Tuesday, September 30, 2008

Turf - Creeping Charlie/Ground Ivy

Ground Ivy or creeping charlie is a difficult turf weed to control. The following is more information.

Creeping Charlie or ground ivy is a perennial weed in the mint family that spreads by seeds, rhizomes and creeping stems that root at the nodes. This European native was introduced to North America by early settlers who thought it was a good groundcover for shade. Creeping Charlie thrives in moist, shady spots such as under trees and shrubs.Creeping Charlie thrives in moist shaded areas, but also tolerates sun very well. It is a common plant in grasslands and wooded areas or wasteland. It also thrives in lawns and around buildings, since it survives mowing. It spreads by stolons or by seed. Part of the reason for its wide spread is this rhizomatous method of reproduction. It will form dense mats which can take over areas of lawn, and thus can be considered an invasive or aggressive weed.

Creeping charlie or ground ivy. Photo by Chris Evans, University of Georgia

Establishing and/or improving a grass stand to outcompete Creeping Charlie is essential, this is easier said than done primarily because Creeping Charlie thrives in the shade and turfgrasses have a tough time in the shade. For most effective control a multi-pronged approach is needed including:

> Mowing the established turf at 3" or more
>Broadleaf herbicide applications using materials containing dicamba or triclopyr in the spring after flowering and then again 3-4 weeks later. You could and probably should also apply in the fall (Sep 15-Oct15) and again 3-4 weeks later. Unfortunately, these applications may be needed for many years to be most successful.
>Fall fertilization to thicken the grass stand.
>Regular overseeding in the fall to thicken the stand even more.

Information from Purdue University

Greenhouse - Poinsettia Problems III: Leaf Distortions

This is the third in a series on poinsettia problems taken from a posting from the Purdue Plant and Pest Diagnostic Laboratory.

Leaf Distortions


Poinsettia leaf distortions often occur on young or immature leaves and are believed to be caused by many factors. Physical damage during pinching, ruptured cells and latex residue can cause the expanding leaf to become distorted. Environmental stresses, overhead fertilization with phosphorus fertilizers during propagation or production, abrasion or thrips may lead to distorted leaves. Leaf distortion can also results from dramatic temperature and humidity changes as plants are moved from propagation to production. Typically, as plants grow, mature leaves will cover the distorted or damaged young leaves and not influence the marketability of the crop.

Information and photo from Poinsettia Production Problems and Disorders by Roberto G. Lopez, Ph.D., Assistant Professor & Floriculture Extension Specialist, Purdue University in the September 15 edition of the Purdue Plant & Pest Diagnostic Laboratory Picture of the Week.

Monday, September 29, 2008

Nursery and Landscape - Surfactants, glyphosate and Bark Splitting

The surfactants in some glyphosate herbicide formulations may be responsible for causing bark splitting in some trees and shrubs. The following is an article on the subject from Utah State University.

“Cracking, splitting and separation of bark from the underlying wood usually associated with sunscald in the West may actually be caused by glyphosate,” said Heidi Kratsch, Utah State University Extension ornamental horticulture specialist. “This type of injury was once thought to be largely associated with alternating warm and freezing temperatures during the winter. It now appears that some glyphosate formulations can weaken the bark structure, making it susceptible to the freeze-thaw injury we commonly see on the south and southwest side of the trunks of susceptible trees.”

“We’ve known for some time that glyphosate drift can cause stunted, distorted shoots, chlorosis and often death of woody plants,” Kratsch said. “But now it has been associated with a condition we in the West are all too familiar with – sunscald.”

Suspicion that there was more to the story of bark-splitting arose when reports of sunscald-type damage started coming from mild-winter states like Georgia, the Carolinas and California, she explained. Hannah Mathers, a researcher and Extension nursery and landscape specialist at Ohio State University who heads up national research on the effect of glyphosate products on woody plants, recommends that consumers use glyphosate products with caution.

Studies show that the chemical glyphosate itself is not what causes symptoms, but a surfactant, or wetting agent, in some glyphosate products, Kratsch said. The surfactant helps spread the chemical on target plants and enhances uptake. On product labels, the surfactant can be identified as “adjuvant load.” Mathers’ study recommends using glyphosate products with no adjuvant load around sensitive plants.

Kratsch and Salt Lake County Extension horticulturist, Maggie Shao, suggest the following products registered for use in Utah that contain no adjuvant load: Campaign, Fallow Star, Glypro, Landmaster BW, Rodeo and Roundup Custom.

Woody plants most susceptible to glyphosate include: Pyrus species (especially Callery pear), Prunus species (especially Yoshino cherry and Kwanzan cherry), red maple, Norway maple (especially ‘Emerald Queen’), Japanese maple (especially var. dissectum), paperbark maple, mountain-ash, serviceberry, sycamore, crabapple, dogwood (especially Kousa dogwood), hawthorn and magnolia (especially ‘Butterflies,’ ‘Elizabeth,’ ‘Sawada’s Cream,’ ‘Yellow Bird’ and ‘Yellow Lantern’).

“Risk of damage can be minimized by using glyphosate products at least 30 feet from woody plant materials and using it early when weeds are still seedlings,” Shao said. “Glyphosate should be used as a last resort; emphasis should be on use of pre-emergent herbicides to catch weeds before they germinate. Glyphosate should never be used to control root suckers.”

Glyphosate products have been shown to increase levels of shikimic acid in plants. This acid reduces the level of phenolic compounds, which are natural substances found in woody plants that protect against attack by pathogens, Kratsch said. Research shows that the more glyphosate the plant takes up, the higher the levels of shikimic acid. Glyphosate products accumulate in plant roots where they can be stored for years, causing injury long after the original herbicide application. Glyphosate and all herbicides have benefits and risks; following the label will maximize the benefits and reduce the risks.

Greenhouse - Poinsettia Problems II: Leaf Curl and Dessication

This is the second in a series on poinsettia problems taken from a posting from the Purdue Plant and Pest Diagnostic Laboratory.

Leaf Curl and Desiccation


Symptoms of leaf curl, scorch or desiccation typically occur on leaves in the middle portion of the plants. As your poinsettia crop is actively growing when greenhouse temperatures and light levels are high, it is essential that you provide adequate irrigation to avoid extreme conditions (excessively dry or wet) that can result in leaf desiccation, poor growth, and disease susceptibility. Excessively dry plants should not be irrigated with cold water as uptake and transport by the roots can be inhibited for a short interval. Under extended drought stress, lower leaves will turn yellow and senesce.

Information and photo from Poinsettia Production Problems and Disorders by Roberto G. Lopez, Ph.D., Assistant Professor & Floriculture Extension Specialist, Purdue University in the September 15 edition of the Purdue Plant & Pest Diagnostic Laboratory Picture of the Week.

Sunday, September 28, 2008

Greenhouse and Nursery - Fungicides for Pythium Control

Pythium root rot is a common problem in greenhouse production as well as some nursery production (especially herbaceous perennials). The following are recommended fungicides for the control of Pythium root rot.

Pythium root rot on poinsettia. Photo and fungicide table from "Poinsettia Diseases - Pythium" by Roberto G. Lopez, Ph.D., Assistant Professor & Floriculture Extension Specialist, Purdue University and Janna Beckerman, Ph.D., Assistant Professor & Plant Pathology Extension Specialist, Purdue University.

Greenhouse - Poinsettia Problems I: Poor and Uneven Branching

This is the first in a series on poinsettia problems taken from a posting from the Purdue Plant and Pest Diagnostic Laboratory.

Poor and Uneven Branching

Poor branching is a disorder that results in uneven lateral shoot breaking (top breaks are larger and stronger than bottom breaks) or lack of breaks on branched plants. Often growers wait too long to pinch their plants resulting in poor and uneven branching. In such instances, plants become tall and lateral shoots emerge before pinch and break unevenly after pinch. For most cultivars, 14 days is the maximum recommended time from planting to pinching. Certain cultivars are more susceptible to disorder and a reduction in time to pinch will minimize irregular branching. In addition, production temperatures >75 °F during growth can cause blind shoots, or reduced branching. Uniform poinsettia branching can be achieved with proper plant spacing, pinch timing and technique, and temperature management.

Poor branching on poinsettia.

