Pam Bennett, Barb Bloetscher, Joe Boggs, Jim Chatfield, Erik Draper, Dave Dyke, Gary Gao, David Goerig, Tim Malinich, Amy Stone, and Curtis Young.
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July 26, 2007
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This is the Seventeenth 2007 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 July 24, 2007 conference included: Barb Bloetscher (Entomology/C. Wayne Ellett Plant and Pest Diagnostic Clinic (CWEPPDC)); Joe Boggs (OSU Extension Center at Piketon/Hamilton-Clermont); Jim Chatfield (OSU Extension Center at Wooster/Hort and Crop Science); Erik Draper (Geauga); Dave Dyke (Hamilton); Gary Gao (Delaware); Dave Goerig (Mahoning); Michael Loos (Cuyahoga); Tim Malinich (Lorain); Becky McCann (ABE Center); Joe Rimelspach (Plant Pathology); Dave Shetlar (Entomology); Amy Stone (Lucas); 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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| Weather Station |
Region of Ohio |
Ave. High Temp F |
Ave. Low Temp F |
Total Precip " |
Normal Precip " |
| Ashtabula |
NE |
78.4F |
55.2F |
NA |
2.3" |
| Wooster |
NE |
81.4F |
55.7F |
3.27" |
3.4" |
| Hoytville |
NW |
83.4F |
57.6F |
1.5" |
3.2" |
| Delaware |
Central |
89.0F |
52.4F |
1.56" |
3.4" |
| Piketon |
South |
84.0F |
59.6F |
1.94" |
3.0" |
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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 .
* ANNUAL PLANT OF THE WEEK. EUPHORBIA 'DIAMOND FROST'. Euphorbia 'Diamond Frost' is a beautiful, light textured, airy plant in the spurge family that blooms from spring till frost! This plant has done extremely well in the Annual Plant Trials at the Cincinnati Zoo and Botanical Garden as a bedding plant and in container plantings. Its delicate, airy, white flowers stay attractive the entire season. The delicate look that the plant provides should not fool you on its toughness. It is an outstanding performer in the garden. Its many attributes include: no deadheading, deer resistance, and heat and drought tolerance. This plant also mixes well with other annuals in containers and bedding displays, especially plants with dark foliage. 'Diamond Frost' is low growing, reaching heights of 12 - 18".
* PERENNIAL PLANT OF THE WEEK. JOE-PYE WEED (Eupatorium purpureum subsp. Maculatum 'Gateway'). This herbaceous perennial of the Asteraceae family is hardy in USDA zones 4 to 8. E. purpureum is native to the Eastern and Central United States. Joe-Pye Weed is easy to grow in average, medium-to-wet soils in full sun. It prefers moist, fertile, hummus rich soils which do not dry out.
'Gateway' is a popular cultivar that is more compact than the subspecies, typically growing shorter (4 - 5' tall) and bushier with tighter and thicker blooms. This low maintenance cultivar is erect and clump-forming, with coarsely-serrated lance-shaped dark green leaves, typically in whorls of 3 - 4 on sturdy, wine-red stems. Joe-Pye Weed blooms from July to September with tiny, dusky rose-pink flowers in huge, terminal, domed, corymbs reaching 12 - 18" in diameter.
Its flowers are attractive to bees and butterflies and it has attractive seed heads, which persist well into winter. This is an excellent tall plant for borders, cottage gardens, meadows, native plant gardens, wild/naturalized areas, or water margins.
* WOODY PLANT OF THE WEEK. WHITE OR CONCOLOR FIR (Abies concolor). This medium to large (30-50 feet) conifer has an attractive pyramidal shape. Needles are a fresh and cooling blue to blue-green color. White firs are tolerant of a wide range of dry, cold and hot conditions and are the best adapted fir for many Midwest landscapes. Best sites though are moist, but well-drained soils. The 'Candicans' cultivar has intensely silver-blue needles and an upright form.
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THE WEEKLY WEED
FIELD BINDWEED (Convolvulus arvensis). This crafty perennial has a slender, trailing and climbing stem with alternately attached arrowhead-shaped leaves. The weed develops an attractive, white, funnel-shaped flower from June through September. Bindweed seeds sprout readily and plants develop flowers early in their lifecycle. Many unsuspecting gardeners enjoy the flower and wait too long to pull this weed. In the meantime, the plant is rooting-in for the long haul. From the moment this plant sprouts, it will aggressively begin to develop an extensive and deep system of roots and rhizomes in most soils to depths of up to 4'.
