Pam Bennett, Barb Bloetscher, Joe Boggs, Jim Chatfield, Erik Draper, Dave Dyke, Gary Gao, Dave Goerig, Dan Herms, Tim Malinich, Jane Martin, Pam Sherratt, Amy Stone, and Curtis Young.
|
|
June 03, 2004
|
|
This is the Ninth 2004 edition of the Buckeye Yard and Garden Line (BYGL).
BYGL is developed from a Tuesday morning conference call of Extension
agents, specialists and other contributors in Ohio.
BYGL is also made available on the Internet from the Ohio State University
Horticulture and Crop Science (HCS) in Virtual Perspective website
(http://bygl.osu.edu). Additional fact sheet information on any of
these articles may be found through the OSU fact sheet database (http://plantfacts.osu.edu).
BYGL is a service of OSU Extension and is aided by major support
from the Ohio Nursery and Landscape Association (ONLA), with additional
funding from the Ohio Chapter of the International Society of Arboriculture
(ISA) to the OSU Extension Nursery Landscape, and Turf Team (ENLTT).
Participants in the June 01, 2004 conference included: Pam Bennett (Clark); Joe Boggs(Hamilton/South District); Jim Chatfield (North District/ Horticulture and Crop Science Department-HCS); Erik Draper (Geauga); Dave Dyke (Hamilton); Dave Goerig (Mahoning); Tim Malinich (Cuyahoga); Joe Rimelspach (HCS); Pam Sherratt (Agronomy); Amy Stone (Lucas); Nancy Taylor (Plant Pathology and C. Wayne Ellett Plant and Pest Diagnostic Clinic); 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/)
|
WEATHER WATCH
|
Erik Draper's report from the north included these highlights collected from the Cleveland Hopkins Airport: May's precipitation for the month was 5.90"; this is 169% of normal precipitation for the month; this area has received 17.91" for the year thus far; and this is 122% of year-to-date rainfall. He mentioned that it has finally dried out this week--enough that guys and gals could get out, work the soil and lay plastic mulch for veggies. Just to the north, Randy reported that Lake County has had 14.2" of rain in 2004 with less than 0.5" last week.
Moving south, Jane Martin reported the Columbus area has received 5.24" rain in May, which is +1.50". This area has year to date totals of 19.57", which is +4.87" And finally, in Clark County, weather highlights include: current month's precipitation total was 3.9"; the comparative average of rainfall for the month is less 0.69". The year-to-date total thus far is 19.35, +1.69". Pam Bennett reported that portions of Clark County were under a tornado warning, with some areas receiving hail.
|
|
HORT SHORTS
|
PLANT PHENOLOGY
In Southern Ohio, plants in full bloom include oakleaf hydrangea (Hydrangea quercifolia), golden vicary privet (Ligustrum x vicaryi), and arrowwood viburnum (Viburnum dentatum). Plants in full bloom in central Ohio include: Japanese tree lilac (Syringa reticulata), smokebush (Cotninus coggygria), Little Princess spiraea (Spiraea japonica 'Little Princess'), climbing hydrangea, (Hydrangea anomala petiolaris) and Virginia sweetspire (Itea virginica). Just starting to bloom is sweetbay magnolia (Magnolia virginiana). In northwestern Ohio and smokebush is just beginning to bloom.
|
|
GROWING DEGREE DAYS
The range of Growing Degree Day (GDD) accumulations in Ohio from north to south is 577 to 929. The following is the report of GDD for several locations around Ohio as of June 2, 2004.
As of Wednesday evening, GDD accumulations were: Painesville, 577; Cleveland, 608; Toledo, 684; Youngstown, 677; Lima, 726; Wooster, 710; Coshocton, 748; Columbus, 799; Springfield, 832; Dayton, 860; Cincinnati, 915; Ironton, 928; and Portsmouth, 929.
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 O.A.R.D.C. weather stations and available on the website at:
http://www.oardc.ohio-state.edu/gdd/
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.
