Pam Bennett, Barb Bloetscher, Joe Boggs, Jim Chatfield, Erik Draper, Dave Dyke, Dave Goerig, Tim Malinich, Jane Martin, Hannah Mathers, Pam Sherratt, Amy Stone, and Curtis Young
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August 04, 2005
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This is the second 2005 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 August 02, 2005 conference included: Barb Bloetscher (C. Wayne Ellett Plant and Pest Diagnostic Clinic); Joe Boggs (Hamilton/Piketon); Jim Chatfield (North Region/HCS); Erik Draper (Geauga); Dave Dyke (Hamilton); Dave Goerig (Mahoning); Tim Malinich (Cuyahoga); Joe Rimelspach (Plant Pathology); Pam Sherratt (HCS); Dave Shetlar (Entomology); Amy Stone (Lucas); Nancy Taylor (CWEPPDC); 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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Heavy rains in some areas have brought about a greening of the landscape. However, this week's participants point out that generalizing about the weather can leave the wrong impressionsome areas have gone without rain and soils below the surface remain dry. The Palmer Drought Index shows that parts of southern and central Ohio are now in a "moderate" drought.
Here are the weather summaries from selected OARDC weather stations across the buckeye state. The information is a summary of data collected from July 20 August 3.
| Weather Station |
Region of Ohio |
Ave. High Temp F | Ave. Low Temp F | Ave. Temp F | Normal Ave. Temp F | Total Precip " | Normal Precip " | | Avon |
NE |
85.6 |
69.2 |
N/A | N/A |
1.15 |
N/A | | Hoytville |
NW |
87.5 |
62.1 |
74.6 |
72.7 |
3.91 |
1.76 |
| Delaware |
Central |
89.9 |
66.9 |
77.7 |
73.3 |
0.46 |
1.98 |
| Miami |
SW |
89.2 |
66.8 |
77.7 |
73.4 |
1.94 |
1.33 |
| Jackson |
South |
90 |
64.4 |
76.5 |
74 |
0.08 |
1.83 |
For additional information, or to see the locations of all of the OARDC weather stations in Ohio, check out the websites below.
 
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HORT SHORTS
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WOODY PLANT OF THE WEEK
Panicled hydrangeas, including PeeGee hydrangeas --PeeGee is a shorter version of the actual name Hydrangea paniculata 'Grandiflora'-- are extremely popular landscape plants, and are coming into their own in the late summer garden. Hydrangea paniculata is a small landscape tree or shrub with many variations and cultivars with large panicled blossoms, 6"- 8" to up to a foot long or more. Blossoms often change from creamy white to pinks and finally to brown in fall. Cultivars include 'Grandiflora', 'Tardiva', which often flowers as late as September, 'Pink Diamond' and 'Unique'.
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PERENNIAL OF THE WEEK
Achillea - Common Yarrow. This heat and drought tolerant plant produces showy flat-topped flowers on top of 2 to 3 foot stems. Flowers can be cut for fresh or dried use and are available in a variety of bright colors. Achillea filipendulina 'Coronation Gold' produces clusters of bright yellow flowers June through August. Achillea millefolium 'Summer Pastels' produces blooms in apricot, salmon, scarlet, white, rose and yellow. Achillea 'Moonshine' is a compact variety with yellow flowers.
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VOLUMINOUS VOLES
Participants at this weeks special Cincinnati BYGLive! held at the Boone County (Kentucky) Arboretum at Central Park viewed extensive vole damage on a planting of low-growing junipers. Main stems near the crowns of the plants had large areas of bark stripped down to the white wood causing attached branches to turn brown. The voles did not feed on every main stem. Consequently, browned branches were made more obvious when surrounded by healthy, green, unaffected foliage. The damage occurred during the winter or in early spring, and branch dieback symptoms have continued to develop as the season progressed.
Several participant noted that the damage looked very similar to symptoms produced on juniper by exposure to glyphosate (e.g. RoundUp) where branch tips were sprayed during edging applications of the herbicide. Rather than entire plants being killed, only branches exposed to low dosages of the herbicide die, producing the same brown-among-green color pattern observed with the vole injury.
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BUG BYTES
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ALIEN CATERPILLARS?
