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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.
Home BYGL BYGL Listing BYGL - June 18, 2009
BYGL - June 18, 2009 Print E-mail

This is the 11th 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 June 16th conference call: Pam Bennett (Clark); Barb Bloetscher (Entomology/C. Wayne Ellett Plant and Pest Diagnostic Clinic (CWEPPDC)); Joe Boggs (Hamilton); Jim Chatfield (Horticulture and Crop Science and Plant Pathology); Gary Gao (Delaware); David Goerig (Mahoning); Becky McCann (Agricultural Business Enhancement Center (ABE)); Dave Shetlar (Entomology); Amy Stone (Lucas); Nancy Taylor (CWEPPDC); and Curtis Young (Hancock).

In This Issue:

  1. WEATHERWATCH. 
  2. HORT SHORTS:  Growing Degree Days (GDD); Vegetable Gardening 101 - June 18, 2009 - Do Not Over-Fertilizer Your Tomato Plants; Gobblers in Gardens (Wild Turkeys); Iron Chlorosis in River Birch and Sweetgum; and Plants of the Week: Annual (Lobelia), Perennial (Astilbe), Woody (Oakleaf Hydrangea); and Weed (Black Medic). 
  3. GREEN SHORTS:  Lessons Learned (Poor Species Diversity). 
  4. CLINIC CLIPS.
  5. BUGBYTES:  Gypsy News (Gypsy Moth); Hickory Tussock Moth; Mixed Symptoms on Oaks (Spiny Oak Sawfly and Oak Shothole Leafminer); Magnolia Serpintine Leafmining Caterpillar; Warm Season Mites Arise (Twospotted Spider Mite, Oak Spider Mite, Maple Spider Mite, and Honeylocust Spider Mite); and Webworm Or Borer? (Parsnip Webworm).
  6. DISEASE DIGEST:  Rusty Brambles or Nature's Tattoos. 
  7. TURF TIPS:  Smoking Grass? (Burrowing Sod Webworm); and Masked Chafers Emerging! 
  8. INDUSTRY INSIGHTS:  Want an Accurate Diagnosis?  Send a Great Sample! 
  9. COMING ATTRACTIONS:  The OSU Chadwick Arboretum Open House; Greater Cincinnati Branch of the Professional Grounds Management Society Annual Regional Meeting and Site Visitation; 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:  June 1-17, 2009, with the exception of the soil temperatures which are readings from Wednesday, June 17, 2009 at 6:05 a.m.

Many of the stations are recording lower than normal precipitation totals for the month thus far, with the exception of Piketon.  This particular station is reporting rainfall totals of 1" above average. 

Weather
Station
Region of
Ohio

Ave. High
Temp F

Ave. Low
Temp F
Total
Precip."
Normal
Precip."
Soil Temp F
2"/3"
Ashtabula
NE
70.0
49.5
0.482.40
68.30/68.64
Wooster
NE
74.7
51.81.19
2.30

68.04/68.26

HoytvilleNW77.7
55.8
0.87
2.10
65.43/65.61
ColumbusCentral
79.2
57.3
0.66
2.50
69.11/69.33
Piketon
South
79.2
56.1
2.611.60
71.69/72.91

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

 

2.  HORT SHORTS.

A.  GROWING DEGREE DAYS (GDD)

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 available on the web at the site http://www.oardc.ohio-state.edu/gdd/ .

The range of GDD accumulations in Ohio from north to south is 662 to 1,045.  Following is a report of GDD for several locations around Ohio as of June 17, 2009: Painesville, 662; Cleveland, 721; Toledo, 799; Canfield, 754; Findlay, 829; Wooster, 820; Coshocton, 883; Columbus, 951; Springfield, 951; Dayton, 955; Cincinnati, 1,002; Ironton, 1,007; Portsmouth, 1,010; and Piketon, 1,045.

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.

Multiflora rose, full bloom, 643; northern catalpa, first bloom, 675; black vine weevil, first leaf notching due to adult feeding, 677; Washington hawthorn, full bloom, 731; calico scale, egg hatch, 748; greater peach tree borer, adult emergence, 775; 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, 1,010; June bride littleleaf linden, full bloom, and 1,115; bottlebrush buckeye, first bloom, 1,158.