Field bindweed can be a serious weed in most agronomic and horticultural crops. This weed is found in urban landscapes as well. If left unchecked, the weed will soon vine around the stems and over the top of any desirable plant. Once on top of a plant it shades out the sun from the foliage of the host, which reduces the desirable plant's growth rate. Tender herbaceous plants also can succumb to the tight grip of the vines as they grow around their stems.
Effective control of established field bindweed requires a three phase treatment program, according to Hannah Mathers, (OSU Horticulture and Crop Science). Apply post emergence controls shortly after the plant flowers using glyphosate and/or 2, 4-D Amine, or related chemicals. Re-treat new bindweed growth again when 12 - 18" runners re-grow. Finally, keep preemergence herbicides in the control program to prevent new seedling growth.
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TAXUS DECLINE IN A DRY YEAR?
We have all heard and verified with our own observations that Taxus (yew) is a plant that is not tolerant of "wet feet". Plants differ in their ability to tolerate heavy clay, low oxygen, poorly drained soils and Taxus is definitely on the list of those woody plants that are relatively less tolerant of such conditions. That is why it was so puzzling in the mid-summer of 1992 when large, older Taxus plantings began declining in Ohio and other Northeast and Midwest sites. Puzzling because the first part of the growing season in 1992 was very dry.
After a good bit of soil-searching, we came up with our most educated diagnostic explanation for the severe decline at many locations. First of all, 1991 was a near-record wet year. We suspect that this resulted in a high level of root decline and root rot of Taxus in the abnormally wet soils. Some Taxus did decline in 1991, but many of the older more established plantings still seemed relatively healthy then, presumably due to the fact that these Taxus were sited well (as evidenced by the fact that they had thrived over many years). Then the early season of 1992 was a near-record drought for April-July. We think this resulted in failure of even the mature Taxus to re-establish an adequate amount of feeder roots. It is important to remember that root rot is not an all-or-nothing process for plants with the extensive root system of large, mature Taxus plants.
We isolated a serious water mold fungal pathogen, Phytophthora cinnamomi, from the declining mature Taxus in 1992. But that is only part of the story. The fungus was probably in the soil in these sites all along over the years, with extensive damage occurring in 1991 and then poor reestablishment in 1992. Whether it gained the upper hand and resulted in extensive root rot depended on an unusual set of environmental conditions: an extremely wet year followed by an extremely dry early season the next year. The punch line to this story: these conditions have been repeated in many areas of Ohio in 2006 and 2007. Consequently, we are seeing problems similar to those that occurred in 1991-1992 developing on older Taxus.
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BUG BYTES
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BAGWORM CONTROL REVISITED
Several BYGLers reported that bagworms (Thyridopteryx ephemeraeformis) have finally reached sizes that allow people to connect browning foliage to the "mobile cones." Indeed, Joe Boggs noted that bagworms in southern Ohio are big enough to permit drive-by diagnostics.
It is well known that insecticide applications made to late instar bagworms may force them into early pupation rather than killing the caterpillars. However, Dave Shetlar stressed that forcing early pupation is not a bad thing. Pupation means that the caterpillars stop eating! Late instar bagworms are voracious feeders and can strip foliage almost overnight. Once they strip all the foliage, the hungry caterpillars may even consume bark, killing twigs and branches. Thus, while it may be too late to kill the caterpillars, it is not too late to stop the damage and protect infested plants.
Dave noted that the bagworms that escape to complete their life cycle can be dealt with next year early in the season. He recommended that landscape managers note the location of infested plants and plan to inspect these plants, as well as neighboring plants, next year in mid-June to early July. Insecticides applied at that time will kill the bagworms, ending the recurring misery.
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HICKORY TUSSOCKS MUNCHING ON
Hickory tussock moth caterpillars (Lophocampa caryae) are still appearing in yards and gardens, munching on leaves of various deciduous trees and shrubs. These "furry" caterpillars are covered with tufts of white hairs with long tufts of black hairs on each side of the head, and two more tufts on opposite sides toward the tip of the abdomen. A series of short black tufts may be seen in the center of each abdominal segment.
