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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June 23, 2005
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This is the twelfth 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 June 21, 2005 conference included: Pam Bennett (Clark), Joe Boggs (South Region/Hamilton), Jim Chatfield (Center at Wooster/HCS); Erik Draper (Geauga); Dave Dyke (Hamilton); Pam Sherratt (HCS); Dave Shetlar (Entomology); Amy Stone (Lucas); Nancy Taylor (C. Wayne Ellett Plant and Pest Diagnostic Clinic (CWEPPDC)), Curtis Young (Allen); 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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Summer has officially arrived, although many would have thought it was already here with the hot temperatures experienced earlier this month! After a slight cool down, it is warming back up, as this weekends temperatures are predicted to end on high note, with the mercury exceeding the 90F mark in many areas across the state. Rain showers have been spotty and many counties remain quite dry with turf turning brown. Below is the weather summary data from June 1 - 22.
| 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 |
79.9 |
62.6 |
N/A | N/A |
2.99 |
N/A | | Hoytville |
NW |
83.9 |
60.8 |
72.1 |
68.7 |
0.43 |
2.53 |
| Columbus |
Central |
84.0 |
62.7 |
73.4 |
69.5 |
0.37 |
3.19 |
| Miami |
SW |
83.9 |
63.5 |
73.8 |
69.4 |
1.09 |
2.41 |
| Jackson |
South |
83.3 |
59.5 |
71.6 |
69.2 |
1.23 |
2.70 |
For additional information, or to see the locations of all of the OARDC weather stations in Ohio, check out the website at http://www.oardc.ohio-state.edu/centernet/weather.htm
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HORT SHORTS
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GDD (GROWING DEGREE DAYS)
GDD is a measure of the daily maximum and minimum temperature and directly relates to growth and development of plants and insects. The GDD of any zip code location in Ohio is estimated using the GDD of ten OARDC weather stations and is available on the web at: http://www.oardc.ohio-state.edu/gdd/
The range of GDD accumulations in Ohio from north to south is 781 to 1,148. Following is a report of GDD for several locations around Ohio as of June 22, 2005: Painesville, 781; Cleveland, 788; Toledo, 900; Youngstown, 833; Lima, 932; Wooster, 911; Coshocton, 938; Columbus, 978; Springfield, 1,007; Dayton, 1,069; Cincinnati, 1,148; Ironton, 1,099; and Portsmouth, 1,101.
To put these GDD accumulations into perspective, the following is an abbreviated listing of plant and insect species with their respective phenological event and average GDD accumulations at which these events occur. Due to variations in weather, temperature, humidity, etc., these events may occur a few days earlier or later than predicted by the average GDD. By looking at a city, town, or village near you from the above list, or visiting the above web site, you can see what could be taking place in the landscape around you.
Greater peach tree borer, adult emergence, 775; striped pine scale, egg hatch, 783; winterberry holly, first bloom, 794; Japanese tree lilac, full bloom, 808; rhododendron borer, adult emergence, 815; northern catalpa, full bloom, 816; mountain laurel, full bloom, 822; dogwood borer, adult emergence, 830; oakleaf hydrangea, first bloom, 835; cottony maple scale, egg hatch, 851; panicle hydrangea, first bloom, 856; fall webworm, egg hatch (first generation), 867; mimosa webworm, egg hatch (first generation), 874; fuzzy deutzia, full bloom, 884; winged euonymus scale, egg hatch, 892; spruce budscale, egg hatch, 894; winterberry holly, full bloom, 897; panicled goldenraintree, first bloom, 924; June Bride littleleaf linden, first bloom, 953; azalea bark scale, egg hatch, 957; Japanese beetle, adult emergence, 970; rosebay rhododendron, first bloom, 1010; greenspire littleleaf linden, full bloom, 1047 southern catalpa, full bloom, 1073; June bride littleleaf linden, full bloom, 1115; and bottlebrush buckeye first bloom, 1158.
