Pam Bennett, Barb Bloetscher, Joe Boggs, Jim Chatfield, Erik Draper, Dave Dyke, Gary Gao, David Goerig, Tim Malinich, Amy Stone, and Curtis Young
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May 10, 2007
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This is the Sixth 2007 edition of the Buckeye Yard and Garden Line (BYGL).
BYGL is developed from a Tuesday morning conference call of Extension
agents, specialists and other contributors in Ohio.
BYGL is also made available on the Internet from the Ohio State University
Horticulture and Crop Science (HCS) in Virtual Perspective website
(http://bygl.osu.edu). Additional fact sheet information on any of
these articles may be found through the OSU fact sheet database (http://plantfacts.osu.edu).
BYGL is a service of OSU Extension and is aided by major support
from the Ohio Nursery and Landscape Association (ONLA), with additional
funding from the Ohio Chapter of the International Society of Arboriculture
(ISA) to the OSU Extension Nursery Landscape, and Turf Team (ENLTT).
Participants in the May 08, 2007 conference included: Pam Bennett (Clark); Barb Bloetscher (Entomology/C. Wayne Ellett Plant and Pest Diagnostic Clinic (CWEPPD Clinic)); Joe Boggs (OSU Extension Center at Piketon/Hamilton-Clermont); Jim Chatfield (OSU Extension Center at Wooster/Hort and Crop Science); Erik Draper (Geauga); Dave Dyke (Hamilton); Gary Gao (Delaware); David Goerig (Mahoning); Tim Malinich (Lorain); Dave Shetlar (Entomology); Amy Stone (Lucas); Nancy Taylor (Plant Pathology/CWEPPD); Curtis Young (Allen); and Randy Zondag (Lake). .
Additional factsheet information on any of these articles may be found
through the OSU Factsheet Database (http://plantfacts.ohio-state.edu/)
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WEATHER WATCH
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The following weather information has been summarized from data collected from May 1-May 9, 2007. BYGLers have chosen six locations to highlight different regions of the state to be included in BYGL each week as seen in the table below. Additional, there are weather station sites in Avon (Lorain County), Madison (Lake County), Perry (Lake County), at the Muck Crops Research Station (Huron County), at the North Central Research Station (Sandusky County), and at the Western Research Station (Clark County). The weather data collected from all the sites can be seen at http://www.oardc.ohio-state.edu/newweather/.
| Weather Station |
Region of Ohio |
Ave. High Temp F |
Ave. Low Temp F |
Total Precip " |
Normal Precip " |
| Ashtabula |
NE |
69.7 |
43.0 |
NA |
0.9" |
| Wooster |
NE |
74.8 |
45.0 |
1.14" |
0.9" |
| Hoytville |
NW |
73.2 |
46.4 |
0.81" |
0.8" |
| Delaware |
Central |
72.7 |
49.2 |
0.23" |
0.9" |
| Piketon |
South |
76.7 |
50.7 |
0.17" |
1.4" |
| Jackson |
South |
77.2 |
48.1 |
0.04" |
1.2" |
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HORT SHORTS
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GDD (GROWING DEGREE DAYS)
GDD is a measure of the daily maximum and minimum temperature and directly relates to growth and development of plants and insects. The GDD of any zip code location in Ohio is estimated using the GDD of ten OARDC weather stations and available on the web at http://www.oardc.ohio-state.edu/gdd/.
The range of GDD accumulations in Ohio from north to south is 233 to 540. Following is a report of GDD for several locations around Ohio as of May 7, 2007: Painesville, 233; Cleveland, 257; Toledo, 294; Canfield, 290; Lima, 303; Wooster, 335; Coshocton, 303; Columbus, 355; Springfield, 417; Dayton, 436; Cincinnati, 489; Ironton, 528; Portsmouth, 530; Piketon, 540; Marietta, 500; and Jackson, 536.