Although their favorite food is oak and hickory leaves, they are willing to munch on a wide variety of deciduous trees and shrubs. Serious damage can occasionally occur on small trees when populations are high. Trees should be closely inspected to make certain these caterpillars aren't creeping up on landscape trees and shrubs.
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BLISTER BEETLES FESTER
Dave Dyke reported observing a pack of swarming MARGINED BLISTER BEETLES (Epicauta pestifera) consuming amaranth leaves in southwest Ohio. He noted that the beetles were almost oblivious to his presence, perhaps because they can pack a serious defensive punch! The beetle's blood contains cantharidin, a chemical that can cause serious blistering of the skin if the beetles are mishandled, hence the common name. This chemical can also be toxic to people and animals if ingested. Oddly, cantharidin is extracted from a European blister beetle to produce "Spanish Fly." BYGLers noted that Dave was closely guarding his beetle stash.
Blister beetles range in size from 3/4 - 1 1/4" long. They have long legs and narrow, elongated soft bodies. Their heads appear almost bulbous because they are much wider than the pronotum ("neck"). The beetle's flexible front wings often fail to extend to the tip of the abdomen. Margined blister beetles are so named because the margins of their black wings are bounded by gray edges. The body of the striped blister beetle (E. vittata) has black and orangish-yellow stripes, and the body of the black blister beetle (E. pennsylvanica) is... black.
The adults of most species are plant feeders and may be found consuming leaves or flowers on plants in the families Amaranthaceae, Asteraceae (= Compositae), Fabaceae (= Leguminosae), and Solanaceae. The larvae are specialized predators. Some feed on grasshopper eggs while others feed in the nests of solitary bees where they consume bee eggs, larvae, and food stored in the nest. Blister beetle adults may emerge en mass and produce rapid plant damage. Fortunately, their visits are usually very short lived, lasting only a week or two. They can be easily controlled if necessary by using a gloved hand to knock them into a bucket of soapy water (to be carefully disposed!), or by using an insecticide labeled for the host plant.
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MAGNOLIA SERPINTINE LEAFMINER
Joe Boggs reported observing the highly visible handiwork of the magnolia serpentine leafminer (Phyllocnistis magnoliella) on bigleaf magnolia in southwest Ohio. The tiny caterpillars of this aptly named moth feed close to the upper leaf epidermis, producing long, thin, serpentine mines that appear as silvery tracks snaking across the leaf surface.
Hosts for this leafminer includes southern, cucumber, sweet bay, star, umbrella, and the aforementioned bigleaf magnolias. Large numbers of mines on a single leaf can cause the leaf to turn brown and drop from the tree. Joe was unable to uncover life-cycle information for this moth that would support the effective timing of insecticide applications to control the caterpillars. Fortunately, heavy populations involving multiple leaves appear to be rare occurrence. Thus, populations may be managed by removing and destroying infested leaves when mines first appear.
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YICKY-YUCKY YUCCA
Joe Boggs also reported that YUCCA PLANT BUGS (Halticotoma valida) are causing noticeable injury to their namesake in southwest Ohio. The bugs use their piercing-sucking mouthparts to extract the essence of yucca. This produces small, yellowish-white spots (stippling) which may coalesce causing the foliage to turn yellow. The bugs deposit spent yucca extract in the form of black, tarry waste spots. Off-colored foliage splattered with black specks makes yucky yucca look yicky.
Adults of this small (3/16" long) native of the southwestern U.S. have black wings and orangish red legs, head, thorax, and abdomen. The nymphs share this striking color scheme, but they appear more reddish in color since their black wing pads fail to cover their entire abdomen. Both adult and immature yucca plant bugs have a somewhat oval-shaped body. The bug has multiple, overlapping generations, so populations can build rapidly. Intense annual feeding activity may eventually cause yucca plants to die. Insecticides labeled for use on yucca can provide effective control of this insect.
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BORERS RAISING CANE
Michael Loos reported receiving a sample of raspberry cane with raspberry cane borer damage. There are two cane borers that can typically be of concern to the home fruit grower, and both borers are beetles. The damage caused by the females laying eggs in the cane differs between the two. However, the larvae of both cause damage to the canes by tunneling through them and control measures are the same.
