Pam Bennett, Barb Bloetscher, Joe Boggs, Cindy Burskey, Jim Chatfield, Erik Draper, Dave Dyke
Gary Gao, David Goerig, Tim Malinich, Becky McCann, Amy Stone, and Curtis Young

Buckeye Yard and Garden onLine provides timely information about Ohio growing conditions, pest, disease, and cultural problems. Updated weekly between April and October, this information is useful for those who are managing a commercial nursery, garden center, or landscape business or someone who just wants to keep their yard looking good all summer.

This is the 21st 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 fischnich.1@cfaes.osu.edu 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 August 25th conference call:  Maureen Austin (Stark); Barb Bloetscher (C. Wayne Ellett Plant and Pest Diagnostic Clinic (CWEPPDC)); Joe Boggs (Hamilton); Cindy Burskey (Clermont); Gary Gao (Delaware); Dave Goerig (Mahoning); Bridget Meiring (CWEPPDC); Dave Shetlar (Entomology); Nancy Taylor (CWEPPDC); Curtis Young (Hancock); and Randy Zondag (Lake).

In This Issue:

  1. WEATHERWATCH. 
  2. HORT SHORTS:   Sluggish Garden (Gray Garden Slugs); Waning Wingstem Waving; and Plants of the Week:  Annual (Impatiens), Perennial (Asters), Woody (Seven-Son Tree), and Weed (Foxtail).
  3. GREEN SHORTS:  Colony Collapse Disorder (CCD) of Honey Bees - Research Buzz. 
  4. CLINIC CLIPS.
  5. BUGBYTES:  Rusty Baldcypress (Baldcypress Rust Mite); Robbers on the Wing (Robber Flies); Net-Winged Beetles; Captivating Orbweavers (Spiders); and Bagworm Update. 
  6. DISEASE DIGEST:  Anthracnose Dropping Walnut Leaves; Armillaria 'Shrooms (Honey Mushrooms); and Verticillium Wilt of Smoketree. 
  7. TURF TIPS:  Grub Nemesis on the Wing (Bluewinged Wasp); and Time for Turf Renovations. 
  8. INDUSTRY INSIGHTS:  Why Trees Matter Forum. 
  9. COMING ATTRACTIONS:  Pesticide Applicator Training Offered; Horticultural Diagnostic Workshop in Central Ohio on September 16; Diagnostic Clinic in Northwest Ohio on September 17; 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:  August 1-August 26, 2009, with the exception of the soil temperatures which are readings from Wednesday, August 25, 2009 at 11:15 a.m.

Summer-like weather continues across Ohio.  Overcast periods with scattered showers are followed by bright intense sunshine.  BYGLers reported receiving some rain this past week with the Wayne County area getting almost 5".  As the month of September looms, nighttime temperatures are cooling down considerably.

Weather
Station
Region of
Ohio
Ave. High
Temp F
Ave. Low
Temp F
Total
Precip."
Normal
Precip."
Soil Temp F
2"/3"
Ashtabula
NE
79.9
61.5
1.393.20
83.6/82.6
Wooster
NE
81.5
60.64.89
2.9
80.4/77.5
HoytvilleNW86.2
64.2
1.03
2.3
90.1/83.1
ColumbusCentral
83.0
62.7
1.04
3.0
77.8/76.1
Piketon
South
83.1
62.1
1.52.0
86.4/81.8

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

 

2.  HORT SHORTS.

A.  SLUGGISH GARDEN. 

Dave Goerig reported his vegetable garden in Northeast, Ohio was somewhat sluggish.  This report was not based on the fact his tomatoes and peppers are suffering from all the same disease symptoms BYGL reported on this year.  Nor was it even based on all the woes his vine crops have experienced this year either.  His report was based on the fact that last weekend he noticed his garden was inundated with slugs.  It could be the happy mollusks are a result of the cooler temperatures that came with the excessive rain that recently fell on that part of the state. 

One of the more common slugs found in Ohio is a member of the genus Deroceras.  The GRAY GARDEN SLUG also known as the MILKY GARDEN SLUG (D. reticulatum) is of European origin and is found throughout most of North America's temperate region.  They eat most all garden plants, but Dave said they have been favoring his cabbage as of late, noticing they were found several leaf layers deep within the head he harvested.  To get them to exit, his wife Beth simply submerged the head of cabbage into an 8 quart stock pot of salt water (1/2 cup of table salt in 6 quarts of water).  This brine solution not only brought out the slugs, but also a few cabbage looper caterpillars as well.

As a slug travels it secretes a slime-like (mucus) substance that persists on the surface of most leaves.  If that isn't bad enough, they have big appetites with rasping tongues which can bring on noticeable damage to many of our favorite herbaceous plants in a short time.  Slugs are generally nighttime feeders although they can be seen foraging in the day during overcast skies.  Successful slug population control strategies include: trapping; reducing favorable habitat; and commercial slug baits. 