Home gardeners have been reporting giant green caterpillars which appeared "overnight" in their garden, devouring tomato plants. These smooth, luminous green caterpillars have a "horn" on the back end and white lines along each side, hence their names, the TOBACCO HORNWORM or TOMATO HORNWORM, family Sphingidae. These cleverly camouflaged caterpillars have been munching away for several weeks, unnoticed by even an enlightened observer. Only the piles of rounded black frass which have landed on lower leaves and the ground, could cue one to look more closely, to find stems stripped of leaves, and eventually the masked marauder. Both the tobacco and tomato hornworms look similar but the tomato hornworm has a black horn and V-shaped yellow-white lines, while the tobacco has a red horn with horizontal white lines.
The large, showy moths may be seen in the evenings, nectaring from trumpet-shaped flowers. They lay small oval, white eggs on the lower leaves, which hatch in about a week. After 20 days of feasting on tomato leaves, flowers, and small fruits, the caterpillar will reach 8 cm. When ready to pupate, they will drop to the ground and burrow into the soil about 10-15 cm. They do not spin a silken cocoon, but form a brown, bare pupa.
As several beneficial insects prey upon the caterpillars, control is usually not necessary for these green monsters unless one insists on picking the caterpillars and squashing them. Paper wasps, yellow jackets, and other wasps will grab them, chew them up, and take the remains to their nests to feed their larvae. A tiny parasitic wasp is excellent at locating them, then paralyzing and inserting eggs into the caterpillar. As the wasp larvae develop, they consume the contents of the caterpillar, until the hornworm begins to sag. The full grown larvae then erupt through the epidermis of the hornworm and form oval, white pupal cases. Intensely parasitized hornworms may have several rows of these white pupae. When these "nurseries of parasitoids" are found, leave them in the garden, so that the Braconid wasps will return the following year to control the next years population of hornworms.
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FOREST TENT CATERPILLAR DAMAGE REMAINS EVIDENT
Another observation from this weeks Cincinnati BYGLIVE! was widespread damage in the forests surrounding the Arboretum from the early spring leaf-feeding activity of forest tent caterpillars (Malacosoma disstria). This was the second time this season that the Cincinnati BYGLive! group visited the Arboretum. During the first visit in May, the group found large caterpillar colonies (BYGL 2005, 05/05/05). Mike Klahr (County Extension Agent for Horticulture, UK Cooperative Extension Service, Boone County) noted that his county experienced localized pockets of heavy defoliation in the spring.
The damage observed Monday ranged from leaves being almost completely consumed, with only midveins remaining, to leaves with large sections consumed, causing them to appear tattered, to leaves with only small areas consumed. A close inspection confirmed that the feeding damage was not recent. The edges of some damaged areas had closed indicating the feeding had occurred as leaves were expanding, while edges of other leaves had browned indicating the feeding was not recent, but had occurred after the leaves had fully expanded.
The most significant leaf-feeding damage was observed on sugar maple, a favored host of this moth caterpillar. However, tattered leaves were also found on ash, sweetgum, oak, birch, cherry, and basswood. Forest tent caterpillar moths have one generation per year. The BYGLive! group found a considerable number of egg masses left from this season's crop of moths indicating that next season's populations could be even more significant.
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SPIDERMANIA
Calls concerning spiders in and around homes have ballooned in recent weeks. This is the time of year when populations of predators, including spiders, seem to explode. There are over 600 species of spiders found in Ohio. These four are considered dangerous: the northern black widow (Lactrodectus varioles); the southern black widow (L. mactans); and two "fiddle-backed" spiders, the brown recluse (Loxosceles reclusa), and the Mediterranean brown spider (L. rufescens). However, bites from these four species are extremely rare.
Readers should remember that all spiders are predators, and all spider species found in Ohio feed primarily on insects. Beyond their beneficial status, spiders are also fascinating creatures that exhibit a wide range of beautiful color patterns and some spectacular engineering feats.
