This is the 15th 2009 edition of the Buckeye Yard and Garden Line (BYGL).  BYGL is developed from a Tuesday morning conference call of Extension Educators, Specialists, and other contributors in Ohio.

BYGL is available via email, contact Cheryl Fischnich This e-mail address is being protected from spambots. You need JavaScript enabled to view it to subscribe.  Additional Factsheet 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 ONLA (Ohio Nursery and Landscape Association) http://onla.org/ ; http://buckeyegardening.com/ to the OSU Extension Nursery, Landscape and Turf Team (ENLTT).  Any materials in this newsletter may be reproduced for educational purposes providing the source is credited.

BYGL is available online at:  http://bygl.osu.edu, a web site sponsored by the Ohio State University Department of Horticulture and Crop Sciences (HCS) as part of the "Horticulture in Virtual Perspective."  The online version of BYGL has images associated with the articles and links to additional information.

Following are the participants in the July 13th conference call:  Barb Bloetscher (Entomology/C. Wayne Ellett Plant and Pest Diagnostic Clinic (CWEPPDC)); Joe Boggs (Hamilton); Jim Chatfield (Horticulture and Crop Science and Plant Pathology); Erik Draper (Geauga); Dave Dyke (Hamilton); Gary Gao (Delaware); Dave Goerig (Mahoning); Bridget Meiring (CWEPPDC); Dave Shetlar (Entomology); Amy Stone (Lucas); and Curtis Young (Hancock).

In This Issue:

1. WEATHERWATCH.
2. HORT SHORTS:  Vegetable Gardening 101 - July 15, 2009 - Black Walnut Toxicity of Tomatoes; and Plants of the Week:  Annual (Cosmos), Perennial (Coral Bells), Woody (Arborvitae), and Weed (Dodder).
3. GREEN SHORTS:  What Is A Rain Garden? 
4. CLINIC CLIPS.
5. BUGBYTES:  Yellownecks Arise (Yellownecked Caterpillars); Giant "Pinching" Beetles (Stag Beetles); Fleecy Flatids (Planthoppers); Cypress Twig Galls; Chigger Challenge; and Bag Full of Surprises (Bagworms).
6. DISEASE DIGEST:  Mistaken Tomato Diseases.
7. TURF TIPS:  Turf Insect Pest Report.
8. INDUSTRY INSIGHTS:  Optimal Timing of Treatment Options Imperative When Battling the Borer (EAB). 
9. COMING ATTRACTIONS:  The OSU Chadwick Arboretum Open House; Greater Cincinnati Branch of the Professional Grounds Management Society Annual Regional Meeting and Site Visitation; Northwest Ohio Green Industry Summer Session; Pesticide Applicator Training Offered; Wood Destroying Insect Inspection Training; and Dates Set for Commercial Applicator Recertification Conferences. 
10. BYGLOSOPHY.

1.  WEATHERWATCH. 

The following weather information summarizes data collected at various Ohio Agricultural Research Development Center (OARDC) Weather Stations spanning the dates:  July 1-July 15, 2009, with the exception of the soil temperatures which are readings from Wednesday, July 15, 2009 at 6:05 p.m.

While some areas of the state have received recent rains, other areas remain very dry.  Amy Stone reported that soil in the Toledo area is dry, although year-to-date totals remain above average (+3.50").  Jim Chatfield reported that the Wooster area's year-to-date (nearly -4"), and monthly totals are both below average.

For a link to the OARDC Weather Stations, visit:  http://www.oardc.ohio-state.edu/centernet/weather.htm

2.  HORT SHORTS.

A.  VEGETABLE GARDENING 101 - JULY 15, 2009 - BLACK WALNUT TOXICITY OF TOMATOES. 

Gary Gao talked with a home gardener who had wilting tomato plants.  After going through some of the usual suspects, such as Fusarium and Verticillium wilts, watering practices, etc., Gary asked her whether there were any black walnut trees near her tomato plants.  She said "yes."  Gary told her that black walnut toxicity is the most likely cause of her tomato problem.  The tomatoes were planted within 20' of the black walnut tree.  The plants that are closest to the tree are stunted and wilting.  The tomatoes that are furthest away from the walnut look quite normal so far.

