mahoning); Tim Malinich (Lorain); Joe Rimelspach (Plant Pathology); Dave Shetlar (Entomology); Amy Stone (Lucas); Curtis Young (Allen); and Randy Zondag (Lake)..
Additional factsheet information on any of these articles may be found
through the OSU Factsheet Database (http://plantfacts.ohio-state.edu/)
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WEATHER WATCH
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The following weather information has been summarized from data collected from May 1-15, 2007. BYGLers have chosen six locations to highlight different regions of the state to be included each week as seen in the table below. Additionally, there are weather station sites in Avon (Lorain County), Madison (Lake County), Perry (Lake County), at the Muck Crops Research Station (Huron County), at the North Central Research Station (Sandusky County), and at the Western Research Station (Clark County). The weather data collected from all the sites can be seen at http://www.oardc.ohio-state.edu/newweather/ .
| Weather Station |
Region of Ohio |
Ave. High Temp F |
Ave. Low Temp F |
Total Precip " |
Normal Precip " |
| Ashtabula |
NE |
68.7 |
42.6 |
NA |
1.6" |
| Wooster |
NE |
75.1 |
45.4 |
1.14" |
1.8" |
| Hoytville |
NW |
74.4 |
46.3 |
0.81" |
1.5" |
| Delaware |
Central |
74.0 |
50.9 |
1.25" |
1.8" |
| Piketon |
South |
78.6 |
50.7 |
0.17" |
2.3" |
| Jackson |
South |
79.1 |
48.0 |
0.04" |
2.0" |
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Many BYGLers across the state mentioned lack of rainfall in their counties. Pam Bennett in Clark County was going to turn on the irrigation at the Gateway Learning Gardens at the Extension office to provide the water that Mother Nature has not.
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HORT SHORTS
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GDD (GROWING DEGREE DAYS)
GDD is a measure of the daily maximum and minimum temperature and directly relates to growth and development of plants and insects. The GDD of any zip code location in Ohio is estimated using the GDD of ten OARDC weather stations and available on the web at the site below.
The range of GDD accumulations in Ohio from north to south is 327 to 661. Following is a report of GDD for several locations around Ohio as of May 16, 2007: Painesville, 327; Cleveland, 356; Toledo, 403; Canfield, 391; Lima, 412; Wooster, 437; Coshocton, 408; Columbus, 470; Springfield, 539; Dayton, 558; Cincinnati, 609; Ironton, 645; Portsmouth, 648; Piketon, 661; Marietta, 616; and Jackson, 650.
To put these GDD accumulations into perspective, the following is an abbreviated listing of plant and insect species with their respective phenological event and average GDD accumulations at which these events occur. Due to variations in weather, temperature, humidity, etc., these events may occur a few days earlier or later than predicted by the average GDD. By looking at a city, town, or village near you from the above list, or visiting the above web site, you can see what could be taking place in the landscape around you.
Blackhaw viburnum, full bloom, 322; redosier dogwood, first bloom, 323; dwarf fothergilla, full bloom, 325; winter king hawthorn, first bloom, 328; lilac borer, adult emergence, 330; slender Deutsia, first bloom, 338; Japanese kerria, full bloom, 342; common horsechestnut, full bloom, 344; red chokeberry, full bloom, 351; doublefile viburnum, first bloom, 353; Pagoda dogwood, first bloom, 363; red Java weigela, first bloom, 365; black cherry, first bloom, 368; common sweetshrub, first bloom, 371; lesser peach tree borer, adult emergence, 372; Ohio buckeye, full bloom, 374; holly leafminer, adult emergence, 375; Vanhoutte spirea, full bloom, 406; euonymus scale (first generation), egg hatch, 406; black cherry, full bloom, 419; Miss Kim Manchurian lilac, first bloom, 422; locust leafminer, adult emergence, 437; doublefile viburnum, full bloom, 444; black locust, first bloom, 467; common ninebark, first bloom, 478; oystershell scale, egg hatch, 497; smokebush, first bloom, 501; arrowwood viburnum, first bloom, 534; American yellowwood, first bloom, 546; and bronze birch borer, adult emergence, 547; black locust, full bloom, 548; American Holly, first bloom, 556; mountain laurel, first bloom, 565; potato leafhopper, adult arrival, 568; juniper scale, egg hatch, 571; common ninebark, full bloom, 596; American yellowwood, full bloom, 599; arrowwood viburnum, full bloom, 621; multiflora rose, full bloom, 643; and northern catalpa, first bloom, 675.