Information and photo from Poinsettia Production Problems and Disorders by Roberto G. Lopez, Ph.D., Assistant Professor & Floriculture Extension Specialist, Purdue University in the September 15 edition of the Purdue Plant & Pest Diagnostic Laboratory Picture of the Week.

Saturday, September 27, 2008

Landscape - Program to Teach Professionals How to Create and Manage Backyard Woodlots

The following program being offered in PA may be of interest to Delaware Landscapers on managing backyard woodlots.

The University of Maryland Cooperative Extension in cooperation with Penn State Cooperative Extension and the Penn State School of Forestry will conduct a program designed to educate green industry professionals about managing backyard forests. “Landscapes and Backyard Woodlots: Business Opportunities for the Green Industry” will take place Thursday, November 11 in Gettysburg, PA at the Adams County Cooperative Extension office. PDA and MDA pesticide credits, as well as ISA credits will be awarded to licensed applicators. Topics will include: principles of forest & wildlife management, establishment and maintenance of small tree plantations, creating natural areas through, natural succession, invasive species control, recreational trails, wildlife habitat improvement, forest health improvements, merchandizing trees, and much more. Cost of the program is $75 by November 4 and $95 thereafter. The registration fee covers lunch, program materials, The Woods in Your Backyard workbook and CD (NRAES -184), and break snacks. Preregistration is required. A brochure with registration information is available at http://www.naturalresources.umd.edu/PDFs/Landscapes%20and%20Backyard%20Woodlots%20.pdf.

For additional information, please contact Steve Bogash at 717-263-9226 or smb13@psu.edu.

Friday, September 26, 2008

Greenhouse - Comparison of Numbers from Different Types of Greenhouse Media Tests

The following is a chart that shows a comparison of soluble salt numbers from the three common greenhouse media testing methods.

Information from "Current Methods of Greenhouse Media Testing and How They Differ" by Douglas Cox, Plant and Soil Sciences, University of Massachusetts.

Greenhouse - Methods for Greenhouse Media Testing

Many growers are experimenting with various ways of performing their own soil tests for pH and soluble salts on-site. Others are sending samples to different labs in search of timely and inexpensive media testing. Often growers end up with a confusing collection of tests done different ways with widely different "numbers". It is important to know what test is being done and the associated numbers for making decisions. The following is information on current testing methods being used.

There are three commonly used methods of testing soilless media based on the use of water as an extracting solution, they are: saturated media extract, 1:2 dilution method, and leachate pourthru.

Saturated media extract (SME).

SME is currently "the" method of testing soilless greenhouse media and it is almost universally done by commercial and university labs, including the UD Soil Testing Lab. In this test a paste is made using soil and water and then the liquid portion (the extract) is separated from the solid portion for pH, soluble salt, and nutrient analysis. Special skills and laboratory equipment are required to perform this test. SME is probably not suitable for a grower to use unless the greenhouse operation is large enough to support a lab, a technically trained person is hired to carry out the tests, and there is a committment to frequent testing and tracking of the results.

1:2 dilution method.

This method has been used for many years and has good interpretative data to back it up. In this test an air-dried sample of soil media and water are mixed together in the volume ratio of 1 part soil to 2 parts water (e.g., using a measuring cup, 1 fl. oz. of soil + 2 fl. oz. of water). The liquid extract is then separated from the solids using laboratory grade filter paper or a common coffee filter. The extract is then ready for analysis. This is a very easy test to master and quite suitable for on-site greenhouse testing of pH and soluble salt using the so-called pH and EC "pens" available from greenhouse suppliers. In my opinion the 1:2 method is a very good choice for occasional pH and soluble salts testing by growers on-site.

Leachate PourThru.

This is the newest way of testing soilless media and its apparent simplicity has caught the interest of many growers. One of the major advantages to leachate pourthru is that there is no media sampling or preparation. Unlike SME and 1:2 methods, plants do not have to be sacrificed or disturbed for testing because the extract is the leachate collected from the container during routine irrigation. The leachate can be analyzed on-site using the pH and EC pens or it can be sent to a commercial laboratory for a complete nutrient analysis.

Leachate pourthru is best used for continuous monitoring and graphical tracking of pH and soluble salts. To make this method work best an irrigation and leachate protocol must be established and carefully followed when sampling takes place. Based on my observations, leachate pourthru is not a good choice for casual checks (use 1:2 method for this). Some growers like to "whip out" the old pH or EC pen now and then and check the drainage from some pots. Unfortunately, with casual use like this, the "numbers" are often quite variable, inconclusive, and probably unreliable. A North Carolina State University Fact Sheet tells exactly how to correctly use the leachate pourthru method. http://www.ces.ncsu.edu/depts/hort/floriculture/crop/crop_PTS.htm

Information adapted from "Current Methods of Greenhouse Media Testing and How They Differ" by Douglas Cox, Plant and Soil Sciences, University of Massachusetts

Thursday, September 25, 2008

Landscape - Nor'easters, Flooding, and Trees/Shrubs

With the nor'easter coming over the next several days, I thought it would be appropriate to post information on flooding and trees and shrubs.

Severe storms (“nor’easters”) may cause flooding in coastal areas. Some plants can tolerate flooded or waterlogged soil, such as green ash, deciduous holly, red maple, and red osier dogwoods. Others are intolerant of flooding: European mountain ash, basswood, beech, birch, cedar, crabapple, American holly, dogwood, forsythia, hawthorn, hemlock, black locust, Norway maple, white oak, white pine, privet, redbud, sassafras, sourwood, spruce, tulip tree,
black walnut, yellowwood, and yew. Dormant plants, no matter how intolerant, can tolerate flooding or waterlogging for several weeks without much damage.

Information from Steven K. Rettke, Ornamental IPM Program Associate, in the November 2, 2006 edition of the Plant and Pest Advisory, Landscape, Nursery and Turf Edition from Rutgers University.

Landscape - Fall Tree Planting: What Not to Plant

November is the time we do fall plantings for deciduous trees. However, there are some trees that are best planted in spring. The following is information on trees that are best not planted in the fall.

Fall tree transplanting is recommended for many tree species.Some trees, however, perform better when transplanted in the spring. These sensitive species include: birch, red maple, oak, dogwood, hornbeam, hawthorn, hemlock, golden-rain tree, tulip tree, plane tree/sycamore, popular, Prunus spp., willow, silver linden, and zelkova. If these species must be planted in the fall, be sure to allow for extra water at the time of planting and until the ground freezes in December/January. Of course, most evergreens are best planted in the spring.

Information from Steven K. Rettke, Ornamental IPM Program Associate, in the November 2, 2006 edition of the Plant and Pest Advisory, Landscape, Nursery and Turf Edition from Rutgers University.

Wednesday, September 24, 2008

Landscape - Construction Effects on Trees

Damage during construction or other landscape activities is one of the major ways that we lose trees. The following is an article on the subject.

Trees, like people, are easily disturbed by changes in their surroundings. It may be several years, however, before obvious symptoms appear. Construction of buildings and roads is a major cause of tree injury and loss.

● Although trunk injury can kill trees, it is root injury during construction that is most likely to kill trees.
● Prevent damage to trees near construction sites by fencing or otherwise protecting them from earthmoving equipment.
● Avoid the placement of excessive soil fills or impervious materials within the drip line (the entire area under the branches) of a tree. It is even better to protect an area several feet wider than the drip line. Since fill materials can cut off oxygen to plant roots, the extent of damage to roots is directly related to depth of material applied and the length of time it is allowed to remain.
● Alternatively, lowering the grade during construction or removing soil can also destroy plant roots.
● Carefully design and construct trenching for cable and water lines to avoid or minimize root damage.

Reprinted from "Common Injuries to Trees in the Urban Landscape" by Ann B. Gould, Ph.D., Specialist in Plant Pathology and Mark C. Vodak, Ph.D., Specialist in Forestry in the September 21, 2006 edition of the Plant and Pest Advisory, Landscape, Nursery, and Turf Edition, from Rutgers University.

Landscape - Proper Tree Planting

Fall tree planting season is coming up in early November. Many problems with trees in the landscape can be traced back to improper planting. The following is an article on the subject.

Many times trees are injured when improperly handled during planting or if planted at the wrong depth. Symptoms due to improper planting may occur soon after planting or not until several years afterward. Correct handling and planting techniques help to ensure survival of newly planted trees.