The following is a list of plants and their phenological events that occur at or around the following average GDD's, and insects and their phenological activities that have average GDD's close to the listed plants: juniper scale, egg hatch, 571; common ninebark, full bloom, 596; American yellowwood, full bloom, 599; arrowwood viburnum, full bloom, 621; multiflora rose, full bloom, 643; northern catalpa, first bloom, 675; black vine weevil, first leaf notching due to adult feeding, 677; sweet mockorange, full bloom, 717; Washington hawthorn, full bloom, 731; calico scale, egg hatch, 748; European fruit lecanium scale, egg hatch, 767; greater peach tree borer, adult emergence, 775; striped pine scale, egg hatch, 783; winterberry holly, first bloom, 794; Japanese tree lilac, full bloom, 808; rhododendron borer, adult emergence, 815; northern catalpa, full bloom, 816; mountain laurel, full bloom, 822; dogwood borer, adult emergence, 830; oakleaf hydrangea, first bloom, 835; cottony maple scale, egg hatch, 851; panicle hydrangea, first bloom, 856; fall webworm, egg hatch (first generation), 867; mimosa webworm, egg hatch (first generation), 874; fuzzy deutzia, full bloom, 884; winged euonymus scale, egg hatch, 892; spruce budscale, egg hatch, 894; winterberry holly, full bloom, 897; panicled goldenraintree, first bloom, 924; and June bride littleleaf linden, first bloom, 953.
|
|
TEN THINGS YOU NEED TO KNOW ABOUT LICHENS, PART I - WHAT ARE LICHENS?
In last week's BYGLosophy we quoted Thoreau when he penned: "I find myself inspecting little granules as it were on the bark of trees - little shields or apothecia springing from a thallus - such is the mood of my mind - and I call it studying..." He was talking about lichens, a few examples of which have such exotic names as rock pimples, earth wrinkles, angels hair, freckle pelts, fog fingers, dragons funnel, tar-jelly and old mans beard.
What are lichens? They are a mutualistic symbiosis, or in the words of Irwin Brodo, Sylvia and Stephen Sharnoff , in their wonderful "Lichens of North America", they are a "composite of a fungus and an organism capable of producing food by photosynthesis." The usual symbionts are a member of the Ascomycetes or 'sac fungi' in the Kingdom Fungi and a green alga in the Kingdom Protoctista or a cyanobacterium (formerly blue green alga) in the Kingdom Protista. The "apothecia" of which Thoreau speaks are a type of cup-like fruiting body common in the Ascomycete fungi. The "thallus" of which he speaks is "the vegetative body consisting of both algal and fungal components." (glossary entry from "Lichens of North America").
The alga or the cyanobacterium (the photobionts) produce carbohydrates through photosynthesis which then serve as food for the fungus. The fungus in its turn provides a steady supply of moisture to the photobiont, provides a substrate helpful in providing the right amount of light to the photobiont, and protects this alga or cyanobacterium photobiont within the fungal tissues. There are many variations of this relationship (more later) including the fact that sometimes club fungi rather than sac fungi and brown algae instead of green algae are involved. For this week's BYGL, though, lets close with a great quote from lichenologist Trevor Goward, who said that lichens are a case of "fungi that have discovered agriculture."
|
|
WORKING WET
Torrential rains this spring have left many landscapes under water or at least with saturated soils. When it comes to working with wet soils the best advice is, dont do it! Good garden soil is a mixture of about forty-five percent mineral particles, five percent organic matter, thirty percent water and twenty percent air. It is this balance of air, water and soil that enables plants to thrive. Lack of a good balance can lead to nutrient and disease problems when plants cannot establish a healthy root system.
After a good rain, the air space in the soil is filled with water. Gravity and time allow this excess water to drain away, leaving fresh air in its place. Some soils drain rapidly, others very slowly. Our consistent and heavy rains have not allowed some soils to drain. Tilling, digging or planting before this natural drainage process is finished compacts the soil and minimizes the air spaces.
If the garden soil crumbles in your hand, moisture levels are probably correct for planting or tilling. If the soil is sticky and will not crumble it is probably too wet. Hold off on planting until soils can dry to a desirable level. If wet conditions persist and you need to get plants in the ground then you will need to minimize compaction damage by working in as small an area as possible. Also, avoid equipment and pedestrian traffic on waterlogged soils.
|
|
BUG BYTES
|
MAGGOT MAGNET
Dave Goerig reported the Mahoning Extension office received a sandwich bag containing several adult APPLE MAGGOTS this past week. The homeowner was curious as to why these specimens and numerous other friends of theirs were assembled on the side of his house. The Apple Maggot, Rhagoletis pomonella, is a member of a large family of fruit flies that develop in fruits, stems and leaves of plants. Typical damage is the classic maggot tunnel that occurs in the fruit as the insect larvae feed. The Apple maggot overwinters in the pupae stage under the ground near the host plant. Adults emerge in early summer and begin to lay their eggs on developing fruit one egg at a time.