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SEEING RED - ON BURNING BUSH THAT IS
Pam Bennett reported that she is beginning to see Euonymus alatus beginning to show signs of fall color in Clark County and Joe Boggs noted the same thing in his area. Several plants are showing reddish fall color at this time. BYGLers generally attribute this to dry conditions and had a great discussion about the use of burning bush in the landscape. The best way to avoid early coloring is to place these plants in landscape situations where they are irrigated during dry spells. Over the past several years, it has been observed that during these dry spells, they tend to turn fall color early.
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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 - Astilbe spp. These plants are just beginning to wow gardeners in the central Ohio area and few plants rival these showy blooms in shady areas. Astilbes come in an endless array of colors and heights. Colors range in the shades of purple, pink, peach, red, and white. They prefer moist soil and to be located in partial to filtered shade. They will dry out in the full sun. Recommended cultivars include 'Bridal Veil', 'Deutschland', 'Fanal', 'Peach Blossom', and 'Red Sentinel'. Newer cultivars, such as Astible chinensis 'Visions' are more sun tolerant than others.
* WOODY PLANT OF THE WEEK. Elizabeth Taylor, Montgomery Clift, the mysterious and magical plant in the woods, and Raintree County - the legendary movie is not set in Ohio, but the golden yellow panicles of Koelreuteria paniculata (goldenraintree) blooms are starting to grace landscapes now. Goldenraintree is a medium-sized tree (30 - 40') with magnificent sunny yellow flower panicles in late June and early to mid-July along the south-north axis in Ohio. It has an overall densely rounded form. Goldenraintree has good tolerance of drought, alkaline soil pH and pollution conditions and does well as an urban tree where there is space for its growth
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POISON-HEMLOCK BOOMS AND BLOOMS
Several BYGLers reported that poison hemlock (Conium maculatum) is now in full glory with plants covered in white bloom and reaching their full heights, which may exceed 10'. They also noted that this non-native plant appears to be "everywhere" in Ohio. Both poison-hemlock and the similar looking native perennial SPOTTED WATERHEMLOCK (Cicuta maculata) are among the most toxic plants in North America. All parts of the plants are toxic, especially the young leaves, stems, and seed. The toxicity of poison-hemlock centers on toxic alkaloids, including coniine and gamma-coniceine, which cause respiratory failure and death when ingested by humans and other animals.
Poison-hemlock is a biennial member of the carrot family (Apiaceae (= Umbelliferae)), and it thrives along borders of fields, roadsides, ditch banks, and in meadows. It has also become a landscape challenge, particularly in new housing developments built on fallow farm land. The plants may grow to a monstrous size, and it produces white umbel-like flowers which are typical of this family. In fact, poison-hemlock's flowers, dark glossy-green, fern-like, triangular leaves, and general growth habit may cause it to be mistaken for other weeds in the same family including QUEEN ANNE'S LACE, or wild carrot (Daucus carota).
Waterhemlock and poison-hemlock have light-green to bluish-green, hairless stems, that are smooth to only slightly ridged vertically. Their leaves lack hairs along the margins. Leaves of waterhemlock are 2-3 times pinnately compound while leaves of poison-hemlock are 3-4 times pinnately compound. Leaflets of both are much larger and more sharp-pointed than the twice-pinnately compound, lobed leaves of Queen Anne's lace. While both waterhemlock and poison-hemlock have purplish spots on the stems, waterhemlock's spots tend to become more elongated into streaks. Waterhemlock has a cluster of fleshy taproots at the base (it is a perennial weed), a feature that is not shared with poison-hemlock or Queen Anne's lace.
Waterhemlock and poison-hemlock can be controlled using selective post-emergence herbicide mixtures containing 2,4-D, 2,4-DP and MCPP, or 2,4-D, dicamba, and MCPP (e.g. Trimec). These weeds can also be killed using a non-selective post-emergence herbicide such as glyphosate (e.g. Roundup) where conditions pose a minimal risk to preferred plants. Applications of herbicides made now will control both the first season rosette stage of poison-hemlock and the second season flowering stage, before seeds are produced.
