Pam Bennett, Barb Bloetscher, Joe Boggs, Jim Chatfield, Erik Draper, Dave Dyke, Dave Goerig, Tim Malinich, Jane Martin, Amy Stone, and Curtis Young
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May 11, 2006
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This is the Sixth 2006 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 09, 2006 conference included: Pam Bennett (Clark), Barb Bloetscher (Entomology/C. Wayne Ellett Plant and Pest Diagnostic Clinic), Joe Boggs (Hamilton/OSU Extension Center at Piketon), Jim Chatfield (OSU Extension Center at Wooster/ Hort and Crop Science), Monte Clayton (Consultations), Eric Draper (Geauga), Dave Dyke (Hamilton), Dave Goerig (Mahoning), Dennis Lewandowski (Plant Pathology), Jane Martin (Franklin), Dave Shetlar (Entomology), Amy Stone (Lucas), Nancy Taylor (Plant Pathology/CWEPPDC), 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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This week's weather summary includes May 1-May 10. This month's average temperatures at the 5 OARDC locations highlighted below are all slightly higher than the listed normal average temperatures at this time of year. It is important to note that rainfall amounts are lower than the normal or what is average for the same time period.
| Weather Station |
Region of Ohio |
Ave. High Temp F | Ave. Low Temp F | Ave. Temp F | Normal Ave. Temp F | Total Precip " | Normal Precip " | | Perry |
NE |
69.1 |
45.1 |
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NA |
0.28" |
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| Hoytville |
NW |
71.0 |
46.0 |
59.1 |
55.8 |
0.79" |
0.94" |
| Columbus |
Central |
72.9 |
49.4 |
60.7 |
57.8 |
0.29" |
1.22" |
| Miami |
SW |
71.6 |
49.7 |
60.2 |
57.5 |
0.73" |
1.61" |
| Jackson |
South |
72.6 |
45.5 |
58.7 |
58.2 |
0.57" |
1.28" |
For a link to the OARDC Weather Stations, check out: http://www.oardc.ohio-state.edu/centernet/weather.htm
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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 281 to 535. Following is a report of GDD for several locations around Ohio as of May 10, 2006: Painesville, 281; Cleveland, 301; Toledo, 334; Youngstown, 325; Lima, 364; Wooster, 361; Coshocton, 405; Columbus, 450; Springfield, 399; Dayton, 420; Cincinnati, 464; Ironton, 512; Portsmouth, 515; and Piketon, 535.
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.
Imported willow leaf beetle, adult emergence, 274; sargent crabapple, full bloom, 298; red horsechestnut, first bloom, 304; pine needle scale, egg hatch - 1st generation, 305; cooley spruce gall adelgid, egg hatch, 308; eastern spruce gall adelgid, egg hatch, 308; common lilac, full bloom, 315; winter king hawthorn, first bloom, 328; lilac borer, adult emergence, 330; 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; and American yellowwood, first bloom, 546.
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PLANT PHENOLOGY
Beginning in southern Ohio, Joe Boggs noted that weigela (Weigela spp.), rhododendron (Rhododendron spp.), and black locust (Robinia psuedoacacia) were in full bloom and that the black locusts were spectacular.
In central Ohio, Pam Bennett and Jane Martin reported that the following were in full bloom: doublefile viburnum (Viburnum plicatum var. tomentosum), Vanhoutte spiraea (Spiraea x vanhouttei), weigela, Ohio buckeye (Aesculus glabra), red buckeye (A. pavia), and common and late lilac (Syringa spp.). Just starting to bloom were black cherry (Prunus serotina), black locust and 'Miss Kim' lilac (S. patula 'Miss Kim').
Curtis Young noted that dogwoods (Cornus florida), doublefile viburnum, Vanhoutte spiraea, and Ohio buckeye were in full bloom.
In the northern part of the state, Erik Draper noted that dogwoods, crabapples (Malus spp.) and redbuds (C. Canadensis) were in full bloom. Randy Zondag added that 'Mariesii' doublefile viburnum was in full bloom.
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WOODY PLANT OF THE WEEK
Our woody plant of the week is showcasing the red buckeye, Aesculus pavia. The red buckeye is a small, round topped tree or large multi-stemmed shrub reaching heights of 25'. The foliage is a typical palmate, five leaflet arrangement that are dark green most of the season. This time of year you may be noticing the large, red, 4-8" long panicles that adorn this plant. The tree is most likely to bloom in Ohio after the area where it is planted passes the 300 growing degree day mark. It is sometimes confused with the Red Horsechestnut, Aesculus X carnea. The red horsechestnut grows somewhat taller and the bloom is similar to red buckeye as it should be, because the plant resulted from a cross between A.pavia and A. hippocastanum. As you travel throughout your neighborhoods this week, take notice of these wonderful plants.