For more information, see:

Search PlantFacts.osu.edu

 

B.  VEGETABLE GARDENING 101 - JUNE 18, 2009 - DO NOT OVER-FERTILIZER YOUR TOMATO PLANTS.  Gary Gao received a phone call from a gardener whose tomato plants grew a lot of leaves and stems, but did not set much fruit.  She was surprised by the lack of fruit for she had applied quite a bit of manure to her tomato plants.  Gardeners should keep in mind that a little bit is good, a whole lot is not always better.  Nitrogen is needed by plants for both vegetative growth and fruit production.  However, too much nitrogen will result in all growth, no fruit production.  Typically, two applications of fertilizer are enough, one at the planting time and one more time about one month later.  Now is about time for a second application.  If gardeners notice their plants are growing too much, it is time to stop fertilizing for a while.  Be more patient.  Poor fruit set in tomatoes can also be related to tomato cultivars.  Some cultivars are more productive than others.  This is why cultivar trials and experience are quite important.  Hopefully, the flowers on these tomato plants soon set fruit and gardeners will be rewarded with delicious tomatoes later on in the season.

For more information, see:

 

C.  GOBBLERS IN GARDENS.  Last week the Mahoning Extension office took a call from a suburban homeowner who wanted information on how to keep wild turkeys (Meleagris gallopavo) out of her garden.  According to the Ohio Department of Natural Resources (ODNR), Division of Wildlife turkeys and other wild creatures do occasionally wander into people's yards looking for food, water or shelter.  So, rule number 1; if you do not want wildlife to hang out on your property as they pass through the area, then do not keep easily accessible food, water or shelter opportunities in your yard.  One should understand that things like bird feeders and back yard ponds make great sources of food and water for other wildlife beyond song birds. 

If you enjoy song birds and gardens there is still hope.  One of the most effective methods is exclusion techniques.  Exclusion techniques employ various ways to lock animals out of an area.   Examples of exclusion techniques are fencing and netting.  Fencing off your yard from a neighboring field or forest provides a barrier that will redirect wildlife traffic around your property.  Sometimes the same effect can be done by planting a hedge row of plant material.  Polypropylene netting can be installed over fruit and vegetable crops to eliminate entry from visiting wildlife. Rule number 2; if you want to grow tasty food crops or have a garden pond in your landscape, use exclusion techniques to make it more difficult for wildlife to get near your prized plants.

Repellents deter wildlife.  How effective are they?  According to the ODNR, using repellents is the process of applying offensive scents either natural or synthetic to plants in your garden or landscape with the hope of deterring wildlife away from your property. Products like these can be purchased at hunting/outdoor equipment stores or mail order catalogs.  They are somewhat expensive and very water soluble. Water solubility dictates that each time it rains, they will have to be reapplied.  Officially, most literature states the verdict is still out as to their cost effectiveness using them on a commercial scale, but homeowner size scale results are more promising.  Also remember some of these remedies are not approved by regulatory agencies as wildlife repellents. So, rule number 3; Repellants can help keep some wildlife away from your property or at least a special plant or two if you can keep fresh product on the plant.

Finally, gardeners have one more option in our arsenal of items to deter wildlife from entering our private outdoor domains.  Frightening techniques are methods we employ to simply distract wildlife into thinking they are not safe or welcome on a site.  These products range from reflective tape to predator decoys, propane canons, and scarecrows. In each case we need to remember to move the decoys and scarecrows from one garden to another often.  Wild animals are keen observers and are more likely to approach an area that looks familiar. Desperate gardeners may want to turn to domestic pets for help in keeping wildlife afraid of your property.  If you live in area that permits the legal use of firearms, be sure you follow all State and local laws pertaining to seasonal game and varmint control.