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WILD PARSNIP
Curtis Young and Joe Boggs noted that another non-native member of the carrot family, wild parsnip (Pastinaca sativa) is also at full height, and in full flower in western and southern Ohio. This weed is a native of Eurasia and has been gradually making its way into Ohio fields and landscapes. Some consider it to be highly invasive. Gardeners should exercise extreme caution around this plant; the plant's juices can cause phytophotodermatitis to the skin. If the plant juices come in contact with skin in the presence of sunlight, a rash and/or blistering can occur, as well as skin discoloration that may last several months.
Wild parsnip can achieve heights similar to poison-hemlocks and waterhemlocks. It is not unusual to find plants topping 8'. The plants are perennial, but have an interesting life-cycle. The first year is spent as a rosette, with leaves confined to growing from a short stem only a few inches above the ground. While in this stage, the plant produces a long, thick taproot. During subsequent years, the plant will generate a single, thick, greenish-yellow stem that sprouts lateral branches topped with hundreds of clusters of yellow umbellate flowers. Wild parsnip is a prolific seed producer, and this is the primary means by which the plant spreads. Leaves are alternate, pinnately compound, branched, and have saw-toothed edges. Each leaf has 5 -15 ovate to oblong leaflets with variable toothed edges and deep lobes.
This weed can be controlled by mechanical means, but with extreme care to avoid skin contact with the sap. Growth and establishment of young plants can be stopped by using a sharp shovel to cut the tap root below ground-level. This will prevent re-sprouting. Plants that are flowering can be cut, but they must be taken off-sight since seed will still develop and mature. Continual mowing will eventually cause plants to die, but it should be noted that mowers release a significant amount of sap. Wild parsnip is also susceptible to glyphosate (e.g. Roundup). This may be the safest approach given the serious concerns with the sap.
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BUG BYTES
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HICKORY TUSSOCK MOTH
Joe Boggs reported observing early instar hickory tussock moth (Lophocampa caryae) caterpillars skeletonizing oak leaves in southwest Ohio. Early instar larvae are gregarious, feeding side-by-side in large groups across the leaf surface. Their handiwork produces one of the best examples of leaf skeletonizing, with even the smallest veins remaining intact. Later instars disperse, feed separately, and consume entire leaves.
Although larvae of all instar stages are covered with stiff white hairs, which may cause a rash when handled, there are different color forms. All color forms are variations of a black on white motif and range from thin black stripes across the back (tiger striping) to a row of black spots down the back. Most color forms also have two prominent side-by-side tufts of long black hairs immediately behind the head which is typical for a tussock moth caterpillar. In past years, these caterpillars have been responsible for heavy defoliation of oaks in southern Ohio.
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PINE BARK ADELGIDS - A FUZZY PROBLEM
Pam Bennett reported receiving a call regarding control of pine bark adelgid (Pineus strobi) on a white pine in a Clark county landscape. This aphid relative sinks its sucking mouthparts into the bark of twigs, branches, and main stems of many species of pines, but they have a particular affinity for eastern white pine. Adult females cover themselves with waxy, white, fuzzy material. Trunks of heavily infested pines may appear flocked. High populations of this sucking insect can cause a gradual decline of heavily infested trees.
The pine bark adelgid is difficult to control using standard insecticides. It has a complicated life-cycle making application timing a challenge, and the waxy flocculent material interferes with insecticide penetration to the insect. However, the fragile puffballs are no match for a concentrated stream of water which dislodges the adelgids and plunges them to certain doom..."what a world, what a world!" The water pressure available in most homes is sufficient to wash adelgids from small trees. Larger trees may require the use of a pesticide sprayer, without the pesticide. Machines delivering high pressure water for cleaning purposes are not recommended because they may dislodge bark, along with the adelgids, damaging the tree.
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SCALE CONTROL
Curtis Young noted that he received a report from an Extension Educator of heavy infestations of a cottony scale blossoming in several towns in northwest Ohio. There are two "cottony scale" insects that are becoming evident right now in Ohio: the COTTONY MAPLE SCALE (Pulvinaria innumerabilis) and the COTTONY MAPLE LEAF SCALE (P. acericola). Both are becoming evident because the females are exuding their conspicuous, elongated, white, cottony ovisacs which may contain over 2,500 eggs. Cottony maple scale ovisacs are found on twigs and branches, while the ovisacs of cottony maple leaf scale are found on the underside of leaves. Despite their common names, both of these scales may infest a wide range of trees and shrubs, beyond their namesakes.