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.
lder leafminer, adult emergence, 224; honeylocust plant bug, egg hatch, 230; common lilac, first bloom, 234; Ohio buckeye, first bloom, 245; common horse chestnut, first bloom, 251; hawthorn lace bug, adult emergence, 253; hawthorn leafminer, adult emergence, 260; flowering dogwood, first bloom, 263; red buckeye, first bloom, 265; blackhaw viburnum, first bloom, 269; imported willow leaf beetle, adult emergence, 274; sargent crabapple, full bloom, 298; red horsechestnut, first bloom, 304; pine needle scale, egg hatch - 1st generation, 305; cooley spruce gall adelgid, egg hatch, 308; eastern spruce gall adelgid, egg hatch, 308; common lilac, full bloom, 315; pink princess weigela, first bloom, 316; blackhaw viburnum, full bloom, 322; redosier dogwood, first bloom, 323; dwarf fothergilla, full bloom, 325; winter king hawthorn, first bloom, 328; lilac borer, adult emergence, 330; slender Deutsia, first bloom, 338; Japanese kerria, full bloom, 342; common horsechestnut, full bloom, 344; red chokeberry, full bloom, 351; doublefile viburnum, first bloom, 353; Pagoda dogwood, first bloom, 363; red Java weigela, first bloom, 365; black cherry, first bloom, 368; common sweetshrub, first bloom, 371; lesser peach tree borer, adult emergence, 372; Ohio buckeye, full bloom, 374; holly leafminer, adult emergence, 375; Vanhoutte spirea, full bloom, 406; euonymus scale (first generation), egg hatch, 406; black cherry, full bloom, 419; Miss Kim Manchurian lilac, first bloom, 422; locust leafminer, adult emergence, 437; doublefile viburnum, full bloom, 444; black locust, first bloom, 467; common ninebark, first bloom, 478; oystershell scale, egg hatch, 497; smokebush, first bloom, 501; arrowwood viburnum, first bloom, 534; American yellowwood, first bloom, 546; and bronze birch borer, adult emergence, 547.
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PLANTS OF THE WEEK
Read all about perennials and landscape trees and shrubs in the ONLA publications "Perennial Plants for Ohio" and "Landscape Plants for Ohio." The descriptions and photographs of plants were provided for these publications by the OSU ENLT Team along with other industry plant lovers. These full-color publications are available at http://Buckeyegardening.com for $5.00 each. Click on "garden store" and then "ONLA plant guides." ONLA members can purchase these in quantities at a reduced price at http://onla.org.
* PERENNIAL OF THE WEEK: CREEPING PHLOX (Phlox subulata). This plant is one of the most popular-selling plants in the garden center in early spring when in bloom, that it practically sells itself! Creeping phlox forms a carpet of bright pink, purple, or white during the early spring. It's an excellent ground cover for the front of the border, a rock garden filler, or hanging over walls. It gets around 6" tall but can spread anywhere from 3-6'. After it finishes blooming, however, it tends to get a bit straggly. Cut it back by half to rejuvenate the foliage and keep it looking nice during the summer. When you do this it can add a spiky texture to the garden. Try the cultivar 'Emerald Cushion Blue' with its emerald green foliage and blue flowers or 'Emerald Cushion Pink' with pink flowers.
* WOODY PLANT OF THE WEEK: PAWPAW (Asimina triloba). Nascent blossoms of this native tree were nipped in the flower buds throughout much of Ohio this year, but some northern areas will see some of what Michael Dirr notes as "lurid purple flowersrarely seen by the uninitiated." Here is the description of one of our few native fruit trees from Landscape Plants for Ohio:
Pawpaws have rising popularity as a small 15-20' landscape tree. It is a native tree that grows in woodland "patches." Pawpaws have a pyramidal shape. Their leaves that are large, spanning 6-12" with attractive fall color. Flowers develop before leaves, and are sparse but fascinatingly beautiful, as often nodding deep purple rosettes. Greenish-yellow fruits that ripen to brownish-black are tasty, but will only develop if you plant two trees.
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THE WEEKLY WEED
During BYGL conference call this week, the group has decided to experiment with a new item. Each week, a weed will be chosen and highlighted in the Weekly Weed section. We hope you enjoy!