● Depending on tree species, plant in the early spring or fall.
● Prepare the planting hole properly so that roots are not cramped.
● Prevent roots from drying out before planting.
● Remove plastic and burlap wrapping on balled trees whenever possible. Plastic must be removed. Alternatively, after placing the tree in the planting hole, burlap should be loosened from around the trunk and/or cut away and removed from the top part of the ball, with the remainder left in place.
● Plant the tree at the same depth that it was growing in the nursery.
● Water immediately after planting (and periodically) for two seasons to maintain a moist, but not waterlogged, soil. Ideally, trees need about 1 inch of water every 7 to 10 days.
● Support the tree with rubber-protected guy wires attached to two sturdy stakes or poles. Support wires must be removed once trees roots have become established (usually within 2 years). Guy wires that are left on trees will eventually strangle the trunk.
● Mulch soil at the base of the tree to maintain soil moisture, control weeds, and minimize mower damage. Maintain mulching to a maximum depth of 2 to 3 inches. DO NOT pile mulch “beehive style” around the base of the tree – excessive mulch restricts aeration to the roots and keeps the trunk abnormally moist.
● Do not fertilize when planting; wait until about one year after planting

Reprinted from "Common Injuries to Trees in the Urban Landscape" by Ann B. Gould, Ph.D., Specialist in Plant Pathology and Mark C. Vodak, Ph.D., Specialist in Forestry in the September 21, 2006 edition of the Plant and Pest Advisory, Landscape, Nursery, and Turf Edition, from Rutgers University.

Tuesday, September 23, 2008

Landscape and Turf - Perennial Weed Control

The following is information on perennial weed control in turf and landscape beds.

Perennial plants are the most difficult weeds to control in turfgrass and landscape beds because they have below ground reproductive structures that are difficult to remove by hand or completely kill with herbicides. These below ground structures have potential for regrowth to produce new plants in subsequent growing seasons. Several of these weeds, including thistles, dandelions, ground ivy and mugwort reduce aesthetics and functionality of these plantings. Fall is the most effective seasonal timing for non-selective herbicides such as glyphosate as well as selective turfgrass herbicides such as 2,4-D, triclopyr, dicamba and clopyralid used for broadleaf weed control. However, herbicide applications should be made prior to the first hard frost. As daylength becomes shorter in the fall, perennial plants begin to allocate sugars and reserves to below ground structures such as rhizomes, tubers, and bulbs. Physiologically, this allocation of plant reserves may improve the translocation of herbicides to belowground tissue to more effectively control perennial weeds.

Information from Dr. Stephen Hart, Extension Weed Specialist and Patrick McCullough, Program Associate, Rutgers

Landscape and Nursery - Cool Season Mites

The following is information on cool season mites in the landscape. These mites will be more active now with the reduced temperatures.

COOL SEASON MITES.

As temperatures consistently return to the 60's and 70's during the next few weeks, spruce spider mite and southern red mite activity will increase. Spruce spider mites feed on fir, arborvitae, spruce, Douglas-fir, and other conifers, feeding on older foliage first. Spruce spider mites are olivedark red with reddish-yellow legs and two reddish eye spots with a pale stripe down the back (visible with a microscope). Spruce spider mites start feeding in the fall around 2301 3957 [3094 peak] GDD and continues until there is a hard frost. In the summer, damage appears as bleaching, yellowing, stippling or bronzing of the needles. Damage visible on trees in summer is from intensive fall feeding.

Southern red mites feed on a wide variety of plants including azaleas, camellias, hollies, clethra, juniper, elaeagnus, hibiscus, photinia and rose. Nymphs and adults are active starting around 2401 3584 [3034 peak] GDD and 1913 3518 [2933 peak] GDD respectively. This mite has a dark reddish to brown abdomen with a pinkish to red cephalothorax and a pale mid-stripe. It feeds on the lower leaf surface but during high populations may be found on upper surfaces. Damaged leaves may be brown to gray and drop prematurely.

Monitor with a clipboard and a white sheet of paper, looking for dots the size of periods. Watch for predatory mites and small lady beetles; both are predators of the spruce spider mite and should be conserved. Miticides available for control include hexythiazox (Hexygon, Savy), bifenazate (Floramite), abamectin (Avid) and others. Research has shown bifenthrin (Talstar) can cause mite 'resurgences' because natural enemies are killed; thus mite eggs are able to hatch without threat of predators.

Information from Dr. Brian Kunkel, Ornamental IPM Specialist, UD

Monday, September 22, 2008

Landscape and Turf - Soil Testing Fees Increase

Soil testing fees at the University of Delaware are increasing to deal with rising costs. The following is information sent to county extension offices from Karen Gartley, Soil Testing Program Director.

Soil testing fees will be increasing October 1, 2008 for all non-university clients. The increase in fees, the first since 1996, is the result of rising costs of supplies and labor and will bring our fee schedule in line with that of other laboratories in the region.

I am also in the process of updating our website and all soil testing program forms to reflect the changes. A separate letter is being sent to all of our major clients (e.g., landscapers, lawn care companies) to notify them of the fee increase. Given the short notice (which I had intended to be longer), I will be giving companies a grace period of one month to purchase kits at the current price. To avoid difficulties for the county offices, clients will be instructed in the letter that they must contact my office directly in order to obtain that benefit when purchasing the kits. All sales at the county offices will be at the new prices.

The new fees for the most common soil tests purchased through the county offices are as follows:

Routine Soil Test $10.00
Soluble Salts $4.00

Please let me know if you have any questions.

Karen L. Gartley
Director UD Soil Testing Program
152 Townsend Hall
531 S. College Avenue
Newark, DE 19717-1303
831-1392 (Phone)

Turf - Fall Maintenance Activities

The following are some fall maintenance activities to consider in turf.

Fall fertilization

The benefits of any Labor Day fertilizer applications are certainly being felt now, but if you haven’t applied a fertilizer and are still interested in giving the turfgrass a boost, fall is definitely a great time to fertilize. A fertilizer application in the fall will allow the turf to recover from any summer maladies and will help the turfgrass store carbohydrates that will be used next spring to initiate growth.

Fall broadleaf weed control

Fall is the ideal time to control broadleaf weeds because the weeds are storing carbohydrates in their root system and are more susceptible to herbicide applications. So if your turf has been overtaken by a bevy of broadleaf weeds, applying a herbicide now will make a difference in what you battle next year. Apply the herbicides on a sunny day when rain is not in the forecast for 24 hours. We want the herbicides to dry on the leaf surfaces and not be immediately washed off. We have had enough rain to ensure the turfgrass and weeds are actively growing right now, which is important to ensure the herbicides will be taken up and transported within the weeds. There are many different herbicides that could be used including the most common three-way broadleaf weed control mixtures. The greatest shortcoming of killing broadleaf weeds at this time of year is that you really don’t get to watch them die. In many cases you may not see the obliteration of these weeds this fall,but next year they won’t be there or you will have at least reduced their numbers.

Fall seeding

If you’re going to reseed an area,now is the time to get going. The ideal seeding window in Delaware is during the month of September.

Core aeration

Another fall turf activity is core aeration. Core aeration improves soil aeration (oxygen which roots need to grow), relieves compaction, and removes organic matter. You can follow core aeration with overseeding to thicken up thin areas.

Mulching leaves

If you look closely you can already see some leaves changing which means we’ll soon see leaves falling. If you haven’t tried to mulch leaves back into the turf maybe this is the year you start. Here’s what you need to know to successfully mow leaves into the turf. First of all make sure your mower has a sharp blade, after a long season of mowing the blades may be dull at this time of year and trying to chop up leaves will be more challenging with a dull blade. Second, raise the mower as high as it will go and mow at your normal speed, don’t “rev” the throttle to the high jackrabbit setting and blaze around the yard. Try to mow the leaves when they are moist from the morning dew, but don’t mow them when they’re really wet. This will prevent the leaves from blowing all over the place and will help with your allergies. Finally, don’t let the leaves pile up too high before you mow, too high would probably be greater than three to four inches of leaf depth on the turf. Mulching leaves helps the turf by returning nutrients and organic matter which can be especially beneficial on poor soils.