The female RASPBERRY CANE BORER (Oberea bimaculata) girdles the cane by chewing two rings of puncture marks around the cane, between which she lays her eggs. This causes the tip of the cane to wilt, blacken and possibly fall off. The RED-NECKED CANE BORER (Agrilus ruficollis) lays eggs on the bark of new canes, usually within about 10" of the base of the cane. When the larvae hatch and begin tunneling through the canes, galls or swellings form near the feeding sites, indicating the presence of this insect. Canes may die and break off at the point where these galls occur.
For both types of borers, the primary method of control is to prune out and destroy the infested canes. With the raspberry cane borer, canes can be cut about an inch below the girdled area. However, for the red-necked cane borer, the entire infested cane should be removed. The removal of wild brambles nearby can also help to prevent infestations. Refer to the OSU Extension Bulletin #780, "Controlling Insects and Diseases in Home Fruit Plants."
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THRIPS STREAKING IN LETTUCE
Barb Bloetscher reported that onion thrips (Thrips tabacii) were identified this week in the CWEPPDC on lettuce leaves being grown in a greenhouse. Although few of the tiny (less than 1/16" long) thrips were found, brown stippled spots and a grayish sheen, symptoms characteristic of this pest, was noticeable along the veins of the leaves, especially on the lower leaves.
Thrips damage the leaves by using their rasping-sucking mouthparts to rasp the lower epidermis and suck nutrients. While imbibing their liquid lunch, the action separates the epidermis from the tissue below, creating an air space which eventually causes death of the adjacent cells. Because the onion thrips concentrate on the major and secondary veins, the damage appears as "streaks" along the veins. Another indicator of the thrips is the indiscreet black spots of their feces on the bottom of the leaves.
Thrips have an interesting life cycle with 6 stages. The eggs are placed in small openings in the leaves made by the females. Larvae will feed on the bottom of the leaves, molt into the second instar, then drop to the soil to pupate. The pre-pupal stage lasts 1 - 1.5 days at 77F; then the thrips enters the pupal stage, when the wings develop. The adults then emerge from the soil to continue the life cycle. Males are usually not needed for this species to continue. The egg-to-egg cycle can take as little as 14.6 days at 77F.
Because lettuce can be picked and eaten daily, chemical treatments are limited. The most heavily infested plants should be removed and destroyed. Dead leaves and detritus beneath plants should also be removed. Greenhouses should be kept free of weeds, which can serve as alternate hosts of thrips. Yellow sticky traps are very useful for monitoring for the presence of thrips and other insect pests. Several beneficial insects are also available.
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DISEASE DIGEST
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SLIME FLUX / WET WOOD
Dave Dyke reported receiving a call about an elm (Ulmus spp.) tree oozing a watery, sweet and/or fermented smelling liquid. That, of course, succinctly describes the symptoms of bacterial slime flux (a.k.a. wet wood), a disease that makes its appearance from time to time in some of the trees in our landscape. Wet wood is an unsightly seepage from the trunk of shade trees. It occurs in apple, birch, elm, hemlock, maple, mulberry, oak, poplar, and willow. Its odor may be foul-smelling or quite appealing (sometimes a sweet molasses smell), depending on the individual smelling it and the specific conditions under which it forms. In Ohio, slime flux appears in large, mature, landscape oaks, tulip poplar, and very commonly elms. This disease is not normally a serious problem if the tree is otherwise healthy.
The infected wood is frequently discolored or appears water soaked (wet wood). Gas (carbon dioxide) is produced by bacterial fermentation. The gas produces pressure in the wood. This pressure forces sap from the trunk through cracks in branch crotch unions, pruning wounds, lawn mower wounds, other injuries, and occasionally, unwounded bark. This oozing of sap is termed fluxing. The flux is colorless to tan at first but darkens upon exposure to the air. As fluxing continues, large areas of the bark become soaked. Many different microorganisms grow in the flux, producing a foul or alcoholic smell. There are no curative or preventive measures for slime flux except to maintain trees in a general good state of vigor and minimize wounds and injuries. More damage can be done to the tree in attempting to cure slime flux than the flux will do alone.