For more information, see:

 

B.  WANING WINGSTEM WAVING.  


One of the telltale signs of late summer and early fall is the high-flying yellow blossom set of Verbesina alternifolia, Wingstem.  This native prairie perennial has a wide distribution throughout the US Great Plains, east to the Atlantic Ocean.  Driving along Ohio's roadways this time of year it can be readily seen waving its ray flowers atop the 6-13' feet tall stems.  Wingstem prefers alluvial soils, and is mostly found growing along woodlot edges and in protected fence rows, particularly near streams or vernal pool areas.  As a member of the Family Asteraceae (a.k.a. Family Compositae), it is sometimes confused with JERUSALEM ARTICHOKE (Helianthus tuberosus) which is also has yellow ray flowers, is blooming now, and is just as tall. Wingstem's ray flowers reflex downward from the disk flowers, whereas Jerusalem artichoke ray flowers surround the disk flowers and do not droop. aggressively buzz any transgressor who dares to enter their territory; including people.


Wingstem's common name refers to the modified leaf-like structure which extends beyond the base of the leaf and onto the stem.  The lanceolate foliage is rough-pubescent (scabrous) to the touch, has a serrated margin, and is alternately arranged on the stem.  Wingstem has value in the garden although it is under utilized.  It could be grown as a temporary screen, background border, or included in a mixed mass in a rain garden.

For more information, see:

 

C.  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 - IMPATIENS (Impatiens walleriana).  Impatiens are the standard annual that fill many of our gardens during the summer.  They are a tried and true "well performer."  If the shady garden calls for ankle high color, the many cultivars of impatiens offer every color imaginable and ask for minimal care in return.  Impatiens like full to partial shade and bloom from early spring until frost.  They thrive in a neutral pH and well-drained soil.  They are excellent in hanging baskets and planters, and can add interest to a mixed bed.


*PERENNIAL - ASTER (Aster spp.).  Asters are an easy to grow perennial that will thrive in well-drained and moderately fertile soil.  Asters love full sun but will tolerate light shade.  Taller varieties of Aster may get a bit leggy if grown in too much shade.  Some plants will require an annual edging, as they are good spreaders.  Asters bloom from late summer to late fall providing nice color to flower beds and can reach heights of 24-48" tall.  Asters are easily grown from division.  Aster plants do best if divided every two to three years.  Simply dig out half to two thirds of the plant, leaving the remainder in place.  Then separate the portion you dug out into two sections and plant in another location or give them to a friend.  Some of the recommended varieties include: A. amellus (violet), A. coloradoensis (lavender), and A. lateriflorus (white).

*WOODY - SEVEN-SON TREE (Heptacodium miconoides).  The Seven-Son tree is a very attractive large shrub or small tree during late summer into fall.  This plant has attractive, fragrant, cream colored, clusters of blossoms in late summer which are succeeded by clusters of showy, purple fruit.  The calyx on all the fruit of this plant is unique, purple, and showy as well.  The fall color of H. miconoides is a bright purple with bronze over-tones.  As the foliage falls away the Seven-Son tree shows off even more by revealing an impressive exfoliating bark.  This plant should do well in most parts of Ohio with moderate care.  It will grow to 20' in height and spread half that distance if planted in full sun and well draining soils.

*THE WEEKLY WEED - FOXTAIL (Setaria spp.).  In this issue, our weekly weed focuses on the genus Setaria.  There are three species of Setaria that are developing seed heads now.  Proper identification will be helpful when control strategies are being developed for this last half of the growing season.  YELLOW FOXTAIL (S. lutescens), GIANT FOXTAIL (S. faberii), and GREEN FOXTAIL (S. viridis) are all monocot summer annuals.

The foxtails are clump-forming, wide bladed, erect grasses that can reach beyond 3' in height.  The most recognizable characteristic on these plants are the spike-like panicle seedheads that resemble the tail of a fox.  Each foxtail can produce more than 50 seeds per plant if left to mature.  In just one season, a small stand of these plants can deposit thousands of seeds into a planting bed making control the following season even more difficult.  Yellow foxtail is easily identified by its yellowish, bristly, erect, seedhead.  The seedheads on green and giant foxtail are larger and come in shades of green and purple.  Giant foxtail can be distinguished even further by its nodding character.

The foxtails are weeds of cultivated areas including landscapes, and nurseries.  They prefer to grow in nutrient-rich soil.  Members in the genus Setaria can be found growing around the world.  By midsummer, the effects of spring applications of pre-emergence herbicide controls begin to wear down and afford foxtail seeds their foothold.  Control strategies of these annual plants now will include hand and mechanical cultivation, mechanical seedhead removal, and post-emergence herbicides.  It should be noted, post-emergence herbicides will kill the plant but any viable seed within the seedhead generally will germinate next year.

 

3.  GREEN SHORTS.

A.  COLONY COLLAPSE DISORDER (CCD) OF HONEY BEES- RESEARCH BUZZ.  Three years and hundreds of thousands of empty bee hives later, researchers in several university honey bee research labs are getting closer to determining the causes for CCD, in which all but a handful of nurse bees and the queen honey bee mysteriously disappear in a short period of time usually between fall and spring.  In the US, Canada and many other countries, strong hives in the fall would be devoid of bees the following spring yet a good honey crop still remained in the hive. The unexplainable fact that the honey remained in the hive unprotected, yet not robbed by other bees continued to puzzle beekeepers and researchers, leading them to suspect a contaminate was present which repelled other bees.

