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 11, 2005
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This is the Eleventh 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 09, 2005 conference included: Barb Bloetscher (C. Wayne Ellett Plant and Pest Diagnostic Clinic (CWEPPDC)); Joe Boggs (Hamilton/Piketon); Jim Chatfield (North Region/HCS); Erik Draper (Geauga); Dave Goerig (Mahoning); 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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While rain has fallen in some areas of the Buckeye State, others remain very dry. Joe Boggs reported that the Palmer Drought Index for the week ending August 6, has moved Southern Ohio as well as northern Kentucky from "moderate drought" into the "extreme drought" category. The index is one of the NOAA tools used to measure long term drought conditions. Check out their website below.
| 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 |
86.2 |
66.0 |
N/A |
N/A |
0.10 |
N/A | | Hoytville |
NW |
89.1 |
62.0 |
75.6 |
71.5 |
0.00 |
0.97 |
| Columbus |
Central |
90.4 |
65.4 |
78.0 |
73.7 |
0.31 |
1.28 |
| Miami |
SW |
89.3 |
67.8 |
78.2 |
72.3 |
1.64 |
0.77 |
| Jackson |
South |
90.7 |
63.4 |
75.7 |
73.1 |
1.21 |
1.25 |
For additional information, or to see the locations of all of the OARDC weather stations in Ohio, check out the website below.
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HORT SHORTS
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WOODY PLANT OF THE WEEK
Tired of seeing yellowed, dropping leaves on CRABAPPLES? Don‛t make the egregious error of thinking that this is just part of the package with this versatile ornamental tree. There are crabapples of many colors and variations of form, flower, fruit, and foliage with excellent resistance to the apple scab disease that is the cause of those yellowed, defoliating leaves on certain varieties. Here are just a few crabapples with excellent scab resistance, featured in the ONLA Landscape Plants manual.
* ‛Adirondack‛ with its narrow upright tree form and white flowers
* ‛Bob White‛ with its rounded tree form and exceptional golden yellow fruits
* ‛Excalibur‛ a small rounded tree with golden fruits in Lake County‛s Round Table Series
* ‛Louisa‛ a weeper with soft pink flowers
* ‛Prairifire‛ with its outstanding coral pink flowers, purple-red tinged foliage and purple fruits
* ‛Red Jewel‛ with its gem-like fruits colorful and firm all the way into late winter
* and many Sargent dwarf crabapples from the straight species to the dwarf ‛Sargentina‛, to the pink and red tinged flowers of the ‛Candymint‛ Sargent selection
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PERENNIAL OF THE WEEK. SUMMER PHLOX or GARDEN PHLOX (Phlox paniculata)
. . .can be successfully grown across Ohio. The plant is native to southeastern United States. It grows in a clump, with shoots reaching up to 4' in height. At the top of these shoots, beginning in mid July, the plant produces large panicles of disk-shaped flowers. Cultivars of summer phlox come in shades of reds, pinks, lavenders, and blues. P. paniculata 'David' is a white version that shows good powdery mildew resistance. Summer phlox are best used as border plantings.
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THE LATEST ON THE EMERALD ASH BORER
Last week, the Ohio Department of Agriculture (ODA) made two announcements related to the emerald ash borer, the exotic metallic wood-boring beetle attacking and killing ash trees. They first announced the latest find in the Buckeye State. Infested trees have been discovered in Auglaize County in western Ohio, at a rest stop along Interstate 75.
The second announcement expanded Ohio's EAB quarantine to include two counties in Indiana, in addition to the entire state of Michigan and the already regulated areas identified in the buckeye state. Regulated items include non-coniferous firewood, ash trees, logs, branches, bark, wood chips, and other ash materials. Violators can face fines up to $4,000. Note that the quarantine borders can be expanded and changes can occur quickly. Therefore, everyone is urged to stay updated with the latest information. If you have access to the internet, check out the ODA website at: http://www.ohioagriculture.gov. For specific information on the quarantine check-out this website at: http://www.ohioagriculture.gov/pubs/divs/plnt/curr/eab/plnt-eab-quarantine.stm. You may also contact the ODA by phone at 1-888-OHIO EAB.
