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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August 24, 2006
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This is the twenty-first 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 August 22, 2006 conference included: Carolyn Allen (Clark); Pam Bennett (Clark); Barb Bloetscher (Entomology/C. Wayne Ellett Plant and Pest Diagnostic Clinic (CWEPPDC)); Joe Boggs (Center at Piketon/Hamilton); Jim Chatfield (Center at Wooster/HCS); Erik Draper (Geauga); Dave Dyke (Hamilton); Dave Goerig (Mahoning); Becky McCann (ABE Center); Joe Rimelspach (Plant Pathology); Dave Shetlar (HCS); Nancy Taylor (CWEPPDC); and Curtis Young (Allen). .
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 weather across the state has been relatively decent for August at this point. Some, however, could use a bit of rain, especially the southwestern and some central areas of Ohio. This week's weather summary includes data from August 1 to August 22 and is obtained from 4 OARDC weather stations across the Buckeye state. Note: In the summary below, all areas are just a bit below the normal amount of precipitation for the 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 |
80.6 |
63.1 |
NA
|
NA |
1.11" |
NA |
| Hoytville |
NW |
84.6 |
59.6 |
72.1 |
70.8 |
0.43"
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2.18" |
| Oxford |
SW |
87.3 |
67.0 |
76.8 |
72.3 |
0.61" |
1.69"
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| Jackson |
South |
87.4 |
62.3 |
74.5 |
72.5 |
1.68" |
2.71" |
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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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 PLANT OF THE WEEK. Rose mallow (Hibiscus moscheutos) -- Hardy hibiscus plants have made a splashing display in perennial gardens these past few weeks and continue to bloom in central Ohio. These hardy giants are meant for the back of the perennial border, growing to around 4-5' tall at times and getting just about as wide. Depending upon the cultivar, flower colors range from white, to white with red centers, to pinks and reds. In addition, some cultivars have cut-leaf foliage while others have a coppery-red cast to the foliage. In the spring, these plants are one of the last ones to emerge. Be patient and they will eventually reward the gardener, but be sure to give them room to rule the garden!
*WOODY PLANT OF THE WEEK. SOURGUM or BLACKGUM (Nyssa sylvatica). Ever notice the occasional bright red leaves that have fluttered to the ground along woodland trails or which dot the canopy of landscape trees this time of year. One possibility is that you are seeing Nyssa leaves. Every August this native tree has a few leaves that color up early, providing a spectacular augury of autumn glory to come.
Typically sourgum is a medium-sized (30-50 feet) native landscape or woodland tree, though it can grow much larger. In youth, it is often regularly pyramidal in form but it often opens up over the years. It has outstanding lustrous green leaves in spring and summer, and is absolutely spectacular for fall color with bright orange to intense red foliage. Sourgum (also known as blackgum and tupelo) thrives in moist sites.
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DOLGO BUTTER
At our SALSA (Secrest Academy of Landscape Science and Arts) we did a little natural history exercise, collecting the plum-colored fruits of 'Dolgo' crabapple from the Crablandia plots. Why so? In order to enjoy the tart, earthy pleasures of Dolgo butter at our next SALSA workshop on September 21. Perhaps with some fresh bread, hot from the oven. Here is the Nearly Famous Dolgo Crabapple Butter recipe, courtesy of Mike Lee of Bailey Nurseries (perfected when Mike lived in the Buckeye State):
Start with 8 lbs of crabapples. Wash in a large kettle and cover with water. Heat to a boil. Simmer until fruit softens. Drain, then process through a mill. To the sauce add 3 lb of sugar, two quarts of cider, one tablespoon of cinnamon, and a teaspoon of cloves. Simmer under low heat or use a large crock pot for 2-4 hours. Stir occasionally. As Mike notes, the house will then smell great. Pour off hot Dolgo butter into jars. Process in a hot water bath or freeze. Man oh man!
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FESTERING FUNGI
Fallow, is generally the term used to describe land that has been left unsown during the growing season. In a landscape setting we often leave ground devoid of plants and unsown for various reasons. To compensate for the lack of rooted vegetation on that land, gardeners apply organic mulches to protect the soil from wind and rain erosion. Other reasons we use organic mulches in our gardens are to conserve moisture, moderate soil temperatures, stimulate activity of beneficial microorganisms (fungi), and limit the growth of undesirable vegetation. However, there are some precautions that need mentioning as you consider organic mulches. Occasionally some mulching materials can give rise to nuisance microorganisms.
