April 11, 1996
From: Pam Bennett, Joe Boggs, Jim Chatfield
Gary Gao, Jane Martin, and Randy Zondag
This is the 2nd 1996 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. This conference is then summarized by the seven writers listed above and e-mailed to Extension offices in Ohio, Indiana, Kentucky and Pennsylvania.

BYGL is also made available via the Internet on PENpages and The Ohio State University (OSU) Department of Horticulture and Crop Science and Ohio Department of Natural Resources, Division of Forestry Web sites. A number of Extension offices throughout Ohio offer FAX subscriptions to the green industry.

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). ONLA, Ohio Chapter ISA, and Ohio Turfgrass Foundation members are not charged for FAX subscriptions.

Participants in the April 9, 1996 conference included: Pam Bennett (Clark), Joe Boggs (Hamilton), Jim Chatfield (Northeast District/Horticulture & Crop Science), Gary Gao (Clermont), Jane Martin (Franklin), Mimi Rose (Horticulture & Crop Science), Dave Shetlar (Entomology), Amy Stone (A.B.S. Center), Nancy Taylor (Plant & Pest Diagnostic Clinic), and Randy Zondag (Lake). .

WHERE'S SPRING?
Several BYGL participants noted that certain plant and pest events appear to be "late" this spring. For example, around this time last year (BYGL 95-2, 4-13-95), we reported : DANDELIONS were blooming heavily in central and southern Ohio; LARCH CASEBEARER was out in northeastern Ohio (See item "B" in "Bug Bytes" below); 25 percent of the SPRUCE SPIDER MITE eggs had hatched in central Ohio; and EUROPEAN PINE SAWFLY eggs had hatched and larvae were feeding on scotch pine in southwestern Ohio.

Of course, an alternative view would be that these 1995 events were actually "early." In 1994, European pine sawfly did not hatch until LATE April (BYGL 94-4, 4-28-94). Although "early" and "late" are relative terms, a "late" spring affords the opportunity for landscape, turf, and nursery managers to remain ahead of developing pest problems by giving them an extended period of time to scout for pests - take advantage of it!
DIAGNOSTIC DIGEST.
A. WHAT'S WRONG WITH THIS PLANT: NOTHING! Nancy Taylor of OSU's newly-named C. Wayne Ellett Plant and Pest Diagnostic Clinic, notes that this is the time of year people notice such things as lichens (normal and not plant damaging), old insect galls from last year, and other miscellaneous things on plants, and wonder if something is suddenly wrong. This is a normal rite of spring as people reacquaint themselves with their landscapes; calmly explain what is observed, but also counsel a reasoned approach.

B. BLACK ROOT ROT. Nancy also reported finding Thielaviopsis black root rot on blue holly. This disease causes stunted growth, "sparse foliage, poor foliar color, and dieback from the death of fibrous roots," according to Sinclair and Lyon's "Diseases of Trees and Shrubs." Black root rot also results in tell-tale black root lesions which are visible if affected roots are washed. In past seasons, the Clinic has found black root rot on a number of other plant materials including: petunias, verbena, impatiens, fuchsia and periwinkle.

C. WHAT'S WRONG WITH THIS PLANT: CAN'T TELL FROM THE SAMPLE. A correct diagnosis requires a proper sample. Although this may seem logical, it is sometimes forgotten by Clinic clientele. For example, it is not possible to diagnose PHYTOPHTHORA ROOT ROT last year from a branch sample this year (a recent request to the Clinic). If phytophthora root rot or BLACK ROOT ROT is suspected, samples to the Clinic MUST include roots.
SALT INJURY IN THE LANDSCAPE.
Injury from road salt spray is particularly evident on conifers along the highways and byways of Ohio this spring. The salt used to treat icy roads becomes airborne, and may affect plants 100 to 150 feet from a highway, depending on the force and direction of the winter wind. Salt damage on evergreens tends to appear in late winter, and worsens in early spring. Needles turn progressively brown from the tips towards their base. Damage to deciduous plants will not be apparent until budbreak at which time bud and branch dieback may be noticed. "Classic" symptoms of airborne salt injury appear on one side of the plant; the side facing the highway. However, this year we are seeing whole-plant injury of trees along highways and speculate that heavier doses of highway salt, perhaps combined with winter desiccation, are causing this.

