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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September 20, 2005
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This is the Twenty-fifth 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 September 22, 2005 conference included: Pam Bennett (Clark); Joe Boggs (Hamilton/Piketon); Jim Chatfield (Center at Wooster/HCS); Erik Draper (Geauga); Dave Dyke (Hamilton); Dave Shetlar (Entomology); Amy Stone (Lucas); 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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Check-out this week's weather summary. The weather data was collected from September 1 - 20, 2005.
| 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 |
77.8 |
60.2 |
N/A
|
N/A |
2.7 |
N/A | | Hoytville |
NW |
81.7 |
55.9 |
68.3 |
66.1 |
1.01 |
1.99 |
| Columbus |
Central |
84.0 |
59.2 |
70.9 |
68.0 |
1.38 |
1.93 |
| Miami |
SW |
83.9 |
59.5 |
70.7 |
67.0 |
1.2 |
1.48 |
| Jackson |
South |
83.9 |
54.0 |
68.0 |
67.3 |
0.66 |
2.09 |
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 new publications "Perennial Plants for Ohio" and "Landscape Plants for Ohio" published by the Ohio Nursery & Landscape Association (ONLA). The descriptions and photographs of plants were provided for this new publication by the OSU ENLT Team along with other industry plant lovers. These full-color publications are available at 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 onla.org
* PERENNIAL OF THE WEEK - Sedum spectabile, Showy Stonecrop Sedum, or Live-Forever are a couple of the names that describe this very popular, easy-to-grow perennial. Like the names imply, these fleshy leaved plants are indestructible, but not invasive. The flowers are small, around ½", but the large dense clusters make a showy splash of color. They are available in pinks, reds, or whites, and are visited this time of year by butterflies gathering nectar. S. spectabile is hardy to zone 3 and will grow nicely in full sun or partial shade. They are best utilized in rock gardens, borders, or in specimen displays of three or more.
* WOODY PLANT OF THE WEEK - Carpinus caroliniana, American Hornbeam, Ironwood, or Musclewood is the plant you remember from your walks in wooded areas. It was the small (25-30 ft.), smooth barked, understory tree with simple, oval type leaves that could not be readily identified. The American hornbeam naturalizes well in our urban gardens. The bark is similar to that of C. betulus, a close relative and popular nursery selection. It is hardy to zone 3 and has a remarkable yellow to reddish-purple fall color transition. Ironwood is monoecious (male flowers and female flowers on same plant), producing small, ribbed, seed-like nutlets enclosed in an irregular 3-lobed bract, in the fall. It is a native tree worth looking at again.
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DIGGIN' & STORIN' FOR THE WINTER
Gardeners must be getting ready for winter. BYGLers have been receiving telephone calls about how to dig up summer-flowering "bulbs" for winter storage. Many gardeners lump true bulbs, tubers, corms, and rhizomes incorrectly into one large category called bulbs. Here are a few examples of plants that need to be dug and wintered over in a more protected location.
Tuberous begonias: Remove stems after the frost has killed the tops. Let tubers dry for one week, then store cleaned tubers in peat moss or sawdust at 50F. Do not allow the tubers to freeze.
Caladium: In the fall, dig tubers and store at 65F to 70F.
Canna: Once the frost has killed the canna tops in the fall, cut off the dead tops and lift the rhizomes for the soil. Use care in digging. Hose off soil around rhizomes and store inside at 45F to 50F. Do not allow rhizomes to freeze.
Dahlia: Lift dahlias after the first frost, or before the end of October. Before lifting tubers, remove all ties and stakes. Cut the foliage off so that there remains a 3 to 4" stem on the roots. Store tubers in sawdust or peat at 60F. Divide the tuber clump in the spring leaving a part of the true stem attached to the tuber.
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BUG BYTES
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VIBURNUM LEAF BEETLE SURGES IN OHIO
For the past several years Curtis Young has been conducting surveys across Ohio for different exotic insects, including the viburnum leaf beetle (VLB) (Pyrrhalta viburni). In 2002, VLB was discovered for the first time in Ohio in the far northeastern corner of state in the town of Conneaut, Ashtabula County (Viburnum Leaf Beetle Survey, 2002). Little changed in population size and distribution of VLB in Ohio during 2003 and 2004. However, Curtis revisited the known VLB infestation areas in Ohio on September 16 & 17, 2005 and discovered that the VLB population and distribution had exploded. In the past, Curtis had to scour multiple plants to discover only a few oviposition scars that the female produces when she lays her eggs. This year he only had to walk to the edge of the same wood lots to discover hundreds of oviposition scars. Foliar injury was also evident on numerous host plants. Further investigation revealed populations distributed across the width of Ashtabula County from Conneaut to Geneva-on-the-Lake. Most of the survey sites were located along SR 531. Two new counties were added to the distribution list of VLB in Ohio, Lake County (Madison-on-the-Lake), and surprisingly, Summit County (Macedonia, Ohio).