A thorough survey of beekeepers throughout the US from Pennsylvania State University revealed that although commercial beekeepers lost the majority of hives, the part time/hobby beekeepers (who can spend more time per hive than commercial keepers) actually lost the greater percentage of colonies.  Comparing different management practices, none appeared to contribute more toward CCD. It was also determined that although the disappearance of bees was sudden, the syndrome had been developing in the colony for several months.

Penn State also measured relative pesticide levels in afflicted bees, beeswax and pollen.  Both colonies with CCD and without had high levels of several pesticides including fungicides, insecticides and herbicides.  Common backyard pesticides (pyrethroids, organophosphates, carbamates, chorothalonil) were found in high concentrations, however the miticides used to control varroa mites, fluvalinate (Apistan) and coumaphos (CheckMite) were the highest in concentration in all samples.  Scientists found that the combination of pesticides and their byproducts are causing the impaired immune response (bee AIDS) in CCD colonies and greater susceptibility to stresses.  This discovery validates the necessity for beekeepers to use miticides judiciously according to label laws, and to incorporate other management techniques to maintain hive health and low levels of varroa mites.  It also compels beekeepers to replace older, darker frames with new foundation every few years.  Landscapers, growers and gardeners are urged to only treat precious or important plants that are being severely damaged by insects (still present on the crop) and to treat the leaves only-not the flowers.

One Penn State study showed that colonies that had suffered CCD had actually isolated and "walled off" pesticides in honeycomb cells with wax.  These thickly sealed cells had very high levels of pesticide residue packed behind the wax coating.  This implies that honey bees can detect and will "embalm" foreign products in their hives, as they will sting and/or embalm arthropod and animal intruders.

Although the newer systemic insecticides have been implicated in the CCD of honey bees and have been found to accumulate in some plants over time, it has not been found in the stricken colonies at high levels compared to other common pesticides.   Another consideration with pesticides is that CCD, also called Disappearing Disease and Fall Dwindle Disease has occurred several times since 1915, long before many insecticides and miticides were developed, thus pesticides alone are probably not causing CCD.

The presence of Nosema ceranae, a disease attacking bees, as well as several viruses have also been studied.  It was found that when varroa mites break the exoskeleton of bees to suck hemolymph (bee blood) the bees become susceptible to invasions of viruses, fungi and bacteria.  It also weakens their resistance to other stresses.  When healthy colonies were artificially infected with nosema and suspected viruses alone though, the colonies vanquished the pathogens and showed no symptoms of CCD.

The latest studies were done in the Universities of Minnesota and Illinois.  The University of Minnesota discovered that propalis which is a sticky "glue" made by bees and derived from tree sap is used to line feral colonies and protect the hive from pathogens and microbes.  In doing so, it gives the whole colony a form of "social immunity," which lessens the need for each individual bee to have a strong immune system.  Hives which had the propalis removed were more susceptible to stresses.

The University of Illinois Bee team analyzed the gene expression in the bees' guts because this is where pesticides are detoxified.  Neither the presence of pesticide nor the impaired immune system suspected were expressed to any degree in the genes of the afflicted bees.  Instead the attack of several viruses which attack the same area of ribosomes (the cell's protein making factory) forced the ribosomes to make virus proteins instead of honey bee proteins.  The presence of several viruses attacking the ribosomes actually wore the ribosome so that it was no longer functioning properly.

The effect of several viruses attacking the bees is another contributing factor to CCD but probably just one more straw on the bees' back.  More research has been conducted and will continue.   Hopefully the key to avoiding CCD will be determined before another third of all hives is lost again.

For more information, see:

Search PlantFacts.osu.edu

 

4.  CLINIC CLIPS.

Two beautiful long-horned beetles, Neandra brunnea were submitted to the CWEPPDC for identification when found on a maple tree, near some ominous looking borer holes.  It is unknown if the beetle larvae of this species caused the damage, as no description of the holes was supplied, however normally this species lays eggs in chips of bark of mature trees with water or decay damage.  More spruce with spider mite damage was submitted as well as some white pines with eriophyid rust mite damage on older needles.  Calls regarding yellow jacket nests in wall voids, garden sheds and under ground cover plants continue to ring.  Although many assume the bright yellow and black striped hornets are honey bees, honey bees will not nest in the ground, compost piles, or tree stumps.  If the person can not describe the flying acrobats, ask them to look for a dead one near the opening or describe the object in which they are nesting for clues as to their identity.

 

5.  BUGBYTES.

A.  RUSTY BALDCYPRESS. 

Curtis Young reported that the damage from the warm-season BALDCYPRESS RUST MITE (Epitrimerus taxodii) is just becoming evident on its namesake host in northwest Ohio.  Damage observed thus far ranges from a subtle off-coloring of the foliage on trees with low populations to a very obvious reddening of the inner foliage on trees with heavy infestations.  Heavy populations eventually cause the entire tree to become orangish-red, and defoliate.   The key to the prevention of severe damage is early detection.  Symptoms produced by this eriophyid mite are often mistaken for foliage damage from lack of water, particularly on newly planted trees.