Adapted from "Autumn turf tips" by Kevin Frank, Crop and Soil Sciences, Michigan State University in the September 19, 2008 MSU Landscape Alert Newsletter.

Sunday, September 21, 2008

Greenhouse - Reducing Heating Costs III

This is a continuation of the series on reducing greenhouse heating costs. The following tips are on how you can manage houses and alter growing practices to reduce heading costs.

Space Utilization
  • Increase space utilization to 80% - 90% with peninsular or movable benches.
  • Install multi-level racks for crops that don't require high light levels.
  • Grow a crop of hanging baskets on overhead rails or truss-mounted conveyor system.
  • A roll-out bench system can double growing space. Plants are moved outside during the day.
  • Use plastic sheet or foam insulation partitions to reduce the heated area of houses in the winter if not using the whole house. Heat only the portion of the house that you are using.
  • Have smaller houses for overwintering, propagation, or early plant starting that require less heat.
Management
  • Lower night temperature - Fuel consumption is reduced 3% for each 1ºF night temperature is lowered.
  • Delay starting the greenhouse by a week or more. Build a germination/growth chamber to start seedlings.
  • Keep growing areas full at all times.

Information in part from "Greenhouse Energy Conservation Checklist" by John W. Bartok, Jr., Agricultural Engineer, Natural Resources Mgt. & Engr. Dept., University of Connecticut , Storrs CT

Landscape - Western Conifer Seed Bug

I have identified samples of a pest that congregates around houses in the fall of the year called the Western conifer seed bug. The following is some information on this pest and a picture.

The Western conifer seed bug (Leptoglossus occidentalis) is often found near white pine stands. It is approximately ¾ inch long, has a dusky brown to brownish black bodiy and an aggressive looking “beak” head and is similar in appearance to squash bugs. The upper surface of the abdomen is light yellow to orange. Alternating patterns of brown and black appear at the edges of their wing covers along their backs. While these insects look large and aggressive, they will not bite. They emit a powerful musky odor when disturbed or handled. Adults enter buildings seeking a site to overwinter after feeding on pine or Douglas-fir cones. They have migrated eastward across North America.

The best defense against fall pests that enters structures is to deny entry. Doors, windows, walls, soffits, etc. should all be examined and repaired to eliminate gaps especially South and West exposures. This is also a “green practice” for its energy conservation benefits. Vacuuming/sweeping them up cuts down on almost all but the most extreme problems. Adjusting lighting in infested spaces by turning off lights, darkening windows, using darker paint colors, or avoiding light colored exterior plantings also help these pests are attracted to lights and light colors. Don't use pesticides against these fall invaders; it provides only short-term relief and does not address bigger structural management issues.

Western Conifer Seed Bug. Photo from Whitney Cranshaw, Colorado State University, Bugwood.org.

Information in part from Casey Sclar, IPM Coordinator, Longwood Gardens

Saturday, September 20, 2008

Greenhouse - Reducing Heating Costs II

This is the second in a series on reducing heating costs in greenhouses. This post focuses on increasing the efficiency of heating systems.

Efficient Heating Systems
  • Installation of floor or under-bench heat will allow air temperature to be set 5º - 10ºF lower.
  • Yearly maintenance - Check boiler, burner and backup systems to make sure they are operating at peak efficiency. Have furnaces cleaned and adjusted and an efficiency test run before heating season. A 2% increase in efficiency for a 30' x 150' greenhouse will save about 200 gallons of fuel oil or equivalent in propane.
  • Clean heating pipes and other radiation surfaces frequently.
  • Check accuracy of thermostats - correcting a reading that is 2ºF high will save $100-$200.
  • Install electronic thermostats or controllers with a 1 ° F accuracy. Potential yearly savings of 500 gallons of fuel oil or equivalent in propane in a 30' x 100' greenhouse when changing from a mechanical to electronic thermostat or controller.
  • Aspirate thermostats or sensors for more uniform temperature control. Differential between on and off can be reduced as much as 6ºF.
  • Install horizontal air flow (HAF) fans to get more uniform temperature in the growing area.
  • Insulate distribution pipes in areas where heat is not required.
  • Check and repair leaks in valves, steam traps and pipes.

Reprinted from "Greenhouse Energy Conservation Checklist" by John W. Bartok, Jr., Agricultural Engineer, Natural Resources Mgt. & Engr. Dept., University of Connecticut , Storrs CT

Landscape - Hard Year for Cherry Trees

This has been a hard year for cherry trees in the landscape. The following is some information on the topic from the University of Maryland.

Cherry Trees Defoliating

It has been a tough year for cherry trees. Many of the cherry trees in landscapes have had lots of yellowing foliage over the last 9 weeks from the very dry conditions. The winds and heavy rains last week have knocked a lot of foliage off of the cherry trees. I visited a site this week in where every cherry lining a driveway was 90 - 95% defoliated. When cherry trees defoliate this early in the season they reduce their winter hardiness. If we have a cold winter this year, expect to see dying branches on cherries in 2009. Also, weakened cherry trees are often attacked by peachtree borer. The adult peachtree borer has been flying from late June and is just finishing up flight activity in mid-September. The larvae bore into the trunk, usually at the trunk flair. Infested cherry trees will produce large amounts of sap that will gel on the trunk.

Reprinted from the September 19, 2008 edition of the TPM/IPM Weekly Report for Arborists,Landscape Managers & Nursery Managers, University of Maryland Cooperative Extension

Friday, September 19, 2008

Greenhouse - Reducing Heating Costs I

The following is the first in a series on tips for reducing greenhouse heating costs.

Reduce Air Leaks

>Keep doors closed - use door closer or springs.
>Weatherstrip doors , vents and fan openings. For example, a 48" fan louver that fails to close properly leaving 1" gaps, allows 23,000 Btu/hr of heat to escape.
>Lubricate louvers frequently so that they close tight. A partially open louver may allow several air changes per hour. Additional fuel is needed to heat this air. Shut off some fans during the winter and cover openings with insulation or plastic to reduce infiltration of air.
>Repair broken glass or holes in the plastic covering.

Double Covering

>Line sidewalls and endwalls of greenhouse inside with poly or bubble wrap to achieve the thermopane effect. Install double wall polycarbonate structured sheets to get insulation effect and reduce recovering labor.
>Use poly with an infrared inhibitor on the inner layer for 15% savings. Payback is 2-3 months.
>Add a single or double layer of plastic over older glasshouses to reduce infiltration and heat loss by 50%.

Energy Conserving Blanket

Install a thermal blanket for 20%-50% savings. Payback is 1 year. Tight closures should be maintained where curtains meet sidewalls, framing or gutters. Use a U-shaped trap to prevent heat from escaping overhead. Heat and water lines should be insulated or located below the blanket.

Foundation and Sidewall Insulation

>Insulate the foundation - place 1-2" polyurethane or polystyrene board to 18" below ground to reduce heat loss. This can increase the soil temperature near the sidewall as much as 10 degrees during the winter.
>Insulate the kneewall or sidewall to bench height. Use 1" to 2" of insulation board. Applying 2" of foam insulation to a 3' high kneewall on a 28' x 100' greenhouse will save about considerable amount of fuel.

Reprinted from "Greenhouse Energy Conservation Checklist" by John W. Bartok, Jr., Agricultural Engineer, Natural Resources Mgt. & Engr. Dept., University of Connecticut , Storrs CT

Landscape - Pest Proofing

Fall is the time of year that many clients complain about insects and other pests entering homes and other structures from the landscape. Landscape maintenance firms may wish to add pest proofing to their business portfolio. The following is more information.

Outlined below are six tips for pest proofing a home or business. Steps 1-3 will also conserve energy and increase the comfort level during winter and summer. Equipment and materials can be purchased at most hardware or home improvement stores.

Install door sweeps or thresholds at the base of all exterior entry doors. Lie on the floor and check for light visible under doors. Gaps of 1/16" or less will permit entry of insects and spiders; 1/4"-wide gaps (about the diameter of a pencil) are large enough for entry of mice; ½" gaps are adequate for rats. Pay particular attention to the bottom corners as this is often where rodents and insects enter. Garage doors should be fitted with a bottom seal constructed of rubber (vinyl seals poorly in cold weather). Gaps under sliding glass doors can be sealed by lining the bottom track with ½ to 3/4 inch-wide foam weather stripping. Apply sealant along bottom outside edge and sides of door thresholds to exclude ants and other small insects.

