Pam Bennett, Barb Bloetscher, Joe Boggs, Jim Chatfield, Erik Draper, Dave Dyke, Gary Gao, Dave Goerig, Tim Malinich, Jane Martin, Pam Sherratt, Amy Stone, and Curtis Young.
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April 16, 2004
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This is the Second 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 April 13, 2004 conference included: Pam Bennett (Clark); Barb Bloetscher (Entomology/C. Wayne Ellett Plant & Pest Diagnostic Clinic); Joe Boggs (Hamilton/Southwest District); Jim Chatfield (Northeast District/HCS); Erik Draper (Geauga); Dave Dyke (Hamilton); Gary Gao (Clermont); Dave Goerig (Mahoning); Tim Malinich (Cuyahoga);Jane Martin (Franklin); Joe Rimelspach (Plant Pathology); Pam Sherratt (HCS); Dave Shetlar (Entomology); Amy Stone (Lucas); Curtis Young (Allen County); 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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Rains early this week fell across much of the buckeye state. Many BYGLers have reported experiencing lots of cloudy overcast days. Erik Draper reported the weather data from the Cleveland Hopkins Airport. This area has received 2.60" of precipitation thus far in April, which is 77% of the average precipitation for the month. The months of January, February, and March have brought, 10.87" of precipitation, which is slightly above average. Also in the north, Amy Stone reported that Toledo has received 0.08" of precipitation for the month of April, and 4.17" for the year. This is 3.61" below average for 2004.
Joe Boggs mentioned that the Cincinnati area was 1.59" below the year-to-date average, BEFORE this weeks rain event. Pam Bennett reported that the Springfield area is up over 2.17" for the year thus far.
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HORT SHORTS
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GROWING DEGREE DAYS
The range of Growing Degree Day (GDD) accumulations in Ohio from north to south is 54 to 183. The following is the report of GDD for several locations around Ohio as of April 14, 2004.
As of Wednesday afternoon, GDD accumulations were: Painesville, 54; Cleveland, 61; Toledo, 79; Youngstown, 78; Lima, 82; Wooster, 86; Coshocton, 85; Columbus, 101; Springfield, 120; Dayton, 139; Cincinnati, 175; Ironton, 183; and Portsmouth, 183.
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/
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: northern lights forsythia, first bloom, 58; star magnolia, first bloom, 83; border forsythia, first bloom, 86; eastern tent caterpillar, egg hatch, 92; Manchu cherry, first bloom, 93; northern lights forsythia, full bloom, 94; Norway maple, first bloom, 116; chanticleer callery pear, first bloom, 123; sargent cherry, first bloom, 127; larch casebearer, egg hatch, 128; saucer magnolia, first bloom, 133; Bradford callery pear, first bloom, 142; European pine sawfly, egg hatch, 144; weeping Higan cherry, first bloom, 145; P.J.M. rhododendron, first bloom, 147; Chanticleer callery pear, full bloom, 149; Norway maple, full bloom, 149; inkberry leafminer, adult emergence, 150; Sargent cherry, full bloom, 151; star magnolia, full bloom, 151; Allegheny serviceberry, first bloom, 153; Manchu cherry, full bloom, 155; Spring Snow crabapple, first bloom, 155; apple serviceberry, first bloom, 159; spruce spider mite, egg hatch, 162; Bradford callery pear, full bloom, 164; Allegheny serviceberry, full bloom, 169; saucer magnolia, full bloom, 174; PJM rhododendron, full bloom, 178; boxwood psyllid, egg hatch, 179; weeping Higan cherry, full bloom, 179; and Koreanspice viburnum, first bloom, 185.
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PLANT PHENOLOGY
BYGL'ers noted that most plants didn't show much change this past week. However, despite the cool weather across the state, spring still continued to progress. In the northern regions of the state, forsythias (Forsythia x intermedia) are in bloom and lilac (Syringa vulgaris) buds are beginning to swell. In the southern portions of the states, forsythias are finished and crabapples (Malus spp.) are just beginning to open. In full bloom in the central part of the state are callery pears (Pyrus calleryana), forsythia, saucer magnolia (Magnolia soulangiana), Norway maple (Acer platanoides), and common flowering quince (Chaenomeles speciosa). Serviceberries (Amelanchier laevis and A. canadensis) are just beginning to open and star magnolias (Magnolia stellata) are dropping petals.
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SHOTGUN /ARTILLERY FUNGUS
Shotgun fungus is already showing up in Ohio landscapes or, to be more accurate, on Ohio houses, decks and lawn furniture. This fungus, Sphaerobolus, is commonly found in mulched gardens. It is one of the many organisms responsible for decomposing organic matter in the landscape. Mulched beds provide perfect conditions for it to thrive. The problem arises when the fungus produces small cup-shaped fruiting structures that shoot spore masses high into the air. These 1/10 inch diameter black globules remain stuck to anything they touch. They can pepper houses, decks, grills or any outdoor surface with tiny black marks resembling spots of tar. To prevent the problem, landscapers and gardeners can try using a border of non-organic mulch, such as stone, next to houses or other at-risk areas.