Some of the more interesting spiders currently being seen include FUNNEL WEB SPIDERS (Family: Agelenidae); SHEET WEB SPIDERS (Family: Linyphiidae); and the ORB WEAVERS (Family: Araneidae). Funnel web spiders produce large, flat, sheet-like webs spun across grass, under rocks or boards, or over the branches of shrubs such as yews and junipers. The webs slope gently towards a narrow funnel or tube where the spider resides, awaiting its next victim. The spiders are medium-sized and resemble small wolf spiders.
Sheet web spiders produce a web that may be formed into a bowl or dome that is anchored to the branches of shrubs. The spiders are very small, and they await their prey while standing upright on the surface of the web, or by hanging upside down on the underside of the web, depending upon the spider species.
The webs of both the sheet and funnel web spiders are becoming very evident, particularly in areas of the state that have received little rainfall in recent weeks. The webs have escaped destruction from heavy rains, and are being covered with dust making them very conspicuous. A covering of morning dew can make the webs even more obvious. The webs can be easily removed using a broom if they become too unsightly.
Orb weavers are the true master engineers of the spider world. They spin vertical round webs with radiating spokes of structural silk covered by a spiral of sticky silk. One of the most spectacular orb weavers found in Ohio is the GARDEN SPIDER (Argiope aurantia). This large spider has a leg span that can exceed 2". The legs are black with reddish or yellow bands. The mostly black abdomen is conspicuously marked with yellow or yellowish-orange spots and bands. This spider is active during the day and usually spins its web in tall weeds. The spider can be found resting in the middle of the web atop a zig-zag pattern of coarse webbing that reflects ultra-violet light and attracts insects.
Although there are several insecticides labeled for spider control, this is not a recommended practice. Spiders are important in reducing insect pest populations. Homeowners are urged to practice restraint, appreciation, and understanding. Aside from providing free Halloween decorations, spiders also provide a great service by reducing the need for controlling more significant pests.
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TROUBLED TILIA
Joe Boggs reported observing heavy infestations of BASSWOOD LACE BUGS (Gargaphia tiliae) on several silver linden (Tilia tomentosa) trees at the Boone County (Kentucky) Arboretum. These same trees were heavily infested last year (BYGL 2004-17, 7/29/04). Lace bugs are so named because of the lacy-like venation of their broad, flat, whitish colored forewings that cover most of their body. The bugs feed with sucking mouthparts, as do all insects belonging to the insect order Hemiptera; the True Bugs.
Most lace bug species reside on the underside of leaves, and basswood lace bug is no exception. However, feeding first appears on the upper leaf surface as stippling, small yellow spots. The spots may coalesce causing the upper leaf surface to become light green, to yellow, and eventually bronze colored. Lower leaf surfaces are covered by unsightly black tar-like spots of lace bug excrement.
Silver lindens have long been appreciated for their distinctive foliage. Their leaves feature an upper surface that is a lustrous, glistening dark green, while the lower surface is a soft silver. Breezes produce glimmering displays as the silvery undersides of the leaves flicker in and out of view. Unfortunately, lace bugs can muffle this captivating feature. Indeed, the heavy basswood lace bug infestation observed in Kentucky had caused the normally dark green upper leaf surfaces to appear light green to yellowish-green.
While such heavy damage on Tilia is rare for this insect, it is not unknown, and it is not confined to one species of lace bug. WALNUT LACE BUG (Corythucha juglandis) may also be found on the undersides of Tilia leaves, as well as on butternut and black walnut leaves. Most insecticides labeled for use on Tilia will control these insects. However, the damage done thus far this season will not be eliminated.
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DISEASE DIGEST
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CEDAR RUSTS
Joe Boggs finally understands how beautiful and interesting plant diseases caused by fungi can be! In his southern Ohio perch, he had rarely, if ever, seen CEDAR APPLE RUST or CEDAR HAWTHORN RUST on CRABAPPLE. Indeed, these rusts are not nearly as common here, as in states such as Kentucky or North Carolina where more of their alternate hosts, juniper, grow. The three common cedar rusts, cedar apple rust (Gymnosporangium juniperi-virginianae), cedar hawthorn rust (G. globosum), and CEDAR QUINCE RUST (G. Clavipes), go back and forth between susceptible junipers and the most common rosaceous hosts: apples, crabapples, and hawthorns.