Adult Apple maggots are approximately 1/5 inch in size. At first glance they look like common flies. Closer observation reveals a distinct black patterning on their wings as well as a white spot on their back. These pests can be found on apple, pear, and large fruited crabapple trees. As for the unfortunate home owner, it was discovered his new home was in a development being built in an old orchard. The flies were assembled on the west side of his home during a warm sunny day. This could explain the early adult emergence in that neighborhood. For more information on Apple Maggot and ways to control their populations see More Info 1.
|
|
HOLLYHOCK HORRORS!
Curtis Young reported a hoard of hollyhock maladies present on hollyhocks (Alcea rosea) at the current time. First, numerous lower leaves of the hollyhocks are being skeletonized to the point that very little green leaf tissue is left. The leaves are nearly transparent because of the feeding. Some leaves have completely fallen apart with only the main veins and petiole left to indicate where a leaf had once been. This damage has been caused by the larvae of the HOLLYHOCK SAWFLY (Neoptilia malvacearum).
The larvae are pale green worms with black-colored heads and tiny black-colored spines on each body segment. The adults are small (3/16 inch), black-colored, fly-like insects with a reddish-brown thorax. The adult sawflies are interesting because their antennae split almost to the base so they appear to have four antennae instead of two. This sawfly can have as many as three generations per year.
The hollyhock sawfly larvae are leaf skeletonizers that feed on the lower leaf surface of the foliage leaving behind the upper surface and the main leaf veins. They frequently feed in groups. Control of the Hollyhock sawfly is not difficult. Sevin should be a very effective insecticide, but it should be applied as soon as the larvae are discovered.
The second attacker present on the hollyhocks is the HOLLYHOCK WEEVIL (Apion longirostre). The hollyhock weevil is a very small snout beetle approximately 1/4"-3/8" long. Its body is covered with gray colored hairs. With its long snout, the hollyhock weevil also eats holes in flower buds and seeds. The female weevil has the longest snout which is nearly twice as long as the males. The female uses her long snout to chew deep holes in developing flower buds in which to lay eggs. The grub stage of this insect feeds on the developing seeds. Pupation takes place within the seed, with new adults emerge in August. Check the newly expanding leaves and developing flower buds for aggregations of the hollyhock weevil. To control this weevil, an insecticide can be applied to kill the adults now or cut and destroy flower stalks with infested seed pods before new adults emerge later this summer.
Two other unidentified attackers of the hollyhocks are a leafminer that was producing a serpentine leaf mine in the leaves and a fungal disease that was producing pustules on the undersides of the leaves. Because of all the different things that can attack the hollyhock, hollyhocks are not for the fastidious gardener who hates to see any blemishes on their plants in their displays. However, hollyhocks are tough plants that can put up with a lot of strife and still continue to return on an annual basis.
|
|
WINDSHIELD WIPE- CLEARWING BORER REPORT
Randy Zondag reports that two important species of clearwing borers are flying in NE Ohio: LILAC/ASH BORER (Podosesia syringae) and LESSER PEACH TREE BORER (Synanthedon pictipes). Nurseries should be applying their first round of borer sprays to their susceptible plants such as lilacs, ashes, sand cherries and purple leaf plums to protect them from borer attack.
|
|
DISEASE DIGEST
|
EASTERN FILBERT BLIGHT
This disease caused by the fungus Anisogramma anomala, has been observed on Harry Lauders walking stick (Corylus contorta) in the past few years. A plant can be affected for more than 15 months before actually showing symptoms. The summer following infection, the fungus starts to produce the spore-producing structures. These are very distinct and used for identification. The black, raised fungal bodies are produced in relatively straight rows lengthwise along the branch in cankers. As the cankers expand from year to year, they eventually girdle the branch. Vigor can decline significantly when plants are infected with this fungus. Prune out infected branches 2 to 3 feet below the cankered area. Fungicides may be used at bud break.
|
|
FUNGICIDE FAILURES, PART VI: CONFUSING FUNGICIDE NAMES
Previous BYGL issues discussed faulty diagnosis of disease, faulty diagnosis of the type of disease, faulty fungicide selection, and improper timing, and over reliance on fungicides as reasons that fungicides sometimes seemingly "fail". This week, lets look at another reason for "failure" - confusion over fungicide names.