It is a natural process for fungi to break down organic materials. Imagine our neighborhoods if the leaves that fell from the trees never decomposed. This week Dave Goerig and others reported calls were coming into Extension offices relating to the undesirable slime molds, (Division, Myxomycota), shotgun, or artillery fungus (Sphaerobolus), and of course, the toad stools (Lepiota Americana). These fungi are great decomposers of organic materials, but may have undesirable effects in the garden as they develop and complete their lifecycles. The impact of adding mulches and composted materials to soils is generally determined by the type of organic material from which it was produced, as well as the degree to which it was decomposed and treated prior to its use in the landscape. Moisture content, pH, and temperature at the time we use these materials also effects the future severity of these festering fruiting bodies.
Once the mulch products are applied to a landscape planting, very little can be done to control nuisance fungi should they appear. If they arise, remove them with a rake or hoe. Next, using a four prong hook or rake, break up the crusted mulch and incorporate it into the soil layer as best you can. Finally, water down the site thoroughly. If fresh dry mulch is applied over the bed that has had this problem, it is likely to occur again as soon as it dies out. Mulches should not be applied any thicker than two inches.
 
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BUG BYTES
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WARM SEASON SPIDER MITES
Dave Shetlar urged landscapers located in dry areas of Ohio to take a close look at yellowing or browning tree leaves. The damage may have been caused by warm-season mites rather than moisture stress. Dave reported that he is seeing considerable damage from OAK SPIDER MITE (Oligonychus bicolor); MAPLE SPIDER MITE (O. aceris); and LINDEN SPIDER MITE (Eotetranychus tiliarum).
Populations of these warm-season mites explode during the hot, dry conditions of mid-summer. As with all mites that feed on plants, they use their fang-like mouthparts (chelicerae) to stab plant cells. The mites then feed on the cell contents that spew forth. Their feeding activity at first produces small, distinct, yellowish spots (stippling). Numerous spots often coalesce causing leaves to turn yellow, then brown mimicking symptoms caused by moisture stress.
Maple and linden spider mites feed on the lower leaf surface while oak spider mites feed on the upper surface. Unfortunately, it is too late in the season for control measures to reverse leaf damage that has already occurred, and it is too late to effectively reduce mite populations. They are already declining with cool night-time temperatures. Dave recommended that landscapers make note of properties that suffered high mite populations this summer and focus on controlling mites next June, prior to the outbreak of damaging populations.
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CALICO SCALE CRAWLER DAMAGE
The collective feeding activity of high populations of adult soft scales, such as calico scales (Eulecanium cerasorum), can cause significant harm to tree hosts. However, landscape and nursery managers should remember that the immature stage (crawlers) of soft scales also sucks plant juices. While much smaller than the globular adults, the combined feeding activity of huge numbers of crawlers can likewise produce damage.
Dave Shetlar and Joe Boggs reported that high populations of calico scale crawlers currently attached to honeylocust leaflets are causing leaves to turn yellow-to-brown in central and southwest Ohio. Both noted that the leaf discoloration may be mistaken for moisture stress. The tiny crawlers are tannish-brown, flattened, and oval shaped. They are attached to the midvein on the underside of honeylocust leaflets. As fall approaches, the crawlers will move to stems where they overwinter.
Calico scale can infest a wide variety of deciduous trees. The stems of off-colored trees should be closely examined for globular, reddish-brown, or dark-brown dead female scales. Trials in Ohio have indicated calico scale can be managed using soil drenches of neonicotinoid systemic insecticides such as imidacloprid (e.g. Merit, Marathon), clothianidin (e.g. Arena), and dinotefuran (e.g. Safari) made from September into November.
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WEBWORMS SACK TREES
Several BYGLers reported that second generation MIMOSA WEBWORMS (Homadaula anisocentra) and FALL WEBWORMS (Hyphantria cunea) are rapidly expanding towards their zeniths for the season. Caterpillars of both species of moths feed gregariously as skeletonizers on leaves within webs spun over the foliage. Leaves damaged by mimosa webworms turn orangish brown and appear fire scorched, while leaves damaged by fall webworms simply appear to fade away.
Despite its common name, mimosa webworm is found primarily on honeylocust in Ohio. Fall webworms may graze on more than 120 species of deciduous trees. Both webworms have at least two generations per season, with mimosa webworm enjoying an occasional third generation in late-September. Female moths of each species lay eggs on nests produced by earlier generations. Consequently, the nests keep getting bigger with each generation. The dense second generation nests impede penetration of insecticides. Fortunately, both have a wide complement of predators and parasitoids.