Most popular crabapple cultivars in Ohio rarely exhibit cedar rust diseases, but those with Bechtel crabapple or Malus ioensis in their background sometimes show symptoms on the crabapple hosts. In some cases, this rust manifests itself as bright orange rust lesions on the upper surface of leaves and spore laden tendrils of the fungus growing out of pustules on the lower surfaces of the leaves. In other cases on some hosts, instead of an orange color, the spots on the upper surface of the leaves are an almost ornamental bright reddish color.
And that is what budding pathologist Boggs was so impressed by in his rust sighting. Joe likened the red coloration to a garish red lipstick. At any rate there is no going back now, infections occurred all the way back in late April or May. At that time, spores of the fungus arrived with the wind, blowing from junipers to the crabapples. To prevent this disease in the future, protective fungicides would need to be applied during that mid-spring infection period.
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CROP CIRCLES IN PUMPKINS?
Erik Draper reported on strange crop circles which have started to appear in Geauga County pumpkin fields. After stomping out to the middle of a pumpkin patch to investigate collapsed leaves and vines, the culprit was not alien spacecraft landings but the fungal disease called PLECTOSPORIUM BLIGHT. Plectosporium blight, formerly known as Microdochium blight, is caused by the fungal pathogen Plectosporium tabacinum and can infect pumpkins, squash and other cucurbits.
This disease has some unique, telltale symptoms which occur mostly on leaf veins, leaf petioles, stems, and the fruit. As infections occur, lesions first appear as scattered white distinctive diamonds or even spindle-like shapes. Individual lesions are small initially, about 1/4" in length, but they may expand and coalesce, eventually turning scaly and white, the entire surface of stems, leaf veins, petioles and fruit handles (peduncles). Specifically note that the leaf tissue between veins is not affected by this fungus, so early symptoms are usually not as apparent as with other foliar diseases. Leaves turn yellow, wilt, collapse and die, often creating the 10-25 foot diameter "crop circle" at the site of initial infection. The dead leaf petioles and vines become so brittle that they pop and shatter when stepped on or are moved aside.
Plectosporium blight usually reappears in following years, if planted back into cucurbits, because the pathogen can survive in soil and on decaying plant debris from the previous year. To help manage this disease crop rotation is necessary. Although the minimum effective rotational period has not yet been determined, at least a three year cucurbit-free period, is recommended. Plectosporium tabacinum is not thought to be seed-borne and little is known about the disease cycle, but spores are most likely spread by wind and rain. Fungicides can also help to manage this disease with both Mancozeb and Cabrio® (a strobilurin) being registered for use in controlling Plectosporium blight. So if there are circles in the pumpkin patch, walk through the circle and look for diamonds- which would indicate Plectosporium blight.
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MOIST CHAMBER
Powdery mildews are evident on everything from beebalm to zinnia, but signs and symptoms do not appear to be particularly severe this year.
* Observers are noticing that once again BYGLers did not lie: sycamores plagued by near defoliation this spring by SYCAMORE ANTHRACNOSE now look normal, with refoliation making earlier ugliness a faint memory. Much the same is true of other anthracnoses, such as ash anthracnose, but curled and distorted leaves on oaks are still evident, especially on lower leaf surfaces, though damage to the health of the trees appears to be minimal.
* Disease samples of note from the Plant and Pest Diagnostic Clinic include Phytophthora root rot on Fraser firs, a common problem on poorly drained soils, and Septoria leaf spot on black-eyed Susan.
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TURF TIPS
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BROWN PATCH WEATHER
Average daily temperatures in the high 70's coupled with high humidity created the perfect environment for brown patch disease (Rhizoctonia solani). Most susceptible of the cool season grasses are tall fescue and perennial ryegrass. The fungus produces circular patches on the turf. In humid weather, the outer edge of each patch may have a dark gray/dark purple ring early in the morning while the grass is still covered with dew. This "smoke ring," disappears later in the day. Initially, the grass has a dark, water-soaked appearance but soon dries out to a light brown. It is most severe when excess nitrogen fertilizer has been used, so avoid excessive use of nitrogen before hot weather and avoid excessive thatch buildup. In addition, do not water at night as leaf tissue will be wet for a prolonged period of time, creating a suitable environment for the disease.