Seal utility openings where pipes and wires enter the foundation and siding, such as around outdoor faucets, receptacles, gas meters, clothes dryer vents, and telephone/cable TV wires. These are common entry points for ants, spiders, wasps, rodents and other pests. Holes can be plugged with mortar, caulk, urethane expandable foam, copper mesh (like the material in pot scrubbers), or other suitable sealant.

Seal cracks around windows, doors, fascia boards, etc. Use a good quality silicone or acrylic latex caulk/sealant. Although somewhat less flexible than pure silicone, latex-type caulks clean up easily with water and can be painted. Caulks that dry clear are often easier to use than pigmented caulks since they don't show mistakes. Buy a good caulking gun. Features to look for include a back-off trigger to halt the flow of caulk when desired, a built-in 'slicer' for cutting the tip off of new caulking tubes, and a nail for puncturing the seal within. Hardware stores sell caulking guns with these features for less than $10.00. Prior to sealing, cracks should be cleaned and any peeling caulk removed to aid adhesion. For a professional look, smooth the bead of caulk with a damp rag or a moistened finger after application. A key area to caulk on the inside of basements is along the top of the foundation wall, where the wooden sill plate is attached to the concrete foundation. Ants, spiders, and other pests often enter through the resulting crack.

Repair gaps and tears in window and door screens. Doing so will help reduce entry of flies, gnats, mosquitoes and midges during summer, and cluster flies, lady beetles, and other overwintering pests in autumn. Certain insects are small enough to fit through standard mesh window screen. The only way to deny entry of these tiny insects is to keep windows closed during periods of adult fall emergence.

Install 1/4-inch wire mesh (hardware cloth) over attic, roof, and crawl space vents in order to prevent entry of birds, bats, squirrels, rodents, and other wildlife. Be sure to wear gloves when cutting and installing hardware cloth as the wire edges are razor sharp. Backing the wire mesh from the inside with screening will further help to prevent insects such as ladybugs, paper wasps and yellowjackets. If not already present, invest in a chimney cap to exclude birds, squirrels, raccoons and other nuisance wildlife. Raccoons, in particular, are a serious problem throughout Kentucky. Many chimneys become home to a family of raccoons which, in turn, are often infested with fleas.

Consider applying an exterior (barrier) insecticide treatment. While sealing is the more permanent way to exclude pests originating from outdoors, comprehensive pest-proofing is laborious and sometimes impractical. For clients needing an alternative, pest proofing can be supplemented by an exterior treatment with an insecticide. Use recommended insecticides for exterior treatments and treat at the base of all exterior doors, garage and crawl space entrances, around foundation vents and utility openings, and up underneath siding. It also may be useful to treat around the outside perimeter of the foundation in a 2 to 6-foot-wide band along the ground, and 2-3 feet up the foundation wall.

Adapted from "TIME TO PEST-PROOF YOUR HOME" By Mike Potter in the September 15 edtition of the Kentucky Pest News from the University fof Kentucky, Colleger of Agriculture. http://www.uky.edu/Ag/kpn/kpn_08/pn080915.htm#houtim

Thursday, September 18, 2008

Greenhouse and Nursery - Alternative Energy Sources for Heating

There is increased interest in alternative energy sources for heating greenhouses and heated nursery facilties. The following are some of the possibilities:
  • Burning biomass grass crops such as switchgrass and miscanthus
  • Burning biomass wood crops such as hybrid poplar, willow, and other quick growing species
  • Burning recycled wood from construction, demolition, pallets, etc.
  • Burning corn and other grains (high price currently)
  • Burning spent oils, recycled oil, spent vegetable oils
  • Burning biogas from digested organic materials such as manures (methane)
  • Heat recovery from commercial composting
  • Solar hot water accumulators

I will be writing more about these and other options in the future.

Gordon Johnson, Extension Horticulture Agent, UD, Kent County

Greenhouse and Nursery - Don't Mistake Chrysanthemum Rusts

The following is information on white rust vs. brown rust on chrysanthemum from the UD plant disease diagnostic lab.

There have been some questions about another rust on chrysanthemum caused by Puccinia tanaceti, brown rust. This occurs in the U.S., but is easily distinguished from white rust caused by Puccinia horiana. The pustules are dark rusty to chocolate brown and occur on both surfaces of the leaves. Microscopically, the spores of brown rust are round urediniospores, very different from the teliospores of white rust. What we have seen in the past day or two is some darkening with age of the pustules of white rust to a buff or tan color.

Please do not hesitate to send in samples for confirmation,

Nancy F. Gregory, Plant Diagnostician, Department of Plant & Soil Sciences, University of Delaware

Wednesday, September 17, 2008

Greenhouse and Nursery - Crysanthemum White Rust Found Again in Delaware

Chrysanthemum white rust has recently be identified again in Delaware. The following is more information on this regulated disease.

White rust of chrysanthemum was confirmed today, September 16, 2008, on potted mums from a retail location in Dover. Inspections by Delaware Department of Agriculture personnel found the infections at a low incidence (see the previous post for pictures and description of the disease). The following are I made during a webinar hosted by Yoder Brothers on white rust. In it there is a link to a fact bulletin with further information and pictures.

Chrysanthemum White Rust Webinar Notes August 5, 2008

A webinar presented on a live web site training session by Yoder Brothers on August 5, 2008. Information may be found on Yoder.com under the grower section under technical guides. A bulletin pdf link is found at: http://www.yoder.com/ASSETS/E5705D12F42B4ED7A50627CA6288FB43/08177_CWR_Bulletin.pdf
The following notes are condensed from information in the webinar presentation:

Chrysanthemum white rust is caused by the obligate parasite Puccinia horiana. Symptoms include a 3 to 4 mm dimpled pale yellow spot on the upper leaf surface. Pustules are found on the lower leaf surface and are white to buff colored with a waxy appearance and feel. Pustules may occasionally develop on flowers. White rust infects twelve species of chrysanthemum in four genera within the Asteracae. Teliospores of the fungus are produced in the pustules that may survive up to 8 weeks in dried tissue. Spores survive only one week if buried in soil. Small basidiospores are produced from the germinating teliospores after 3 hours of moisture at an optimum temperature of 63 F (63-75 degree range). Basidiospores are easily transported by wind and water, but are sensitive to dessication. Germination occurs in a film of water and the fungus infects plant tissue, with symptoms developing after 5 to 14 days. High humidity results in faster disease development.

Imported flowers are a common source of new infections of Puccinia horiana, and should never be handled near mum-growing facilities. Flower crops should never be used to start new cuttings. Scout regularly, keep foliage dry, keep humidity low, and use preventative fungicides.
Effective preventative fungicides include chlorothalonil and mancozeb. See the Yoder bulletin for recommendations and use according to labels. Myclobutanil may be effective after infection has been observed; however, it may not be used after color break.

If chrysanthemum white rust is found, it must be reported to state agricultural officials, as there is a national protocol for eradication and treatment. The best approach is to exclude the pathogen by means of dealing with reputable suppliers, spraying to prevent infection, and eradicating existing infections.

Nancy F. Gregory, Plant Diagnostician, Department of Plant & Soil Sciences, University of Delaware.

Landscape and Nursery - Plants for Delaware Landscapes: Seven-son Flower

This is a continuation of the series on lesser known plants that are well adapted to Delaware landscapes.

Heptacodium miconioides, Seven-son flower



Heptacodium has small, white flowers in late August. However, it is grown for the pink sepals which appear in the early fall and persist until mid-November. Both the shape and attractive exfoliating bark of this shrub are similar to that of a crape myrtle. This plant is not known to have major insect or disease problems. Grow in full sun. It is adapted to most soils but prefers a moist, well-drained fertile site. It is easily transplanted and grown. Originates in China

Information and photo from the Greenhouse TPM/IPM Weekly Report from the University of Maryland Cooperative Extension and the University of Connecticut.


Tuesday, September 16, 2008

Floriculture - Plants for Cut Flowers 1

This is the first in a series on plants for cut flower growers that are well adapted to Delaware.