The roots of black walnut (Juglans nigra) and butternut (J. cinerea) produce a substance known as juglone (5-hydroxy-alphanapthaquinone).  Persian (English or Carpathian) walnut trees are sometimes grafted onto black walnut rootstocks.  Many plants such as tomato, potato, blackberry, blueberry, azalea, mountain laurel, rhododendron, red pine, and apple may be injured or killed within one to two months of growth within the root zone of these trees.  The toxic zone from a mature tree occurs on average in a 50-60' radius from the trunk, but can be up to 80'.  The area affected extends outward each year as a tree enlarges.  Young walnut trees 2-8' high can have a root zone diameter twice the height of the tree.  Susceptible plants within that root zone of these young trees could die, and plants at the margin of the root zone could die or be unthrifty.

Refer to the OSU Extension Fact Sheet, HYG#1148-93, "Black Walnut Toxicity to Plants, Humans and Horses" for more information.  This fact sheet is available online at:  http://ohioline.osu.edu/hyg-fact/1000/1148.html .

For more information, see:

• Black Walnut Toxicity to Plants, Humans and Horses

B.  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 - COSMOS (Cosmos sulphureus and C. bipinnatus).  Looking for an annual that reaches up to 36" high, blooms from early summer until frost, and is easy to grow?  How about one that thrives in the full sun, tolerates dry, porous soils, and requires little fertilization?  Maybe you should include into your garden design next year our featured annual plant of the week, Cosmo sp.  This annual is a member of the Asteraceae, (Compositae) family.  The flowers of both species are simple heads, with 2-3" ray flowers surrounding the disk.  They are available in double forms as well.  Cosmos flowers come in shades of yellows, oranges, reds, whites, rose, and violets.  C. bipinnatus is aptly named for its very finely, cut foliage.  These garden favorites can be easily grown by direct seeding in early to mid May; that is unless you have incorporated a preemergence herbicide into your flowerbed in April.  If you used preemergence herbicides, simply sow your cosmos seed into containers for transplanting.

*PERENNIAL - CORAL BELLS (Heuchera sanguinea).  This rough and ready perennial of the week is in the Saxifragaceae family.  Although hardy to zone 3, coral bells perform best if securely mulched in before winter sets in.  The flowers can be described as tiny bells that hang on to arching cymose panicles.  The flowers arrive in late spring to early summer and are available in reds, pinks, and whites.  Many cultivars have been developed over the years that have given Huechera lovers new looks of colorful foliage all season long.  Coral bells do best in soils with good drainage and good organic matter content.  Locate these plants in full sun or partial shade. *WOODY - EASTERN ARBORVITAE (Thuja occidentalis).  Whether grouped together to screen an unsightly area or planted as a green hedge which will contrast the flowering shrubs in front of it, the eastern arborvitae has been at work in our urban landscape environments for many years.  At times this mainstay is a bit overused but no less important in its functional roll.  Eastern arborvitae is a dense, upright, pyramidal, evergreen, tree that is native to eastern North America.  It will tolerate full sun, acidic or limestone soils, tight shearing, cold temperatures, and once established will survive in heat and drought conditions.  The single trunk specimens are less susceptible to strong wind and heavy snow damage.  Available in many cultivars including the popular slow growing 'Techny', and the compact 'Emerald', a bright, emerald, green foliage that does not discolor in winter like many other forms.

* THE WEEKLY WEED - DODDER (Cuscata spp.).  Dodder is a parasitic vining plant that lacks chlorophyll, so it must extract food and nutrients from a host plant.  Initially, seeds germinate and produce a temporary root system to support a thread-like stalk.  If the stalk makes contact with a susceptible host, modified roots called "haustoria" penetrate the host plant.  The red, orange, or yellow stalks continue to entwine the plant, often covering it under a mat of dodder stems.  There are many species of dodder found in the U.S. and each may attach to a wide range of host plants.  All species of dodder are annuals. 