The VLB is restricted to feeding on species of Viburnum. It exhibits a strong preference for the popular arrowwood viburnums (V. dentatum), European cranberrybush viburnum (V. opulus), American cranberrybush viburnum ... which may actually be European (V. trilobum), and Rafinesque viburnum (V. rafinesquianum). Other viburnums known to serve as hosts include Sargent viburnum (V. sargentii), wayfaringtree viburnum (V. lantana), nannyberry viburnum (V. lentago), and blackhaw viburnum (V. prunifolium). Particularly resistant species include Koreanspice viburnum (V. carlesii), Burkwood viburnum (V. burkwoodii), doublefile viburnum (V. plicatum var. tomentosum), Judd viburnum (V. x juddii), lantanaphyllum viburnum (V. x rhytidiphylloides), and leatherleaf viburnum (V. rhytidiphyllum).
Because of climatic similarities with its native habitat, and a preferred host range that includes Viburnum species commonly used in ornamental plantings, VLB is considered to have a high probability of becoming established and spreading in Ohio. Heavy infestations by VLB could defoliate shrubs, cause dieback, and eventually kill plants.
Costs to homeowners, parks, arboretums, municipalities, and nurseries to manage heavy infestations of VLB and to replace killed plants could be high. Additionally, Ohios nursery industry is the nations fifth largest. Quarantines imposed, as a result of establishment of VLB in Ohio, would represent an economic burden to the many growers who export nursery stock from Ohio. Because of the potential economic impact to both the public and the nursery industry in Ohio, it is important to maintain surveillance on the spread of VLB in Ohio.
The VLB is listed as a secondary target pest species by APHIS for Cooperative Agricultural Pest Surveys (CAPS). The Ohio VLB surveys have been supported by grants given through the USDA APHIS PPQ CAPS Program. If you see suspicious feeding activity on Viburnum, drop Curtis a note at: young.2@osu.edu.
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DOGWOOD SAWFLIES ON A CRAWL-ABOUT
Joe Boggs reported receiving a phone call from a homeowner concerned about yellow and black "caterpillars" crawling about her deck. She was worried they would eat plants alongside the deck. The insects in question were not caterpillars; they were dogwood sawfly larvae. And, the larvae posed a greater threat to the deck than to the plants.
There are at least two, and possibly three species of sawflies in Ohio that will feed on dogwood. All are referred to as "dogwood sawflies." All belong to the same hymenopteran family (Tenthredinidae), and the same genus (Macremphylus). However, M. tarsatus is the sawfly species that is most commonly encountered and identified as "dogwood sawfly".
Newly hatched larvae are amber in color and somewhat transparent. Early instars exude a white, powdery material that covers the surface of the larvae, including the black head capsule. When disturbed, the larvae curl into a ball. This behavior, coupled with the white covering, makes the larvae look like bird droppings. At their final molt, the larvae are about 1" in length and they lose their white powdery covering to reveal a body covered in garish yellow and black patches.
The damage that M. tarsatus produces also changes as it develops. Newly hatched larvae feed together, skeletonizing the leaves. As the larvae mature, they consume the entire leaf except the mid-vein. High populations can produce complete defoliation of dogwoods.
When the larvae reach the final instar stage their behavior, along with their appearance, changes radically. The yellow and black larvae begin to wander about in search of suitable wood to bore into for the winter. They seem to prefer rotting logs, but may also construct overwintering chambers beneath cedar house-siding, under pine bark, within the wood of split-rail fences, and within composition fiber wallboard and redwood furniture. They occasionally cause serious structural damage and may attract woodpeckers, which cause further damage.
M. tarsatus has one generation per season. However, since adults are present from May though early July, eggs are laid over an extended period of time. Consequently, a wide range of instar stages may be present at the same time ... from the powdery-white leaf-feeding stages to the yellow and black wandering stage.
It is too late to make insecticide applications to prevent defoliation by dogwood sawflies this season. Preventative applications to wood to kill the wandering sawflies is not recommended since their distribution and patterns of dispersal are too unpredictable. Joe recommended to the homeowner that they simply perform the step-and-stomp "sawfly dance." This control method is 100% effective, and no dogwood sawflies have thus far become resistant.