Mexican Bush Sage, Salvia leucantha

This short-day blooming salvia produces flowers from late summer until frost. The velvety purple flowers are very eye catching for the fall cut flower market. If you are growing under a high tunnel, they should last until early December if the weather cooperates. This plant also attracts bees, butterflies, and hummingbirds. Once a plant is established it is easy to propagate additional plants by dividing of the clump. This is a zone 8 plant so to overwinter you will need protection.



Information and photo from the Greenhouse TPM/IPM Weekly Report from the University of Maryland Cooperative Extension

Nursery - Sustainable Field Nursery Practices Field Day

The following is information on an upcoming nursery workshop in Maryland.

University of Maryland Cooperative Extension Field Day: Staying Profitable Through Sustainable Field Nursery Production Practices
September 25, 2008
Location: Raemelton Farm, Adamstown, MD

Do you want to learn

􀀹 About what information a sensor network can give you for irrigation and growth management?
􀀹 New techniques for controlling potato leafhopper in the nursery?
􀀹 Some tricks for single-pass weed control?
􀀹 How to use cover crops for pest management and improving soil quality?
􀀹 About a 2-year study at Waverly Farm Nursery on nitrogen fertilization of nursery trees?


Registration is free but is LIMITED TO THE FIRST 50 REGISTRANTS
To register, contact Debby Dant @ 410-827-8056 X115 or ddant@umd.edu by SEPTEMBER 19TH
For additional program information, please contact John Lea-Cox @ 301-405-4323 or JLC@umd.edu

You can download the program and directions at http://www.ipmnet.umd.edu/08Sep25C.pdf

Monday, September 15, 2008

Turf and Landscape - Slow Release Fertilizers: Polymer Coated Fertilizers 1

This is the first in a series on slow release fertilizers for turf and landscapes. This post contains information on one of the newer polymer coating technologies.

Reactive Layer Coating. A relatively new coating technology known as reactive layer coating (RLC) polymerizes two reactive monomers as they are applied to the fertilizer substrate in a continuous coating drum. These in situ reactive layer polymerizations form an ultra-thin membrane coating which controls nutrient release by osmotic diffusion. A number of these products are being marketed under the trade name Polyon. These include coated basic fertilizer materials, i.e., urea, potassium nitrate, potassium sulfate, potassium chloride, ammonium sulfate, ammonium phosphate and iron sulfate, in various particle sizes. Coating weights on urea vary from 1.5 to 15%, depending on the release duration desired.

Nutrients are released from Polyon-coated fertilizers by osmotic diffusion. The RLC process permits application of ultra-thin, and hence lower cost, membrane coatings, which distinguishes this technology from many other polymer-coated fertilizers. The coating thickness determines the diffusion rate and the duration of release. Polyon-coated urea at 4% coating (44%N) will release at twice the rate and will have half the duration as an 8% coating (42% N).

During the manufacturing process two polymers react to form a polyurethane coating which is chemically bonded to the fertilizer core. The advantage of RLC technique is that the liquid coating materials can be applied and polymerized to the desired coating thickness in a continuous coating process drum without the need for solvents and associated recovery equipment. As a result, production costs are lower than many of the other commercial polymer-coated fertilizer technologies.

Reprinted from Selected Fertilizers Used in Turfgrass Fertilization by J. B. Sartain and J. K. Kruse, University of Florida Extension.

Nursery and Greenhouse - Ellepots

Nursery and greenhouse growers that grow out specific orders for landscapers may want to consider paper biodegradable pots. The following is some information.

Ellepots are are a paper pot product being offered in the horticultural industry. It was developed by a Danish company http://www.ellepot.dk/. The pot is formed by wrapping a piece of paper around growing medium. Growing trays are still needed to hold these pots. There is more air circulation around this paper pot so be careful when watering that plants don’t dry out too much. Holding plants, especially when ready to go to market, can be a challenge. It is being marketed primarily for landscapers. These pots reduce transplanting time by about 25% and will biodegrade in the landscape which eliminates the need to dispose of plastic pots. This product does increase the cost of each plant, but the increased cost could be covered by the reduced labor when transplanting. There is also has a product called, Ellepress, which is a pot in a compressed form. Ellepots are available pre-made or you can also buy equipment to make and fill your own.



Information and photo taken in part from the September 21, 2007 edition of the Greenhouse TPM/IPM Weekly Report from the University of Maryland Cooperative Extension.

Sunday, September 14, 2008

Soil Sampling Season

Fall is the time of year that most soil samples are taken. The following are some guidelines for taking soil samples.
  • Take soil samples from a uniform depth. Soil tests have been calibrated at the depth of the cultivated layer (6-8 inches) for all but extablished turf. A 7 inch depth should be targeted. This would include areas where new lawns are to be established, flower beds, landscape beds, and areas with trees and shrubs.
  • Established turf should be sampled at a depth of 4 inches.
  • Use a soil coring tool (soil sampling tool).
  • Ideally, a minimum of 20 cores should be taken and composited for a sample. When you mix the cores to form the samples, make sure that you have mixed them well before you take the subsample to send to the lab. All clods or core pieces need to be broken up. The most common mistake in soil sampling is not mixing cores adequately.
  • Take cores in a random pattern in the areas sampled.
  • Divide landscapes up into sampling areas. Beds, turf areas, and garden areas should be sampled separately.
  • If fertilizer has been spot applied to an area (such as fertilizer stakes), samples should stay off of the spots if at all possible. If the spots are not known, then plan to take extra cores.
  • Different soil types within a landscape or turf area should be sampled separately.
  • Avoid any features in a landscape that might skew the test results. Examples would be disturbed areas (such as where pipes were trenched in), wet pockets, or areas right next to pavement or cement walkways. Do not take cores from these areas for the composite. If you are interested in the fertility of these areas, take separate samples.
  • Take samples at least once every 3 years.
  • Target soil sampling at the same time of year each time you take the sample. Time of year is not as important as being consistant in when you take the sample. However, fall sampling gives the most consistant results.

Gordon Johnson, Extension Horticulture Agent, UD, Kent County

Greenhouse and Nursery - Crysanthemum White Rust,

Fall mum growers are reminded to watch for Chrysanthemum White Rust. This is a disease that must be eradicated if found. The following is some information.



Chrysanthemum White Rust

Chrysanthemum white rust caused by the fungus Puccinia horiana affects cultivated chrysanthemum plants in the Family Asteraceae. The disease is not established in U.S. chrysanthemum production, and could have significant impact on both greenhouse and outdoor plants of chrysanthemum, as well as cut flowers. The disease has occasionally been found in United States nursery stock in greenhouses, but it is easily and quickly cleaned up when found. Symptoms include yellow spots on the upper surface of the leaves that are up to 5 mm in size. On the underside of the leaves, raised bumps or pustules develop which have a waxy, warty appearance and are light in color.

Growers are reminded that if you see signs of white rust on leaves or flowers of a plant you are growing in Delaware, contact the Delaware Department of Agriculture. Plants must be destroyed but you need to work with the DDA for proper destruction procedures.

Information in part from Nancy Gregory, Plant Diagnostician, Department of Plant & Soil Sciences, University of Delaware

Saturday, September 13, 2008

Nursery and Greenhouse - Biodegradable Pots From Renewable Materials

With consumers asking about ways to be ecofriendly or "green", nursery and greenhouse growers may want to consider using pots from renewable materials that are biodegradable instead of plastic. Certainly, we have used peat pots in the industry for decades; however, peat is not considered a renewable resource in that it is not being replenished. I saw a presentation on using solids from dairy manure to make pots several years ago. Many other materials are being researched and several will be coming on the market in the near future. The following is a short article on the subject in the current IPM/TPM report from the University of Maryland.

One of the things that several landscape managers mentioned is that customers are asking what are you doing to be more “Green”? Anything made out of petroleum plastic is being looked at in a negative light. Many of the annuals and perennials that are sold in the industry are shipped in plastic pots. Several companies are developing pots made out of materials such as wheat, sugarcane, and corn. The wheat based pots can take temperatures up to 50 °C before they heat shift and look pretty promising. They last about 20 weeks before they start to break down. This would work for crops such as chrysanthemum that are 12 week crops. The wheat based pots are completely compostable in most home compost piles. These food based pots have been about twice as expensive as petroleum based plastic but this is rapidly changing and expect to see more competitive prices in the near future.