As with other eriophyid mites, the baldcypress rust mite is almost microscopic in size.  Standard 10X and even 20X hand lenses will only render images of moving specks of dust.  Under 40X magnification, the carrot-shaped, cream-colored, semi-translucent mites come into sharp focus and their unusual body arrangement can be seen.  The mites only have two pairs of legs which are clustered at the front end.  No other mite has only two pairs of legs at any stage in their development.  High magnification will also reveal the brownish, sunken areas on the needles caused by the mites rasping through the epidermis to extract the cell contents below.

Unlike spider mites, eriophyids can be controlled with many standard insecticides including carbaryl (e.g. Sevin).  Certain pyrethroid insecticides such as bifenthrin (e.g. Talstar) are also effective, as well as the miticide abamectin (e.g. Avid).  Note that baldcypress is extremely sensitive to horticulture oils; their use is not recommended for control of eriophyid rust mites.

 

B.  ROBBERS ON THE WING. 

Joe Boggs reported that he observed (and heard) one of the largest sized species of ROBBER FLIES found in the state while on a recent walk-about in an Ohio forest.  The fly, Promachus rufipes, measures around 1 1/4" long.  What he heard was the sound made when this "buzz bomber" slammed mid-air into a hapless insect victim.

Robber flies belong to the family Asilidae.  There are over a thousand species in this family in North America representing a wide range of forms and sizes.  Adults of all species are predators and they will attack a variety of insects including bees, wasps, grasshoppers, dragonflies, and damselflies.  They often seize prey that is much larger than their own body size.  Their larvae are also predaceous and live in the soil, or in decaying wood and other organic matter, where they feed on insect larvae.

Adult robber flies have a stout thorax that appears slightly humped when viewed in profile.  Each long, strong leg is tipped with two formidable tarsal claws that look and function like grappling hooks.  In a smashing display of aerial acrobatics, the robber fly slams into its airborne quarry which stuns the victim.  The high-speed collision produces a snapping sound that may be heard several feet away.  The fly then grasps its dazed prey with its claws, and uses its piercing-sucking mouthparts to inject saliva containing neurotoxic and proteolytic enzymes.  The enzymes paralyze the victim and digest the internal tissues.  The fly then lands, and sips away the life of its victim.

For more information, see:

Search PlantFacts.osu.edu

 

C.  NET-WINGED BEETLES. 


Joe also reported observing significant numbers of NET-WINGED BEETLES (Family Lycidae).  The front wings (elytra) on most beetles are hardened and they cover and protect the hind wings and abdomen.  Indeed, the name of the beetle order, Coleoptera, clearly describes this arrangement (coleo = sheath; ptera = wing).  However, net-winged beetles have soft elytra.  Their common name comes from the network of raised longitudinal and transverse ridges on the elytra that resemble netting.

There are around 50 species of net-winged beetles in North America.  The two most common species found in Ohio are the banded net-winged beetle (Calopteron reticulatum) and the end band net-winged beetle (C. terminale).  Both are medium-sized (about 5/8" long), elongate, slightly flattened beetles, with elytra that are widened towards the posterior end.  The pronotum (segment behind the head) of both beetles is black with yellow margins, and the elytra are orange to yellowish-orange with the hind portion black.  The banded net-wing has a narrow black band crossing the front of the elytra. 


The beetles contain pyrazines that give the beetles a repugnant scent.  They also contain lycidic acid and other fatty acids that may impart a foul taste if the beetles are consumed by a predator.  It is speculated that their bright coloration provides a warning to predators that these beetles are not good to eat.  Adults are active during the day and they feed on decaying plant material, and occasionally on other insects.  The larvae are predaceous and consume a wide range of prey including insects, slugs, sowbugs, and millipedes.  Thus, net-winged beetles are considered beneficial insects.

For more information, see:

Search PlantFacts.osu.edu

 

D.  CAPTIVATING ORBWEAVERS. 


Orbweaver spiders (Family Araneidae) are the true master engineers of the spider world.  They spin round (orb) gossamer webs with radiating spokes of silk covered by spiraling rings of silk.  Travelers in Ohio may be treated to the beautiful early morning view of dew-covered orbweaver webs shimmering in fields along roadways.  Three of the more common orbweavers currently on display in Ohio are the large YELLOW-AND-BLACK ARGIOPE (a.k.a. common garden spider, zigzag spider) (Argiope aurantia), the TRASHLINE SPIDER (Cyclosa turbinate), and the BARN SPIDER (Araneus cavaticus).

The yellow-and-black Argiope is one of the largest orbweavers found in Ohio.  Females may measure over to 2" from the tips of their legs.  The spider sports black legs, a yellowish-silver cephalothorax, and a black abdomen with intricate yellow markings.   Stabilimentum are silk structures located in the center of some orbweaver's webs.  The stabilimentum of this spider appears as a zigzag pattern of coarse silk, thus the colloquial common name of "zigzag spider".  The spider is active during the day and is usually found centered in webs they have spun between weed stems.  Unfortunately, their webs are often at "face height" leading to close, entangling encounters between spiders and hikers producing dramatic responses from both the hikers and spiders.