An ounce of prevention is worth a pound (ton?) of dodder.  Dodder lacks a specific seed dispersal mechanism, so movement to new areas usually occurs through movement of infested plants, contaminated soil or by seeds hitchhiking on shoes or equipment.  Closely inspect transplants for dodder and avoid using soil taken from areas with a dodder infestation.  Thoroughly clean shoes and equipment after working in or around a dodder infestation.  Dodder may be effectively managed through a combination of hand-pulling and applications of pre-emergent herbicides.  It is very important to pull the dodder before the plants produce seed because dodder seed may remain viable for years.

For more information, see:

• University of Minnesota Yard and Garden Brief
• University of California IPM Note

3.  GREEN SHORTS.

A.  WHAT IS A RAIN GARDEN?  Much has been written recently about rain gardens, which are also occasionally called rain water gardens.  Many of these gardens are being installed throughout urban areas in many parts of the country, including Ohio.  However, they are often misunderstood.  A rain garden, first and foremost is a garden!  It is simply a garden designed with a ponding area that will allow it to capture water to nourish its plant life and reduce storm water runoff.  Therefore, it will usually appear as a garden with a sunken area.  

A rain garden should be an attractive landscape feature that is an integral part of a comprehensive landscape design.  It also should be relatively easy to build and maintain, reliably capture runoff water throughout the warm season and also runoff generated from the majority of cold weather thaws, and sustain their performance with few inputs (minimal additions of fertilizer, seasonal pruning, etc.) over the long term.

Just as importantly, rain gardens should not be a bog, wetland, or pond.  Water in a ponding area should be no deeper than 10".  Water should never stand in the garden for more than 40 hrs.  Therefore, a minimum water infiltration rate of 1/2" per hour is required for any rain garden.  If the soil does not provide that infiltration rate, an under drain must be installed or a new site must be chosen.

For further information on rain gardens refer to "Rain Garden Guidelines for Southwest Ohio - A Practical Handbook for Home Gardeners" at:  http://hamilton.osu.edu/.

4.  CLINIC CLIPS.

Bed bug samples continue to wander into the Clinic from Ohio counties as well as springtails (Family Entomobryidae) found in homes.  A recluse spider was identified today from a rail yard office in a northern Ohio county.  It will be sent out for verification of the species.

A chrysanthemum sample which had been recently potted was exhibiting scorch symptoms.  The grower indicated that the rooted cuttings had been held in the cooler for a week before planting when outside temperatures were in the 90's.  Apple scab, frogyeye leaf spot on apple, and pearleaf blister mite on a fruiting pear were identified, while on plum, brown rot was causing fruit to deteriorate.  Black root rot was identified on a holly which exhibited dieback in the spring.

We had asked for a root sample to confirm our suspicion of black root rot which is caused by Thielaviopsis basicola.  A saucer magnolia sample which had black blotches and yellowing on the leaves was infected with powdery mildew.  On tomato, a Pythium problem and pith necrosis were identified.  A sugar maple was diagnosed with maple anthracnose, maple leaf spot or Phyllosticta, and woodpecker damage.  Anthracnose and Phyllosticta are common leaf diseases of maples in Ohio, but the woodpecker damage may signify an insect problem in the tree.  Farmers in Ohio are sending soil samples in to check for soybean cyst nematode in their soybean fields.

5.  BUGBYTES.

A.  YELLOWNECKS ARISE. 

Joe Boggs reported that first instar YELLOWNECKED CATERPILLARS (Datana ministra) are appearing in southwest Ohio.  The caterpillars pass through different "color phases" as they develop.  First instar caterpillars are copper-colored with no distinct lines.  Second instars have distinct alternating longitudinal yellow and orangish-red lines.  Caterpillars in the final instar stage have alternating longitudinal black and yellow lines.  Although all instars are hairy, the hairs are most evident during the last instar stage.  Another notable characteristic is that the caterpillars will lift their anterior and posterior ends to make their bodies "U"-shape when disturbed.