D.  IRON CHLOROSIS IN RIVER BIRCH AND SWEETGUM. 

Nancy Taylor and Gary Gao reported that iron chlorosis was observed on river birch and sweetgum trees.  Iron chlorosis is characterized by yellowing of leaf tissue between veins when plants are unable to acquire enough iron from the soil.  This iron deficiency can be caused by low iron concentration in the soil or alkaline soil conditions.  Iron is needed for the production of chlorophyll and without the iron, the leaves lose their green color.  If uncorrected, twigs and branches may die, and if severe enough, may lead to the death of the tree. 

Treatment options include: foliar sprays of the canopy with an iron solution; an addition of chelated iron to the soil; applying sulfur to the soil to lower pH; and trunk injections of iron solutions.  A foliar spray is a quick and temporary fix of the problem.  Trunk injections are also temporary solutions to the problem.  Lowering soil pH is more permanent.  However, it is quite difficult to maintain a lower soil pH in the upper 12-18" of the soil where the majority of the trees feeder roots are located because of the soil's buffering capacity.  Another more realistic approach is to add chelated iron into the soil by drilling holes to increase the concentration of available iron.  A soil test will be needed to determine soil pH.  Follow fertilizer labels for instructions.  Homeowners might also want to hire a certified arborist to do this service for them.

For more information, see:

 

E.  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 - LOBELIA (Lobelia erinus).  A bedding plant that has been around a long time, lobelia is really making a comeback with the many new cultivars on the market.  The tiny, delicate, bright cobalt blue color lasts all summer and is a great addition to the red, white, and blue garden.  It grows to around 6" tall and has a spreading nature; it's a great plant for containers, hanging baskets, and borders.  Most of the cultivars perform best in light to heavy shade, though some will grow in full sun as long as ample water is supplied.  If they tend to get a bit straggly, a quick haircut is the remedy. Cultivars are also available in white and pinkish colors as well as an upright growth habit.  

For more information, see:


*PERENNIAL - ASTILBE (Astilbe spp.).  These colorful shade-loving plants are exploding into full bloom in Ohio gardens.  One of the best plants for color in the shade, Astilbe prefers rich organic matter and consistently moist soil; however, many cultivars tolerate not-so-rich clay soils once they establish.  If the soil dries out completely, leaf margins burn, therefore, keep consistently moist throughout the summer during drought conditions.  Once the plume-like blooms finish, shear the plant back to just below the flower stems.  The result is a beautiful foliage plant that accents the garden.  Flower color depends upon cultivar and ranges from pinks, to whites, to apricots, to dark reds.  Try A. chinensis 'Visions' for plants that have tougher foliage that is more tolerant to sun than A. arendsii cultivars.  Plants grow anywhere from 6-8" tall (ground cover species) to 3' tall.

For more information, see:

Search PlantFacts.osu.edu

 


*WOODY - OAKLEAF HYDRANGEA (Hydrangea quercifolia).  This incredibly beautiful woody shrub can't be missed if it's in Ohio landscapes at this time.  The creamy white flower panicles are outstanding and fully open.  They last well into July, and then begin to fade pink to eventually a dry-papery brown.  Oakleaf hydrangea takes full sun to dense shade.  It is one of the better choices for a blooming shrub in dense shade.  The plant adapts to full sun sites but doesn't tolerate drying; therefore, adequate watering during droughty times is essential to keep it looking its best.  The best long-term performance for this plant is in partial to full shade sites. 

 


The typical growth habit is rounded and somewhat irregular; it colonizes in shrub borders and can spread to around 15' in width while growing 4-6' tall.  The fall color is an outstanding purplish-red.  An all season plant, oakleaf hydrangea also looks great in the winter when the cinnamon-brown stems with exfoliating bark are revealed.  Prune after summer blooms since flower buds are formed on old wood.  Try the cultivar 'Pee Wee' that grows 3-4' tall with a 2.5-3' spread or 'Sikes Dwarf' that is 3-4' tall by 3-4' wide. 