Salt injury from airborne saltspray is caused primarily by cell and tissue sensitivity to the chloride ion. Chloride moves in the transpiration stream to leaf tips and margins and may accumulate in toxic concentrations. Salt injury from salt runoff into soil is more complex. Toxic accumulation of ions in plant tissues may occur, but salts also increase the osmotic potential of the soil solution, which can severely impair the ability of roots to absorb water and nutrients. Roots, in essence, experience drought in saline (high salt) soils even when moisture is available.

Plants which are sensitive to salt injury include azalea and rhododendron, beech, river birch, boxwood, black cherry, cornelian cherry, cotoneaster, crabapple, dogwood, Douglas-fir, white fir, sweet gum, forsythia, hemlock, hickory, American holly, common lilac, red and sugar maple, eastern white pine, flowering plums, flowering quince, Allegheny serviceberry, white spruce, sycamore, tulip tree, and yew.
IS FLOREL A SILVER BULLET IN PREVENTING UNWANTED FRUITS?
Several extension offices have received inquiries about Florel as a fruit eliminator in ornamental trees and shrubs. An excellent summary of information on this product appears in Purdue University's, "Educator's Update" (April 8, 1996), from the Plant and Pest Diagnostic Laboratory. In part, the summary states:

"Homeowners now have another tool to help prevent undesirable fruit production in their landscape. A product called Florel is being promoted for the lawn and garden market as a fruit eliminator. The active ingredient in Florel is ethephon, a chemical that releases ethylene, which in turn promotes fruit drop before it really sets.

According to the label, a foliar application of Florel will reduce or eliminate undesirable fruit development on many ornamental trees and shrubs such as apple, cottonwood, crabapple, elm, flowering pear, horse chestnut, maple, oak, pine, sweetgum, and sycamore. Florel has not been tested on all varieties of trees or shrubs which may have undesirable fruit."

Although the material "sounds good," BYGL participants concurred that more university research is needed before OSU Extensioneers should recommend this product to backyard gardeners. Specifically, participants were unaware of long-term studies targeting a number of landscape materials. It is known that BOTH efficacy and phytotoxicity are VERY temperature and dose dependent. In brief, Florel should be treated with extreme caution - it may not yet be a silver bullet.

NEWLY UPDATED BULLETIN.
Bulletin L-187, "CONTROL OF TURFGRASS PESTS," is now available. This bulletin, by Bill Pound, Dave Shetlar, Joe Rimelspach and John Street, is an outstanding turf pest management tool for county agents as well as commercial turfgrass managers. The cost is $3.25.
THE OSU/SCOTTS CO. NURSERY SHORT COURSE & FIELD DAY.
This Field Day will be held Wednesday, July 24th, 1996. Mark your calendars now for this jointly sponsored program to be held at the Scotts Co. headquarters, Marysville, Ohio.

Jerry Lee of Wright Nursery will deliver the keynote address, titled "Growing Quality Plants and Protecting our Environment." The full-day program will also cover fertilizer technology for the nursery industry, growing media testing and nutrition, water quality, and regulatory issues. It will also feature tours of research and production facilities at Scott's Co. The registration fee for the full program, including lunch, is twenty dollars. Send your registration fee to: OSU Extension; 560 Sunbury Rd. Suite 5; Delaware, OH 43015.
BYGLive!
This series of monthly, statewide programs is up and running with the first having been held at Spring Grove Cemetery and Arboretum in Cincinnati on Monday, April 1. On Monday, May 6, BYGLive! will be held in at Cox Arboretum in Dayton and again at Spring Grove. From then on, BYGLive! will be held monthly (until October) at various locations throughout the state (see below).

BYGLive! involves landscape observations, sleuthing, diagnostics, BYGL reviews, and more. Observations by the group will then be mainlined into the BYGL phone conversation on Tuesdays. Contacts for more information and starting dates are as follows:

Spring Grove Program (Cincinnati, started April 1, next date is May 6):
Joe Boggs: 513-825-6000 (Ext. 14) or Boggs.47@osu.edu
Although this program has started, there is still room for five additional participants.