Take some time to the GDD website at http://www.oardc.ohio-state.edu/gdd/ and see what it offers because it is more than just current GDDs. New additions to the Summary of Phenological Events chart include links to factsheets, bulletins and images related to most of the plants and pests highlighted on the web page. The information covered by these materials include diseases, pests and research.
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PLANTS OF THE WEEK
Read all about perennials and landscape trees and shrubs in the ONLA publications "Perennial Plants for Ohio" and "Landscape Plants for Ohio." The descriptions and photographs of plants were provided for these publications by the OSU ENLT Team along with other industry plant lovers. These full-color publications are available at http://Buckeyegardening.com for $5.00. Click on "garden store" and then "ONLA plant guides." ONLA members can purchase these in quantities at a reduced price at http://onla.org.
*PERENNIAL OF THE WEEK. DIANTHUS or PINKS (Dianthus spp.) - There are hundreds of species and cultivars of dianthus and many of them are in full bloom in the central Ohio area. Flower colors range from pink to red to white. Flower petals are fringed or double; some can be fragrant. Foliage colors vary from green to bluish green to silverish green and can be somewhat frilly. These low-growing, mound-like plants make great borders or rock garden features. They prefer hot weather and dry soil; during rainy or humid seasons, plants may 'melt out' or die in the center. Try 'Bath's Pink' for the excellent foliage and 4-6" flowers or 'Tiny Rubies' for the double rose-pink flowers that are somewhat fragrant.
*WOODY ORNAMENTAL OF THE WEEK. RED BUCKEYE (Aesculus pavis) - These beautiful ornamental trees are in full bloom in central Ohio at this time. This small native tree grows to around 15-25' tall and does best in moist soils and partly shaded to sunny sites. Plants grow well in shade but have more flowers in the sun. The palmate leaves surround the beautiful exotic bright red, upright flower panicles.
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THE WEEKLY WEED
Joe Boggs reported that POISON-HEMLOCK (Conium maculatum) is now producing flower heads in southern Ohio. This non-native invasive biennial weed spends the first year as a basal rosette, and the second year as an erect, towering flowering plant that can measure 6-10' tall. Poison-hemlock is a member of the carrot family (Apiaceae (= Umbelliferae)), so it shares many characteristics with other weeds found in Ohio including QUEEN ANNE'S LACE (Daucus carota), COW PARSNIP (Heracleum lanatum), and GIANT HOGWEED (H. mantegazzianum), the bane of the northeast part of the state.
However, since poison-hemlock is among the most toxic plants in North America, it is important to correctly identify this weed. Flowering plants have hairless, light-green to bluish-green stems that are covered with obvious purplish blotches. The bluish-green leaves are 3-4 times pinnately compound, and the deeply cut parsley-like leaflets have sharp points. Clusters of tiny white flowers are borne on structures called umbels that look like upside-down umbrellas. The plant contains highly toxic piperidine alkaloid compounds, including coniine and gamma-coniceine, which cause respiratory failure and death in mammals. Indeed, this is the Greek plant responsible for Socrates' famous last words, "I drank what?"
For reasons not entirely known, poison-hemlock has moved from the relative obscurity of appearing along borders of fields, roadsides, and meadows to commonly arising en masse in landscapes. It can be controlled by mowing, tilling, or by using selective or non-selective post-emergent herbicides including glyphosate (e.g. Roundup), or herbicide mixtures containing 2,4-D, 2,4-DP and MCPP, or 2,4-D, dicamba, and MCPP (e.g. Trimec). Applications of herbicides made now will control both the first season rosette stage and the second season flowering stage, before seeds are produced. All parts of the plant are toxic, especially the young leaves, stems, and seed. In accordance with the wisdom of Socrates, hand pulling is not recommended.
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EMERALD ASH BORER (EAB) AWARENESS WEEK
EAB Awareness Week, May 20-26, kicks off camping season and the increased movement of firewood as citizens head outdoors. Many citizens are unaware that firewood may carry EAB, threatening the natural areas they're traveling to enjoy.
To raise awareness, municipalities have been asked to declare May 20-26, EAB Awareness Week through a local proclamation. Municipalities and volunteer groups have also been asked to identify highly visible ash trees within their communities and tag those trees with a caution sign.
The goal of the awareness campaign is to illustrate the commonality of ash trees in Ohio's landscapes and forests and help draw attention to the potential repercussions of an EAB infestation. Beginning May 20, take a look around and see if you notice any ash trees in the area tagged as part of this project. Help us get the word out about the emerald ash borer and the impact this exotic invader can have!