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HIP ON HOGWEED
As reported in the BYGL 2005-17 (07/28/05), Heracleum mantegazzianum, commonly known as GIANT HOGWEED, truly is herculean in stature. This herbaceous plant can reach heights of 10-14' in most any soil type, then crown itself with clusters of small flowers arranged in large, flat topped, umbels that measure up to 2 1/2' in diameter. The foliage unfolds and expands up to 5' as it reveals its deeply incised, lobed shapes. Most would agree it is an impressive plant! To many, we would consider it worthy and deserving of a prominent place in our gardens. But wait ... there's a dark side to this unique plant.
Giant hogweed is a public health hazard! It has the potential to cause severe skin irritations in some people. The plant's sap produces painful, burning blisters within 24 to 48 hours after contact with your skin. The sap can also cause your skin to turn a blotchy red to purple color that can persist for months. If that isn't enough to keep you from wanting one, consider this; giant hogweed is listed on both the federal and state of Ohio noxious weed lists which makes it unlawful to propagate, sell, or transport.
Officials have found H. mantegazzianum in Ohio. These finds are located in counties that border the commonwealth of Pennsylvania. According to plant health officials, the finds in Ohio have been eradicated and the plant has not established itself in the state. The plant cannot move far from the site in which it was originally planted. The plant produces a dry seed that does not disperse by wind or animals. The only way this plant can end up in a neighborhood, is through a person planting the seed or its fleshy root.
Your help is needed to stop the spread of this plant in Ohio. Resist the temptation to buy, sell, or plant it in your garden if you are offered one. If you move to a new home and it is on the property, use caution when working to destroy it. If you do not feel comfortable around the plant, call your local county extension professional or the Ohio State Plant Health Directors office (614-834-4625) for more information on eradicating it from your property.
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WATERING WOES
Wondering why watering did not work wonders during plant establishment during the droughty May and June conditions we had this year? Don‛t beat yourself up to much, as Stan Hywet‛s former grounds superintendent and horticulturist extraordinaire the late Bill Snyder always said: "There is no way to mimic the rains of Mother Nature when we have an early drought." That earlier drought is why many are seeing annuals that just seemed to be sitting there, not filling in as fully as usual. That earlier drought is why burning bush (Euonymus alata) in marginal situations picked this year to decline. That earlier drought is why mature yewes (Taxus spp.) that lost some feeder roots to root rot last year due to wet feet are not recovering as well this year as we would have hope. That critical May and June period of root establishment and root re-establishment just was not amenable for many plants this year.
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EARLY LEAF COLOR- GOOD OR BAD?
Several BYGLers mentioned that they had observed that a few plants were beginning to show fall coloration; specifically, red maples (Acer rubrum), burning bush (Euonymus alata), tulip popular (Liriodendron tulipifera) and redbud (Cercis canadensis). Does the early leaf color signify that they are on their way out and this last-ditch effort is to try and survive one more year? Definitely not!
There are many valid reasons for early leaf color including: high rust mite populations and their feeding causing bronzing of leaves; foliage diseases like rust or scab can cause leaves to yellow and drop; stresses like the hot dry weather; environmental factors such as soil compaction; physical factors like damage to the plant's base from mowers or string trimmers; and finally it might just be the nature of the dang thing too!
The important thing to do for plants with early fall color is to pay closer attention to what is happening with that plant. Inspect the plant for signs of borers, insect damage, or other physical damage to the trunk or plant base. It is definitely time for a little extra attention to this plant's needs, such as water if it's in the middle of a drought, or checking out the root zone area for problems, such as a groundhog decided to make a home there!
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STOP, LOOK, AND LEARN!
County Educators and specialists commented that many homeowners have been approached by major lawn/landscape care companies, with the alert that the homeowners trees and shrubs were being eaten by pests and needed to be treated at once! They then presented a proposal for substantial amounts of money to spray most of the plants in the landscape. Homeowners, of course feel compelled to consent to save their landscape from possible devastation.