Entomologists once puzzled how such a large, brightly colored spider resting in the middle of its web in the middle of the day could be so successful in capturing insects in their web.  It would be like sheep running to wolves.  The answer rests with understanding insect vision.  It has long been known that many insects are able to see ultraviolet light in the wavelength range that is invisible to most other animals, including humans.  And, some flowers that appear white to people actually have intricate ultraviolet light reflective patterns on their petals to attract more insects.  Research conducted in the early 1990's showed that when Argiope spiders and their webs are photographed with ultraviolet sensitive film, the spider disappears, the web disappears, but the zigzag stabilimentum blazes like a giant, neon "eat here" sign.  Insects are lured to their doom thinking they are visiting the mother of all flowers!

Trashline spiders are relatively small measuring around 1/4-1/2" from the tips of their legs.  Their legs, cephalothorax, and abdomen are covered with mottled black and white markings.  These spiders also have a vertical stabilimentum of coarse silk; however, a close examination will reveal that the silk enshrouds the drained bodies of their previous victims.  This morbid structure is responsible for the "trashline" in the common name.


These spiders are found in the middle of the day in the middle of their trashline.  Their mottled coloration makes them very difficult to see resting among their similarly sized and colored bundles of trash.  Indeed, recent research conducted on another trashline spider, C. mulmeinensis, by a team of scientists at Tunghai University in Taiwan showed that the trash bundles serve to confuse predators such as birds and wasps intent on making a meal of the spiders, and the greater the number of trash bundles, the greater the confusion.  This is an interesting twist on the saying, "You are what you eat."

Barn spiders are medium-sized round spiders measuring 1/2-3/4" from the tips of their legs.  The top of the abdomen as well as their legs and cephalothorax are covered with mottled light brown to black markings.  They have a very distinct marking on the underside of their abdomen that is pitch-black with two yellowish-white marks along the edge of the black background.  Barn spiders are nocturnal.  They construct their orb webs each evening, and then they consume their webs in the morning.  This spider is often encountered in doorways in the morning, hanging where there was no spider the day before.

For more information, see:

Search PlantFacts.osu.edu


E.  BAGWORM UPDATE. 

Joe Boggs reported that bagworm (Thyridopteryx ephemeraeformis) populations in southern Ohio have begun to advance to the next stage of their lives.  When bagworm caterpillars (larvae) have consumed enough food to support their growth and development through their final instar, they will cease feeding, spin silk threads around a twig or a silk pad on the surface of an object to anchor themselves in place, pull down inside of their bags and seal the opening at the top of the bag.  Once secured inside of their bags, they will pupate and begin the process of metamorphosis.  Male bagworms tend to advance through these stages faster than female bagworms.  Curtis Young reported that bagworms in northern Ohio have not yet reached this point in their development.

Since the bagworms in Joe's area have finished or nearly finished their feeding they are beyond treatment with insecticides for this year.  Those who missed their treatment window will have to wait till next June before they can effectively use an insecticide against the bagworm again or they must resort to hand removal of the bagworms from the host plants upon which they had been feeding.  Northern Ohio populations may still have a very narrow window of opportunity for insecticidal treatment yet this year.

For more information, see:

Search PlantFacts.osu.edu

 

6.  DISEASE DIGEST.

A.  ANTHRACNOSE DROPPING WALNUT LEAVES. 

Several BYGLers reported that the annual dropping of walnut leaflets and leaves due to walnut anthracnose has commenced in Ohio.  The disease is caused by the fungus, Gnomonia leptostyla, which is specific to walnut.  Unlike some of the other anthracnose diseases, walnut anthracnose is characterized by small dark brown spots rather than the larger irregularly shaped necrotic lesions seen with ash or oak anthracnose.

The dark brown spots on the walnut leaflets can be 1/16-1/4" in diameter and are usually surrounded by a yellow halo.  Initially, the lesions are seen only on the underside of the leaflets, but they eventually cover both leaflet surfaces as the season progresses.  Infected leaflets turn yellow and drop individually, or the entire compound leaf drops.  Severe infections can defoliate a tree by early to mid-August.  Trees in good health can tolerate the leaf loss; however, repeated defoliation of trees that are in poor health can kill the trees, or leave them susceptible to other insect or disease problems.  Infection of walnut husks can result in incomplete nut development and a reduction in the quality of the nut meat.

The fungal spores overwinter on fallen leaves and infections occur on the new growth in the spring.  The fungus needs to have 12 or more hours of continued leaf wetness to infect the plant.  These first lesions produce spores to create more infections throughout the season.  Control may be impractical on large trees and in forest plantings.  Control in landscape or nursery situations can be achieved with fungicide sprays during the primary infection period in the spring and through the early growing season.  Removing fallen leaves from the area will also reduce the infections of next year's leaves.

For more information, see:

Search PlantFacts.osu.edu

 

B.  ARMILLARIA 'SHROOMS. 

Dave Shetlar reported that he is commonly seeing mounds of Armillaria spp. mushrooms sprouting in landscapes in central Ohio.  The appearance of the mushrooms, which are sometimes called "honey mushrooms" due to their amber color, provide evidence that nearby trees are possibly being colonized by an Armillaria root rotting fungus.