For more information, see:

Search PlantFacts.osu.edu

 


* THE WEEKLY WEED - BLACK MEDIC (Medicago lupulina).  Our weekly weed is also commonly referred to as the black clover, hop medic or hop clover.  Black medic is a low growing summer annual in most areas of Ohio.  It produces seeds throughout the growing season which tend to germinate in early autumn and spring.  As a member of the Leguminosae (Pea) family, it has the characteristic trifoliate, palmately compound leaf.  Generally, just looking at the leaf one could misidentify it as the WHITE CLOVER, (Trifolium repens), or the YELLOW WOODSORREL (Oxalis stricta).  Look to the inflorescence to distinguish these plants apart.  The white clover inflorescences are typical legume clusters consisting of up to 40 small, white to pinkish-white small flowers.  Black medic blooms are clusters as well, but are bright yellow and somewhat smaller.  The yellow wood sorrel belongs to the Oxalidaceae (woodsorrel) family. It also produces clusters of yellow flowers; however, they grow with only 5 simple petals each.

 

3. GREEN SHORTS.

A.  LESSONS LEARNED.  Last year, Master Gardener Volunteers from Lucas County assisted a township in the county with a tree inventory.  The need arose when ash (Fraxinus spp.) trees throughout the community began to die and they needed to have a better handle on how many ash trees were in the public right-away and needed to be addressed. 

Some of the information gained during this process was shared at a recent township trustee meeting.  Of the 2,017 trees in the public right away, 962 or 47% were pears (Pyrus spp.).  While the majority of the pears were ornamentals, 23 were actually large, edible fruit bearing trees.  As you can imagine, if the pears where not harvested and consumed, the fallen fruit made a real mess and was a magnet for yellow jackets in the fall.  We also learned that the top 3 genera planted in the township made up 83% of the street tree canopy - yikes!

This is just another reminder about the importance of tree diversity.  While this particular community was glad that they weren't facing the wrath of the "pear borer," they now see the importance of planting a variety trees. 

 

4.  CLINIC CLIPS.

Samples continue to pour into the PPDC.  Barb Bloetscher, our resident clinic entomologist, has identified springtails and pomace flies in commercial buildings and diagnosed an abundance of ornamental insect damage including pear sawfly on crabapple and arborvitae leafminer tip damage.  A juniper had multiple pest problems including the juniper plant bug, juniper tip dwarf mite and spruce spider mite.  The overall growth of the branches submitted was stunted, plus the needles had the diagnostic stippling of the spruce spider mites that had been active in early spring.

Plant pathology diagnosticians Bridget Meiring and Nancy Taylor diagnosed Dothistroma needle blight on an Austrian pine sample from southern Ohio, and fire blight on bearberry cotoneaster, Callery pear, and serviceberry.  Botryosphaeria canker was identified on 'Wichita Blue' juniper.  This disease was causing dieback of the branch ends, and can cause cankers on main stems leading to dieback of entire branches.  Abiotic (non-infectious) problems included seasonal leaf drop of holly, leaf scorch on dogwood and northern red oak, and iron deficiency symptoms on river birch. 

 

5.  BUGBYTES.

A.  GYPSY NEWS.  GYPSY MOTH (Lymantria dispar) caterpillars continue their feast in Ohio.  During this week's call, there was interesting discussion about BYGLers' observations from out in the field.  Dave Shetlar reported seeing smaller sized caterpillars in populations with higher numbers.  In reverse, the smaller populations had larger caterpillars - almost snake-like (just kidding). 

Dave also reported seeing caterpillars being killed by Entomophaga maimaiga and Nucleopolyhedrosis virus (NPV), parasitoids buzzing about, and some beginning pupate.  The majority of caterpillars in the Toledo area are at 4th instar and finally becoming obvious to residents who want to be outside enjoying the weather. 

For more information, see:


B.  HICKORY TUSSOCK MOTH. 


Dave Shetlar reported observing 1st instar HICKORY TUSSOCK MOTH (Lophocampa caryae) caterpillars munching American elm leaves this week in central Ohio.  First instar caterpillars feed gregariously in colonies as leaf skeletonizers; the appearance of "see through" leaves is a good indicator the caterpillars are afoot.  Later instars are solitary feeders and they consume entire leaves.