The BYGL group discussed this situation and agreed that in some cases the cover sprays were not warranted and often needless. Depending upon the guilty culprit, the insect may have already moved on to another area, or pupated, and/or would not contact the insecticide. Mature, healthy trees and shrubs can tolerate a great deal of defoliation with no ill effects. Different insecticides have varying levels of effectiveness on insects in different orders and life stages, and may not even control some pests. More importantly, many conventional insecticides kill the beneficial predators and parasites of the pest species and do not recover quickly, as the pest species will. Pest species normally have more tolerance of insecticides and faster life cycles than the predators that control them. Carbaryl (i.e. Sevin), for instance, kills the predatory mite which preys on the phytophagous mites, but has little effect on the pest itself. The result is a raging population of pest mite species and no natural control for them. Spraying many plants in one landscape will wipe out the predatory insect species, allowing the pest species to rebound and actually cause more damage.
The solution is to ask the company representative to show the homeowner the pests, and list the recommended insecticides for each pest. The homeowner can contact their local Extension office and/or research the pests to determine which ones, if any, need to be treated. As Alan Siewart, ODNR Forester warned, In horticulture, as in medicine, treatment of plant symptoms/problems without correct diagnosis
is MALPRACTICE!
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BUG BYTES
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BAGWORM UPDATE FROM THE NW
As we enter into the month of August, feeding damage from the bagworm (Thyridopteryx ephemeraeformis) is becoming more evident on several types of plants, as well as the bagworms themselves as they reach their maximum size. Feeding damage is most easily observed on heavily infested evergreens such as Colorado blue spruce, arborvitae and juniper. As sections of these plants are stripped of their needles, the plants turn from green to brown and can be seen from far distances. Closer inspection reveals the numerous bags hanging from the bare branches. Actively feeding bagworms are dispersed on other branches where needles are still available.
Some plants injured by bagworms are not as obvious as the evergreens or may obviously be injured but bagworms may not be the first insect to come to mind when the damage is seen. Bagworms can utilize over 100 different species of plants as their host including numerous deciduous trees. One example of the unexpected bagworm damage was observed by Curtis Young on a heavily defoliated Crimson King maple tree. At a distance, the damage looked like the results of Japanese beetle feeding. The leaves were highly skeletonized and tattered in appearance. On deciduous trees, newly hatched and young bagworms skeletonize leaves and older caterpillars consume most of the leaves between the veins. Once Curtis was beside the tree, he could see bagworm bags hanging from a couple of branches. No active bagworms could be found, but a few current season bags were located with dead caterpillars inside. The tree had been treated with an insecticide by the landscape managers responsible for the tree. The main damage done to the maple tree was aesthetic, it stood out like a sore thumb. However the real significance of this observation is that overlooked bagworm populations on deciduous trees will be reservoirs of bagworm caterpillars to spread to other nearby plants in the next growing season.
The bagworms are fairly large in size. Some bags are 1 1/2" to 1 3/4" in length. These are probably female bagworms that tend to be larger than the males. The caterpillars inside of the bags are also about 1 1/4" long and fat. Bagworm caterpillars this large are very close to completion of feeding and if they are exposed to insecticides at this time, they may stop feeding without acquiring a lethal dose of insecticide and pupate prematurely. Thus, removal of the bags with their inhabitants may be the only management practice available to stop their development at this time.
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LOCUST LEAFMINER ON YELLOWWOOD?
Erik Draper reported observing a yellowwood tree in northeast Ohio with its leaves being hammered by locust leafminer beetles (Odontota dorsalis). His report was a reminder that despite this insect's common name, adults are known to feed upon a wide range of trees. Indeed, in BYGL 2005-9 (06/02/05), Curtis Young noted that locust leafminer adults were feeding on oak leaves in Akron, Ohio.