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DOG VOMIT FUNGUS SPEWS
BYGLers reported that the so-called dog vomit fungus has been spewing across Ohio landscapes. This somewhat grotesque, slimy barf-colored growth is actually not the fungus that its name indicates. It is a slime mold (Fuligo septica) that actually crawls across the surface of the mulch, digesting organic matter as it slimes along. It can be yellow, orange, or pink in color. As it reaches maturity, the colony stops moving and firms-up, forming a mound that looks just like what it is named after. This pile-o-puke eventually dries down and brownish clouds of spores are released when the mass is disturbed.
The most effective time to control this problem is when new mulch is being spread. Fresh mulch is easily colonized by slime mold. Watering new mulch increases the moisture level in the relatively dry organic matter. This allows bacteria and other competitors to get established prior to the arrival of slime molds. This fierce competition for organic matter reduces the successful development of the dog barf until later in the season. If the slime mold is currently in the landscape, the gelatinous or dry stages of the slime mold can be lifted off the mulch and disposed. It is, however, an amazing organism that can simply be enjoyed for what it is...or, be blamed on the neighbor's dog!
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A SMUTTY REPORT
Smut was on the minds of BYGL callers this week, COMMON SMUT of corn, that is. This common disease, caused by the fungus Ustilago zeae, survives as resistant spores in the soil. The resistant spores are blown into fields on soil particles. They germinate in moist air and produce new spores that germinate in rainwater on the plant. Infection occurs when the germinating spores enter the corn plant through wounds caused by weather, insects, or cultivation.
Smut galls can be seen in as few as ten days after infection. They are a mass of black greasy or powdery spores covered in a sheath of silvery-white corn tissue. They are most often noticed encompassing the ears, but are also found on tassels and leaves (usually at the midrib). As the gall dries, the spores drop out and spread to new areas. Infection occurs early in the season and is less common after the formation of ears. Late varieties of sweet corn are also usually more resistant.
On a small scale, smut galls can be removed before they break open. They should be removed from the area or destroyed. Deep plowing will effectively bury the smut galls. Potential for infection can be reduced by avoiding injury during cultivation and controlling damaging insect pests.
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SPOTTED TOMATOES
Erik Draper reported receiving a green tomato this week from a grower who wanted to know what was causing the small, raised bird's-eye like spots on the skin of the tomato. These are classic symptoms of a disease known as BACTERIAL SPOT resulting from an infection by the bacterium Xanthomonas campestris pv. vesicatoria. This pathogen can enter healthy plants through wounds or stomata. Maximum infection occurs under very moist conditions in warm weather (68 - 95F), especially when night temperatures are warm (75 - 82F).
Bacterial spot symptoms begin on the leaf as small, irregular to circular greasy or water-soaked spots, easily visible on the underside of the leaflets. As these water-soaked lesions enlarge, colors change from dark green to purplish-gray, and the lesions develop a distinctive black center. These infected lesions may be surrounded by a white to yellowish halo but the infected leaf tissue becomes paper thin and may crack. In wet weather, infected leaves may appear to have a marginal scorch. Multiple or very large lesions can cause the plant to defoliate.
Bacterial spot lesions on the fruit are small water-soaked spots that become slightly raised and enlarged until they are about 1/8 - 1/4" diameter. In the early stages of infection, a white halo may surround each lesion. The centers of these spots later become irregular, light brown, slightly sunken but have a rough, scabby surface. These fruit lesions are usually superficial and rarely develop into a fruit rot.
Control involves reducing the populations of the bacteria on the leaf surface by using fixed-copper sprays or fungicides that contain copper. Also, foliage should be allowed to dry before doing any cultural practices or harvesting of fruits to reduce the spread of this disease. It is important to note that this disease can be spread from tomatoes to peppers if sanitary precautions, like washing hands and sterilizing tools, are not observed.
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LEAF SPOTS ON TOMATO PLANTS
There are many fungal diseases on tomatoes which cause leaf spots; however, SEPTORIA LEAF SPOT, which is caused by the fungal pathogen Septoria lycopersici, is one that can occur anytime during the growing season. More often than not, Septoria becomes more severe after blossom set and fruits begin to develop. Leaf lesions develop first on mature leaves, especially on leaves nearest to the ground. Disease development progresses rapidly with moderate temperatures and abundant rainfall.
Septoria leaf spot first appears as small, water-soaked spots, 1/16 - 1/8" in diameter on the underside of the oldest, lowermost leaves. Eventually the center portion of this fungal lesion turns light beige to tan or gray while the margin remains dark. Small black, pimple-like fruiting structures (pycnidia) of the fungus, easily visible without a hand lens, are formed in the center of the lesion. These fungal lesions may also appear on stems, calyces, and blossoms, but rarely occur on fruit. Heavily infected leaves will turn yellow, dry up, and drop off.