The caterpillars feed gregariously in colonies and their feeding behavior also changes as they develop.  First instars feed as leaf skeletonizers, and later instars consume entire leaves.  The colonies typically focus their attention on defoliating one branch before moving to another.  Small trees with multiple colonies can be rapidly defoliated.  Adding to the potential to produce heavy defoliation, yellownecked caterpillars also have at least two generations per season in northern Ohio and a possible third generation in the central and southern parts of the state.

Yellownecked caterpillars may be found feeding on a wide variety of trees and shrubs including:  crabapples and other ornamental fruit trees, oak, maple, elm, beech, linden, honey locust, azalea, and boxwood.  Early instar caterpillars are susceptible to the biological insecticide, Bacillus thuringiensis (Bt) (e.g., Dipel, Thuricide, or Caterpillar Attack).  More traditional insecticides are needed to control later instars.  Of course, a more direct (satisfying?) control method is to knock the caterpillar colonies to the ground and perform the "caterpillar dance."  Thus far, no populations have developed resistance to this control method.

For more information, see:

• OSU Extension "Bug Doc" Fact Sheet
• Penn State Entomology Notes

B.  GIANT "PINCHING" BEETLES. 

Joe also reported that participants in this week's Southwest Ohio BYGLive! Diagnostic Walk-About were captivated by a COMMON STAG BEETLE (Psuedolucanus spp.) that was brought to the program to stimulate thoughtful discussion and/or wreak havoc.  There are 30 species of stag beetles in the U.S. and the species living in Ohio are some of the largest beetles found in the state.  The reddish brown to black beetles may measure over 1 1/2" in length.

All male stage beetles have prominent, forward thrusting mandibles.  The mandibles are used like jousting lances in altercations between rival males.  Some species, such as the ELEPHANT STAG BEETLES (Lucanus spp.) have enormous branching mandibles that resemble a stag's horn, thus the common name.  Common stag beetles have scary looking sickle-shaped mandibles that appear capable of cutting flesh.  However, their alternate common name of "pinching beetles" speaks to the true capabilities of these melodramatic mandibles.  Of course, no BYGLive! participant stepped forward to test the validity of the alternate common name.

Stag beetle larvae feed on decaying wood and are considered a beneficial member of forest ecosystems owing to their important role in nutrient recycling.  Adults appear to do little feeding with the ornate mandibles of the males limiting their feeding to plant sap or honeydew exuded by aphids.  Females do feed on leaves; however, they cause little damage and are not considered a significant pest.  The beetles are sometimes considered a nuisance pest owing to their attraction to porch lights at night where they may scare the beejeebers out of unsuspecting homeowners.  Indeed, BYGLive! participants discovered the beetles have great entertainment value.

For more information, see:

• University of Kentucky Fact Sheet
• Texas A&M Fact Sheet

C.  FLEECY FLATIDS. 

Participants at this week's BYGLive! in southwest Ohio observed the white, fleecy handiwork of PLANTHOPPER nymphs on the lower stems of herbaceous perennials and low-growing woody ornamentals.  Planthoppers belong to the Family Flatidae (Order Homoptera), and are sometimes referred to as "flatids."   The nymphs of several flatid species cloak themselves in a dense tangle of waxy, white "fluff."  They also congregate in groups, or "colonies," and their profusion of flocculent material on affected plant stems draws attention to the insects.  The nymphs also produce copious quantities of honeydew which may coat the plant and become colonized by black sooty molds.

Planthoppers are related to aphids and the nymphs are sometimes mistaken for woolly aphids.  However, planthoppers … hop.  Aphids just mosey around.  Planthopper adults are 1/4- 3/8" long, purplish blue, lime green, or powdery white, and they hold their broad wings vertically in a tent-like fashion covering the sides of the body and legs.  They usually have little impact on the overall health of landscape plants and seldom become more than a nuisance pest.  If management is required, any insecticide labeled for use on the affected plant will be effective.  A course stream of water will also do the trick.