These cottony scales are "soft scales," meaning that they are not covered by a hardened waxy shield. As with all soft scales, they insert their sucking mouthparts directly into phloem tubes and extract sugar water, along with essential amino acids. They void the excess sugar water in the form of sticky "honeydew" that may rain down on twigs, branches, and leaves of their host plant as well as other plants growing beneath the infested host. The honeydew may become colonized by black sooty molds creating an unsightly mess.
BYGLers discussed the management of these soft scale insects, along with CALICO (Eulecanium cerasorum), FLETCHER (Parthenolecanium fletcheri), and EUROPEAN FRUIT LECANIUM (P. corni) scales. Dave Shetlar noted that previous recommendations focused on applying the neonicotinoid insecticide imidacloprid (e.g. Merit) as a soil drench in the fall to control the third instar nymphs of these soft scales. This stage settles, feeds, and overwinters on the bark of twigs and branches. Dave updated this recommendation by indicating excellent results have been achieved by making the application now to target the first and second instar nymphs as they settle and feed on leaves. Indeed, he reported that results may actually be better because these early instar stages are more susceptible to the insecticide.
The discussion focusing on soft scale management also generated a brief dialogue regarding management of hard scales (e.g. armored scales). These sucking insect have been notoriously difficult to control, with efforts primarily focused on targeting first instar nymphs (crawlers). The application timing is critical. Imidacloprid has not been effective in controlling this group of insects. However, Dave noted that a new third generation neonicotinoid insecticide dinotefuran (e.g. Safari) has been providing promising control in research studies of certain armored scales and deserves a close look by nursery producers and landscapers.
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GYPSY MOTH NUMBERS BECOMING MORE EVIDENT
Both Amy Stone and Dave Shetlar mentioned the gypsy moth in their BYGL reports this week. Numbers in the Toledo area remain relatively low, but infestations seem to be expanding beyond the known hot spots, as caterpillars are being detected in numerous monitoring bands across the county where they had not been found before. Pam Bennett reported that gypsy moth calls have been almost silent in Clark County following a high number of gypsy moth egg masses that triggered an Ohio Department of Agriculture treatment earlier this spring.
As the caterpillars continue to feed and grow and feed and grow, they become more evident and property owners begin to notice this annoying leaf eater. Dropping leaf litter and falling frass can put a damper on outdoor festivities. Treatments for control of the insect are most effective at early instars. For more information on this insect pest, check out OSU Extension HYG FactSheet, 2173 - "Gypsy Moth in Ohio Landscapes."
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WHO'S KNOCKING AT THE DOOR?
Curtis Young in NW Ohio received an unusual specimen to identify this past week. The specimen to be identified came not from a landscape, but from a warehouse and the specimen was accompanied by a couple of chunks of trim boards. The company who provided the materials and the insects was a door and trim installation company. Their concern was that they discovered several of these beetles around a stack of trim boards they had been using on a number of their jobs. Upon investigating a little more closely, they determined that the beetles were emerging from the interior of several boards in their stack. Thus, if they were emerging in the warehouse, they could also be emerging from boards that had been installed on job sites.
Curtis identified the insect as a beetle belonging to the Family Bostrichidae. The BOSTRICHID BEETLES are branch and stem borers in nature. Some members infest raw lumber while it is being air dried to season it. The larvae bore through the wood producing circular tunnels that follow the grain of the wood and are packed with frass and sawdust. The adult beetles range in size from 1/4 - 1/2" in length. Most of the beetles in this group are elongate and somewhat cylindrical, and the head is bent down and scarcely visible from above. The beetles collected in this case were about 1/2" in length. At this point, one may be wondering why this is of any importance to a landscape oriented newsletter. Well, as Paul Harvey says, "Now for the rest of the story!"