Once attached to a surface the spots are almost impossible to remove. Calls received now may be about spots produced last year. Power washing does not work, but a newsletter out of Penn State Extension indicates that products such as Purple Muscle or Foaming Wheel Cleaner (both from Turtle Wax) can provide some relief. Make sure the products are safe to use on the affected surface and always test an inconspicuous area first.
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BUG BYTES
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NOISY BOXWOODS...FROM THE X-FILES?
Last season, we reported an interesting phenomenon associated with BOXWOOD LEAFMINER (Monarthropalpus flavus): faintly audible crinkling or rustling noises that seem to radiate from heavily infested boxwoods (BYGL 2003-06). This season, the sounds are baaack! Joe Boggs noted that he has observed some heavy localized boxwood leafminer infestations in southwest Ohio, and he is receiving reports from understandably hesitant inquirers of noises that seem to be emanating from heavily infested plants. Indeed, one skeptical landscaper actually prefaced their inquiry with, "Extension Agent Mulder, this may sound crazy, but..." Of course, sanity is not the issue -- just an acute sense of hearing!
Last season, we speculated that the sounds were being produced by the wiggling activity of the pupae. However, Joe indicated that pupation has not yet occurred. Based on past observations, this tiny fly generally pupates at the same time weigela begins to bloom. The orangish-yellow larvae are soft-bodied, and they lack hardened mandibles. So, the exact noise-making mechanism remains a mystery. But, they do make noise.
Unusual sounds aside, this leafminer can become a very serious pest. Heavy infestations may weaken plants by causing severe branch dieback. The fly spends the winter in the larval stage in blister-like leaf mines. As spring approaches, the larvae resume feeding for a short period, then pupate. The larvae feed on parenchyma tissue and leaves may have multiple mines. The mines turn yellowish-brown in late spring, usually after the small, gnat-like adults have emerged. Damaged leaves are often evident throughout the summer. Larval control options to prevent mines include an application of imidacloprid (e.g. Merit) made as a soil drench in late fall or early spring, or an application of acephate (e.g. Orthene) made as a foliar systemic spray in mid-to-late May, targeting the early instar larvae of the next generation.
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INSECT ERRATUM - WEEVILS MORPH
. In last weeks BYGL, we reported that overwintered "NORTHERN PINE WEEVIL" adults were becoming active in northeast Ohio. Fortunately, we used the correct scientific name, Pissodes strobi, for WHITE PINE WEEVIL, the insect that was actually observed in the northeast part of the state and described in the BYGL report. Unfortunately, we used the wrong common name. The scientific name for northern pine weevil is Pissodes approximatus....we were only approximately right.
Both weevils overwinter in the adult stage, and both are almost identical in size, shape, and general appearance. Both insects are considered Christmas tree production pests; however, white pine weevil has the potential for causing much greater damage, not only to conifers in Christmas tree plantations, but also to trees growing in nurseries and landscapes.
White pine weevil (Pissodes strobi) adults deposit eggs in the terminals of their conifer hosts, which include their namesake as well as Scotch, jack, red, and pitch pine, plus Douglas-fir, Colorado blue, and white spruce The resulting white, legless, slightly curved, grub-like larvae tunnel downward just beneath the bark until pupation occurs in mid-to-late summer. The tops of infested trees eventually become wilted, turn brown, and die. Main leaders are often curved into a shepherds crook. Larval tunneling usually does not progress past the top two lateral limb whorls; however on small trees, larvae may tunnel to the base of the main stem, killing the entire tree.
Northern pine weevil (Pissodes approximatus) is almost exclusively relegated to Christmas tree plantations, or to coniferous reforestation. Overwintered females deposit eggs in the spring on stumps left from the fall cutting of Christmas trees, or on conifers that have declined or died in the fall. Larvae feed and mature under the bark of this breeding material, and adults emerge in late summer to feed on twig tissue. Adult feeding activity seldom causes significant injury. Pales weevil (Hylobius pales), another Christmas tree production and conifer reforestation pest, breeds on the same plant materials as northern pine weevil. However, this larger weevil has the potential to cause much greater damage. Control efforts aimed at pales weevil (e.g. stump treatments, stump removal, etc.) will also control northern pine weevil.