For more information, see:

• University of Minnesota IPM of Midwest Landscapes

D.  CYPRESS TWIG GALLS. 

Joe Boggs reported that the galling handiwork of Taxodiomyia cupressiananassa, a tiny midge fly with a large scientific name, is becoming evident on baldcypress in southwest Ohio.  The spongy, elongate, 1/8" - 1/2" long galls produced by the fly appear white due to a covering of fine, powdery material.  Rubbing the powder off the galls reveals their true light green color.  The galls arise from the base of leaflets.  Needle growth extends through the galls with the needles protruding beyond the surface of the galls.  A portion of this season's growth usually extends beyond the tips of the galls.

Opening the galls will reveal the tiny, orangish-yellow midge fly larvae (maggots) that directed gall formation.  Each maggot is individually housed in its own tiny compartment.  Once maggots pupate, and a new set of adults emerge, the galls will eventually shrivel and detach from the trees.  At this time, the leaflet growth extending beyond the gall will sometimes die and turn reddish brown producing an unsightly appearance.  Adult flies emerge from the fallen galls on the ground.

The flies may have two generations per year with a second set of galls appearing in late-July or August.  The second generation gall-makers spend the winter on the ground as pupae in fallen galls.  Although the galls and browned-tipped foliage may reduce the aesthetic appeal of infested trees, the flies appear to cause no appreciable harm to the health of the tree.  Populations are often regulated by a wide range of parasitoids that target the maggots.  Therefore, insecticide applications are not recommended.  Pruning and destroying galls now on small trees will reduce the number of future galls.

For more information, see:

• University of Florida Creature Feature

E.  CHIGGER CHALLENGE. 

Several BYGLers noted that chiggers (Trombicula alfreddugesi) encounters are on the rise in central and southern Ohio.  Chiggers are mites with an unusual life cycle.  The chigger life stage that bites humans and animals is the six-legged "larval" stage that hatches from eggs.  All other life stages (nymphs and adults) have eight legs.  Both the nymphs and adults feed on insects.

Contrary to popular belief, chiggers do not burrow into the skin.  Instead, they stay on the surface of the skin and crawl to the base of a hair follicle to feed.  Once settled, the larva injects the skin with digestive fluids using its piercing, sucking mouthparts (capitulum), and then they ingest the resulting "cell puree".  Some people are highly sensitive to the chigger's feeding activity, and their skin will swell and surround the larva.  This often kills the chigger, and the dead larva found within the swollen skin gives rise to the misconception that chiggers burrow into the skin.

Chiggers are usually associated with spring and early summer; however, they can undergo three generations per year in warm climates.  To avoid being the victim of chiggers, avoid walking through brushy areas or wear long white pants with the socks pulled over the pant legs.  Insect repellents such as DEET can help to ward off chiggers.  It takes several hours for the chiggers to settle, so bathing immediately after hiking in weedy areas can significantly reduce the number of bites.  Calamine lotion and similar products will help to reduce itching and the risk for subsequent skin infections.

Insecticides can be sprayed to control chiggers.  For the best results, target areas where chiggers are most likely to converge, such as fence rows and garden edges where shrubbery is dense.  Products containing bifenthrin (e.g. Ortho Home Defense MAX), carbaryl (e.g. Sevin), cyhalothrin (e.g. Spectracide Bug Stop Indoor and Outdoor Insecticide), and permethrin (various brands) are effective.  A single application in May is often sufficient, although if they are still a problem treat again in June.  Cover the ground and vegetation up to a height of around 3 feet with the product.