The caterpillars may be found on a wide range of deciduous trees and shrubs including ash, crabapples, elms, oaks, and sweetgum, as well as their namesake host.  Additionally, as with all tussock moths, the caterpillars are protected by stinging (urticating) hairs.  Direct contact with skin can produce a rash similar to reactions to poison ivy. 


Although larvae of all instar stages are covered with stiff white hairs, 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.  It is suspected that hickory tussock moths have two generations per year in Ohio.

 For more information, see:

Search PlantFacts.osu.edu

 

C.  MIXED SYMPTOMS ON OAKS.


Dave also reported observing feeding damage from SPINY OAK SAWFLY (Periclista albicollis) mixed with varying sized holes produced by the OAK SHOTHOLE LEAFMINER (Agromyza viridula) on oak leaves in central Ohio.  The appearance of both symptoms on the same tree may produce a management challenge based on proper pest identification, particularly on oaks in nurseries.  Both of these hole-making culprits have completed their seasonal development adding to the diagnostic challenge since the pest identification must now be based on symptoms rather than seeing the actual insects.

The tiny shothole leafminer fly (Family Agromyzidae) produces distinct holes in leaves through the feeding behavior of the adult females and the leaf mining activity of the larvae (maggots).  Females wing their way to oak leaves just as the leaves emerge from the bud.  They use their sharp, flexible ovipositors to penetrate the nascent leaves to release sap and their sponging mouthparts to lap up the nutrient rich fluid.  The resulting feeding wounds produce tiny holes in the juvenile leaves.  Occasionally, the female will insert an egg into the leaf and the resulting maggot produces small, circular leafmines.  The mined leaf tissue drops from the tree to produce holes once the maggots mature and vacate the leaves.  Both the adult feeding holes and larval leafmining holes become larger as the leaves expand.  



The semi-transparent spiny oak sawfly larvae are green to yellowish-green in color and they have black head capsules.  The black spines are bifurcated and arise from black spots on the body.  The larvae feed in loosely organized groups and they produce holes in oak leaves.  As with the leafmining fly damage, the holes expand as the leaves expand.  However, Dave noted that the sawfly damage appeared to be more tattered and most concentrated on leaf tips and edges while the fly leafmining holes were very "clean" and found over the entire leaf.

 

 

Search PlantFacts.osu.edu

 

D.  MAGNOLIA SERPINTINE LEAFMINING CATERPILLAR. 

Participants in this week's Master Gardener Advanced Training Diagnostic Workshop in Clark County observed a magnolia leaf specimen adorned with the highly visible handiwork of the magnolia serpentine leafmining caterpillar (Phyllocnistis magnoliella).  The tiny caterpillars of this aptly named moth feed close to the upper leaf epidermis, producing long, thin, serpentine mines that appear as silvery tracks snaking across the leaf surface.

Hosts for this leafminer includes southern, cucumber, sweet bay, star, umbrella, and the aforementioned bigleaf magnolias.  Large numbers of mines on a single leaf can cause the leaf to turn brown and drop from the tree.  Little is known regarding the life-cycle of this moth making the effective timing of insecticide applications to control the caterpillars problematic.  Fortunately, heavy populations involving multiple leaves appear to be rare occurrence.  Thus, populations may be managed by removing and destroying infested leaves when mines first appear.

 

E.  WARM SEASON MITES ARISE. 


As seasonal temperatures rise, so do the populations of warm season spider mites.  Among the spider mites that tend to flare-up during periods of hot, dry weather conditions, the most notorious is the TWOSPOTTED SPIDER MITE (Tetranychus urticae).  However, other warm-season mites may also join the ranks as temperatures rise including:  OAK SPIDER MITE (Oligonychus bicolor); MAPLE SPIDER MITE (O. aceris); and the HONEYLOCUST SPIDER MITE (Platytetranchus multidigituli).   Proper identification of these warm-season mites is essential for developing effective pest management strategies.