JAPANESE KNOTWEED (Polygonum cuspidatum) is a deep rooted perennial weed that can cause long term problems. Originally introduced as an ornamental, this invasive weed propagates primarily by underground rhizomes but can also spread by seed. This weed can grow 3-6' in height. It prefers moist well-drained soils, but is a common weed of ditches and roadsides. Strong red shoots emerge in early spring and produce dense clumps of plants with reddish or speckled stems; its other alias, Mexican bamboo, refers to the hollow, chambered stems. Small white flowers are produced from leaf axils in late summer.
Control of Japanese knotweed is difficult at best. Mechanical control requires constant pulling, cutting, and removal of rhizomes or stems until the remaining roots starve to death. This can require mechanical removal every two weeks. New plants can be produced from any remaining rhizomes and emerge through mulches and occasionally, even asphalt.
Control with systemic herbicides has some success. But, product entering the plant is often insufficient to kill the extensive deep root system. Multiple applications are required to control this weed and application should be targeted for when the sufficient leaf mass to pick up the herbicide.
Products containing glyphosate have some effect on this plant and there are also reports of triclopyr, imazapyr, and 2,4-D products being useful. Make a trial spray of a product to test its effectiveness. As Japanese knotweed can occur in waterways or aquatic areas, read the herbicide label and be certain that the product is labeled for use in the area where the application is to be made.
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BUG BYTES
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GYPSY MOTH MEDIA PANIC MODE
Dave Dyke and Joe Boggs bemoaned recent public panic induced by the inadequate and often inaccurate media coverage of the Ohio Department of Agriculture's (ODA) applications of Bacillus thuringiensis var. kurstaki (Btk) to try to eliminate gypsy moth populations in Hamilton County. Despite an extensive and broad-based media notification effort by the ODA to make the public aware of the applications, the low-flying aircraft produced a media coverage flying circus.
Joe reported one television station showed images of a collection of ambulances, with lights flashing, parked in a neighborhood where people were complaining of a wide range of "poisoning" symptoms. The reporter seemed to fan the flames by constantly referring to Btk as if it were a highly toxic compound! Only a short interview at the end of the segment revealed that Btk is approved for use in organic produce production. Dave noted that a competing television station (not to be outdone!) showed aircraft along with images of forest tent caterpillar, and the silk nests of eastern tent caterpillar. Of course, the exact application details were similarly misrepresented.
The take-home message is that BYGLers and BYGL readers should help support ODA's efforts to inform the media, and consequently the public, of the details and significance of ODA's Slow-the-Spread program. This is only the beginning. Typically, two applications of Btk are made in a season. Additionally, thousands of acres will be treated across Ohio in 2007 using either insecticides or pheromone flakes. Program details, along with maps of application blocks and dates, can be found on the ODA's gypsy moth website: [ http://www.ohioagriculture.gov/gypsymoth/ ]. Help slow the spread of media-induced panic!
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APHIDS HAVE SPRUNG ON SPRING
Observations made in landscape plantings have revealed a couple of different aphids building in populations. Two examples of aphids that have shown up in the landscapes, where their feeding activities have given away their positions on the landscape plants are the BLACK BEAN APHID (Aphis fabae) feeding on EUONYMUS (Euonymus alatus) and the SNOWBALL APHID (Neoceruraphis viburnicola) feeding on KOREAN SPICE VIBURNUM (Viburnum carlesii). The black bean aphids' feeding is causing the leaves and the stems of the new terminal growth to twist and curl; copious quantities of honeydew are accumulating on the curled leaves below the feeding colonies. The snowball aphids' feeding is causing new leaves on the viburnum to pucker, curl, and cup. The damage from these two aphids is mostly of aesthetic kind in the landscape and includes: disfigured leaves and stems; accumulations of honeydew on plants and objects below the feeding colony; and attraction of flies, yellow jackets, wasps, and ants. However, in nurseries the distorted leaves and twigs may result in stunted and distorted growth patterns of immature stock resulting in slow progress to a salable product. The aphids are not limited to landscape plants. They are also showing up in agricultural crops, such as winter wheat. The BIRD CHERRY-OAT APHID (Rhopalosiphum padi) is causing a little excitement among grain producers.