The wood used to produce the trim was imported from overseas, possibly Indonesia, into California, then it was distributed to other states, including Ohio. Thus the bostrichid beetle may very well be an introduced exotic beetle. Curtis contacted Dave Shetlar for more information about the beetle. Dave suggested that the beetle is one that has been identified from other samples of wood from overseas (e.g. wooden handles on a barbeque tool set received by Barb Bloetscher in the CWEPPD clinic. Even though a probable identification was made on the beetle, Dave highly recommended that the specimen, including the wood, be sent to clinic so that it would be properly recorded and reported to the appropriate authorities. The reason for taking the extra step in this case is to make sure the beetle gets an absolute identification so any quarantine actions that might be needed are set in motion as soon as possible. Dave also recommended that the infested wood be destroyed (burned) to limit or prevent any further introduction of the insect beyond the warehouse where it was discovered.
The take home message of this story is, if you discover an insect or other animal or plant that looks out of place, different than ever seen before or causing damage never seen before, collect a sample if possible, get it identified and take the extra step to send it to the CWEPPD clinic so that it can be officially recorded through the proper channels. This is the only way to discover and react in a timely manner to newly introduced exotic organisms. It may turn out to be nothing at all or it just might be the next emerald ash borer. Who's knocking at your door?!
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DISEASE DIGEST
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FIREBLIGHT ON CALLERY PEAR
Around the state, fireblight on callery pears is a problem this year in sites where these pears were in bloom during warm wet weather. This has resulted in a number of calls to BYGLers, requesting the latest data on the pears that are most susceptible to least susceptible to fireblight. With this type of data, rational re-plant decisions can be made. BYGLers certainly have observed that 'Aristocrat' appears to be relatively highly susceptible compared to other callery pears, but beyond that, detailed data is hard to find.
Fireblight tends to be a bigger problem in nurseries than in landscape settings due to the buildup of inoculum in large plantings. There is also an increased tendency for fireblight development on trees in nurseries where there is higher nitrogen nutrition to further growth. It has also been observed that callery pears are relatively tolerant of fireblight compared to some edible pears that can be killed by the fireblight bacterium, Erwinia amylovora. Typically, although fireblight can cause considerable dieback in bad years, the plants recover.
The question remains as to which cultivar to recommend for lower or no incidence of fireblight. What is needed is a replicated, randomized evaluation plot. As a matter of fact, an ornamental pear (Pyrus calleryana cultivars, Pyrus faurei types, et al) evaluation plot is in the planning stages at OSU‛s Ohio Agricultural Research and Development Center‛s Secrest Arboretum.
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APPLE SCAB - ACT 1
Every summer, Erik Draper and Jim Chatfield rate crabapples for apple scab and other diseases monthly in the Crablandia plot at OSU‛s Secrest Arboretum in Wooster (new Ohio Crablandia projects also underway in OSU Extension Centers in Piketon and Lima). The first rating for 2005 was this past Tuesday and early results are in and they include the following details.
Compared to recent years, overall apple scab incidence in the plot to this point is down. Of the 77 cultivars, 31 are exhibiting no symptoms of apple scab at this time. Defoliation of severely affected plants is just beginning. Most of the leaf drop on crabapples in the past several weeks was due to frogeye leaf spot rather than scab (e.g. on 'Professor Sprenger' and 'Spring Snow'). The biggest surprises thus far are scab on 'Bob White', something virtually never seen before in these plots and an unusual amount of spotting from frogeye leaf spot on 'Coralburst'. Fireblight strikes on crabapples in the plot are rare this year, probably due to the lack of extended warm wet weather during bloom for most of the cultivars.
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BROWN BERRIES NEED STRAW
Erik Draper reported some strawberry fields were having problems with both green and red strawberry fruit turning brown. When sampled for taste, these fruits had a bitter, oily, terrible flavor. This was the classic symptom of the fungal disease called LEATHER ROT. Leather rot is caused by the soil-inhabiting fungus Phytophthora cactorum that causes immature and ripening fruit to discolor. The leather rot fungus may also infect blossoms, but it primarily attacks the fruit.