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PERENNIAL PLANT OF THE WEEK
Cranesbill or hardy geranium - Geranium spp. Hardy geraniums include many species and cultivars with a variety of characteristics. Not to be confused with the annual bedding plant Pelargonium, these lower growing species and cultivars are nice groundcovers and fillers for the perennial bed. Plants form mounds of attractive foliage and flower colors range from light pinks to violets to deep blues. When finished blooming, shear the plants and more blooms appear later in the season; this second flush is not as heavy but nonetheless, adds to the garden.
Try some of the following cultivars: 'Biokova' - low growing (10") with white-tinged pink flowers; 'Wargrave Pink' - pure pink blooms on 15-18" talk plants; 'Max Frei' - a good groundcover, 8-12" tall with deep magenta flowers; and 'Ballerina' - a 4" groundcover with large lilac-pink flowers with dark purplish centers.
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TAKE COVER - HELICOPTERS GALORE!
BYGLers across the state are taking cover from the attack of the "helicopters," otherwise known as schizocarps which are maple seeds falling from the trees. Silver maples produced heavy amounts of seeds this year, with some trees much more heavily-laden than others. As these seeds ripen and turn brown, they are falling and covering lawns, sidewalks, driveways, cars, and any other item that gets in the way. A word to the wise, clean these "helicopters" out of your landscape beds as best as you can. It's not easy, but many of these will sprout in the future, necessitating more weeding! In addition, make sure the gutters are cleared as large numbers of seeds left in the gutters may lead to sprouting and a consequent forest growing at the edge of the roof!
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A FROSTY ENCOUNTER
Erik Draper reported another two nights of frost in Geauga County. Frost injury is rarely uniform across all plants within a landscape. This is due to many factors such as species response, the stage and succulence of the new plant tissue, and the length of time the frost remained on the plant tissue. Often it may be confused with other problems like disease, winter damage, herbicide damage or root damage and failure. It is relatively easy to identify frost damage to delicate tissue, like that of flower petals, with the characteristic browning and eventual necrosis of that damaged tissue. Sometimes just the edges or tips of the flower petals are affected or the entire bud may be damaged to the center; however, damage to plant tissue is much harder to diagnose.
Sometimes the new twig expansion may blacken and collapse or it may slowly turn brown and develop a shepherd's crook appearance or begin to fade and eventually appear bleached out. Some plants showing damage from Geauga's frosts: boxwood, bird's nest spruce buds, succulent Japanese maple's new twigs, succulent crabapple new twigs, and damage to English yew buds. There are no universal symptoms which can be easily diagnosed as frost injury.
For example, Jim Chatfield and Curtis Young noted a strange look to a Gingko biloba tree in Bucyrus, Ohio. Closer inspection revealed all of the leaves on this large tree were stunted, exhibited a strange brown-gold color and were beginning to dry up. None of the other trees in the area showed any similar symptoms. Later that day in Findlay, Ohio another Gingko was observed with those same symptoms, which were attributed to frost damage. So if strange symptoms begin to appear in a landscape near you, keep frost in mind as a possibility.
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BUG BYTES
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THE TWO FACES OF PINE BARK ADELGIDS
Pine bark adelgids are seldom seen as a significant problem in landscapes. However, as Joe Boggs, Dan Herms (OSU Entomology), and Dave Apsley (OSU South Centers) observed this week in eastern Ohio, this sap sucking pest can be a significant problem on closely spaced white pines planted for reforestation or for paper pulp production. Indeed, the adelgid appeared to be killing heavily infested trees. Dave Shetlar speculated that the outbreak may be linked to tree stress-related conditions. This and other factors are being investigated by OSU and the Ohio Department of Natural Resources, Division of Forestry.
The adelgid sinks its sucking mouthparts into the bark of twigs, branches, and main stems of many species of pines, but they have a particular affinity for eastern white pine. Adult females and nymphs cover themselves with waxy, fuzzy, white material. Trunks of heavily infested pines may appear flocked. The adelgids complicated life cycle coupled with the protective nature of the flocculent covering makes it a difficult pest to control with standard insecticides. In landscapes, the adelgid can be controlled by washing the insects from the bark using a concentrated stream of water. However, this approach is not practical in the white pine plantations.