There are several options for managing aphids in both the landscape and agricultural fields. One option is to do nothing at all and leave nature take its course. There are many 'helpers' in nature that will reduce or eliminate aphid populations if they are given a little bit of time. While examining the bird cherry-oat aphid populations in winter wheat field, Curtis Young noted that there were numerous predators arriving in the fields to feast on the aphids, including: LADY BEETLES, such as Coleomegilla maculate and SYRPHID FLIES (Hover flies)(Family Syrphidae), 1-3 eggs were with each batch of aphids. Homeowners can use a garden hose to syringe the aphids off of the plants, most will not be able to recover from the blasting. Several insecticides for both professionals and homeowners will be effective in reducing populations, including insecticidal soaps, synthetic pyrethroids, malathion, and systemic insecticides such as acephate and imidacloprid. Dave Shetlar also mentioned that some aphid species may be a bit more difficult to control with the contact insecticides because they are covered with waxy secretions. A 1-1 1/2% solution of horticultural oil mixed with these insecticides may increase their effectiveness by aiding the penetration of the waxes.
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RESCUE TREATMENT FOR WHITE PINE WEEVILS
For those who have not yet protected the pines, spruces, and firs from damage of the white pine weevil, a few options are still possible, if done immediately. According to Dr. Shetlar, the upper whorls can still be sprayed with a labeled insecticide containing dimethoate. Some products still labeled include Helena Dimethoate 4EC, Clean Crop Dimethoate 400, and Cheminova Dimethoate 4EC. Christmas tree growers need to read the labels carefully, as some are NOT labeled for use on Christmas trees.
A trunk injection of Bidrin or MSR (Metasystox R) would also still be effective, if applied soon. For those areas where the white pine weevil attacked in prior years, treatment is advisable. Look for golden droplets of sap dripping from the leader of the trees. The dripping sap indicates that the female weevil has already "bled" the leader and has probably deposited eggs above that area.
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FOREST TENT CATS CONTINUE TO ROAR
As noted in previous BYGLs this season, localized infestations of forest tent caterpillars (Malacosoma disstria) are heavy in central and southwest Ohio. Dave Shetlar reported that most caterpillars in central Ohio are around 1/2"' long, and are producing pockets of noticeable defoliation to preferred hosts including oak, sugar maple, ash, sweetgum, birch, crabapple, hawthorn, and cherry.
Joe Boggs noted that caterpillar development in the southwest part of the state appears to be less synchronized. Newly constructed cocoons were observed on Monday, while large numbers of caterpillars have not yet grown beyond 1/2"' long. The wide range in development is presumably the result of disruptions and delays in egg hatch caused by high temperatures in late March, when eggs began to hatch and cool temperatures in early April as the caterpillars fed.
High populations coupled with the extended tour of caterpillar duty are producing some truly dramatic leaf loss including some wooded areas suffering 100% defoliation. Joe reported making a site visit to a home surrounded by a defoliated wooded area. Hungry caterpillars descending upon the home's landscaping had completely defoliated a dogwood and lilac, and they were munching away on group of burning bush euonymus, and a katsuratree. Even the peonies were heavily damaged!
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WINDSHEILD WIPES
*Dave Shetlar reported that three sawfly leafminer species should be out and actively laying eggs in their respective host plant leaves. The three leafminers include: the BIRCH LEAFMINER (Fenusa pusilla); the ELM LEAFMINER (F. ulmi); and the HAWTHORN LEAFMINER (Profenusa Canadensis). Controls for these leafminers should be applied around mid-April to early May.
*Joe Boggs and Dave Shetlar both received calls in reference to the adults of the BOXWOOD LEAFMINER (Monarthropalpusi flavus). The adult boxwood leafminer is approximately 1/10" long. The body of this gnat-like fly is delicate and orange-yellow to red in color. Large groups of the newly emerged adults were covering the tops of the infested host plants. Surprisingly, none of the callers had noticed the leafmining damage produced by the larvae on the leaves.
*Other insects observed floating around landscapes included the black turfgrass ataenius adults, May/June beetle adults, black field ant workers, European pine sawfly larvae still feeding on Mugo pines in northwest Ohio, and carpenter bees.