The Armillaria genus includes the notoriously pathogenic species, A. melia, which was once thought to be the most malevolent form of this fungus, and the species most commonly associated with the disease "Armillaria root rot."  However, in recent years, pathologists have determined that there are a number of other species of Armillaria that may also infect woody plants.  In their book "Diseases of Trees and Shrub, 2nd Edition," Sinclair and Lyon indicate that there are 10 known species of Armillaria that occur in North America.  Some, like A. calvescens, and A. cepistipes, are only mildly plant pathogenic, while others like A. melia and A. ostoyae are aggressive plant pathogens.

The Armillaria fungi are collectively referred to as "shoestring" fungi for their black shoestring-like structures (called rhizomorphs) found under the bark, around roots, or in the soil.  The fungi may also appear as white, fan-shaped mycelial mats beneath the bark.  The rhizomorphs grow freely through the soil and penetrate roots, causing new infections.  They are the principal means for the tree-to-tree spread of the pathogenic species of Armillaria fungi.

The outward symptoms of infection include:  thinning foliage that becomes discolored, turning yellow, then brown; reduced shoot and foliar growth; and branch decline and dieback.  The pace of symptom development varies with trees vigor.  Trees that are stressed by other factors, such as drought or pest infestations, may rapidly decline and die.  Lesions or cankers may form at the base of infected trees, and removal of the bark over the affected areas will reveal the mycelial mats and rhizomorphs.  Since the fungi spread through the soil, tree decline may occur simultaneously to groups of trees.

Identifying different species of Armillaria in the field is difficult.  All will produce rhizomorphs.  An odd characteristic of Armillaria is that they are bioluminescent.  Indeed, the eerie greenish-blue glow seen in forests after dark, commonly called "foxfire," may indicate the presence of Armillaria.  However, this characteristic will not illuminate the exact species, nor is it a sure-fire identifier of Armillaria since there are other glow-in-the-dark fungi.  Mushrooms, which are the fruiting structures of the fungi, do provide a more reliable identification feature, with the honey mushrooms most often being associated with A. melia.

A word of caution:  Armillaria mushrooms are considered edible; however, eating wild mushrooms should be viewed as a high-risk endeavor.  Their harvest should be left to cautious, well-trained experts.  Remember the quote, "There are old mushroom hunters, and bold mushroom hunters, but no old, bold mushroom hunters!"

For more information, see:

Search PlantFacts.osu.edu

 

C.  VERTICILLIUM WILT OF SMOKETREE.  Gary Gao reported receiving a sample of smoketree with symptoms of Verticillium wilt.  Several branches on the plant have wilted and died while others were still looking healthy.  Verticillium wilt is a common vascular wilt of many landscape trees, shrubs, and herbaceous crops, ranging from ornamentals to fruits, vegetables, and agronomic crops.  The Verticillium fungus infects plant roots, then spreads upward and outward through the vascular system. Damage to the plant is then due to reduced availability of water to the stems and leaves and associated toxic effects of the fungus on plant tissue.

Management practices include: 

*1)  Disease resistance.  If Verticillium wilt is diagnosed at a particular landscape or nursery site it is prudent to replant into that area with a plant that exhibits resistance to this disease. A few common examples of plants typically free of this disease include: crabapple, mountain ash, beech, birch, boxwood, dogwood, sweet gum, hawthorn, holly, katsuratree, honeylocust, oak, pear, London planetree and sycamore, rhododendron, willow, and zelkova. The red maple cultivars Armstrong, Autumn Flame, Bowhall, October Glory, Red Sunset, Scarlet and Schlessinger have also been reported as resistant.

*2)  Keep plants as healthy as possible.  Proper transplanting practices, proper water management to avoid droughts, a good fertility program, and pruning out dead branches are all good plant health care management practices. These can help limit infections and help limit the effects of these infections to some extent. Pruning out infected branches is useful as a general horticultural practice for overall plant vigor and aesthetics, but does not eliminate Verticillium from the plant since infections spread from the roots.  Fungicides are not effective for control of this disease.

For more information, see:

 

7.  TURF TIPS.

A.  GRUB NEMESIS ON THE WING. 

Dave Shetlar reported that the BLUEWINGED WASP (Scolia dubia) is starting to appear in noticeable numbers over lawns and sports field in central Ohio.  The wasps may be seen cruising a few inches above the turfgrass, often in loops or a figure-8 pattern, searching for white grub indicators.  They are excellent flyers and their flight plans sometimes cause them to be mistaken for the much larger, and different colored CICADA KILLER WASP (Sphecius speciosus).  The wasp will parasitize all white grubs, but is particularly fond of GREEN JUNE BEETLE (Continus nitida) grubs.

Once grub activity is located, the wasp will dig into the soil, or simply enter the green June beetle grub's burrow.  It first stings and paralyzes the grub, then it lays an egg in the grub's body.  When the egg hatches, the wasp larva first consumes the non-essential parts of the paralyzed grub, keeping the hapless grub alive and "unspoiled."  Later, the ravenous wasp larva applies the coup de grace, killing the grub.  The immature wasp pupates inside the carcass from which a new wasp emerges.