The beetle has two generations per year in much of Ohio. In the spring, overwintered beetles emerge to feed on the leaves of several different species of trees including dogwood, elm, oak, beech, cherry, wisteria, hawthorn, and crabapple, as well as several herbaceous plants such as soybeans. The adults are less than 1/4" long, and are orangish-red with a median black line down the center of the back. They are fairly flat beetles and frequently feed in clusters.
Eventually, the beetles will begin laying eggs. While black locust is the preferred larval host, the beetles will also select yellowwood. Eggs are laid in clusters of three to five in late May or early June on the undersides of leaves. The larvae hatching from these eggs work their way into the leaf through one entrance hole and live in a common blotch mine. Later, they go to other leaves and make separate mines. Larvae feed for about three weeks, pupation takes place in the mine, and beetles emerge a week or 10 days later.
Erik recently observed the second generation adults. Heavy leaf skeletonizing by the final generation of beetles for the season is responsible for the reddish-brown fire-burned appearance of black locust trees that is currently becoming evident in southern and central Ohio.
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AILANTHUS WEBWORM - HOPE SPRINGS ETERNAL
In an optimistic report, Joe Boggs reported observing heavy defoliation caused by ailanthus webworms (Atteva punctella) on TREE OF HEAVEN (Ailanthus altissima) sprouts in southwest Ohio. Such an observation would normally cause concern if the damage occurs on a preferred tree species, but since the defoliation was occurring on a non-native, invasive tree, the webworm's biocontrol efforts were applauded!
Larvae of this ermine moth produce nests by pulling several leaflets into a network of loose webbing. They live within the nests consuming the leaflets bound by the webbing. The webworms can grow up to 1 - 1 1 /2" long and they have a wide, light greenish-brown stripe down their backs and several thin, alternating white and olive green stripes along their sides. The caterpillars are sparsely covered with short, erect hairs, which help to suspend the caterpillars within the webbing. When disturbed, the caterpillars move backwards out of the nest and drop towards the ground on strands of silk.
Ailanthus webworms are capable of defoliating their odoriferous namesake and they may feed on stem tissue once all leaves are devoured. Unfortunately, such extreme damage on large trees is rare. Although feeding by this webworm has yet to halt the spread of tree of heaven, hope springs eternal since this is one of only a few insects known to infest this encroaching interloper.
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SQUISHED SQUASH
Earlier in the season (BYGL 2005-14, 07/07/05), we reported that home gardeners and vegetable growers were experiencing the stem-collapsing handiwork of the SQUASH VINE BORER (Melittia cucurbitae). This stem-boring caterpillar is now being joined by another squash nemesis, the SQUASH BUG (Anasa tristis). This sucking insect can be a damaging and often difficult to control pest of cucumbers, pumpkins, and of course squash.
Both nymphs and adults suck sap from the leaves and stems, while apparently at the same time injecting a toxic substance into the plant causing a wilting known as ANASA WILT of Cucurbits. The wilt closely resembles bacterial wilt, a true disease. After wilting, vines and leaves turn black, crisp, and brittle.
Squash bug adults are large flat-backed insects, about 5/8" long. Their overall brownish-black color is sometimes mottled with gray or light brown, and they really stink when crushed! Nymphs are whitish to greenish-gray, with black legs. The nymphs vary in size, first appearing as tiny, spider-like individuals after hatching, to older nymphs which are nearly as large as the adults. Squash bugs are secretive in habit and will readily drop to the ground and hide if disturbed. Both adults and nymphs may be found clustered near the plant crown, beneath damaged leaves, under soil clods or in any protective groundcover.
Only one generation develops each year and new adults do not mate until the following spring. Mated females become egg laying machines, depositing numerous masses of a dozen or more reddish-brown eggs on the undersides of leaves, in angles formed by the veins. Egg laying continues until midsummer. Due to this extended egg laying period, all life stages can occur throughout the summer months
Control recommendations include the physical removal of the bugs using gloved fingers (they can deliver a painful bite!), or an application of an insecticide labeled for use on the affected host plant. Based upon past BYGLive! observations (BYGL 2004-24, 09/16/04), an additional management tactic would be to focus attention removing burcucumber (Sicyos angulatus). This non-native vining annual weed, which is commonly found growing within Ohio field crops, may serve as an additional host and continual reservoir for squash bugs.