For more information, see:

• University of Kentucky Entomology Fact Sheet
• University of Florida Fact Sheet

F.  BAG FULL OF SURPRISES. 

A couple of BYGLers reported that they had clients bringing in samples of "dying" arborvitae to have them diagnose why their plants were going "downhill" and fast.  While probing the clients for additional information about the arborvitae (i.e. site conditions, winter injury, etc. ("The 20 Questions of Plant Diagnostics")), the samples rested on the counters awaiting their turn to be more closely examined.  But, before too long the causative agents of the arborvitae's demise revealed themselves . . . BAGWORMS!  Up until now the bagworms' (Thyridopteryx ephemeraeformis) feeding has been overlooked because the very small, early instar larvae (caterpillars) produce damage slowly, but now they have reached the point in their growth and development that they are rapidly eating the foliage of their host plants to the extent that their damage is becoming evident even to the casual observer.  Although it may appear to the casual observer that the plant is thinning and turning brown for no apparent reason, once inspected more closely one could see the caterpillars as they move around on the host plant and stick their heads out of their bags to feed.  The sizes of the bagworm bags range from 1/2" to 3/4".

We are fast approaching the time that branch death of the most susceptible plants (e.g. arborvitae) can result from bagworm feeding!  Thus, if you have not inspected plants for bagworm yet, you need to do it soon.  Fortunately, the larvae still have to feed and a foliar application of one of several different insecticides will still stop them from producing any more damage.  At this time it may be too late to use the biological insecticide Bacillus thuringiensis or Bt (e.g., Biobit, Dipel, Thuricide, Caterpillar Attack).  The more traditional insecticides may need to be used to get satisfactory results.  However, don't wait till late in the growing season to manage the bagworm, because even the traditional insecticides lose their effectiveness against the large bagworms.  Refer to OSU Extension Bulletin 504, "Insect and Mite Control on Woody Ornamentals and Herbaceous Perennials" for details on effective insecticides. One additional note to make is that conifers are not the only plants that these pests feed on.  Conifers are just the plants that can be easily killed by the bagworm feeding!  Bagworms can feed and thrive on a long list of deciduous trees and shrubs as well such as sycamore, crabapple and honeylocust trees.  These trees may not be killed by the bagworm, but they can make them look very bad in the landscape and they can act as the refuge where the bagworms survive to spread back to treated conifers in future growing seasons. For more information, see: OSU Extension FactSheet on Bagworm University of Kentucky FactSheet on Bagworm

6.  DISEASE DIGEST.

A.  MISTAKEN TOMATO DISEASES.

Erik Draper reported visiting a commercial vegetable grower who was concerned that the late blight fungus had infected his acres of tomatoes.  After careful scrutiny of the disease symptoms, the problem turned out to be SEPTORIA LEAF SPOT caused by the pathogen Septoria lycopersici.  This fungal disease is easily identified by the distinct circular spots featuring a dark border or margin with a tan center.  Using a hand lens, in that tan center of an older lesion, it is possible to see little black, pimple-like structures called pycnidia.\ Usually older, mature leaves near the ground begin to show symptoms first; however, in warm rainy weather, symptoms will rapidly appear on younger foliage and stems.  Heavily infected leaves will turn yellow and drop prematurely.  Although Septoria leaf spot is mainly a disease of the foliage and stems, the rapid leaf loss will expose developing fruits, subjecting them to sunscald.  Control of this fungus is easily achieved with most foliar fungicides used by commercial growers and homeowners can get excellent control with any fungicide containing chlorothalonil.  Practice good sanitation by keeping the garden weed-free and cleaning up or plowing down the previous season's tomato crop debris and rotating planting areas.

For more information, see: OSU FactSheet on Septoria Leaf Spot of Tomatoes Cornell University FactSheet on Septoria Leaf Spot of Tomatoes

7.  TURF TIPS.

A.  TURF INSECT PEST REPORT.  Dave Shetlar provided the following update on turfgrass insect pests.

• The "summer cats" such as BLACK CUTWORMS (Agrotis ipsilon) are beginning to show up on golf courses in central Ohio.
• The number of SOD WEBWORM (Parapediasia teterrella) adults finding their way into Dave's black light traps in central Ohio is declining which means caterpillars should be showing up in about two weeks.
• Dave noted that turfgrass managers should be monitoring for second generation HAIRY CHINCH BUGS (Blissus leucopterus), particularly in the southern part of the state.
• The application window for applying neonicotinoid WHITE GRUB control products remains open.  Turfgrass with a history of grub infestations should be targeted.  Dave cautioned that the turfgrass should be actively growing at the time of the application which means irrigation may be required in areas of the state where dry conditions have caused the grass to become dormant.