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SPRUCE SPIDER MITES THEY'RE BACK!
The summer eggs of spruce spider mites (Oligonychus ununguis) are hatching in southwest Ohio. The feeding (damaging) stages of this cool-season mite appear on the scene in the spring and fall. Summer and winter months are spent in the egg stage. Thus far populations are low, indicating eggs are just beginning to hatch. This also means management decisions should be made now, before populations climb to damaging levels.
Hosts of this mite include spruce, arborvitae, juniper, hemlock, pine, Douglas-fir, true firs, and sometimes other conifers. The mites feed by rupturing individual cells of the hosts foliage, producing characteristic tiny yellow spots, or "stippling." As the stippling coalesces, foliage becomes bleached and eventually bronze-colored. Inner foliage is generally affected first.
Rainfall can have a significant impact on population numbers and the subsequent damage produced by this mite. Heavy rainfall will reduce populations by washing mites from the needles. Conversely, long periods of dry weather can allow numbers to build rapidly and substantial damage to occur.
It is important to monitor for this tiny mite, and a "beating tray" is the most effective tool for discovering and assessing mite populations. This tool can be a purchased piece of equipment or simply a stick and an 8.5" x 11" tablet of white paper. No matter what you choose, the idea is the same. Hold the white target beneath the conifer foliage and strike the foliage several times with a stick or rod causing the mites to drop onto the white target. Next, tilt and lightly tap the collection paper or tray to allow plant debris to fall off.
Look closely for small, slow-moving dots, not much bigger than the period at the end of this sentence. These are the spider mites. The faster moving dots are likely to be predaceous mites, the good guys that feed on the spider mites. A finger can be used to mash and smear the mites to further help distinguish the good mites from the bad. Greenish-brown streaks are "pate de spider mite."
Effective management efforts include simply washing (syringing) mites from the foliage using a heavy stream of water, applications of soaps and oils, or applications of traditional miticides. Syringing will conserve predaceous mites, but may be a difficult endeavor on large trees. Soaps and oils are also kind to predators, but oils will wash away the blue color on Colorado blue spruce.
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DISEASE DIGEST
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SANITATION NOW
One of the landscaping and gardening tasks to take seriously now and for the rest of the season is to clean up diseased plant tissue, removing it from your plantings. Many plant pathogens overwinter in diseased plant debris from the previous season, with new spores being produced from this tissue in the planting next spring. Common examples include ROSE BLACK SPOT and HOLLYHOCK RUST. Take a look right now in your rose garden. In many cases there is a tremendous amount of yellowed and black-spotted foliage on the ground -under the plants. Clean this diseased foliage and black-spotted canes up before next spring‛s refoliation or else you will be giving this damaging disease a big head start next year, right from your own garden.
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THE MAPLE'S SPOTS SELDOM CHANGE
Both Dave Goerig and Curtis Young reported seeing MAPLE TAR SPOT on Norway Maple trees this week. Tar Spots are among the most showy and least damaging foliar diseases of woody and herbaceous plants. These tar-like lesions are a result of a fungal infection that sets in during late spring and early summer after leaves are fully developed and environmental conditions are favorable. Favorable infection conditions include the presence of a host, (in this case Acer platanoides, Norway maple), a fungus, the species Rhytisma, specifically, R. acerinum, and a sheltered location were climate conditions favor a moist environment.
First signs of infection appear as yellowish-green to light green circular patterns. The color patterns are noticeable as early as mid-June. By mid to late summer these circular patterns develop raised, black, tar-like stromata on the upper leaf surface. Leaves with multiple spots may wither and drop prematurely, but this seldom occurs in numbers that affect the general health of the tree. In autumn, as leaves turn in color, tar spots present a striking contrast on the leaves.
Management of this disease in landscape settings is generally not necessary; however, major outbreaks of maple tar spot can be significantly reduced culturally by removal of infected tissue after leaves fall. Tar spots caused by R.acerinum are scarce in urban and industrial areas. Low concentrations of sulfur dioxide actually prevent new infections from becoming established on the plant, although they will not cure spot development after infection sets in.
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TURF TIPS
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JAPANESE BEETLE GRUBS SPOTTY
Dave Shetlar reported that Japanese beetle (Popillia japonica) grubs are now large enough to cause noticeable damage, and to be attractive to grubbers such as skunks, racoons ... and researchers. However, he also noted that populations across the state are very spotty.