The Chinese philosopher Krishtalka noted that "The beginning of wisdom is calling things by their right names". The same can be said about proper and successful use of fungicides and of course all pesticides. Pesticides have three different names, the chemical name, the common name and the trade name. Horticulturists usually deal with common and trade names but often fail to realize what they have in their pesticide cabinets. For example, just a few trade names for the fungicide with the common name of chlorothalonil are Exotherm Termil, Ortho Daconil Plant Disease Control, PathGuard 6F, Thalonil, Bravo, Bravado, and Echo 500. Different formulations and different trade names, but all contain the active ingredient chlorothalonil. An applicator needs to know what he has at hand by knowing both trade names and common names.
Another example of knowing what is in the products you buy and use is that there are a number of combination products which combine fungicides with different activity. Some products combine a contact and a systemic fungicide. Examples would be combining thiophanate-methyl and chlorothalonil. Brand names of this combination include ConSyst WDG and Spectro WDG. Other combination products mix in a good water mold fungicide with a fungicide good for control of other fungi. Examples would be etridiazole and thiophanate-methyl sold under the brand name of Banrot. Horticulturist, know thy products!
|
|
INDUSTRY INSIGHT
|
TOMATO SPOTTED WILT VIRUS ON IMPATIENS
Several flats of impatiens with leaves showing numerous small black spots were brought to the attention of Dave Dyke in a southwestern Ohio greenhouse. Samples of the infected plants that were sent to Nancy Taylor at the C. Wayne Ellett Plant Pest Diagnostic Clinic (CWEPPDC), yielded a diagnosis of tomato spotted wilt virus (TSWV). Nancy noted the presence of small black flecking next to the veins on the underside of the leaves was very symptomatic of TSWV.
Nearly every greenhouse ornamental is subject to TSWV; the only major crops that have not shown symptoms in the past two years are geranium, poinsettia, and rose. Vegetatively propagated ornamentals are the most likely source for a TSWV infestation since the virus is not seedborne. Many plants serve as a reservoir for this virus. At least six strains of TSWV have been reported however, the symptoms produced and the range of plants infected vary among strains. Virus spread is rapid in a greenhouse with a western flower thrips population; some plants will develop symptoms within 5 days of feeding by infected thrips.
Tomato spotted wilt is one of only a few viruses transmitted by thrips and is by far the most important. Nine species are reported as vectors: Frankliniella occidentalis (western flower thrips); F. schultzei, F. fusca (tobacco thrips); Thrips tabaci (onion thrips); T. setosus, T. moultoni; F. tenuicornis, Lithrips dorsalis, and Scirtothrips dorsalis. The first four are considered the most important vectors because of their wide distribution and the overlapping host ranges of these species and TSWV. The western flower thrips is the chief TSWV vector in greenhouse settings around the world.
The vector-virus relationship between thrips and TSWV is important to understanding how virus spread occurs. While the virus can be acquired only by the larval stage, transmission is due almost exclusively to adult thrips. Larvae of T. tabaci can acquire the virus within 15 minutes. Larvae cannot transmit the virus immediately, but after a latent (incubation) period of 3-10 days (depending on the vector species), transmission occurs. Once thrips become infective, they can transmit virus for a maximum period of 22-30 days, or for the remainder of their adult lives. Adults do not transmit virus to their progeny. Overlapping stages in the thrips life cycle can account for continuous virus spread.
Since there is no direct way to attack the virus other than roguing visibly infected plants, it is necessary to aim control efforts at its thrips vectors. The primary greenhouse vector is the western flower thrips. Resistance to specific organophosphates, carbamates, and synthetic pyrethroid insecticides is known in certain populations. Early detection of a thrips infestation is critical because the symptoms of their feeding are often not noticed until after the damage has occurred, and because small infestations are easier to control.
For further information on this disease please refer to the excellent publication, Fact Sheet Page: 735.90, Cornell University Vegetable MD Online, "Vegetable Crops--Tomato Spotted Wilt Virus", Cooperative Extension, Cornell University. See More Info 1.
|
|
COMING ATTRACTIONS
|
WOSU GREEN SCENE
Join host Tom Wiebell and guests Joe Boggs and Jim Chatfield this Friday night from 6:30 to 8:00pm for WOSU's News 820 Green Scene garden and Landscaping Q&A program. Tom, Jim and Joe will talk horticulture and even take a stab at answering your questions. Call 614-292-8513 or just listen in on WOSU 820AM.
|
|
BYGLOSOPHY
|
"In June, as many as a dozen species may burst their buds on a single day.
No man can heed all of these anniversaries; no man can ignore all of them."
-Aldo Leopold
|
|