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FLIES TAKE THE BITE OUT OF SUMMER
This is the time of year when pesky DEER FLIES (Chrysops spp.) and HORSE FLIES (Tabanus spp.) begin buzzing gardeners, hikers, and other outdoor enthusiasts in hopes of taking a bite out of summer fun. These large, buzzing 1/4 - 1 1/8" yellow-brown flies are distinctive not only for their colorful green or purple eyes and black stripes on their abdomen, but mostly for their annoying kamikaze-style landings on people and their ensuing bodacious bites! Unlike the common house fly, both deer and horse flies have jabbing, tearing, and lapping mouthparts that allow them to rip through the tough hide of animals to imbibe blood.
Horse flies are particularly adept at locating warm-blooded animals, including people near swimming pools, streams, ponds, marshy areas and in the woods. The flies are apparently sensitive to the infra-red end of the electromagnetic spectrum which gives "thermal vision," allowing them to zero-in on moving objects that give off heat.
Both deer and horse flies have a close association with water. Indeed, Joe Boggs reported encountering a near air-lifting experience while on a recent photo-outing near a stream in southwest Ohio. The females of both insects lay masses of 100-1000 eggs in a jelly-like goo near water or areas with moist, decaying organic material. Upon hatching, the larvae fall into stagnant water, stream edges, or pools of rotting plant material.
Tabanid larvae eat small insects, snails, earthworms, mosquito larvae, and each other as they develop through 4-9 instar stages. Late instars then migrate to the edge of the water or muck to pupate. Chrysops larvae feed on decaying plant matter before moving to slightly drier conditions for pupation. Depending upon the species and availability of water as larvae, it may take 3 months to 3 years for the adults to emerge. For this reason, it is difficult to predict where high populations of these insects will occur.
Other than remaining indoors, it is hard to consistently avoid these winged biting machines. Insect repellents that contain DEET offer some protection, particularly against deer flies. However, both deer and horse flies are very determined insects, and they seem to have a knack for finding spots of unprotected skin, or biding their time until repellents wear off. Other suggestions for thwarting these flies include: avoid areas where the flies are most active; avoid daytime outdoor activities since neither are night flyers; stay alert while outside because unlike most other flies, the horse flys flight is silent, and they are known for landing stealthily on exposed skin then delivering a painful bite.
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MILKWEED MIMICRY
In recent years, a number of plants in the milkweed family (Asclepiadaceae) have transcended "weed status" to join the ranks of plant respectability by being used in butterfly gardens and naturalized areas. Most gardeners cite the strong interplay between these plants and the MONARCH BUTTERFLY (Danaus plexippus) as the reason for planting milkweeds. Of course, other butterflies and plant pollinators are also attracted to the flowers of these plants.
As most plant enthusiasts know, milkweeds protect themselves from herbivores by infusing their milky sap with some very serious alkaloid toxins called cardiac glycosides (cardenolides). These toxins play a pivotal role in the relationship between monarchs and milkweeds. The caterpillars incorporate the toxins into their flesh, making them unpalatable to insectivores, and the commandeered toxins also protect the adult butterflies. The monarch advertises its noxious nature through splashy warning coloration. The use of "red light" colors to dissuade predators is called aposematism. Monarch caterpillars are conspicuously ringed with black, white, and yellow bands. The butterflies are bright orange with black markings.
In 1878, German naturalist Fritz Muller noticed that some unpalatable animals evolved to closely resemble other unrelated unpalatable animals. This convergence in appearance of nasty tasting unrelated species became known as Mullerian mimicry, and it is well represented by the milkweed fauna. There are over 50 different taxonomic groups of milkweed herbivores that are known to sequester and store cardiac glycosides, and many share common aposematic color patterns.