Unfortunately, this fungus can infect berries at any stage of development. During serious outbreaks of this disease, infection of green fruit is common. On green fruit, diseased areas may be dark brown or the typical green outlined by a brown margin. As the rot spreads, the entire berry turns brown, with a rough texture, and its appearance is leather-like. Leather rot is much more difficult to detect on ripe fruit. On fully mature berries, symptoms vary from very little color change to complete discoloration that ranges from brown to dark purple. Picking this infected fruit will cause fingers to be stained a yellow-brown color, rather than the typical deep red of ripe berries. Infected ripe fruit tends to be softer to the touch than healthy fruit.
When weather conditions are warm and rainfall is abundant, the pathogen releases its spores into the soil. These infested soil particles may infect roots but are most often dispersed onto the fruits by splashing rain, wind and even overhead irrigation. Leather rot, therefore, is most commonly found in poorly-drained areas where there is or has been free-standing water and the berries are in direct contact with the soil. Several fungicides are labeled for leather rot control, but these are generally not available at local garden centers. The best way to avoid problems with leather rot on strawberries is to avoid planting in areas that remain wet and to use raised beds or even a raised row type of planting. The best and easiest way to avoid leathery brown, bitter berries is to use a straw mulch layer, about 2 - 3" deep to keep the berries from ever coming into contact with splashing soil.
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ANGULAR LEAF SPOT ON CUCURBITS
Erik also reported that commercial vegetable growers are dealing with a disease that is spotting leaves of zucchini, cucumbers and even some pumpkins. Angular leaf spot is difficult to control because it is a bacterium, specifically Pseudomonas syringae pv. lachrymans. This disease can affect leaves, stems, and fruit. To identify this nuisance of vine crops, closely examine the lesions or spots on the leaf. The bacterium causes angular, watersoaked areas which later turn brown or straw-colored and eventually, in some areas, the lesion dries clear and thin, almost like tissue paper. Leaf lesions are delimited by the veins, hence the sharp, angular appearance of the lesions. Affected leaf tissue often dries and drops out, leaving irregularly shaped holes in the leaves. Heavily infected leaves may turn yellow. Lesions may also occur on petioles and stems.
On fruit, the bacterium causes circular spots. These spots often crack open and turn white in color. Rot may extend internally and predispose infected fruit to secondary infections like bacterial soft rot.
This bacterium can overwinter in the seed and on infected plant debris. Seed-borne bacteria spread to the cotyledons when the seed germinates. Splashing rain spreads bacteria from infected plant debris to plant parts and from plant to plant. The organism is easily spread in the field by cultural practices and by wind-blown rain. Angular leaf spot infection periods occur between 75 - 82F (24 - 28C) and are favored by high humidity and/or precipitation.
Copper sprays may be used but are probably most useful after rain or wind storms. They will not prevent further infections if environmental conditions favor disease development. The best control is genetic resistance and dry weather.
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TURF TIPS
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MANAGING TURF IN DROUGHT-LIKE CONDITIONS
Unseasonably hot, dry weather has been a challenge for turf managers in Ohio. Daytime air temperatures in the mid-80F and low humidity (29% relative humidity today) means the turf is drying out at a super fast rate. Evapotranspiration (ET) rates are around 2/10ths inch per day. Perennial ryegrass (Lolium perenne), Kentucky bluegrass (Poa pratensis) and, to a lesser extent, tall fescue (Lolium arundinaceum, formally Festuca arundinacea) are all looking droughty and are starting to wilt if not irrigated.
Some turf actually looks worse than others, depending upon whether the turf was adequately fertilized, mowed, and irrigated prior to the stress period. Soil type is also influential - fine textured soils prone to compaction severely restrict turf root growth, which in turn leads to shallow rooting and poor drought tolerance. Tall fescue has such great drought tolerance because of its extensive root system.