Spore production is prolific when temperatures are 60 - 80F. The spores are easily spread by wind, rain, the hands and clothing of harvesters, and even insects. Septoria can cause extensive defoliation, resulting in tomato plants developing a palm tree-like appearance. The open canopy causes sunscald on the exposed fruit and an overall reduction in the total number of fruit produced.
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TURF TIPS
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CHINCH BUG - BILLBUG DIAGNOSTIC CHALLENGE
Dave Shetlar and Joe Boggs reported on an instructive hands-on diagnostic lesson presented at last week's Ohio Turfgrass Foundation (OTF) Regional Seminar in Dayton. OTF Trustee Mark Grunkemeyer (Buckeye Ecocare, Dayton) arranged for participants to make a site visit to a home landscape plagued by a number of issues.
There were areas throughout the lawn with purpling, yellowed, browned, dying, or dead grass. Prior to Mark's involvement with the lawn, the problem had been diagnosed as drought stress, and the home owner had been told to increase the irrigation. A fertilizer application had also been made to support grass plant recovery. The homeowner dutifully followed the irrigation recommendation to the extent that two red maples had been added to the list of dying or dead plants in the landscape. The maples were literally floating in water! However, despite water cascading from the landscape, the condition of the turfgrass was not improved. So, the distressed homeowner had called Mark.
As Mark had discovered, and as the seminar participants learned when they inspected the lawn, the problem was not drought stress. Indeed, as Dave had taught during a classroom session earlier in the day, damage caused by CHINCH BUGS (Blissus leucopterus) and BLUEGRASS BILLBUGS (Sphenophorus parvulus) can mimic summer drought stress. Of course, Dave also taught that insect damage cannot be identified through drive-by diagnostics. It requires an up-close and personal inspection on bended knee.
While the billbugs had completed their first generation, and adults were no longer present, the tried-and-true "tug test" was applied by the participants to see if the stems of the brown grass would break off easily at the soil surface. A close inspection of the ends of the broken stems revealed that they were filled with sawdust-like frass, a tell-tale diagnostic aid to identifying the work of billbug larvae. Parting the grass also revealed that chinch bugs were still present and feeding. Chinch bugs inject toxins into stems as they feed, causing the blades to first turn a purplish color, and then straw-colored. Both symptoms were clearly evident.
The take-home message: while this season's dry weather may tempt diagnostiods to make a quick-draw over-the-phone or drive-by diagnosis of drought stress to turfgrass, the result may be a misfired diagnosis. Remember, treatment without a correct diagnosis is malpractice. The lawn received a treatment of bifenthrin (Talstar). Of course, other properly labeled insecticides could have been used. Regardless, a correct treatment was made based on a correct diagnosis.
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GOT GRUBS?
Dave Shetlar reported that grubs are becoming large enough to begin produce damage to drought stressed turfgrass where grub populations are high. This damage appears as wilting of the turfgrass, with the blades acquiring a slightly bluish, flaccid look. If in doubt, grab a handful of turfgrass blades and give a firm pull. If grass plants, roots, and soil are easily pulled free to expose small, white "C"-shaped" grubs, chances are likely that the grub population is high enough to cause noticeable turfgrass damage.
Grubs tunnel horizontally between the thatch and soil layer, munching on thatch, organic matter, and roots. If enough roots are severed and moisture is low, the turfgrass may eventually die. In these situations, the turfgrass manager may want to apply an insecticide, or decide to irrigate more often to keep remaining roots alive. Systemic insecticides are still effective if used before mid-August. Imidacloprid has shown excellent results if well watered after application, even this late in the summer. Regardless of the management decision, the turfgrass managers should be aware that potential grub problems may be lurking beneath the grass.
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RUSTY TURFGRASS
Joe Rimelspach reported that RUST, a fungal disease (Puccinia spp.) of turfgrass, is already appearing in Ohio this summer. Rust normally affects turfgrass in the late summer and fall. The disease has been seen on turfgrass in lawns and sports fields in the central and southern parts of the state. Rust is most commonly seen in Ohio on perennial ryegrass, and occasionally on Kentucky bluegrass.