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FREEZE-FRAME REPORT
Participants in the Cincinnati BYGLive! Diagnostic Walk-About held this week at Cox Arboretum & Gardens Metropark (Dayton) observed a range of obvious plant symptoms lingering from the deep freeze that occurred in early April. Gingko canopies remain thin and festooned with dead buds. New leaves are just now expanding. Likewise, canopies of some baldcypress appear thin and damaged foliage gives the trees an overall brownish cast. Leaf edges are blackened on lilacs and leaves are distorted on umbrella magnolia. Participants discussed the distinct possibility that the lilac and magnolia symptoms could be mistaken for herbicide injury.
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BUG BYTES
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SCALES MAY WEIGH HEAVILY
Due to the difference in growing degree days from southern to northern Ohio, the time to treat for SCALE CRAWLERS will vary significantly around the state. If scale was a problem last year and the window for treatment is missed, the first generation of scales could escape control.
At this point, the growing degree days (GDD) ranges from 349 in Toledo to 609 in southern Ohio. While the oystershell scale crawlers have been sighted in Lima, this scale remains visibly inactive in northern counties. Other crawlers on the move are the pine needle scale and euonymous scale.
The best time to treat these scales is when the crawlers are moving to new leaves/needles. Once these crawlers settle on the desired location, they form a waxy coat or armor, which is resistant to most contact insecticides. Since both the pine needle and euonymous scales can have 2-3 generations per season, the potential for an extensive infestation is likely. All three of these armored scales can cause dieback of limbs when infestations become heavy.
Control of armored scale is limited to a few contact insecticides, horticultural oil, or a mixture of a pyrethroid with 2% horticultural oil, when the crawlers are active. Once settled, a systemic insecticide is the best offense to curtail future generations. Labeled insecticides include imidacloprid (Merit, Marathon), and Safari (dinotefuran). These products provide the best control when used in late fall or late winter; this allows the product to be circulated through the plant.
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EAB ADULTS ON THE WING
Joe Boggs reported that EMERALD ASH BORER (EAB) (Agrilus planipennis) adults have started to emerge from infested ash trees in the southern-most population known to exist in Ohio, the Warren County infestation. The narrow-shaped beetles are around 1/2" long and 1/16" wide. The thorax is copperish-green and the hardened wing covers (elytra) are a deep green. However, the beetle's metallic color scheme is highly reflective producing a range of apparent colors, depending upon light conditions. The beetles have a reddish-purple abdomen that is exposed during flight.
When viewed head-on, the beetles have round bellies and flat backs, a configuration responsible for producing the characteristic "D-shaped" emergence holes associated with EAB. Numerous new D-shaped holes were apparent on the main stems and branches of the infested ash trees. Joe indicated that no adult leaf-notching activity was apparent on Monday, May 14; however, leaf notching was observed on May 15.
Joe noted the emergence was accurately predicted both by Growing Degree Days (GDD) and plant phenology. According to the OSU OARDC/Extension GDD and Phenology website http://www.oardc.ohio-state.edu/gdd/, the GDD accumulation for predicted EAB emergence is 550. The GDD accumulation for Lebanon (Warren County) for Monday, May 14, the day Joe first observed the beetles, was 559. Full bloom of black locust (Robinia pseudoacacia) is predicted to occur at 548. Despite some apparent damage to bloom buds earlier this spring, black locusts were showing blooms on May 14.
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BOXWOOD PSYLLIDS REACH ADULT STAGE
Curtis Young reported catching boxwood psyllids (Cacopsylla buxi or Psylla buxi) reaching the adult stage of their lifecycles. While taking pictures of psyllid nymphs with long, twisting tails of white flocculent (waxy strings), Curtis caught some of the first adult psyllids emerging from the last nymphal skins. Adults are light green insects that are about 1/8" long. These new adults mate and lay small, orange, spindle-shaped eggs between bud scales of the host plant during the next few weeks. There is only one generation of boxwood psyllids each year, therefore the eggs being laid now do not hatch until spring of 2008. The boxwood psyllid is a common pest of boxwood, Buxus spp. American boxwood (B. sempervirens) appears to be most susceptible to this pest.
Boxwood psyllid nymphs develop on newly expanding foliage of the host plant. Their feeding causes the new leaves to cup and sometimes, new twigs to twist. The amount of cupping that remains on the host plants through the season depends on how rapidly the foliage matures. In some years, the foliage hardens quickly resulting in the cupping remaining on the plants through the entire growing season. If the plants are sheered, much of this damage is removed. There is nothing that can be done to prevent any further damage to the plants this year. However, an application of imidacloprid (e.g. Merit) made as a soil drench in the fall reduces or prevents damage the following spring.