Populations of both species of webworms vary widely throughout Ohio. Jim Chatfield reported that damaging populations of mimosa webworm are occurring in central and northeastern Ohio, while Pam Bennett, Curtis Young, and Joe Boggs noted that populations are relatively low the western and southwest part of the state. Joe reported observing some truly magnificent fall webworm nests in his part of the state; however, populations are generally at low levels. Such is also the case for the rest of the state.
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HORSEHAIR WORMS -- A KNOTTY PROBLEM
This week's "That's Fascinating" BYGL award goes to Barb Bloetscher and Joe Boggs. Both received a phone call from a county health director in southwest Ohio seeking a positive identification of a sample of a long, thin, twisting-squirming, white worm-like creature. The sample came from an apartment dweller that had drowned a jumping spider in a glass of water. The worm-like creature had "appeared" in the water, as if by spontaneous generation. They contended there was something horribly wrong with their drinking water! The writhing critter was a type of roundworm called horsehair worm, which had emerged from the submerged spider. These worms belong to a group of organisms called Nematomorphora. They are harmless to humans, pets, and livestock.
The horsehair name came from early speculations that the worms arise through "spontaneous generation" from horse hairs. Their common occurrence in horse watering troughs provided support for this erroneous belief. They are also called Gordiid, or Gordian worms, because of their tendency to twist their long (4-14") thin bodies into loose, knot like balls that resemble the enigmatic "Gordian knot" of Greek legend. Horsehair worms are common in the Midwest, and they are frequently observed in standing pools of water in late summer.
What made this report so fascinating is that the immature stages of this worm usually live as internal parasites inside plant-feeding arthropods (e.g. spider food). They live inside their host's body cavity absorbing nutrients from the host's "blood" (hemolymph). Eventually, they drive their host to drinking.....water. The host expires in the water and the adult worm emerges from various openings including the mouth, breathing spiracles, or the anus.
The adult worm lays eggs that hatch into encysted larvae that attach to vegetation where they are consumed by a plant-feeding arthropod. The cycle then repeats. In this case, the spider became infected by feeding on an infected arthropod! The prey got even with the predator, in the end.
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ANOTHER TWIST TO THE BAGWORM
An issue that has arisen in reference to the bagworm is a wide range of ages of caterpillars. The majority of the caterpillars has reached or is very near to completing their feeding and development toward the pupal stage. The largest caterpillars have already tied their bags to twigs and stems, sewed the openings of their bags shut, and are preparing to pupate within. Joe Boggs reported seeing some male pupal cases sticking out the bottom of their bags from emerged male moths.
Joe was also challenged by a participant in a workshop, who said he was seeing very young bagworms mixed in with the maturing bagworms suggesting a second generation of the insect. Is this true? Are there two generations of bagworms? The answer is, NO! All of these bagworms, no matter how young or old, are of the same generation. The reason they are not all at the same point in their development is an asynchronous egg hatch. These younger caterpillars may or may not be able to complete their development before the end of the season. Their success will depend on how late heavy frosts and freezing temperatures set in. Many may not make it in time. The control recommendations remain the same for these late bloomers. It is too late to use Bt compounds on these younger caterpillars, thus the standard insecticides are still the choice materials.
One final note, we are still requesting readers to send to us their observations on bagworm populations in their areas, including whether you are not seeing any or you are being inundated by them. Send your comments to Curtis Young at: young.2@osu.edu .
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DISEASE DIGEST
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THE MOIST CHAMBER
From the Plant and Pest Diagnostic Clinic Nancy Taylor reported a sample of POWDERY MILDEW on sweetbay magnolia. Some samples of TUBAKI LEAF SPOT were sent in from declining pin oaks. It is unlikely that this leaf spot was the cause of the serious decline problems. We often see more severe symptoms of this disease on seriously stressed oaks, especially those suffering from micronutrient deficiencies due to iron deficiency in high pH soils.
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TURF TIPS
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TIME TO RENOVATE!
The evenings are cooler and at least parts of Ohio have received adequate quantities of rain. Whether or not your county has received enough rainfall, the time is approaching to renovate turfgrass lawns. Some areas may require overseeding, or filling of bare areas, while others may require a complete makeover. Evaluate the turfgrass and determine what steps, if any, should be taken to improve the quality for future seasons.
Homeowners with lawns that require overseeding or patch repair should spread seed between August 15 - September 15 in northern Ohio, and most of September in central and southern Ohio. Lawns seeded later in the fall may fail because seedling turfgrass roots are not developed well enough to survive the winter. Sodding can be done late into the fall.