The disease can become especially severe on turfgrass that is stressed by drought, and/or soil is compaction. Under these difficult cultural conditions, the disease damages leaf tissue faster than new leaf blades can be produced. Rust causes the turfgrass to take on a generally yellowish-orange appearance. The epidermis of infected leaves ruptures, releasing enormous amounts of spores. The tiny rust-colored spores can be a real nuisance as they easily rub off onto shoes, lawn mowers, pet's fur, clothes etc.
Fortunately, rust is considered more of a nuisance rather than a turfgrass killer, and the disease can be prevented by applying good turfgrass cultural practices. These practices include: 1) using blends of resistant turfgrass cultivars (visit the National Turf Evaluation Program web site http://www.ntep.org/ for lists); 2) providing adequate water and fertilizer to support grass growth; 3) using core aeration to reduce soil compaction and improve water infiltration. A preventative fungicide application may be helpful for turfgrass with a long history of rust infections. Sterol inhibitors and strobilurins (e.g. Bayleton, Eagle, Banner, and Heritage) have proven to be highly effective in OSU research trials.
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WHY DOES MY TURF TURN BROWN?
The browning of turf can be caused by several factors. They include insect damage (see above), disease infections (see above), differences in drought tolerances between turfgrass species, and other turf challenges.
Cool-season grass species dominate turfgrass used in Ohio lawns. They are called "cool-season" because they do best in the spring and fall. The hot, dry summer months can present serious challenges for these species. Tall fescue is the most drought tolerant of them all. Kentucky bluegrass and perennial ryegrass are not as drought tolerant. They will go dormant much faster. Drought dormancy causes the grass to turn brown. It doesn't mean that it's dead, but if turfgrass remains dormant too long and crowns die, the grass will become permanently dormant dead!
Separating normal drought dormancy from other more serious turf problems can be difficult. Obviously, if the application of water fails to revive the turfgrass, dormancy is not the issue. The BYGL reports in this issue on the various insect pests and diseases that can produce brown turfgrass provide helpful diagnostic tips. However, diagnosing other diseases that can produce brown turf, such as Rhizoctonia brown patch and dollar spot, is more problematic. Sending a sample to OSU's C. Wayne Ellett Plant and Pest Diagnostic Clinic is well worth the nominal fee in learning if a disease is involved. Visit the Clinic's website http://ppdc.osu.edu/ to get information on how to submit a turf sample.
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INDUSTRY INSIGHT
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RANDY WINS!
The ANLA EXTENSION WORKER OF THE YEAR for 2006 was awarded to BYGLer Randy Zondag, OSU Extension Horticulture Educator in Lake County. Randy was recognized by the American Nursery and Landscape Association (ANLA) for his extensive educational and research work with the nursery and landscape industry in the United States and abroad. Kudos to Randy for this recognition and for his outstanding continued service to the industry.
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OHIO STREET TREE EVALUATION PROGRAM (OSTEP)
Have you noticed various OSUers such as Draper, Chatfield, Davis Sydnor, Denise Ellsworth, John Conglose, and Lynn Vogel, as well as ODNR urban foresters such as Alan Siewert, Lisa Bowers, Wendi Van Buren, Lola Lewis and other outstanding urban foresters in Ohio cities out and about this summer measuring trees throughout the length and breadth of Ohio? Chances are they are collecting data for the Ohio Street Tree Evaluation Program. It is part of the 'Why Trees Matter" program of determining the economic value of the ecological impacts of our community forests. Look for the results of these multiyear studies at programs and publications starting this fall with the "Why Trees Matter" community forest forum at the Ohio Agricultural Research and Development Center On October 23.
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SUSPECT EMERALD ASH BORER (EAB)? HERE IS THE OFFICIAL PROTOCOL
The Ohio Department of Agriculture (ODA) has developed a new EAB - Suspect Collection Protocol. The exact protocol depends on whether the find comes from an already quarantined county, or if the find may be the first confirmed infestation in a county outside of the established EAB quarantine.