The bluewinged wasp is around 1 1/4" in length.  As the common name implies the wings as well as the head, thorax, legs, and first two abdominal segments are dark blue.  The third abdominal segment is orangish-red with two side-by-side yellow spots on a black background.  The remaining abdominal segments are orangish-red, and all segments are somewhat hairy.  These solitary wasps may be found cruising turfgrass from June through early-October.  Since the wasp is strongly connected to green June beetles, they are most often found in the central and southern parts of the Ohio where the beetles most commonly occur.  The wasps are not aggressive, and they are one of the "good bugs," so they should be conserved, not destroyed.

For more information, see: 

Search PlantFacts.osu.edu

 

B.  TIME FOR TURF RENOVATIONS.  If you think your clients, or even your own lawn is in need of a complete makeover, the time to act is NOW.  The timeline that contains the best probability for success relative to reestablishing a non-performing stand of turfgrass in Ohio is from August 15th to September 15th.  Decisions to support the renovation of a deteriorated lawn include the effects overtime of improper cultural practices, injury to turf as a result of a turfgrass pest, death of turf as a result of chemical toxicity, or outdated turfgrass variety (i.e. wanting newer varieties that are disease resistant or greener in color).  So why is this the best time?  Its as simple as 1, 2, 3 ...

*1)  Simply put, most lawns in our State are seeded or sodded with mixtures of cool season grasses such as the bluegrasses (Poa spp.), the ryegrasses (Lolium spp.), and the fescues (Festuca spp.).  One of the most popular species is Kentucky bluegrass (Poa pratensis).  Kentucky bluegrass was introduced from Eurasia for turfgrass use throughout the cool climates around the world.  Hundreds of species with considerable variability in color, texture, growth habit, and disease resistance have been cultivated and developed over the years.  Perennial ryegrass (Lolium perenne) and Italian ryegrass (Lolium multiforum) have had desirable cultivars selected and marketed specifically for turfgrass use.  Perennial ryegrasses should not be confused with cereal rye (Secale cereale) that is an annual and sometimes used for rapid stabilization of open slopes without vegetation.  Festuca is a large genus containing over 100 species with a lot of variability.  Red fescue (Festuca rubra), commonly labeled as creeping red fescue is a fine textured plant that tolerates some shade while tall fescue (F. arundinacea) is a coarse bunch-type grass that has more heat and traffic tolerance than most other cool-season grasses.  All of these grasses grow best when temperatures are around 60-75 F.

*2)  Competition for growing space between undesirable weed species and new turfgrass species is at its lowest during late summer.  Proper soil preparations will eradicate the old turf varieties and the warm season weed species.  Most cool season weed species have already completed their life cycles by this time of the year. Cool season weed species seeds have not begun to sprout yet.  Undesirable plant eradication can be accomplished with post emergence herbicides and mechanical cultivation.  As fall progresses the air temperature cools but the soil temperatures hold for ideal root growth.  Getting the work done by mid-September insures the newly sprouted seed or newly cut sod has adequate time to anchor itself into the soil.  Well rooted plants have a better chance of surviving the heaving effects of the freeze-thaw cycles during the winter season.  When seeding within the opportune timeline, ensure your success by always purchasing fresh seed.  Always use clean straw if seeding to reduce the chances of weed seed introduction.  Turfgrass seedings after mid-September have less of a chance of reestablishment than sod. 

*3)  Low soil moisture is ideal for working up the seed or sodding bed.  A basic requirement for successful turfgrass renovation is to ensure good contact between the soil and the seed, or the roots of the plant in the case of sod.  Reestablishing grading for proper surface drainage is best to do now verses the spring when soil moisture levels are higher and you risk the chance of machinery causing soil compaction.  Sod installations many times fail to reestablish as a result of too little water.  To ensure successful sod establishment make sure you apply enough water to not only water the sod but also soak the ground underneath the sod enough to promote the roots of the sod to grow into the soil.  After September, the fall rains with the warm soil hasten reestablishment.

For more information, see: 

 

8.  INDUSTRY INSIGHTS.

A.  WHY TREES MATTER FORUM.  Registration is now open for the 4th annual "Why Trees Matter Forum."  This year's forum will be held in Wooster at Fisher Auditorium on Thursday, October 22, 2009. 

In addition to our keynote speaker, Joe R. McBride, University of California, Berkeley, we will also be hearing the following presentations:

Drew Todd, ODNR State Urban Forestry Coordinator: "30 Years of Urban Forestry Assistance."  The Ohio Department of Natural Resources Urban Forestry Program began in 1979. As it enters its 30th year, state coordinator Drew Todd will share a little of that history, and describe current statewide urban forestry activities.

Greg Ina, Davey Tree Institute:  "What's New with i-Tree" - An overview and demonstration of some of the new functionality of i-Tree 3.0 including i-Tree Streets, i-Tree Eco, and i-Tree Vue.

We will continue our tradition of ending the Why Trees Matter Forum with a closer look at specific trees in Secrest Arboretum.  Denise Ellsworth, OSU Extension, Summit County will start our afternoon tour with a stop at the Discovery Pavillion and a brief introduction to phenology as it pertains to specific trees.  Ken Cochran and Joe Cochran of Secrest Arboretum will continue the discussion of tree phenology with a closer look at several genera within in the arboretum.