Reprinted from the September 12, 2008 edition of the TPM/IPM Weekly Report for Arborists, Landscape Managers & Nursery Managers from the University of Maryland Cooperative Extension

Friday, September 12, 2008

Greenhouse and Nursery - Renewable Energy Website

The following is information on a website created for renewable energy topics applicable to greenhouses and nurseries from the University of Massachusetts.

The UMass Extension Vegetable and Floriculture Programs are excited to present the addition of “Renewable Energy for Farms and Greenhouses” to their websites. The pages are designed to provide a practical and reliable resource base for farmers and growers on using renewable energy including solar, wind, biomass, and geothermal technologies. With high fuel prices, decreasing consumption of fossil fuels is an important step you can take to ease your wallet and to reduce greenhouse gas emissions. The site is arranged to be a guide for the process of adding green energy; it provides resources on the different types of energy, tax incentives, finding a contractor, and energy efficiency. There is also a page that lists Massachusetts farms and greenhouses that are using green energy. Visit the website by going to www.umassvegetable.org or http://www.umass.edu/umext/floriculture/ and clicking on the “Renewable Energy” link.

Gordon Johnson, Extension Horticulture Agent, UD, Kent County

Landscape and Turf - Yellowjackets are Dangerous This Time of Year

Yellowjacket stings are a common problem for lawn care workers and landscapers, especially this time of year. The following is some information.

Yellowjackets are dangerous wasps encountered around homes and buildings. Nests are often located underground in an old rodent burrow, beneath a landscape timber, or in a rock wall or wall of a building. If the nest can be located, it can usually be eliminated by carefully applying a wasp spray insecticide into the nest opening.

Late summer is the time of year when populations of yellowjackets and other social wasps become large and noticeable. Because colonies start as a single queen in May, populations are very small through the early part of the summer. Yellowjacket wasp populations reach a peak at late summer when each nest may have up to approximately 5,000 wasps.

Yellowjackets are commonly observed hovering back and forth at the small nest opening or around garbage cans and other areas where they forage for food. The workers from the colony travel up to a few hundred yards from the nest while looking for food. In the early summer the wasps forage for caterpillars and other "meat" items, but in the fall prefer sweets such as pop and candy residue in garbage cans.

The eastern yellowjacket is our most abundant yellowjacket. However, up to 40% of the eastern yellowjacket nests are parasitized by other species of yellowjackets each year. Most of the eastern yellowjacket colonies that are not parasitized reach a population of about 3,000 workers and a few colonies may have almost 5,000 workers. Queens are produced in late summer and early fall. A healthy colony may produce 2500 queens each of which has the potential to found a new nest the following spring! Yellowjackets do not reuse their old nests. Apparently they do not even reuse the individual cells in which the new workers and queens develop.

Sevin (tm), or Ficam (tm), dust is very effective provided a handduster or similar type applicator is used to dispense several puffs of the insecticide dust in to the nest opening (an empty, dry liquid detergent bottle, filled no more than halfway with dust and shaken before dispensing works well).

Treatment should be performed late at night after all yellowjackets are in the nest and less active. It's best to pinpoint the nest opening during the daytime so you will remember where to direct your treatment after dark. Approach the nest slowly and do not shine the beam of the flashlight directly into the nest entrance as this may startle the wasps; instead, cast the beam to the side to illuminate the nest indirectly and place the light on the ground rather than in your hand. Similar to hornets, yellowjackets are extremely aggressive when the nest is disturbed. It may be prudent to call a professional pest control company, particularly when access to the nest is difficult.

Information from the University of Kentucky, North Carolina State University and Iowa State University fact sheets and newsletters.

Thursday, September 11, 2008

Landscape - Red Oak Death

I have noticed many trees in landscape that have died this year. One species that is being reported as having more death than usual is Red Oak. The following is some information from the University of Maryland.

Several arborists and landscape managers are reporting to us that red oaks have major dieback and sometimes death of the trees is occurring in Maryland landscapes. It is mainly trees that were transplanted in the last 3 years or older trees that are being reported with dieback. Three years of summer droughts is taking a toll on these trees. Red oak is often attacked by two-lined chestnut borer, Agrilus bilineatus. Adult beetles have been out since July and are just finishing up flight activity. Eggs are laid on the bark and larvae bore into the bark disrupting movement of moisture and nutrients through the phloem and xylem as they make mines in the trunk and larger branches. The larvae usually have a one year life cycle but may require two years in some trees. You may notice wet spots on the trunk in August and September of infested trees as the trees try to expel the tunneling larvae. You can use a chisel to open the area and see if a larva is present. The larvae are long, cream colored, and appear legless. The two-lined chestnut borer attacks stressed trees and we have plenty of stressed trees.

Control: Dinotefuron (Safari) applied as soil injection, soil drench or trunk injections are reported to give pretty good control of emerald ash borer, which is another Agrilus species. This might have potential against the two-lined chestnut borer. Susceptible trees can have the trunk treated with Onyx or Astro in June to kill larvae before the get under the bark. Examine for new “D”- shaped exit holes in June next year to determine when adults start to emerge.

Reprinted from the September 5, 2008 edition of the TPM/IPM Weekly Report for Arborists, Landscape Managers & Nursery Managers from the University of Maryland Cooperative Extension.

Landscape - Puss Caterpillars

There are numerous stinging caterpillars in the landscape that landscape workers may be exposed to. One recently in the news is the puss caterpillar. The following is a picture and some information.

There are several species of slug-like caterpillars that have poisonous spines. Slug caterpillars are short and stocky and creep about on leaves in a slug-like manner. The head and legs are not visible. Typically, there is one generation per year with the grown larvae found in the late summer. The puss caterpillar is one of these slug-like caterpillars.

The Puss Caterpillar is covered with a dense woolly coat of soft brown hair, with tail-like hairs at the rear end. Beneath the hairs are numerous short poisonous spines that can cause severe irritation. They are often found feeding on various trees and shrubs, including elm, maple, hack berry, oak, sycamore and others. Young caterpillars often feed in groups. Sting severity increases with size of caterpillar. Puss caterpillar stings are often more severe than those of other caterpillars.

Puss caterpillar. Note the long hairs that look tail-like at the rear.

Different color variation of the puss caterpillar. Photo from the University of Maryland TPM/IPM Newsletter.

Information taken from "Stinging Caterpillars" by Ric Bessin, Extension Entomologist University of Kentucky College of Agriculture.

Gordon Johnson, Extension Horticulture Agent, UD, Kent County

Wednesday, September 10, 2008

Turfgrass - Late Summer Bermudagrass Control

The following is information on late summer bermudagrass control in tall fescue turf.

With bermudagrass greening up again with the recent rains, now is the time to apply late summer bermudagrass controls in your tall fescue turf. The best option is to apply Acclaim Extra at a rate of 0.64 fluid ounces per 1000 square feet mixed with triclopyr at 0.70 fluid ounces per 1000 square feet.

Gordon Johnson, Extension Horticulture Agent, UD, Kent County

Turf - Late Season Crabgrass

The following is some information on late season crabgrass management.

While normally we do not advise controlling crabgrass this late in the season, with the recent rains and warm weather still, crabgrass escapes are very noticeable, especially in turf areas thinned out by the drought. At this time of year, crabgrass goes to seed very quickly so you may want to consider a late season control to reduce seed production. The two options at this time are Drive and Acclaim Extra. Both can be used on areas to be reseeded to turf-type tall fescue. With expected cooler weather, crabgrass growth will slow down considerably. Note turf areas with crabgrass problems and target these areas for preemergence herbicides next spring. If you choose not to control crabgrass chemically, mow frequently to reduce seed head production. Even with frequent mowing, there will be some seed production as crabgrass will often produce seed heads below the level of the mower blade in September. If grass stands have thinned out due to the drought, you will want to reseed areas now. If crabgrass is left, it will actually provide some protection to new seedings as it will die out with frost.

Gordon Johnson, Extension Agriculture Agent, UD, Kent County

Tuesday, September 9, 2008

Landscape, Nursery, and Greenhouse - Tarnished Plant Bug

One insect that can cause considerable damage to flowering plants is the tarnished plant bug. It often goes unnoticed until too late. They will feed on leaves but are a bigger concern feeding on buds, flowers, and young fruit. They can also attack conifer seedlings. Numbers have been high this year. The following is some information.