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DISEASE DIGEST
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CSI ROSES - EXTENSION STYLE
Dave Dyke and Joe Boggs reported investigating a case of downy mildew of roses. The infection was severe, with widespread leaf discoloration and heavy leaf loss. While the disease can develop on all parts of the plant, except roots, leaf symptoms are the most obvious. Symptoms progress from very slight discolorations on the upper leaf surface, to distinct reddish-brown spots, to very obvious angular dark green to purple lesions bounded by veins and surrounded by bright yellow tissue. Heavy infections can produce complete defoliation.
Joe and Dave noted that the disease provided an excellent example of the power of the triangle that is, the "Disease Triangle." The triangle illustrates that plant diseases develop when three conditions are met: there must be a susceptible host; a pathogen must be present; and the environment must be conducive to infection and disease development. Practically all roses are susceptible, so the first condition was met.
The pathogen responsible for downy mildew of roses is Peronospora sparsa. This is an Oomycete, which are organisms that were once grouped with fungi but are now grouped in another Kingdom, Straminiphila. A number of protectant materials are effective against this pathogen; however, multiple applications are required and products from different fungicidal groups should be used to avoid resistance. Effective materials include: dimethomorph (e.g. Stature DM); copper sulfate pentahydrate (e.g. Phyton 27); trifloxystrobin (e.g. Compass); pyraclostrobin (e.g. Insignia); azoxystrobin (e.g. Heritage); and fosetyl-AL (e.g. Aliette).
Of course, no spray program alone will be effective. The third side of the triangle, the environment, must first be addressed. The environment conducive to downy mildew development on roses includes high humidity (sustained above 85-90%) and cool temperatures. The roses were in 1 gallon containers and being held in polyhouses to enhance growth prior to installation. The polyhouses were poorly ventilated relying on two doors at each end to provide air movement. Indeed, the highest incident of infection occurred in the center of the polyhouses. Proper ventilation is the key to suppressing this disease which is why downy mildew of roses is rarely observed in landscapes.
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TURF TIPS
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CORE AERIFICATION FOR LAWNS
Soil conditions are good now for core aerating lawns for thatch management. Research has shown that this is the best approach to managing thatch when layers are 1/2" in depth or less. Lawns are aerified by pulling up cores of thatch and soil and depositing them on the lawn surface. Rainfall or irrigation break apart the soil cores, causing the soil to sift down into the existing thatch layer. This addition to the thatch layer improves the environment for soil microbes, resulting in increased microbial activity for thatch breakdown and improved root growth.
Soil cores should be 2-3" in length with a diameter of 1/2-3/4." At least 8 to 9 cores should be pulled per square foot. Depending on the aerifying machine being used, more than one pass over the lawn may be required to achieve the desired number of holes.
Aerification can be performed twice a year, once in the spring (April-May) and one more time in the fall (September-October). If you only aerate your lawn once a year, fall is the preferred time as soil moisture is adequate for tine penetration, temperatures are more conducive to lawn recovery, and root growth is favored during the fall period. If you aerate twice a year, do it in both spring and fall. Spring aerification may result in weed invasion. However, benefits of spring aeration still outweigh the potential problem of weed invasion.
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INDUSTRY INSIGHT
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PESTICIDE LABELS ARE THE LAW
Randy Zondag reminded BYGLers that as promised, the Ohio Department of Agriculture (ODA) has begun their pesticide regulations compliance inspections. It was noted that not only are they checking application recordkeeping but they are also inspecting types of chemicals found in the pesticide storage units. Why examine the chemicals one might ask? They are checking to see if the chemicals being used can be legally applied in nurseries or where Worker Protection Standards (WPS) are applicable. We all know that chemicals are one of the highest costs of growing quality plants. Finding the same chemical for much less is always welcome; unless, of course, the chemicals were not intended or labeled for use in specific situations.
Erik Draper reminded the group of this same dilemma facing vegetable growers who are using the new high tunnel growing systems for tomato production. In the eyes of the ODA, these high tunnel structures are classified as greenhouses, even though they are out in the middle of the field. Most of the chemicals that are used in field production are not to be used in high tunnel production system. For the high tunnel growers, all chemicals applied in that structure must be labeled for use in a greenhouse! This means that if an inspection occurs and a high tunnel production system is in use you'd better have chemicals labeled for use in a greenhouse, as well as chemicals for use in field production.