8.  INDUSTRY INSIGHTS.

A.  OPTIMAL TIMING OF TREATMENT OPTIONS IMPERATIVE WHEN BATTLING THE BORER.

OSU scientists and BYGLers have received several questions in recent weeks regarding the timing of insecticide treatments for EMERALD ASH BORER (EAB) from industry professionals.  Dan Herms has authored this article detailing issues related to the timing of insecticidal options for commercial applicators. EAB can be controlled effectively with insecticides, but as with any pest, optimal timing is required to achieve best control.  Optimal timing of imidacloprid soil treatments is early- to mid-spring (April-mid-May).  Research has shown that fall treatments can also be effective.  Optimal timing of dinotefuran soil treatments is mid-April to late May, while basal trunk sprays should be made between early May to mid-June.  Optimal timing of trunk injections is early May (after trees have leafed out) through mid-June. Treatments should be applied on the earlier side of this schedule in southern Ohio.

There seems to be a common misconception that these timing recommendations are based on the effects of soil moisture on uptake and distribution of systemic insecticides.  This is not the case.  Rather, timing recommendations are based upon the insect's life cycle and differential susceptibility of young verse older larvae.  The objective of insecticide treatments is to prevent larvae from establishing by rendering the tree toxic before adults begin feeding on foliage and eggs begin to hatch.  Adult emergence begins when black locust trees bloom (early to mid-May in southern Ohio to late May in northern Ohio), and peaks just a couple of weeks later.  Peak egg hatch and larval establishment occurs between late May and late June.  No doubt, there is still some egg laying occurring into July, but this would be the tail-end of this year's infestation.  As a general rule, young larvae are much more susceptible to insecticides than are older larvae.  For example, imidacloprid soil treatments are much more effective against white grubs in lawns when applied preventatively at egg hatch, and are much less effective as curative treatments targeted at late instar grubs.

The basis for timing recommendations is based on empirical research.  Research Michigan State University scientists showed that imidacloprid trunk injections made in mid-May were more effective than those made in mid-July.  Amount of uptake was not an issue in this case, as they know how much went into the tree.  Furthermore, trunk injections are distributed through the tree faster than soil treatments.  Uptake and distribution would be even slower with a soil treatment, suggesting that for soil treatments, May applications would be even that much more effective than July treatments.  

Optimally, applications should be made in time to allow adequate uptake and distribution of the insecticide in tree to render it toxic before larvae begin establishing so that neonate larvae encounter a lethal dose as they enter the tree.  Hence, the recommendation for soil treatments is to be completed by mid-May in northern Ohio.  Given that imidacloprid soil treatments require 3-6 weeks for uptake, depending on tree size, treatments made in mid-July would not be effective until early August.  By this time, there would be substantial damage and many larger instars present that are less susceptible.  Furthermore, with late applications, there would be no benefit of control of adult EAB feeding on foliage before they lay their eggs, which may also provide a significant degree of protection, as adult feeding activity would have long since peaked.  With each passing day now, more and more EAB larvae are becoming less susceptible to insecticides, and more and more damage is being done to the tree's vascular system.

With that said, if an infested tree is first discovered in late June or early July, there may still be some benefit to treatment.  However, consider a treatment approach that would maximize rate of uptake.  Uptake of dinotefuran is much faster than that of imidacloprid because it is much more soluble.  Basal trunk sprays with dinotefuran may be taken up faster than dinotefuran soil treatments.  Trunk injections will be taken up faster than soil treatments, assuming the injections can be made under conditions favorable for high transpiration (e.g. sunny day, adequate soil moisture, moderate humidity and air temperature), but will still likely take one to two weeks to become effective.