Perennial ryegrass and Kentucky bluegrass are both grasses that prefer an optimum air temperature between 60 - 75F and a soil temperature of 50 - 65F . Outside these parameters they become stressed. In particular, as soil temperatures get above 75F, around 50% of the root system is lost. It's important, therefore, to do as much as possible to maximize turf health. Tips include:
* Restrict any kind of stressful cultivation practices such as verticutting and aerifying etc.
* Keep foot and vehicular traffic off non-irrigated turf as much as possible.
* Avoid liquid broadleaf herbicide applications on drought stressed turf as it may increase stress.
* Do not apply quick-release fertilizers on non-irrigated turf.
* Grasses can stay dormant for several weeks and recover, but the plant crowns must be kept hydrated by watering deeply every 2 - 3 weeks.
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INDUSTRY INSIGHT
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BLACK VINE WEEVIL AND DIAGNOSTIC LOOK-A-LIKES
Randy Zondag noted that black vine weevil (BVW)(Otiorhynchus sulcatus) adult emergence is beginning to peak in northeast Ohio, and populations are heavy this season in that part of the state. Adults feed on foliage and produce notches on leaf margins. This damage reduces the aesthetic value of the plant, but seldom causes significant damage to the overall health of the plant. However, BVW larvae consume roots and girdle below-ground stems which may kill plants. Damage caused by the high larval populations that preceded this heavy adult activity may mimic symptoms caused by other plant problems such as voles, excessive moisture, or root-rotting fungi. Randy cautioned that growers should conduct thorough whole-plant examinations of dead or dying plants before drawing diagnostic conclusions.
BVW larvae consume roots, and high populations can reduce root systems to a small fraction of their original volume. Once larvae exhaust root-rations, they may focus their ravenous attention on below-ground stem tissue. The larvae consume bark and phloem, girdling the plant and leaving the xylem exposed. This damage may superficially resemble vole damage, except a vole's incisors are much larger than a weevil's mandibles. Voles produce very obvious cuts, scrapes, and gouges etched into the xylem. Root-rotting fungi kill roots, but the decaying root system usually remains evident for some time after the deed is done. It does not vanish, as in the case with weevil larval feeding activity.
Although over 100 plant species may be subject to BVW larval feeding damage, the most significant damage occurs in nurseries. Established landscape plants are seldom killed by BVW. Since adults emergence has been occurring for some time, it is too late for control measures to prevent all leaf notching damage. The current recommendation for the prevention of leaf notching damage on highly susceptible plants in nursery production, such as as rhododendrons, Taxus, and hemlocks is to spray with Talstar (bifenthrin), followed in 2 weeks with Guthion (azinphos-methyl), then again in 2 1/2 weeks with Talstar.
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COMING ATTRACTIONS
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"LEARN HOW TO "NAME THAT TREE"
OSUs Chadwick Arboretum has hundreds of trees, so its a good place to learn to identify them. An Ohio Woodland Stewards Program workshop on Friday, August 12 will show how to do just that. "NAME THAT TREE" covers common Ohio species like oaks, maples, buckeyes (of course) and others, as well as how to identify them. The program begins on the OSU campus at the Agricultural Administration Building, 2120 Fyffe Road, Columbus at 9:00 a.m.
The morning program features an introduction to tree identification, instruction on using a taxonomic key, and practice time with samples. A hands-on field trip fills the afternoon, giving participants plenty of time to practice their new skills.
Registration, due by Monday, August 8, is $30.00 per person and includes lunch and breaks. Make checks payable to The Ohio State University and send, together with the name and address of each person registering, to Ohio Woodland Stewards Program, School of Natural Resources, Ohio State University, 2021 Coffey Road, Columbus, OH 43210. Online registration is available at woodlandstewards.osu.edu, or contact (614) 688-3421 or ohiowoods@osu.edu.
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BYGLOSOPHY
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Now that summer is here, force yourself to take a break and enjoy the fruits of your labors this past spring.
As Jim Chatfield always quotes -
"The true voyage of discovery lies not in finding new landscapes,but in having new eyes" (Marcel Proust). Make yourself leave your daily grind and visit other gardens - you'll come back renewed, rejuvenated, and eager to work again!
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