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COMING ATTRACTIONS
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CHADWICK PLANT SALE FRIDAY AND SATURDAY
The Chadwick Arboretum Plant Sale takes place this Friday, May 11, 7 a.m.-7 p.m., with a tree and shrub auction at 11:00 a.m. Friday. The sale continues Saturday, May 12, 9 a.m.-3 p.m. with another tree and shrub auction at 11:00 a.m. You can download the Plant Sale flyer with the complete list of plants, books, tools, and auction items available at the website location below. The sale is being held
just east of Highway 315 on the OSU campus at the intersection of Lane Avenue and Fyffe Road
More information can be obtained at http://chadwickarboretum.osu.edu/upcoming-events/plant-sale/.
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BYGLIVE! IN CINCINNATI
The 2nd 2007 BYGLive! Diagnostic Walk-About will be held Monday, May 14th, from 12:00 p.m.-3:00 p.m. at Cox Arboretum & Gardens Metropark, 6733 Springboro Pike, Dayton, 45449. This monthly hands-on training for green industry professionals focuses on diagnosing plant pest, disease, and physiological problems. ISA Certified Arborist CEU's will be available.
Driving directions from Cincinnati to the meeting location are as follows: travel north on I-75 to exit 44 (Dayton Mall or Centerville/Miamisburg exit); turn right at the bottom of the exit onto SR725. Turn left at the 2nd stop light (first major intersection) onto SR741/Springboro Pike. The Park entrance is about 4 miles on the left (just past the park's employee entrance). We will meet in the "Overflow Parking Lot." For more information, contact Joe Boggs at 513-946-8993.
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ADVANCED MASTER GARDENER TRAINING - DIAGNOSTIC WALK-ABOUT
Join Jim Chatfield, Joe Boggs, and Tony Nye for an educationally fun-filled diagnostic walk-about at the Wilmington College Hazard Arboretum from 10:00 a.m.-3:00 p.m. on Thursday, May 17, 2007. This hands-on training will focus on identifying and managing landscape tree, shrub, and turf problems. The $10.00 fee for this program will cover the cost of lunch. Reservations must be received by Monday, May 14th. For more information, contact Tony Nye at 937-382-0901.
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OHIO PLANT DIAGNOSTIC WORKSHOP
Join the Hancock County Master Gardeners & Extension Specialist Chatfield on Monday, May 21, 2007 for a fun-filled educational day of Horticultural Diagnostics. The program will be held from 9:30 a.m - 4:00 p.m. at The Lodge at Riverbend, 16618 Township Rd. 208, Findlay, OH.
Get insight into what's invading our neighborhoods - some good, some bad, and some just plain ugly! Hone your skills whether as a beginner or experienced diagnostician. ISA & CFE Credits will be available. Added benefit: you will enjoy the 3rd Annual Ice Cream Sundae Fest happening during the afternoon session! The registration fee is $35.00 which covers lunch, program materials, and of course, the ice cream! For the program agenda and registration information, visit the OSU Extension, Hancock County website at: http://hancock.osu.edu/hort/mgpdf/07DWReg.pdf
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SECOND ANNUAL NORTHEAST OHIO DIAGNOSTIC CLINIC
On Wednesday, June 6, 2007, at the Donald W. Meyer Center of Big Creek Park in Chardon , Ohio, Jim Chatfield and Erik Draper will lead the discussion and confusion as they try to solve any and all plant diagnostic dilemmas. This workshop will be hands-on with samples galore. There will be an update on the Emerald Ash Borer, Dr. Dendro Phile will speak on trees, discuss digital diagnostic, and look at lots of plant samples. Attendees are encouraged to bring along their own diagnostic dilemma samples to see if the combined expertise of the group can help solve the mystery. The $35 fee includes lunch, handouts, snacks, and prizes. To register or for more information call the Geauga County Extension office at 440-834-4656 or for directions see this link http://www.geaugaparkdistrict.org/parks/bigcreek.shtml#DIRECTIONS.
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BYGLOSOPHY
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"A flower is an educated weed." Luther Burbank
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