If treatments are made now, the client should be made aware that this timing is less than ideal, and that they should expect that the tree will continue to decline next year before it begins to show improvement in the second growing season after initiation of the treatment program.  This will be true when starting any treatment regime for a tree already showing decline when treatment begins. Furthermore, treatments will have to repeated again in fall or next spring to provide control of next year's generation of larvae.  The exception is emamectin benzoate trunk injections, which will still be effective next year, and possibly even through 2011.  However, if this treatment is delayed until next spring, then control might be achieved through 2012, thereby providing control of three generations of EAB with a single application. 

For additional information on insecticide options for EAB, check out this link on the OSU/OARDC's Ashalert website at: http://ashalert.osu.edu/userfiles/NC-IPM%20EAB%20Bulletin%20Insecticide%20Bulletin%20v2_12June09(1).pdf

For more information, see:

• Insecticide Options for Protecting Ash Tree from Emerald Ash Borer

9.  COMING ATTRACTIONS.

A.  THE OSU CHADWICK ARBORETUM OPEN HOUSE takes place Sunday, July 19, 2009 from 2:00-5:00 p.m.  Enjoy root beer floats, music and garden tours - this is a free event!  Location: Howlett Hall, 2001 Fyffe Ct., Columbus, OH 43210

B.  GREATER CINCINNATI BRANCH OF THE PROFESSIONAL GROUNDS MANAGEMENT SOCIETY (PGMS) ANNUAL REGIONAL MEETING AND SITE VISITATION is scheduled for July 23 and 24, 2009 in Cincinnati, Ohio.  Program information, schedules, and registration forms are available on the PGMS website at: http://www.pgms.org .

C.  NORTHWEST OHIO GREEN INDUSTRY SUMMER SESSION.  Remember to SAVE the date for the 12th annual Northwest Ohio Green Industry Summer Session on August 5, 2009. The event will be held once again at Owens Community College.  We are especially pleased of this year's great line up of speakers: OSU Extension; Pam Bennett, Dr. Dave Shetlar, Jim Chatfield, Gary Gao, Joe Rimelspach, and Joanne Kick-Raack; Dr. Roger Funk, The Davey Institute; Stephanie Miller, ODNR; and Matt Ross, Toledo Botanical Garden.

Once again we will have a three hour manager session with Dr. Bernie Erven, OSU Extension, Columbus, Ohio, working with you as you look at Managing for Success.  This session will be both informative and very interactive as you look at your business and where you want to grow.

Continuing education credits will be given for ONLA certified technicians, ISA recertification, OLA, and Master Gardener recertification.  Contact OSU Extension, ABE Center at 419-354-6916 or http://abe.osu.edu/upcoming-events for more information.

D.  PESTICIDE APPLICATOR TRAINING OFFERED.  Trained Serviceperson and New Applicator Commercial Schools are planned for August 26, 2009 and September 30, 2009.  These sessions will be taught at the Ohio Department of Agriculture (ODA) in Reynoldsburg, Ohio.  For additional information on these schools, and other educational opportunities, check out the Pesticide Education website at http://pested.osu.edu .

E.  WOOD DESTROYING INSECT INSPECTION TRAINING.  Mark your calendars for training on September 16, 2009.  This training will be held at ODA in Reynoldsburg.  Recertification credit will also be available in Core, 10b and 12.  For additional information, check out http://pested.osu.edu .

F.  DATES SET FOR COMMERCIAL APPLICATOR RECERTIFICATION CONFERENCES.  The following dates have been set for recertification conferences this winter.  Mark your calendars now!

• January 13, 2010, Dayton Convention Center, Dayton
• February 17, 2010, Kalahari Conference Center, Sandusky
• March 3, 2010, John S. Knight Center, Akron
• March 9, 2010, Columbus Convention Center, Columbus

10.  BYGLOSOPHY. 

"Live in each season as it passes: breathe the air, drink the drink, taste the fruit." - Henry David Thoreau