A good lawn can be established by closely following the basic rules for seeding or sodding. Careful attention to detail will help insure success of the new turfgrass. The following steps are essential in developing a new lawn:
1. Eliminate perennial weeds such as quackgrass, Bermudagrass and bentgrass.
2. Remove existing sod and dead material as well as stones and other debris. Have the soil tested and add nutrients as necessary, based upon soil test results. Modify the soil if necessary with topsoil or compost.
3. Grade and level the lawn.
4. Till the soil 3 - 6" deep.
5. Allow soil to settle, or rake smooth.
6. Apply starter fertilizer and rake it lightly into the soil.
7. Select the seed mixture or sod cultivars that match the lawn, or species and cultivars that are better adapted to the lawn conditions.
8. Seed or sod? -If sodding is planned, skip Numbers 8 - 9.
9. Spread seed, based upon rate recommended on the package. Rake lightly, letting some seed remain on surface.
10. Mulch lightly so that the soil can still be seen, using clean straw or peat moss.
11. Irrigate regularly. The rootzone of the seedlings must be kept moist until seedlings establish. Keep the roots of the sod moist until the roots are well rooted into the soil.
Proper watering is essential for a successful lawn renovation. The soil must stay moist for the seed to germinate. Inadequate irrigation will result in poor germination, seedling and/or sod death and poor results.
To overseed an existing lawn, follow the steps above, but rake areas to be seeded before applying the starter fertilizer and seed. Make sure that perennial weed roots have been removed and the seedbed is friable, so that the seedlings can route roots into the soil. Research at OSU has shown that seeding into established turfgrass usually results in failure, because the established turfgrass outcompetes the tender roots of the seedlings, and its leaf blades obfuscate sufficient light from the seedling for adequate photosynthesis to nourish the roots. Therefore, at the minimum, the established turfgrass should be mowed short. Preferably, the turfgrass should be killed and the entire area reseeded.
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RUST ON TURFGRASS
Rust, a fungal disease (Puccinia spp.) of turfgrass, has been noted on samples arriving at the Ohio State University C. Wayne Ellett Plant and Pest Diagnostic Clinic. The disease has also been seen on turfgrass lawns and sports fields in the central Ohio area. Rust affects all common turfgrasses grasses used in the United States. In Ohio it is most common on Kentucky bluegrass and perennial ryegrass. Rust usually affects turfgrass in the late summer and fall.
Rust is usually associated with slow-growing perennial ryegrass. It is especially severe on drought stressed sites and compacted soils where perennial ryegrass or bluegrass is growing slowly and the disease is damaging leaf tissue faster then new leaf blades are being produced. Rust causes the turfgrass to take on a generally yellow to orange appearance. Symptoms are more evident when the weather is dry. The tiny rust-colored spores of the fungus can be a real nuisance. They rub off easily on shoes, lawn mowers, pets, fingers, and clothes. This occurs because the fungus causes the epidermis of the leaf to rupture and release enormous amounts of spores which are orange/yellow/rusty in color.
If the disease has been a problem in the past most likely it will reoccur year after year. Newly seeded juvenile stands of perennial ryegrass (less than a year old) often have the disease more severely than mature established turfgrass lawns and spots fields.
Management Strategies:
Prevention of the disease is important to be successful in control.
- Use blends of more resistant turfgrass cultivars. The National Turf Evaluation Program (http://www.NTEP.org) has free information on turfgrass cultivar quality & disease tolerance.
- Provide adequate water and fertilizer to keep the grass growing.
- Core aerate the site to improve water and fertilizer use by the plant, reduce soil compaction, and improve growth and health.
- Apply a preventative fungicide. Research at OSU has suggested that the sterol inhibitors and strobilurins show good to excellent efficacy (e.g. Bayleton, Eagle, Banner, Heritage, Insignia are some produces to consider). The key is to apply preventatively or at the very onset of the disease. If applied once the disease is severe, results are often disappointing.
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INDUSTRY INSIGHT
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CATERPILLAR BOOK
At our SALSA school this past Monday, we surveyed a number of insect pests on trees, shrubs and herbaceous plants. One striking example was a fat green caterpillar clutching and feeding on black chokeberry foliage. It was about two inches long, with an "almost fluorescent green" color, "flashy silver and red warts" with hair-like growths (setae) wisping from the warts, and a number of other details not properly shared in polite company (the nature of the anal plate, etc.). It was the caterpillar of the polyphemus moth (Antheraea polyphemus), one of many unusual-looking caterpillars that we see this time of year.