Early in the season, Ohio gardeners noticed the appearance on milkweeds of a brightly colored longhorned beetle, the RED MILKWEED BEETLE (Tetraopes tetrophthalmus). The tubular-shaped 3/8 - 1/ 2" long beetles are orangish-red with black dots and streaks on their upper thorax and wing covers. These beetles have a very descriptive scientific name. "Tetraopes" means "four eyes," and a close examination will reveal that the antennae divide the compound eyes causing the beetle to have four eyes. The adults feed on milkweed leaves and the larvae bore into the roots and stems.
At about the same time these beetles appeared, monarch butterflies began to show-up displaying their orangish-red and black color motif. Currently, their caterpillars are being joined in feeding on milkweed leaves by larvae of the MILKWEED TUSSOCK MOTH (Euchaetes egle). The tussock moth caterpillars have rows of short alternating black, orange, and white hairs framed by long black and white bristle-like hairs extending from the front and back ends of the caterpillars. Milkweed seed pods are also being covered by orange and black insects. The 3/4 - 1" long LARGE MILKWEED BUG (Oncopeltus fasciatus) is bright orange to yellow with prominent black markings, including a black band across the middle of its body. The 3/8 - 1/ 2" long SMALL MILKWEED BUG (Lygaeus kalmii) is black with a red "X" on its forewings, and a red band across the front of the thorax.
What do all of the orange, red, and black colors on these insects signal to predators? Don't eat me, I taste really bad! All of these insects sequester, store, and release at the appropriate time foul tasting cardiac glycosides. Only one individual in one of these species needs to be sacrificed to teach a predator this lesson. However, the message is shared by all of these unrelated species flying the same colors. That's Mullerian mimicry.
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BANDED ASH CLEARWING SOON TO EMERGE
Adult banded ash clearwing moths (Podosesia aureocincta) should soon be emerging from infested ash trees. Evidence of the late instar caterpillar activities can be observed around different parts of the ash tree in the form of accumulations of frass (caterpillar excrement) that piles up at the base of the trunk and in branch crotches, and as extrusion adhering to the surface of the bark. The production of this evidence starts when the caterpillars first hatch out of the eggs the adult female moth place on the bark surface and in bark cracks and crevices. The initial caterpillar feeding through the bark and into the living tissues of the tree causes sap to ooze and fine frass to be extruded from the attack sites during late summer and early fall. The next spring and summer, the frass becomes coarse and granular and is extruded in small clumps. Watch these trees closely for the final indicator of adult emergence, pupal skins protruding from exit holes in the bark.
Ash trees infested by banded ash clearwings, as well as its' close cousin, the LILAC/ASH BORER (Podosesia syringae), are usually newly transplanted trees or trees growing under severe stress (e.g. in parking lot tree circles, in sidewalk pits, in poor soil, etc.). If these borers are not managed by one means or another, they will likely lead to the death of the trees. Control of these borers is usually best accomplished with insecticides. For a list of effective materials and control timing consult OSU Extension Bulletin 504 titled, "Insect and Mite Control on Woody Ornamentals and Herbaceous Perennials" [http://ohioline.osu.edu/b504/index.html].
Woodpeckers, other natural enemies, and good cultural practices also help to reduce populations.
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MORE GIANT WASPS CAUSING EXCITEMENT
A couple of different species of large sized wasps are actively flying during the month of August, causing the unexperienced to duck for cover even though there is no need. Curtis Young reported that he discovered a pair of these wasps doing what is natural for them, attacking a dying tree. What he observed was a pair of female PIGEON TREMEX HORNTAIL WASPS (Tremex columba) laying their eggs into the trunk of a shag-bark hickory tree that had been struck by lightening. Horntails are stout-bodied wasps, measuring from 1" to 2" long. They are named for their horn-like plate on the tip of their abdomen. On males it is relatively short, while it is longer and somewhat spear-like in females and more ferocious in appearance. Females also possess a conspicuous ovipositor that is housed inside of the horn-like plate.