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RENOVATING DEAD SPOTS
Dead spots of turf may have been caused by any number of things this summer including: drought, heat stress, disease, insect damage, fertilizer burn etc. Renovation of those areas involves removing all the dead tissue, mechanically or by hand, and exposing the underlying soil in preparation for seeding or sodding. The best time of the year to seed in Ohio is August 15th to September 15th; however, it may be more beneficial to wait until early September if this hot weather continues. The advantages of fall renovation include: (1) soil temperatures are warm and conducive to quick germination; (2) there is usually adequate rainfall to keep the seed moist until is has germinated - if this is not the case, irrigation is required; (3) there is not the same weed pressure in the fall as there is in the spring, so the desirable grass should establish without competition. The key to successful seeding and/or sodding is to make sure there is adequate moisture in the establishment period. Lack of moisture is the number one reason for seed failure. Prior to seeding or sodding a starter fertilizer application should be made.
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HOT WEATHER TIPS FOR HEALTHY TURF
* Do not apply quick release sources of nitrogen as there is an increased risk of fertilizer burn.
* Keep foot & vehicular traffic off drought/heat stressed turf.
* To get maximum results from watering, water early morning or late afternoon. This reduces risk of water evaporating.
*Avoid aggressive management practices, such as scarification and aeration.
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INDUSTRY INSIGHT
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WHAT A BALL!
This past Friday the Ball Horticulture Company celebrated its 100th anniversary with a beautiful and massive display of its plant materials in gardens and hanging baskets at its office in West Chicago, IL. The Cincinnati Flower Growers Association (CFGA), seized this opportunity to see lots of beautiful plants and gardens by renting a bus for a 3-day tour of that area. The 39 participating members visited a great garden center, the Planters Palette, in Winfield, IL and then went on to a wonderful barbeque dinner and a plant/garden tour hosted by PanAm Seed, Elburn, IL. Another day was then spent wandering through the amazing gardens at Ball. The group also visited 2 outstanding garden centers, Platt Hill, Bloomingdale, IL and the Growing Place, Aurora, IL, on the way home.
Anyone wishing to visit the Ball gardens in West Chicago may do so by stopping by the Ball office at 622 Town Road, West Chicago, IL. Simply stop by the reception desk for a map. Gardens are open Monday through Friday; however, on Fridays there should be employees on the grounds to show you around.
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COMING ATTRACTIONS
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38TH ANNUAL SUMMER FIELD DAY
. . .is scheduled to be held Tuesday, August 9 at Chalet DeBonne Vineyards 7743 Doty Rd. in Madison. Last year, this event attracted over 170 exhibitors and 650 participants and this year promises to be another quality event. For more detailed information on attending and/or exhibiting, call 440-241-7969, or visit the Nursery Growers of Lake County Ohio, Inc. website below.
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SALSA (SECREST ACADEMY FOR LANDSCAPE SCIENCES AND ARTS)
SALSA is a learning experience, advancing your knowledge of the arts and sciences of landscape horticulture, through linked interactive hands-on programs. SALSA is not a series of isolated single-topic programs, nor is it a full-fledged 2- or 4-year degree program. SALSA occupies the landscape between these two ... rooted in dedication, blooming with creativity. Class size is limited. The cost of SALSA I is $300 for the full 3 days of programming. This fee includes considerable reference material and class curriculum notebooks, diagnostic aids such as hand lens, lunches and refreshments. For more information contact Joe Cochran at Secrest Arboretum (330-263-3886; cochran.58@osu.edu).
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OSU 2005 TURFGRASS RESEARCH FIELD DAY
Wednesday, August 17, at The Ohio Turfgrass (OTF) Research and Education Facility in Columbus. See http://www.ohioturfgrass.org to download registration materials or phone, 888-683-3445.
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11TH ANNUAL OHIO LAWN CARE DIAGNOSTIC SEMINAR
. . .Thursday, August 18. OTF Research and Education Center in Columbus. See http://www.ohiolawncare.org to download a registration form or phone, 800-510-5296.
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BYGLOSOPHY
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"Despite the gardener's best intentions, nature will improvise." - Michael P. Garafalo
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