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WINDSHIELD WIPES
BYGLers also ran into a few other insects and mites this week, including:
* In an "early warning" report, Dave Shetlar noted that he observed the tiny "dunce cap-like" bags of first instar BAGWORMS (Thyridopteryx ephemeraeformis) while he was making a pit-stop at a rest area in Lexington, KY, on his way to Florida. Dave's report should be heeded by BYGLers in southern Ohio. Indeed, the GDD for the hatch of overwintered bagworm eggs is 630. As of 5/16, the GDD for Cincinnati was 623. Washington Hawthorn is a good indicator tree since it shows first bloom at 635.
* Participants in this week's Cincinnati BYGLive! Diagnostic Walk-About were treated to a sample of COTTONY CAMELLIA SCALE (Pulvinaria floccifera) on underside of holly leaves. The scale has a wide host range which includes yew, rhododendron, maple, hydrangea, euonymus, and of course camellia. The tannish-brown females are currently exuding their white cottony egg sacs. Unlike many other cottony scales, the sacs are flattened, and elongate making them look like white road stripes. First instar nymphs (crawlers) will begin to appear in about 2 weeks.
* As if ash doesn't have enough problems, Joe Boggs reported observing a heavy infestation of ASH MIDRIB GALLS on green ash in southwest Ohio. The elongated, bulbous, light green galls are produced by a midge fly (Contarina Canadensis), and arise from the midvein on the underside of leaflets. As with most plant galls, little harm is done to the overall health of the trees; however, the noticeable leaflet distortion produced during gall growth and development can affect the aesthetics of infested trees.
* Randy Zondag reported that VIBURNUM LEAF BEETLE (Pyrrhalta viburni) have hatched in eastern Lake County. Growers should monitor native and cultivated varieties of Viburnum dentatum, V. carlesii, V. trilobum and other fragrant types.
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DISEASE DIGEST
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DISEASES ARE CONSPICUOUSLY ABSENT.
The lack of typically moisture-laden spring weather has combined with warm temperatures to produce, as of yet, very few diseases. Those BYGLer's who are either plant pathologists or are quite fond of finding plant diseases have been disappointed so far this year. There was that brief moment when the orange, gelatinous teliohorns emerged from cedar-apple galls earlier this year; but, it was over as soon as the rains dried up. For those with a pathological bent, it is truly a sad state of affairs when one dejectedly tries to recall if they have really seen any sycamore anthracnose or maybe an apple scab lesion or two so far this year. But don't worry, diseases can always catch up during the year!
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ASH ANTHRACNOSE SHOWING UP
Pam Bennett received a sample of an ash tree where the homeowner was concerned about ash flower galls. What went unnoticed to the homeowner, however, were the ash anthracnose lesions. Ash anthracnose (Gnomoniella fraxini) leaflets were exhibiting blotchy grayish to brownish lesions on the margins. The infection occurred during a cool wet period during the early leaf development stage. Many are tempted to spray for this disease but it's not a significant tree health problem in the long term. Besides, with the emerald ash borer now on the scene in Ohio, one may be less inclined to spray for anthracnose. Later in the season, leaf drop may be significant, causing people to wonder if they might have EAB; leaf drop is not usually one of the diagnostic symptoms for EAB.
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TURF TIPS
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HERBICIDE INJURY TO LAWNS
Gary Gao reported seeing herbicide injury to home lawns. When he took a walk in his neighborhood in central Ohio, he noticed several lawns with 10 - 15 brown circles. It turns out that these circles resulted from spot treatment of broadleaf weeds, such as dandelions and clover. Joe Rimelspach told BYGLers that there was a good chance that too much broadleaf weedkiller was applied to the lawn.
Broadleaf weed killers are supposed to be safe to lawns when applied at the right concentration. Some homeowners may have applied broadleaf weed killers at too high of concentration. Even though the label on the bottle states "safe for lawns," broadleaf weed killers can still cause injury to turfgrass. When using a 'ready to use' formulation, only apply enough to coat the leaf blades with the herbicide. Drenching a weed for a long time could cause significant injury to the turfgrass. When mixing herbicides from concentrate, make sure to follow label directions. It is quite easy to put too much herbicide in the final solution. Too much herbicide and hot weather are the perfect formula for disaster in the lawn!