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CORRUGATED BIRCH LEAVES
Curtis Young and Dave Shetlar reported observing corrugated leaves on specimens of RIVER BIRCH (Betula nigra) trees in Lima and Columbus, Ohio. This distortion of birch leaves is usually caused by the SPINY WITCH-HAZEL GALL APHID (Hamamelistes spinosus) however this is not an officially recognized common name. This aphid has a complex life cycle in which it alternates hosts between witch-hazel (Hamamelis spp.) and birch (Betula spp.). The aphid can overwinter on either host as an egg on witch-hazel or an adult female aphid on birch. In the spring, the eggs hatch and the adult females resume activity. The feeding activity of the resultant aphids cause plant growth distortions on both hosts.
On witch-hazel, the newly hatched aphids' feeding causes expanding buds to produce a spiny, globular gall around the aphid in which it produces many offspring that will eventually fly to birch. On birch, the feeding activity of the overwintered female will cause the newly expanding leaves to pucker and bulge length-wise producing the corrugations in which the females feed, produce waxy secretions and globs of honeydew, and reproduce. The affected leaves will usually turn yellow and prematurely fall off of the tree. Damage on either plant is usually not severe enough to warrant treatment. Frequently, numerous predators will destroy aphid populations on the birch leaves. If heavy infestations occur on highly visible landscape plants, treatments with acephate, imidacloprid or insecticidal soap may reduce their impact.
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WINDSHIELD WIPES
BYGLers also ran into several other insect, mite and even crustaceans this week including:
* BOXWOOD LEAFMINER (Monarthropalpus flavus) adults are buzzing their namesake in central and southwest Ohio. The tiny midge flies look like reddish-orange mosquitoes. Adults can be targeted with a foliar application of acephate (e.g. Orthene). However, an application of imidacloprid (e.g. Merit) made as a soil drench is a more effective control. While fall is the ideal timing for this application, since it will also prevent damage from BOXWOOD PSYLLIDS (Psylla buxi), an application made now will kill the leafminer larva as they begin to develop in their mines.
* Joe Boggs noted that FOREST TENT CATERPILLARS (Malacosoma disstria) have crawled to the top of his list of "most frequently asked questions." He also noted the hairy caterpillars have squirmed into local news media reports. The caterpillars are now predominantly in the 3rd instar stage, and have shifted their behavior from dangling on silk threads to focusing their attention on consuming leaves of oak, maple, ash, sweetgum, birch, cherry, elm, and basswood. Well established healthy trees should be able to handle the damage. However, deciduous trees planted in the last few years could be seriously stressed by the leaf loss and should be closely inspected. See BYGL 2006-4 (4/27/06) for more information on this general defoliator.
* WATER FLEAS FREED IN AQUATIC GARDENS. Water fleas, Daphnia ambigua, were discovered skipping about in some aquatic tubs filled with water plants in a nursery. Horrified to see the tiny creatures, the manager wanted to eliminate them without killing the plants. Luckily, Dave Goerig was consulted, who identified the tiny crustaceans and realized their role in aquatic diversity. Water fleas are considered to be beneficial as they eat bacteria, detritus, and algae then, in turn, are eaten by small fish, tadpoles, salamanders, newts, and aquatic insects, therefore they play a very important role in the food chain. Only 1/32" long, water fleas consist of two translucent shells which hinge along the back and are slightly open along the ventral side. Water fleas are often used for research, as their circulatory system can easily be observed. Dave encouraged the manager to leave the water fleas alone and advertise the natural authenticity of her water gardens.
* WAREHOUSE BEETLE LARVAE ABOUND. The spiny tailed larvae of the warehouse beetle, Trogoderma variabile, have been reported in both Mahoning and Franklin counties recently. These reddish, carrot shaped larvae are covered with short bristles and are about 1/4" long when discovered. Typical of this genus, the larvae feed on items containing or originating from animal products. They are often found eating stale mouse bait, unused baking products, old wasp/bee nests, improperly prepared taxidermy specimens, insect collections and old, damp, leather chairs to name a few breeding sites.
To eliminate this pest, the inquirer needs to find the source of the infestation and discard it or have it professionally treated. Rugs and some fabrics can be dry cleaned, heat treated or chilled, depending upon the situation. All infested items that are to be kept should be cleaned to prevent future episodes. Insecticides may not be necessary, depending upon the type of business where the beetles are occurring.
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DISEASE DIGEST
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CYCLANEUSMA NEEDLECAST
Nancy Taylor reported receiving a sample of Scots pine with the disease pathogen, Cyclaneusma minor present. This fungal disease is called needlecast because it typically causes the older needles to drop off or be "cast off." This disease mainly attacks Scots and Austrian pine although other susceptible conifer hosts include mugho, Virginia, and eastern white pine. Symptoms may begin to appear in early Autumn as localized spots within a tree and eventually these spot begin to coalesce and may expand throughout the entire tree. The interior needles begin to turn bright yellow and later turn more of a tan color, with darker brown transverse bands developing on the needle surfaces.