The pigeon tremex horntail wasp has a reddish-brown head, a reddish-brown and black thorax, and a black abdomen with yellowish stripes. It also has long, amber-colored wings. This horntail prefers maples, but also commonly attacks many other deciduous trees, including oak, elm, hickory, apple, and birch. Horntails lay eggs in trees that are either dead or dying. The eggs hatch into whitish, legless, cylindrically-shaped, worm-like larvae. They bore into the trunk and large branches, creating meandering tunnels in the sapwood and heartwood. Larvae eventually pupate in these galleries and emerge as adults, chewing a hole through the wood to escape. Because they rarely attack healthy trees, horntails are not considered a pest in the landscape. Adults are most active during August and September.
A second species of giant wasp that goes hand-in-hand with the horntails is the GIANT ICHNEUMON (Megarhyssa spp.). The adults usually have brown bodies, up to 2" in length, marked with black and yellow markings and transparent wings. Females have a very long (up to 4") thread-like ovipositor. Megarhyssa wasps are able to thread their 4"-long ovipositor into the wood of the dead tree, where they are able to deposit an egg in the tunnel of the horntails. The Megarhyssa larvae then attach themselves to the horntail larvae and eventually eat them. They pupate and emerge the following year. Like the horntail, although ferocious looking, the giant ichneumons are also unable to sting with their enormous ovipositors. Both are magnificent specimens of nature to be observed and marveled.
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DISEASE DIGEST
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THE BLOB RETURNS TO ATTACK BEECHES!
A branch was brought into the CWEPPDC with a black, spongy mass protruding all the way around a beech twig. The inquirer stated that this black blob was all over the beeches in the woods near her home and she was afraid that it was going to kill the trees! Fortunately, the blob was quickly identified as a type of SOOTY MOLD (Scorias spongiosa) which is specific to beeches, alders, birches, and pines. The spongy mass, or stromata growing on beeches consists of mycelium growing on the honey dew produced by the beech blight aphid. Originally, these stromata appear as a brittle coating on the branch, but with moisture, grow into a large spongy ball up to 2" high and 4" long!
Although alarming in appearance, direct injury to the beech from either the beech blight aphid or the sooty mold is unknown, and can be left alone. Ornamental beech species growing in a landscape, can be hosed off. In periods of drought however, keep in mind that the aphids removal of nutrients and fluids from the beech append one more stress to the tree. Trees with a severe infestation can be treated with an insecticidal soap, horticultural oil, or conventional insecticides. Systemic insecticides applied in early spring will control the beech blight aphid, as well as other perennial beech pests.
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THE MOIST CHAMBER
Nancy Taylor reported receiving samples of the following plants and diseases in the CWEPPDC
* VIRUS ON HOSTA. Nancy was quite thrilled to receive a sample of a hosta showing the mottling and unique patterns created in leaves by a plant virus. Unfortunately, the best way to prevent viruses from being spread, is to destroy the infected plant material. So the hosta served as an interesting centerpiece in the lab for a day and then became a part of history.
* COTTONWOOD RUST. This fungal pathogen, Melampsora medusae, can occur throughout almost the entire range of poplars around the world. Poplar trees vary in their susceptibility to this disease and if conditions are correct, it can cause leaves to shrivel and drop prematurely.
* PHYTOPHTHORA. This disease was identified as the causal agent responsible for the death of sedum plants and brunnera. This disease is usually associated with saturated soil conditions or water-logged for an extended period of time, leading to root decline.
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TURF TIPS
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MORE BROWN TURF
Turfgrass samples, as well as phone calls, continue to pour into specialists and educators offices, regarding browning or dead patches in lawns and sports fields. Several factors may be involved with the browning, including the most obvious component of drought. To determine all the causes, one must examine the turfgrass closely, tug at the browning grass blades, and examine the leaf blades with a 10X hand lens.
A dull mowing blade can cause turfgrass blades to have torn, brown, tips and a higher susceptibility to leaf diseases. Scalping will also cause the grass to brown, since the crown is then exposed to intense sunlight, increased traffic wear, and decreased humidity. Leaving swimming pools and buckets, etc. on the grass will turn the grass underneath brown within several hours on hot days.