All spider mites feed by inserting their needle-like mouthparts into host tissue and withdrawing the cell contents.  Feeding damage generally first appears as distinct tiny yellow spots (stippling).  The spots may eventually coalesce to produce leaf chlorosis (yellowing), browning, or bronzing, with subsequent defoliation when damage is severe.  Unfortunately, the pattern of symptoms may vary among different host plants.  For example, Joe Boggs reported that some twospotted spider mite symptoms on Knock-Out roses are currently mimicking symptoms produced by a nutrient deficiency or a viral infection.


Effective control of warm season mites can be accomplished with an array of miticides available to professional applicators; however, products should be rotated among active ingredients to avoid the development of miticide resistance.  Homeowners are limited to insecticidal/miticidal soaps or horticultural oil (at 1.5%) which also conserves mite predators.  Keep in mind that applications must target the lower leaf surface, where most mite species reside with the exception of the oak spider mite which resides on the upper leaf surface.

For more information, see:

Search PlantFacts.osu.edu

 

F.  WEBWORM OR BORER? 


Curtis Young had collected samples of POISON HEMLOCK (Conium maculatum) and WILD PARSNIPS (Pastinaca sativa) to use in Pam Bennett's diagnostic clinic to teach the attendees what these two non-native weeds are and how to recognize them.  Both plants have excellent defenses against herbivores, poison hemlock contains piperidine alkaloids and wild parsnips contains furanocoumarins.  Even with these potent chemicals within the bodies of the plants there are still insects that feed upon their foliage, flowers, seeds and stems. 

 

 The sample of wild parsnips was being devastated by a caterpillar, the PARSNIP WEBWORM (Depressaria pastinacella).  It was a bit confusing as to the identity of the caterpillar since it appeared to be boring into the stalk of the parsnips plant.  It looked more like a stalk borer than it did a webworm.  However, it turns out that the parsnips webworm becomes a borer when it is preparing to pupate.  Mature larvae abandon their webs that they construct amongst the flowers and developing seeds in the umbels to migrate to lower portions of the stem.  Once at a thick enough area on the plant, the caterpillars bore into the stalk to pupate in the center of the stem.  When numerous webworms bore into the stalk in this manner, they can completely cut the vascular tissue to the upper portions of the plant resulting in the premature death of the plant.  This is a good thing when the parsnip is growing out of control in areas where they could be a threat to people and animals that could accidentally come in contact with the sap of the plant.  On the other hand, in some parts of the world parsnips are cultivated as an agricultural crop.  Here the parsnips webworm is considered an agricultural pest.  Pest? Beneficial? Webworm? Or Borer?  It's all a matter of perspective.

A final note - do be careful when working around these plants.  They can be quite harmful to deadly.  Just ask Socrates.  Or ask Curtis who now has a few patches of blisters on the back of his hand from the juices of the wild parsnips plant while he was taking pictures of the parsnips webworms.  He got a little careless and got some of the sap of the plant on his skin.

For more information, see:

 

6.  DISEASE DIGEST.

A.  RUSTY BRAMBLES OR NATURE'S TATTOOS. 

Curtis Young discovered numerous brambles in a wildlife area that were covered with ORANGE RUST (Gymnoconia spp.) pustules.  Orange rust-infected plants can be easily identified shortly after new growth appears in the spring.  Newly formed shoots are weak and spindly.  After a few weeks, the lower surface of the infected leaves is covered with blister-like pustules that are waxy at first but soon turn powdery and bright orange.  This fungal disease attacks all varieties of black and purple raspberries and most varieties of erect blackberries and trailing blackberries are very susceptible.  Orange rust does not infect red raspberries.  The disease does not normally kill plants, but causes them to be so stunted and weakened that they produce little or no fruit.  As a kid, Curtis remembers using the bountiful spores produced by the rust to "tattoo" his arms and backs of hands.

Fungicide sprays are not generally considered an effective control method of orange rust.  Whenever possible, start with disease-free, certified nursery stock.  When a diseased plant first is noted in early spring, dig out the entire plant.  Remove all wild raspberries and blackberries from within and around the planting site.  Refer to OSU Extension FactSheet HYG-3010-08, "Orange Rust of Brambles" for additional information.