These infected needles then turn brown and overwinter in this condition, all the while slowly dropping throughout fall, winter, and spring. In these dead needles, the fungus produces tiny, elongate, protruding, tan-colored fruiting bodies. These fruiting bodies release spores during wet weather to initiate infections, typically from April to June, but infection may also occur at low levels throughout the year depending on the environmental conditions. This disease is favored by mild, rainy weather during spring and summer. It is difficult to control Cyclaneusma needlecast because spore production and infection may occur over an extended period of time. A registered fungicide may be used throughout the growing season to help prevent infections, but if possible the best course of action is to cut down the infested tree and get rid of the source of inoculum.
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IS HOSTA VIRUS X LURKING IN YOUR GARDEN?
A southwest Ohio grower recently called Dave Dyke with a concern that some plants in her hosta collection were infected by Hosta virus X (HVX). Acting on Dave's advice to send a sample to the C. Wayne Ellett Plant and Pest Diagnostic Clinic (CWEPPDC) for diagnosis, she submitted a sample of a plant, Hosta 'Ventricosa', which seemed to best exhibit some of the classic symptoms of this virus - wrinkled tissue, green lines and mottling. The CWEPPDC confirmed the HVX infection.
The virus is the most commonly occurring virus of hostas (Hosta spp.) in the United States. It produces symptoms of mosaic (chlorophyll-cleared) areas and can lead to leaf desiccation and death in some hosta cultivars. There are three possible responses across hosta cultivars to HVX: 1) susceptible to infection, with symptoms of varying degrees of severity; 2) susceptible but showing no visual symptoms (tolerant); and 3) immune to infection with no symptoms. Because plants can be tolerant or asymptomatic when purchased, but develop symptoms weeks, months or years later, HVX is often undiagnosed and many infected plants are sold. Diagnosis is further complicated because of the wide range of symptoms exhibited by different varieties. The disease is only mechanically transmitted by sap-to-sap contact between infected and healthy plants. It is thought that many plants in the southwest Ohio collection were infected by a worker using a pruning instrument to deadhead plants without sterilizing it between plants.
For further information on this disease, including a chart of susceptible, tolerant, and immune hosta varieties, refer to, "About hosta virus X" in Michigan State University's "Landscape Alert", Vol. 20, No. 16, August 26, 2005, at: http://www.ipm.msu.edu/CAT05_land/L08-26-05txt.htm and University of Minnesota's "Yard and Garden Line News", Vol. 7 No. 8, June 1, 2005, at: http://www.extension.umn.edu/yardandgarden/YGLNews/YGLN-June0105.html#x. Additionally, Excellent photos of HVX are available at http://hostalibrary.org/.
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MOIST CHAMBER
Until the rain that may be falling as you read this, it has not been a banner year for the "environment conducive to disease" for many plant pathogens. Nevertheless, the invisible fungal spores fly through the night seeking out their victims of foliar glory. Some diseases noted this past week were some early ROSE BLACK SPOT and the reliable annual appearance of MAY-APPLE RUST, the bright orange announcement that May has arrived. On crabapples, no APPLE SCAB is yet evident in Crablandia plots at Secrest Arboretum in Wooster, but we suspect some infections have already occurred and that we will bear witness to the symptoms resultant from such infections over the next few weeks.
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TURF TIPS
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BIRDS OF A FEATHER DINE TOGETHER
Joe Boggs and Dave Shetlar reported receiving calls of large numbers of EUROPEAN STARLINGS (Sturnus vulgaris) scouring tracks of turfgrass in parks and golf courses for something to eat. Their searching could be for white grubs, but more likely what they are capturing and gobbling down are surface feeding SOD WEBWORMS (Crambus spp.) and adult BLACK TURFGRASS ATAENIUS (BTA) (Ataenius spretulus) beetles. As several BYGLers reported, VANHOUTTE SPIREA (Spiraea x vanhouttei) is in full bloom in many parts of Ohio which coincides with the emergence of BTA adults. BTA adults are highly attracted to turfgrass areas with dense layers of thatch and decaying odors. These two qualities are often associated high maintenance turfgrass such as that found on golf course greens and tees.