Different grass species and cultivars have varying tolerances to the heat and drought, for instance Kentucky bluegrass leaves will become dormant and turn brown during periods of prolonged drought, while the deep roots of tall fescue enable it to absorb moisture beyond the depth of Kentucky bluegrass roots. Warm season grasses like zoysia grass or Bermuda grass thrive during droughts. A common weed surfacing this year is roughstalk bluegrass (Poa trivialis) which will become dormant during periods of intense heat. This stemmy, prostrate growing grass, often flourishes in irrigated lawns as it prefers moist conditions, however despite the irrigation, once the temperature rises and remains above 85°F, roughstalk bluegrass will go dormant.
Roughstalk bluegrass can be identified by teasing the stems of browning grass out of the canopy and examining the stems. Roughstalk bluegrass has long, slender stems that root at the nodes. This perennial grows across the soil surface and has very shallow roots. Unlike the short, truncate ligule of Kentucky bluegrass, the upper leaves of roughstalk bluegrass have a long (1/4- 3/8"), pointed ligule.
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BE ON THE LOOK-OUT FOR BILLBUGS
Billbugs have also been active this year. The larvae have chewed down the stem of Kentucky bluegrass and are in the soil by now, either feeding on the roots or pupating. With a steady tug, stems which have been tunneled by billbug larvae will break from the crown and contain frass, which is easily seen even without a hand lens. Patches of Kentucky bluegrass in sunny lawns should be examined for this pest, so that it can be treated preventively next year. Irrigation will help to keep the crowns of affected turfgrass alive.
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COMING ATTRACTIONS
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SALSA (SECREST ACADEMY FOR LANDSCAPE SCIENCES AND ARTS)
The first SALSA series held its first full day of programming July 18, and is in session again next Monday, August 15. The dates have now been selected for the second series of three full day sessions. SALSA II will be held October 10, November 14, and December 12. Featured topics included maintenance practices such as fall planting, fertilization and mulching, plant selection for fall landscape appeal, weed management, wildlife management in the landscape, and the problems with invasive organisms. This horticultural program is at OSU's Secrest Arboretum at the Ohio Agricultural Research and Development Center (OARDC) in Wooster. It is for individuals with professional or personal interest in an intensive, hands-on landscape learning experience, and is a program of Ohio State Universitys Secrest Arboretum and the Ohio State University Extension Center at Wooster.
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 II is $300 for the full three days of programming. This fee includes considerable reference material, class curriculum notebooks, lunches, and refreshments. For more information contact Joe Cochran at Secrest Arboretum (330-263-3886 or
cochran.58@osu.edu).
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OSU TURFGRASS RESEARCH FIELD DAY
. . .is scheduled to take place next Wednesday, August 17, at the OSU Turfgrass Research Center at Waterman Farm. Hear and see the newest research in golf course soils, insect pests, diseases, cultivar improvements, and enjoy the ever popular BBQ wings for lunch! For more information, go to the website below.
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OLCA DIAGNOSITC SEMINAR
. . .will occur on August 18 at the OSU Turfgrass Research Center at Waterman Farm and highlights techniques and training for lawn-care and landscape professionals. For more information, go to the website below.
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ONLA/OSU RESEARCH DAY
Come be part of the ONLA/OSU Research Day on September 22, 2005 in Columbus, Ohio. The program is sponsored by the Ohio State University's Department of Horticulture and Crop Science, ENLTT, and ONLA. The program will be held at the Waterman Farm's Wittmeyer Conference Room. The program runs from noon to 4:00 p.m. and lunch will be provided. Registration is required, however, lunch is free. To register call Hannah Mathers (614-247-6195), or Luke Case (614-292-0209) or email them at: mathers.7@osu.edu or case.49@osu.edu.
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BYGLOSOPHY
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Earth laughs in flowers. - Ralph Waldo Emerson, "Hamatreya"
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