We hope to see you all there!  For a registration flier, please contact Lynn Vogel at vogel.106@osu.edu .

 

9.  COMING ATTRACTIONS.

A.  PESTICIDE APPLICATOR TRAINING OFFERED.  A Trained Serviceperson and New Applicator Commercial School is planned for September 30, 2009.  This session will be taught at the Ohio Department of Agriculture (ODA) in Reynoldsburg, Ohio.  For additional information on this school, and other educational opportunities, check out the Pesticide Education website at http://pested.osu.edu .

B.  HORTICULTURAL DIAGNOSTIC WORKSHOP IN CENTRAL OHIO ON SEPTEMBER 16.  OSU Extension in Delaware County is proud to present a Horticultural Diagnostic Workshop in Delaware Ohio from 9:00 a.m.-4:00 p.m. on September 16, 2009.  The speakers for this all-day program will be Jim Chatfield, Gary Gao, and Dave Shetlar.  They will show attendees how to diagnose common fruit and vegetable insects and diseases, late-season diseases in the landscape, late-season insects and mites in the landscape and what to do now to prevent these critters from causing damage next year.  Attendees are welcome to bring samples to the workshop.  Instructors will bring samples as well.  There is a $25 fee, which includes the program, lunch, handouts, and a certificate of completion.  Space is limited.  The registration will be accepted on first come, first served basis. 

Please follow this link:  http://delaware-cms.ag.ohio-state.edu/horticulture/upcoming-programs and then click "2009 Horticultural Diagnostic Workshop" for the program flyer.  You may also email Cindy Kaelber at kaelber.1@cfaes.osu.edu or call OSU Extension in Delaware County at 740-833-2030 for a program flyer.

C.  DIAGNOSTIC WORKSHOP IN NORTHWEST OHIO ON SEPTEMBER 17.  OSU Extension in Hancock County is proud to present a Diagnostic Workshop in Findlay, Ohio from 9:00 a.m.-4:00 p.m. on September 17, 2009.  The speakers for this all-day program will be Jim Chatfield, Curtis Young, and other OSU Extension personalities.  They will show attendees how to diagnose common fruit and vegetable insects and diseases, late-season diseases in the landscape, late-season insects and mites in the landscape and what to do now to prevent these critters from causing damage next year.  Attendees are encouraged to bring samples to the workshop for diagnosis.  Instructors will bring samples as well.  There is a $30 fee, which includes the program, lunch, and handouts.  Space is limited.  The registration will be accepted on first come, first served basis. 

Please follow this link http://hancock.osu.edu/hort/mg.htm and then click "2009 Diagnostic Clinic Information" for the program flyer.  Registration Deadline: September 11, 2009.  Make checks payable to: Hancock County Master Gardeners.  Mail registration with fee to:  OSU Extension 7868 CR 140 Suite B Findlay, OH  45840.  Contact Nancy Kronberg at 419-422-3851 or e-mail kronberg.3@cfaes.osu.edu for answers to questions.

D.  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 .

E.  WHY TREES MATTER FORUM.  Registration is now open for the 4th annual "Why Trees Matter Forum."    This year's forum will be held in Wooster at Fisher Auditorium on Thursday, October 22nd. 

We are excited to welcome Joe R. McBride, University of California, Berkeley as our keynote speaker.  Dr. McBride is Professor of Urban Forestry in the Department of Landscape Architecture, University of California, Berkeley.  His research in urban forestry has focused on the reduction of air pollution by trees in urban areas, the relationship between urban forest characteristics and the characteristics of the biomes in which cities occur, history of the reconstruction of urban forests following bombing during World War II, the transition of natural forests to urban forests in California, and tree selection for California in the face of global climate change.  McBride is a member of the Society of American Foresters and International Society of Arboriculture.  His presentation for the forum is titled, "Trees Do Matter" and will focus on the importance of the urban forest to children.

John Lloyd of Rainbow Tree Care will also join us to talk about the Urban Forestry Institute, Minnetonka, MN and its connection to Ohio State University.

For a copy of the registration flier which features a full list of speakers and events for the forum please contact Lynn Vogel at:  vogel.106@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!

 

10.  BYGLOSOPHY.

"We talk about a smoking gun.  We have the bullet hole!" said May Berenbaum, University of Illinois, regarding CCD of honey bees.


OSU Extension

Where trade names are used, no discrimination is intended and no endorsement by Ohio State University Extension is implied. Although every attempt is made to produce information that is complete, timely, and accurate, the pesticide user bears responsibility of consulting the pesticide label and adhering to those directions.

OSU Extension embraces human diversity and is committed to ensuring that all educational programs conducted by Ohio State University Extension are available to clientele on a nondiscriminatory basis without regard to race, color, age, gender identity, or expression, disability, religion, sexual orientation, national origin, or veterans status. Keith L. Smith, Associate Vice President for Ag. Adm. and Director, OSU Extension, TDD No. 800-589-8292 (Ohio only) or 614-292-1868.