Joe Boggs on the other hand saw exactly what the birds were dining on, CRANE FLY (Tipula spp.) adults. These were most likely not the European crane flies that are known to damage turfgrass which have not yet been identified to be in Ohio but rather one of several species of native crane flies that feed on the organic matter within the soil some of which emerge as adults in the spring of the year. Investigate and identify what the potential entrees are for the starlings and if they are potential threats to the health of the turfgrass, take the appropriate corrective action.
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STELLAR BILLBUG YEAR?!
Dave Shetlar reported that environmental conditions this spring have been similar to environmental conditions experienced in other years when BLUEGRASS BILLBUGS (Sphenophorous parvulus) have been very successful in reproduction and eventually causing severe damage in turfgrass. Dave says now is the time to take action to limit the potential injury that could be caused by the larvae of these billbugs if they go unchecked. Apply bifenthrin (Talstar), deltamethrin (Deltaguard) or lamda-cyhalothrin (Scimitar) to the blades and stems of turfgrass to kill the adults before they get a chance to lay numerous eggs. An alternative action to take now to limit billbug injury is to apply imidacloprid (Merit) or clothianidin (Arena) to kill the grubs as they begin to feed. These materials will also provide good control of other turfgrass pests such as black turfgrass Ataenius beetle larvae (Ataenius spretulus) and chinchbugs (Blissus leucopterus).
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INDUSTRY INSIGHT
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INSECTICIDE OPTIONS FOR EAB
The questions from homeowners and Green Industry professionals wondering if there are insecticides capable of protecting ash trees from emerald ash borer (EAB) have begun. Research and experience have shown that insecticides do have potential for protecting trees from EAB. However, success is not assured. Research suggests that the best control will be obtained when treatments are initiated just prior to or in the earliest stages of infestation, and will have to be repeated each year. Dan Herms, OSU/OARDC Entomologist, has recently written a fact sheet, "Insecticide Options for Protecting Ash Trees from Emerald Ash Borer and Their Effectiveness" that is posted on the OSU Extension, Ash Alert Website at: http://ashalert.osu.edu/latestnews.asp?id=497.
There has been much confusion surrounding the question of whether insecticides are an effective option for EAB. The answer is, "It depends on the objective." When the objective is to protect trees from being killed, insecticides have been effective. However, when the objective is to eradicate an EAB infestation to keep it from spreading, insecticides are not effective, that is why they have not been used as an eradication tool by the Cooperative EAB Program. According to current policy, if an EAB infestation is discovered outside the northwest Ohio quarantine zone, trees in the immediate vicinity will be destroyed as funding is made available, even if they have been treated with insecticides. For this reason, OSU Extension recommends that ash trees located outside the northwest Ohio EAB quarantine zone not be treated for EAB. "Should I treat My Trees for Emerald Ash Borer?", a companion fact sheet, is also available on web at: .
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APRIL SOUTHWEST OHIO GARDEN CENTER SALES A MIXED BAG
Several local garden centers/greenhouses in southwest Ohio ecstatically reported that the warm and sunny weather throughout the month of April produced record sales for that month. Those retailers included one of the most upscale garden centers in the area, one that sells quality plants at some of the most moderate prices in the area (excluding box stores), and one in the middle of the price pack. At the same time, a few others reported that their sales were at or just below April sales levels of last year (which were generally good). Those reporting fairly level sales tended to be quality producers with pricing just a bit below that of the most upscale producer in the area.
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COMING ATTRACTIONS
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OSU Extension Plant Diagnostic Workshop is planned for northwest Ohio
Invest a day to grow your company's reputation as a valuable knowledge source in your customers' eyes! Join us Wednesday, May 24, 2006 as OSU Extensions Green Industry Center presents the first of this year's OSU ENLT Team workshops. Extension nursery and landscape specialists, Jim Chatfield, Joe Boggs and others will combine their experience to help your company to meet your clients' diagnostic challenges with this yearÂ’s OSU Extension Plant Diagnostic Workshop.
Topics at this year's workshop will include the following and more: Emerald Ash Borer; Diseases and Insects du Jour; Dr. Dendro Diagnostic Case Studies; Digital Diagnostics; Clinic Catharsis Sample Sharing; and Diagnostic Walks. The daylong program begins at 9:45 A.M., and will be held at Toledo Botanical Garden Conference Center. Additionally, certification credits will be provided for ONLA and Master Gardeners.
The registration fee is $30.00, payable by check or cash to OSU Extension, ABE Center, at 639 S. Dunbridge Rd., Suite 4, Bowling Green, OH, 43402. This covers lunch, refreshments and program materials.
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BYGLOSOPHY
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"Nature is painting for us, day after day; pictures of infinite beauty if only we have the eyes to see them" -John Ruskin
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