If someone finds an insect they suspect is EAB inside a quarantined area, the specimen should be placed in a container with the exact address or location noted. GPS coordinates should also be provided whenever possible. The suspect specimen and information should be sent to the ODA's Emerald Ash Borer Program, 8995 E. Main Street, Reynoldsburg, Ohio 43068. Once received, the ODA will complete the proper paperwork and send in the suspect for determination. Confirmation will be sent to the ODA. If the suspect is EAB, the ODA will update the new find on the particular county map. These maps are posted on their website at http://www.ohioagriculture.gov/eab/ . An email notification will be sent to the submitter.
If someone suspects they have found EAB in a county that is outside the quarantine, they should contact the ODA at 888-OHIO-EAB, as soon as possible. The ODA field staff will collect the specimen for federal determination. If the specimen is confirmed as EAB, the ODA will make an official announcement and new or updated maps will be placed on their website. Additional finds were posted just this week on the Hamilton and Cuyahoga County maps. Check the site frequently as updates are made on a regular basis!
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SUPPORT EAB RESEARCH!
The need continues for dollars to support EAB research aimed at slowing the spread of this highly destructive, non-native pest. Make a contribution to the American Nursery and Landscape Association, Horticultural Research Institute's special EAB Project fund. Contributions are tax deductible. Send your contribution to:
The EAB Project c/o
Horticultural Research Institute
1000 Vermont Ave, NW, Suite 300
Washington, D.C. 20005
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COMING ATTRACTIONS
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10th ANNUAL GREEN INDUSTRY SUMMER SESSION SET FOR AUGUST 1
This August 1, 2007, all Northwestern Ohio industry professionals are invited to attend the 10th annual educational event, held at Owens Community College in Toledo, OH. Credits for ONCT, ASLA, ISA, Pesticide Applicators, and/or Master Gardeners will be available. Registration information can be found at http://abe.osu.edu/upcoming-events . If there are questions contact OSU Extension, Green Industry Center (419-354-6916).
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25th PERENNIAL PLANT SYMPOSIUM AND TRADE SHOW
The 25th Perennial Plant Symposium is August 5-11, 2007 at the Hyatt Regency Hotel, Columbus, Ohio. Lectures, workshops, tours, and a trade show will highlight this silver anniversary symposium.
The trade show will be held August 6, 7, and 9 during the Perennial Plant Symposium in the Battelle Hall of the Greater Columbus Convention Center in Columbus, Ohio. Exhibitor information may be obtained by contacting the Perennial Plant Association, (PPA), 3383 Schirtzinger Road, Hilliard, OH 43026. Phone 614-771-8431, Fax 614-876-5238 or email ppa@perennialplant.org .
Program and Registration information can be found a http://www.perennialplant.org/newsdetail.asp?ID=121, or by contacting the PPA.
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40th ANNUAL NURSERY GROWERS OF LAKE COUNTY OHIO (NGLCO) FIELD DAY
40th ANNUAL NURSERY GROWERS OF LAKE COUNTY OHIO (NGLCO) FIELD DAY is August 14, 2007. The NGLCO Field Day will be held at Holden Arboretum in Kirtland Ohio. The program this year will feature garden tours of the 3,500 acre Holden Arboretum, including a garden railroad which is a new feature for at the Arboretum. Information on the time and location for the Field Day are posted on the following website http://www.nglco.com/fieldday.htm . Master Gardeners and students will receive a special price. For further information call 440-241-7969. is August 14, 2007. The NGLCO Field Day will be held at Holden Arboretum in Kirtland Ohio. The program this year will feature garden tours of the 3,500 acre Holden Arboretum, including a garden railroad which is a new feature for at the Arboretum. Information on the time and location for the Field Day are posted on the following website http://www.nglco.com/fieldday.htm . Master Gardeners and students will receive a special price. For further information call 440-241-7969.
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GREEN INDUSTRY FALL GET TOGETHER
The Associated Green Industries Fall Get Together will be a perennial affair this year. On August 30, 2007, the dinner, tours, and presentations will be held at Art Form Nurseries, 16656 Chillicothe Rd., Chagrin Falls, OH. Tours begin at 4:00, with dinner and speakers at 6:00. Topics for the evening include "Identification of Tree Issues" and "New and Valuable Perennials in the Landscape." Registration required by August 17. Go to http://lorain.osu.edu/horticulture/commhort for registration flyer or call 440-350-2582.
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BYGLOSOPHY
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"The word humility (also human) is derived from the Latin humus, meaning 'the soil' ." -- Piero Ferrucci
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