The group identified this caterpillar from an excellent new (2005) book brought by a SALSA attendee which has most wonderful pictures. "Caterpillars of Eastern North America: A Guide to Identification and Natural History" has over 1200 high-quality photos and informative one-page descriptions of over 700 caterpillar (butterfly and moth) species. It is available from Princeton University Press in both paperback and hardcover editions.
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COMING ATTRACTIONS
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SALSA V
The second session of SALSA V (Secrest Academy of Landscape Science and Arts) will be September 18, with the following session on October 16. SALSA is for individuals with a professional or personal interest in an intensive, hands-on landscape learning experience. It is a series of full day-long courses (9am-5:30pm) at the Ohio State University Secrest Arboretum and the Ohio State University Extension Center at Wooster.
Each SALSA series may be taken independently from the others. The three sessions of SALSA V will focus on Plant Physiology, Plant Propagation, Pest and Disease Identification, Disease and Insect Management, Fall Bulbs, Natural History of Plants, Arboretum Walks, and Landscape Design. Faculty for SALSA V include: Jim Chatfield, OSU Extension Center at Wooster and Departments of Horticulture & Crop Science and Plant Pathology, Joe Cochran, Secrest Arboretum, OSU, Ohio Agricultural Research and Development Center, Ken Cochran, Secrest Arboretum, OSU, Ohio Agricultural Research and Development Center, and Erik Draper, Ohio State University Extension, Geauga County.
Class sizes are limited. The cost of the last two days of SALSA Course V is $200 for the full two days of programming. This fee includes reference materials, lunches and refreshments. For more information about SALSA, send an email to: cochran.58@osu.edu or call Jim Chatfield at (330) 466-0270 (chatfield.1@osu.edu) or Ken Cochran at (330) 464-2148 (cochran.7@osu.edu)
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OCTOBER 11 TREE FORUM
The "Why Trees Matter" Community Tree Forum, featuring the "Environmental, Economic and Social Benefits and Impacts of Community Forests" will be held on October 11 at OSU's Ohio Agricultural Research and Development Center in Wooster. This forum is a program of the Ohio State University Next STEP (Street Tree Evaluation Program), OSU's Secrest Arboretum, and the Ohio State University's Extension Center at Wooster. "Why Trees Matter" is for all those interested in Ohio's community forests: street tree commissions, mayors, arborists and urban foresters, utility companies, economic development and resource managers, nurserymen and landscapers, and all citizens of Ohio interested in the resource of trees in our urban and suburban areas.
The keynote address will be by Dr. David V. Bloniarz, the project coordinator of the USDA Forest Service's Northeast Center for Urban and Community Forestry at the University of Massachusetts/Amherst. Dr. Bloniarz has worked on numerous urban forestry projects throughout the northeast U.S., including volunteer street inventories in communities of various sizes in Massachusetts and in New York City. He is a key scientist in developing models and software for determining values of streetscape trees, developing volunteer-driven inventories of urban forests, and in community and natural resource management in community forests. Dr. Bloniarz will address "Why Trees Matter" in terms of current and emerging research of environmental, social and economic benefits of trees.
Additional discussions at the Forum will include the current and future Street Tree Evaluation Program of OSU partnering with the Ohio Department of Natural Resources Division of Forestry and the development of the new OSU Community Tree research plots at Secrest Arboretum and in communities throughout Ohio. For further information and registration materials for October 11, contact Sue Beasley at the OSU Extension Center at Wooster Beasley.37@ osu.edu, 330-263-3799, fax = 330-263-3667, 1680 Madison Avenue, Wooster, OH 44691.
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PLANT DIAGNOSTIC WORKSHOP FOR THE GREEN INDUSTRY
Mark your calendars. Thursday and Friday, October 5-6 will mark the annual flagship 2-day Ohio Plant Diagnostic Workshop, held this year in Wooster, Ohio, at the Ohio Agricultural Research and Development Center, Secrest Arboretum and OSU Extension Center at Wooster. Highlights will feature an expanded series of diagnostic feature presentations, a diagnostic night walk in the arboretum, outstanding gourmet catering, and intensive and advanced clinic catharsis and diag-mosh-tics. Check out the BYGL for the next few weeks for details on registration and speakers.
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BYGLOSOPHY
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A society grows great when old men plant trees whose shade they know they shall never sit in. - Greek Proverb
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