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BEES BURROWING
Barbara Bloetscher reported that the PPDC received several phone calls concerning "swarms of bees" in the ground. These ground nesting bees, flying around a 3- 10' patch of ground, are actually one of several species of solitary bees, but dig their tunnels in a "commune" with others of the same species. Within each tunnel, the female will excavate individual chambers, and pack them with pollen and nectar. She then lays an egg in each chamber and seals them. As the larvae grows, it consumes the food reserve, then pupates and emerges from the tunnel the following spring. As each successive year progresses, these communes enlarge as more bees return to the site.
The bees most commonly associated with these nests are digger bees (Anthophoridae), sweat bees (Halictidae) and mining bees (Adrenidae). Generally, these bees are hairy and about the size of a honey bee or smaller, although the digger bees are slightly larger and more robust.
Complaints are normally due to the fear of being stung, followed by an annoyance of the bare spot in the yard. Although they may appear menacing with their buzzing and strafing activities, these bees are not aggressive and not likely to sting. Also bear in mind that the bees tunneled in that location because the turf or ground cover was not dense and vigorous.
Control is not recommended since they are great predators of spring insect pests, however at times, their help is not appreciated. After the spring activity is over, the area can be overseeded, sodded, or mulched, etc. to provide a more dense cover, but to ameliorate the situation, cover the area temporarily and keep people away.
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CHINCH BUGS ACTIVE!
Dr. Shetlar reported that chinch bug adults have become active after their winter dormancy. If chinch bugs were present at levels high enough to damage turfgrass last year, consider treating preventively with a labeled pyrethroid (bifenthrin and deltamethrin provide good results) between mid April and early May. Imidacloprid (Merit) can be applied from late April - May to control grubs, billbug larvae, greenbug aphids, and at least suppress chinch bug populations.
Depending upon the amount of rainfall (or irrigation frequency) received in the summer and the level of infestation of neighboring lawns, a second application may need to be made in August or September where two generations occur. Turfgrass which receives a great deal of moisture often supports the fungus Beauveria spp. which infects and kills chinch bugs.
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LEATHERJACKETS LAYING ON THE SIDEWALK
No, not the expensive outerwear kind of leather jacket, rather the tough skinned, gray-brown, worm-like larvae of CRANE FLIES. Dave Shetlar reported receiving a call from a homeowner in Cincinnati concerned about "worms" on his sidewalk. After viewing an image sent to Dave via e-mail, he identified the "worms" as crane fly larvae which are called leatherjackets. There are a number of native species of crane flies that could be found in moist to wet turfgrass areas. The larvae of most species eat decomposing plant matter found in the soil and in turf thatch zones. However, a few species feed on roots of young plants and if abundant may cause considerable damage. This damage has been observed in rangelands and in seedling crops.
There are also at least two exotic species of crane fly that are known to infest and damage turf grass in North America, the EUROPEAN (MARSH) CRANE FLY, Tipula palodusa, and the COMMON CRANE FLY, T. oleracea. The European and common crane flies have become established in the Pacific Northwest including British Columbia, Washington, Oregon and possibly parts of northern California. The European crane fly was first recorded in Canada in 1955. More recently, the European crane fly has been discovered in Ontario, Canada. In 1996 and 1997, leatherjackets were found to be causing damage to turf in Whitby, Toronto and Hamilton mountain are in Ontario. Surveys conducted in Ontario have revealed that the European crane fly has spread and is infesting turf in Ancaster, Niagara Falls, Hamilton mountain, Scarborough, Uxbridge, Oshawa/Whitby, Brampton, Markham, Kitchener/Waterloo, Windsor, Cambridge, St. Catharines and Guelph. Many of these locations are not far from Ohio.
Curtis Young has conducted surveys in 2002 and 2003 searching for these new exotic crane flies in Ohio. Leatherjackets were found in turfgrass on sod farms, golf courses, parks, grassy fields and home lawns, but none were found to be the exotic species of interest. Curtis will be conducting this survey again in April, May and June of 2004. Thus, if you know of an area that has experienced leatherjacket activity, please let Curtis know so the site can be included in the survey. These crane flies cause excessive damage and could become a serious pest in Ohio lawns. You can contact Curtis at the following e-mail address: young.2@osu.edu
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MORE ON EMERALD ASH BORER
Lucas County has recently been added to the list of sites for the 2004 Ohio Department of Agricultures (ODA) Emerald Ash Borer (EAB) Eradication Project. An estimated 1,000 ash trees are slated for removal this spring in the Whitehouse area. In all, about 50 properties covering 1,000 to 1,200 acres are in the cut zone. To learn more about the eradication projects in Defiance, Franklin, Lucas and Wood Counties, check out the ODA website below.
Speaking of EAB, Amy Stone spoke to the Toledo Chapter of the Professional Land Surveyors of Ohio (PLSO) this week. The members were interested in learning more about this exotic invader and diagnostic training to assist with the detection of the insect when they are out in the field involved in survey work.