Cox Arboretum Program (Dayton, starts May 6):
Pete Lane: 513-224-9654 or Lane.2@osu.edu




Holden Arboretum Program (Kirkland in Lake County, starts May 21):
Randy Zondag 216-350-2582 or Zondag.1@osu.edu Alan Siewert (ODNR -Division of Forestry) 216-632-5299

Information on additional dates throughout the summer will be available via the Web-wide on OSU's Horticulture In Virtual Perspective's Commercial Ornamental Horticulture Calendar for Ohio. The address is:

http://hortwww-2.ag.ohio-state.edu/hvp/HVP1.html

MIGHTY MITES: REVISITED.
In last weeks BYGL, we reported that "warm season mites (e.g. TWO-SPOTTED SPIDER MITE) overwinter in plant debris and soil..." While the example is mostly true, the implication that ALL warm season mites overwinter in plant debris must be clarified. This issue is important relative to the efficacy of dormant oil applications.

According to Dave Shetlar's "Mites That Attack Trees, Shrubs and Perennials," (Educational Update, The ONLA "Buckeye," March, 1996), the orange two-spotted spider mite females "overwinter in duff or mulch under the plants, in cracks of bark or in cracks found in nearby houses." Obviously, these locations place the mites out of reach of oils. The FOUR-SPOTTED SPIDER MITE also overwinters as adult females OFF the host and the bright-orange HONEYLOCUST SPIDER MITE females "seek harborage in cracks and crevices in and under the bark."

However, the OAK SPIDER MITE, which attacks chestnuts as well as oaks, spends the winter as eggs laid on branches and the BOXWOOD SPIDER MITE overwinters as eggs "attached to the midveins of older leaves." For more information on the lifestyles of these warm season mites, as well as several common cool season mites, false spider mites, and eriophyid mites, check-out Dave's outstanding article in the Buckeye.
LARCH CASEBEARER: WALKING DEAD NEEDLES.
Overwintered larvae of this small moth (adult wing-span is only 1/3rd inches) were spotted in Spring Grove Cemetery & Arboretum in Cincinnati by Jim Chatfield. The insect gets its name from the cigar-shaped case constructed by the larvae. A larva lines a mined-out needle with silk, then inserts its abdomen into the needle and carries the case around (pointed upward) for protection. The arrangement produces a rather sobering image - moving casebearers look like "walking dead needles" (an entomological horror story?).

Feeding damage looks similar to frost damage - needle tips appear "burned" or "bleached" - and trees may have a white/silvery appearance. Though widespread population distribution is rare, populations do tend to build on individual trees (like bagworm) and damage can be substantial.
BOXWOOD LEAF BROWNING: LEAFMINER or WINTER INJURY?
Extension offices are receiving reports of winter injury to BOXWOODS. Dave Shetlar cautioned that not all browning of boxwood leaves is associated with winter injury. BOXWOOD LEAF MINER, a tiny, gnat-like fly, spends the winter as a larva in mined leaves. Injured leaves appear blistered, with yellow-to-brown "blotches." Although affected leaves may be entirely mined and discolored, many mined leaves will still have distinct green areas where no mining has yet occurred, and not all leaves on a stem are affected. As a result, boxwoods damaged by the leafminer will have some green coloration. Winter injury generally causes entire leaves to turn brown and most leaves on an affected stem are brown.
IT'S GrubEx NOT Grub-X.
Questions continue on this new imidacloprid product labelled for homeowner use for grub control. Dave Shetlar noted that although GrubEx is only labeled for white grubs, it can also be used for other turfgrass pests in Ohio (e.g. bluegrass billbug), if applied according to label rates. Ohio's label laws are "site specific" meaning that the pesticide can be used on the SITES (i.e. trees, shrubs, lawn, etc.) listed on the label; the pest does not have to appear on the label. In some states, both the pest and the site must be on the label before the product can be applied.

Other products containing imidacloprid (e.g. Merit) are labeled for pests such as bluegrass billbug as well as white grubs. Dave noted that applications of imidacloprid products for control of bluegrass billbug should be made in mid-May and he re-emphasized that maximum white grub control will be achieved if applications are made from mid-May to mid-August. Note: GrubEx was incorrectly called Grub-X in last weeks BYGL.
BYGLOSOPHY "The best time to plant a tree was twenty years ago. The second best time is now." - Chinese Proverb.
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 the responsibility of consulting the pesticide label and adhering to those directions.

All Ohio State University Extension educational programs are available to clientele on a nondiscriminatory basis without regard to race, color, creed, religion, sexual orientation, national origin, gender, age, disability, or Vietnam-era veteran status.

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