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SEEDY LAWNS
Warm temperatures in Ohio have stimulated some Kentucky bluegrass (Poa pratensis) plants to produce seedheads. This is a natural occurrence. However, it may temporarily reduce overall turf quality. Seedhead production saps energy from the plant, and may cause blades to become sparse and off colored. Also, the seed stalks have fewer leaves and their woody structure resists mower blades, which adds to the eyesore. This change is seldom consistent throughout a home lawn, and it sometimes occurs in patches. Thus, "seedy" Kentucky bluegrass is often made more obvious with patches occurring in an otherwise smooth, dark green lawn.
Although seedhead production can affect turf quality, it is a short term problem. Eventually the turfgrass literally "out grows" the problem. Of course, recovery will occur faster on lawns that have been properly maintained (e.g. proper fertilization, watering, mowing, etc.). Homeowners may be tempted to lower their mowers to hasten the process by removing more seed stalks-this is not recommended since low mowing will stress the lawn. The propensity to produce seedheads in lawns varies among Kentucky bluegrass cultivars and this characteristic is evaluated in the National Turfgrass Evaluation Program http://www.ntep.org. Consequently, a more long term solution may involve selecting cultivars that are less inclined to produce seedheads. A light application of fertilizer and watering could be helpful in keeping turfgrasses in the vegetative stage vs. the reproductive/seedhead stage.
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WOES OF WILTED TURF
With an extended spring dry period underway, turf is already showing signs of water stress. To complicate matters, wilted turf is prone to mechanical damage while under water stress. Excessive foot traffic and mowing of wilted turf can damage crowns and result in browned-out turf areas. The resulting tire tracks and footpaths are far from ornamental; hold off on mowing and other turf traffic until irrigation or rainfall relieves the water-stressed turf.
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INDUSTRY INSIGHT
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WISE WATER USE
Most of the water applied to plants in production nurseries ends up back in the original ponds or streams. The only difference is the fact that it is now carrying fertilizer and other waste products that should have stayed in the container or field. New research being done by the USDA-ARS in Wooster has found that applying water slowly, but more frequently, reduces waste while preventing leaching. The system applies small bursts of water to the media or soil surface when soil moisture probes indicate the need for irrigation. These short bursts maintain optimal water-to-air ratios in the soil while reducing the leaching caused by current irrigation practices.
The benefits to the growers are reduced costs for pumping water, a cleaner water source, less water storage needed, a better water-to-air ratio in the soil and greatly reduced leaching from irrigation. To take advantage of this new irrigation protocol, growers have to invest money in a constantly pressurized irrigation system and new controller. However, the cost of this system is recovered through better plants and less irrigation-related labor. For more information on this topic visit http://www.ars.usda.gov/Research/docs.htm?docid=11113 .
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COMING ATTRACTIONS
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2ND ANNUAL NORTHEAST OHIO DIAGNOSTIC CLINIC
On Wednesday, June 6, 2007, at the Donald W. Meyer Center of Big Creek Park in Chardon, Ohio, Jim Chatfield and Erik Draper lead the discussion and confusion as they try to solve any and all plant diagnostic dilemmas. This workshop will be hands-on with samples galore, an Emerald Ash Borer update, lots of samples, Dr. Dendro Phile speaks for the trees, participants examine lots of samples, discuss digital diagnostic and look at lots of plant samples. Attendees are encouraged to bring along their own diagnostic dilemma samples to see if the combined expertise of the group can help solve the mystery. The $30 fee includes lunch, handouts, snacks and prizes. To register or for more information call the Geauga County Extension office at 440.834.4656 or for directions see this link http://www.geaugaparkdistrict.org/parks/bigcreek.shtml#DIRECTIONS .
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HAMILTON COUNTY EXTENSION RELOADED GREENHOUSE TOUR
An "Extension Reloaded" Greenhouse Tour has been held in conjunction with the April Cincinnati Flower Growers Association Meeting (CFGA) meeting each of the last few years. However, due to a conflict with Easter, it was decided to hold this year's spring tour on June 6. Details include 7 tour stops, the CFGA meeting, dinner at Great Scott Restaurant and a summary presentation by OSU Extension Specialists Claudio Pasian, Dennis Lewandowski, Luis Canas. It should, once again, be a great tour! Please RSVP to Bard's (513) 752-9355, by Monday, June 4. Cost is $20 for the dinner.
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BYGLOSOPHY
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"Life is like an onion; you peel it off one layer at a time and sometimes you weep." Carl Sandburg, American Poet
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