Thirty-seven Extension Master Gardeners from across the state are participating in the Emerald Ash Borer Specialization. Dan Herms, Joe Boggs, Curtis Young, Jane Martin and Amy Stone with OSU Extension, and Tom Harrison with ODA spoke to the groups in Reynoldsburg and Findlay. The volunteers will also be traveling to Michigan in May to see the devastation first hand. It is a goal of the program to train volunteers in the counties to assist with EAB educational programs and displays at a local level.
You too can also join the force in keeping a watchful eye on ash trees in your area. Be sure to check out the latest information to assist with the identification of an unknown tree, find a useful check-off diagnostic list, and more on the web at the site below.
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DISEASE DIGEST
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DOWNY MILDEW ON ROSES
Randy Zondag reported that downy mildew may be a problem for growers or retailers who are forcing roses for Mother's day. The fungus that causes downy mildew in roses can cause downy mildew in grapes and viburnums. The disease usually starts on the bottom of the plant and works its way up in humid environments. Symptoms begin as light green spots on the upper side of the leaf, however the fungus develops on the bottom side of the leaf under the affected spots, producing a clear to white tufted downy mass. These can develop and spread rapidly through a crop in greenhouse environment. Some varieties will defoliate from the infection if not controlled properly.
It is a good idea to remove infected leaves and dead stems before planting because they can bring the disease into the greenhouse from the last growing season. Good air movement, preferably horizontal air flow rather than plastic tubes in greenhouses, will be very beneficial in managing this disease. Rotate your fungicides of different classes to avoid the development of resistance of this fungus to some fungicides.
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TURF TIPS
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USING DEGREE-DAY ACCUMULATIONS FOR CRABGRASS CONTROL
Crabgrass control strategies are usually planned around soil temperatures and calendar dates, but what about degree-day accumulation? Crabgrass does not suddenly germinate when a specific degree-day total is reached. However, in Dr. Mike Fidanzas study at the University of Maryland, crabgrass first germinated within a degree-day range of 42-78, with peak germination occurring at 150-225 growing degree-days and then for a considerable time thereafter. Therefore, pre-emergence herbicides applied after the initial germination period will still provide a significant benefit in preventing additional crabgrass emergence.
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EFFECTS OF PRE-EMERGENCE HERBICIDES ON SPRING SEEDING PRACTICES
If pre-emergence herbicides have been used to prevent crabgrass emergence, it is very important to note that there is a waiting period between herbicide application and seeding desirable grasses. For example, if Dimension has been applied to a sparse lawn, then a waiting time of 3 months is recommended before desirable grass seed can be put down. Siduron (Tupersan) is the only pre-emergence herbicide that can be applied safely at the same time as seeding desirable grass seed.
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MORE ON ESTERS & AMINES FOR BROADLEAF WEED CONTROL
Herbicide formulations play a major role in determining the success or failure of broadleaf weed control in the spring. Ester formulations tend to be absorbed and translocated more readily by the weed under cooler, more erratic conditions of early spring than amines. Amines are more effective later in the spring when air & soil temperatures are warmer. In general, both formulations exhibit poor weed control before late March. The Ester formulations provide good to excellent weed control the first three weeks in April. Amine formulation effectiveness begins to equal that of esters typically from late April & beyond.
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SPRING GREEN-UP
BYGLers received many questions about the spring green-up of different grasses this spring. For example, why might one lawn look browner that the next? This can depend upon many factors - soil & air temperatures, whether the grass received a late season fertilizer application, winter desiccation etc. One of the key factors though is the type of grass. Perennial ryegrass tends to green-up first, followed by tall fescue, then Kentucky bluegrass.
Furthermore, while there are relatively small differences between cultivars within the perennial ryegrasses and tall fescues, plant breeders have found that there are large differences between cultivars of Kentucky bluegrass. In some cases differences among cultivars have been as much as four-fold. For example, one Kentucky bluegrass lawn may green-up quickly in the spring, and another Kentucky bluegrass lawn might be very slow. Another example is establishment speed - one cultivar could be much quicker at germination than another.
As a helpful tool for choosing grasses, cultivars of all the warm & cool-season turfgrasses have been evaluated and the data posted on the NTEP web-site for anyone to access free. Data includes: spring green-up, wear tolerance, disease tolerance, establishment speed, and quality etc
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COMING ATTRACTIONS
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WOSU's GREEN SCENE
Join host Tom Wiebell on WOSU News Radio 820 this Friday night from 6:30 to 8:00 PM as the Garden Sage, Deb Knapke from Columbus State University and Jim Chatfield will be on WOSU's gardening and landscaping Q&A show. Hear all about begonias, bugs and blights or call in with your questions at 614-292-8513.
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BYGLOSOPHY
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Spring makes its own statement, so loud and clear that the gardener seems to be only one of the instruments, not the composer. -- Geoffrey B. Charlesworth
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