For more information, see:

 

7.  TURF TIPS.

A.  SMOKING GRASS? 

Do you see what looks like cigarette wrappers on the surface of the turfgrass?  Are the birds pulling up silken tubes from the turf?  If so, relax, your turfgrass didn't pick up a bad habit, you are seeing the pupal cases of the BURROWING SOD WEBWORM (Acrolophus popeanellus).  This member of the Acrolophidae Family is related to the common sod webworms however it is unusual in that the larvae burrow vertical tunnels along the root of grass species, instead of more or less horizontal through the thatch.  These tunnels are lined with a fine protective layer of silk.  Most of the research on this species has been done on field corn as its abundance in turfgrass is less predictable and harmless.

The adult moth is easily identifiable due to its folded (tent-like) wings and brown/white speckled pattern.  The male has exceptionally large and spectacular palps (mouthparts) that extend over its head and toward the wings.  In June and July, the female moths may be seen flying over the turfgrass at and slightly after dusk.  Intermittently she will drop to the turfgrass surface and crawl onto the thatch where she lays several eggs.  Once the caterpillars hatch, they begin to tunnel alongside a grass root (usually Kentucky bluegrass, tall fescue or Bermudagrass).  These slender velvety looking brown caterpillars reach from their tunnels at nighttime to graze on thatch in the summer then stop feeding in late fall.  The following spring they will resume feeding until they are ready to pupate.  As the newly eclosed adults wriggle from their silken tunnels, the silk tube is often pulled to the surface of the turfgrass where birds and lawnmowers pull them up.

Fortunately, these interesting lepidoptera are not considered to be harmful to turfgrass and do not require treatment.  They are merely an interesting species that arouses concern from unknowing clients.

For more information, see:

Search PlantFacts.osu.edu


B.  MASKED CHAFERS EMERGING! 

Dave Shetlar announced that he has been catching adult masked chafers in his light traps this week, implying that turfgrass managers who have had problems with masked chafer grubs in the past should have their management strategy in place. 

While collecting white grub pupae from his test plots, he noted that while the masked chafers were in the pupal stage or emerging, many of the Japanese beetle larvae had not yet pupated or were in the process of pupating, indicating that they would be emerging in some locations in another 2-3 weeks.  However, areas that received more moisture may already have some adult Japanese beetles, as some have already been reported on OSU campus.

 

 

For more information, see:

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8.  INDUSTRY INSIGHTS.

A.  WANT AN ACCURATE DIAGNOSIS?  SEND A GREAT SAMPLE!  The saying "you get what you pay for" can be translated in plant diagnostic terms to "the diagnosis is as good as the sample."  Nancy Taylor, Director of the CWEPPDC is always reminding BYGLers and the public to send GOOD samples to the clinic (or to any other diagnostician, county Extension office, etc.).  "Dead brown branches" are not good samples; diagnosticians don't perform autopsies!

The accuracy of the diagnosis depends upon the information supplied, the sample material, and the condition of the sample.  First of all, supply as much information as possible.  Help the diagnostician to understand the situation as best as can be described.  Next, make sure the sample is representative of the entire problem.  A single leaf or stem won't reveal much.  However, a branch that shows the good and the bad, as well as the transition area (where the good goes bad) is a great sample.  In addition, send more than one branch, leaf, etc.  Select random samples from the plant and be generous.  In fact, the whole plant is best but of course, this isn't always feasible.  Finally, make sure the sample is in good condition.  Don't leave it in the car all day as it won't be fresh! 

For more information on sending good samples, refer to the Clinic website:  http://ppdc.osu.edu/ .  It is a well-done website with lots of information on exactly what to collect and how to send.  In addition, the forms, fees, and other details are also provided on the website.  Remember, if you want an accurate diagnosis, send great samples!

For more information, see:

 

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.  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 .

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.  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.   

"I appreciate the misunderstanding I have had with Nature over my perennial border.  I think it is a flower garden; she thinks it is a meadow lacking grass, and tries to correct the error." - Sara Stein

 

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.

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