Dave attributed the spotty nature of this season's Japanese beetle grub populations to the droughty conditions that occurred while beetles were laying eggs. Japanese beetles lay dehydrated eggs. This allows them to produce more eggs with less demand on the beetle's resources. However, the eggs must be hydrated from the environment within 12-24 hrs., or they will die. Dave indicated that he is finding the most consistent Japanese beetle grub infestations under irrigated turfgrass.
Many Ohioans are currently dealing with areas of dead turf. The damage may have been caused by other turfgrass insect pests, or by turfgrass diseases. In some parts of the state, drought conditions became severe enough to kill turfgrass, particularly where grass was growing on poor soil, or where a heavy thatch layer was allowed to accumulate.
Thatch may team with grubs to deliver a two-shot whammy to turfgrass. First, Japanese beetles are attracted to thatchy lawns because their grubs feed on decaying organic matter. While they feed the grubs damage turfgrass roots. Of course, the effects of root loss are intensified under dry soil conditions. This is where thatch delivers the second whammy. It interferes with water infiltration. Under extremely dry conditions, the thatch may become hydrophobic; it actually repeals water.
It is almost too late for re-seeding efforts to be successful this season. Sod may be a better option, particularly if a heavy thatch layer needs to be removed. Either way, areas of dead grass should be closely investigated for grubs before turfgrass recovery efforts are initiated. Grubs will quickly shear-off roots of turfgrass seedlings, and even though grubs will be exposed prior to sodding, it would be best to deal with the grubs prior to laying down the sod, rather than after. Use a dull knife to slice open and peel back the dead grass down to the soil. This will expose the grubs.
At stage of the season, fast acting "rescue" insecticides would be recommended. These include trichlorfon (e.g. Dylox, Bayer 24-hour Grub Control) or carbaryl (e.g. Sevin, Grub Stop). The turfgrass should be watered just prior to the application to wet the thatch and top few inches of soil. This will maximize the effects of the application. Then at least 1" of water should be applied just after the application to carry the insecticide down to the grubs. Happy grubbing!
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DON'T FORGET THE STARTER FERTILIZER!
Joe Boggs reported receiving a phone call from a homeowner concerned about very poor establishment of their newly re-seeded lawn. They had used a good quality blend of turf-type tall fescue, purchased a few days before seeding. They had rented a slit-seeder, and the seeding rate was appropriate. And, they had been diligent about watering. However, when Joe asked about a starter fertilizer, the homeowner replied that they had indeed made a "starter" fertilizer application ... in the early spring at the start of the season!
Starter fertilizer applications made at the time of seeding, and 4-6 weeks after seedling emergence is essential to the successful establishment of newly seeded turfgrass. This is even true on soil that has been shown by a soil test to have adequate nutrients. The reason is that upper few millimeters of soil often becomes nutrient poor when exposed to sun, air, and rain. This is the soil that is first encountered by the root radical of germinating turf seed. Until this young root taps into a good nutrient source the seedling is totally dependent upon stored nutrients for growth and development.
A starter fertilizer application should consist of 1.0 - 1.5 lbs. of actual nitrogen (N), and 1.5 - 3.0 lbs. of phosphorus (P) per 1000 sq.ft. These nutrients should be applied using a 1-1-1 to 1-2-1 ratio fertilizer. Starter fertilizer should be applied just prior to seeding or sodding. The fertilizer may be lightly raked into the soil to reduce fertilizer loss during irrigation. A slit-seeder will also do a good job of stabilizing the fertilizer. However, a starter fertilizer should never be tilled into the soil since this will move the nutrients out of reach of the turfgrass seedlings. Apply another starter fertilizer application 4-6 weeks after seedling emergence at a rate of 1.0 lb. of actual nitrogen per 1000 sq.ft. If the first application was not made, it is essential not to miss this second application.
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INDUSTRY INSIGHT
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GOOD NEWS ON THE EMERALD ASH BORER
For a change we actually have some good news concerning the emerald ash borer (Agrilus planipennis) (EAB). On September 15th Governor Bob Taft announced the receipt of $4 million in funding from the U.S. Department of Agriculture (USDA) to continue Ohios EAB eradication program and strengthen the battle to destroy the ash tree-killing pest. That will be very helpful in eradicating populations of this dastardly insect that have arrived, or will do so, in northwest Ohio and other parts of the state.
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BYGLOSOPHY
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Plants are the missionaries of Nature constantly at work Dr L.C.Corbett.
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