Tarnished Plant Bug


Tarnished Plant Bug. Photo by Russ Ottens, University of Georgia, Bugwood.org

Many times growers see pest damage before they notice the pest. This is usually the case with the tarnished plant bug. Symptoms of feeding can result in injury to flower buds, causing them to abort and drop, or the blooms not to open properly or be distorted on one side. Other types of injury include deformed leaves, scarred and discolored stems, or leaf petioles. The tarnished plant bug is a very general feeder, attacking many kinds of trees and herbaceous plants. It feeds on many flowers including dahlia, aster, calendula, chrysanthemum, cosmos, gladiolus, poppy, salvia, daisy, sunflower, verbena, zinnia, and others. It has piercing-sucking mouth parts as do all the true bugs. The long sucking mouthpart is inserted into the plant tissues and introduces toxic saliva into the plant as it feeds. The toxin kills cells near the feeding site causing the distortion of the growth surrounding their "sting marks", yellow or brown spots or wilting of new growth. The heaviest injury often occurs during mid to late summer and is most evident during hot, dry weather, especially adjacent to recently cut hay fields. The first few generations develop on preferred hosts such as small grains, alfalfa, wild grasses, vetch, dock, and fleabane. As hay is cut or as other plants dry out, tarnished plant bugs migrate in large numbers to succulent hosts, which may be your flowers.

The adult is a small, flattened bug, about 1/4" in long, bronze in color with yellow and black markings. There is a clear yellow triangle, marked with a black dot on the lower third of each side. Tarnished plant bugs have a gradual type of development, and the young become more and more like the adults as they go through each stage. Young tarnished plant bugs, called nymphs are small, green and resemble immature aphids. As they get larger, they look similar to the adults except they have wing pads. Adults will fly when disturbed or they will run rapidly and hide underneath the leaves. There are several generations each year throughout the summer.


Foliar sprays of a label pesticide can be applied when plant bugs appear in the field or landscape, and reapplied as needed. There are differences of opinion as to the best timing for treatment. One source recommended treating early in morning when the bugs are still sluggish from cooler temperatures. Another source, for orchards, recommended treating on a warm, sunny, calm day when TPB are most active. All sources however, strongly recommended weed control to reduce overwintering populations. Read labels to determine whether specific products are registered for use against plant bugs on target flowers. Before using a pesticide for the first time or on a new crop or cultivar, treat a few plants and check for phytotoxicity.

Some foliar sprays registered for use against plant bugs on ornamentals include:
Acephate (Orthene 97, Orhtene TT&O), Bifenthrin (Talstar Nursery), Carbaryl (Carbaryl 4L, Sevin 80WSP, Sevin SL), Cyfluthrin (Decatholon 20WP), Fluvalinate (Mavrik Aquaflow), Insecticidal soap (I.S. 49.52 CF, M-Pede), Malathion (Malathion 5 EC), Pyrethrins (Pyrenone Crop Spray), Pyrethrins + rotenone (Pyrellin)


Information from a factsheet by Tina M. Smith, Extension Specialist Floriculture Program, Dept. of Plant, Soil & Insect Sciences, University of Massachusetts, Amherst

Turf - Kentucky Bluegrass Varieties

Kentucky bluegrass is best adapted to northern Delaware, silt loams in Kent County, and heavier soils in other parts of Kent County. In general, it is more disease prone and less heat tolerant than turf-type tall fescue. However, a great deal of improvement has occured over the last decade and more heat and disease tolerant varieties are now available. For those interested in using Kentucky bluegrass for turf areas, the following are recommended varieties from the Maryland/Virginia turf evaluations.

Kentucky Bluegrass – Individual varieties selected must make up not less than 10%, nor more than 35% of the total mixture on a weight basis. All varieties must be certified. Selections can be made from Category I alone or various combinations of Categories I, and II as noted. Kentucky bluegrasses listed as “Promising” (Category II below) can account for no more than 35% of the blend by weight).

Category I – Recommended Kentucky Bluegrass Varieties (65–100% of blend by weight).

Apollo, Award, Awesome, Beyond, Bordeaux, Brilliant, Cabernet, Champlain, Courtyard, Dynamo, Everest, Everglade, Excursion, Glenmont, Impact, Liberator, Limousine, Midnight, Moonlight, NuDestiny, NuGlade, Perfection, Princeton 105, Quantum Leap, Rambo, Raven, Skye, Total Eclipse, and Tsunami.

Category II – Promising Kentucky Bluegrasses (10–35% on a weight basis) – These grasses have performed in the top statistical quality category for a minimum of 2 consecutive years in Virginia and Maryland trials. Seed may be difficult to locate for some cultivars. Note: Durablue, ThermalBlue, and ThermalBlue Blaze are commonly referred to as Hybrid Bluegrasses, but they are classified by USDA as Kentucky bluegrasses. To date they have had better performance in traditionally warmer areas of Virginia.

Alexa II, Aura, Barrister, Belissimo, Bewitched, Bluestone, Diva, Durablue, Emblem, Everglade, Granite, Juliet, Mystere, NuChicago, NuDestiny, Rhapsody, Rhythm, Solar Eclipse, Sudden Impact, ThermalBlue, ThermalBlue Blaze, Touche, Wild Horse, Yankee, Zinfandel

Monday, September 8, 2008

Turf - Recommended Turf Type Tall Fescue Varieties

With fall seeding season in hand, I thought I would post the recommended turf-type tall fescue varieties from the MD/VA turfgrass testing program. These varieties will perform well in Delaware.

Turf-Type Tall Fescue Recommendations

Category I – Recommended Tall Fescue Varieties (90–100% on a weight basis):

2nd Millennium, Avenger, Biltmore, Bingo, Bravo, Cochise III, Constitution, Coyote II, Crossfire II, Davinci, Daytona, Endeavor, Falcon IV, Fidelity, Forte, Good-En, Grande, Greenkeeper WAF, Guardian 21, Houndog 5, Inferno, Justice, Kalahari, Magellan, Masterpiece, Matador, Matador GT, Onyx, Padre, Picasso, Penn 1901, Quest, Raptor, Rebel Exeda, Regiment II, Rembrandt, Rendition, Southern Choice II, SR 8250, Tarheel, Tarheel II, Tempest, Titanium, Turbo, Ultimate, Watchdog, and Wolfpack.

Category II – Promising tall fescue varieties (may be 90–100% of the mixture on a weight basis):

Blackwatch, Escalade, Grande II, Guardian 21, Hunter, SR 8550, SR 8600

Landscape - Leaf Scorch in Trees and Shrubs

Leaf scorch in trees and shrubs is common this year because of the drought. However, there are other causes of leaf scorch that you need to be aware of. The following is a good article on the subject.

Leaf scorching in landscape trees and shrubs occurs when leaves lose water faster than the roots can supply it. When moisture is lacking, the margins tend to dry out first, hence the marginal scorch pattern typically associated with stressed plants. Symptoms of scorch may become evident any time water flow is disrupted within a plant.

Leaf scorching in plants is usually attributed to both biotic (living) and abiotic (environmental) agents. Why is it important to tell the difference, and how does one do it?

Abiotic (or environmental) agents that can cause scorching in leaves include drought, dehydrating winds, salt, flooding, chemicals, air pollutants, toxic metals, and nutrient extremes. Scorching can also occur when plants are placed in sites where roots do not develop normally (such as in planting islands or in soils with a hard pan layer), or when roots are physically damaged (such as occurs during construction). In most cases, this type of scorching is fairly uniform around leaf edges, affects newer leaves as well as older leaves, and will appear on vast expanses of the canopy. In addition, scorch symptoms may develop soon after a known stress (such as drought or an application of de-icing salt) occurs.

On the other hand, scorching can also occur in plants affected by living or biotic agents. Organisms that can cause this symptom include fungi, bacteria, nematodes, viruses, and insects. Leaf scorching due to biotic agents is not clearly defined. The scorch symptoms on leaves are often irregular in shape, and frequently a yellow or red “band” will appear between green and scorched tissues. In addition, symptoms may appear first on the older leaves of one or more branches, and then spread to other parts of the tree.

This growing season, the leaves of many landscape plants are exhibiting the uniform “scorch” consistent with an abiotic stress. Drought stress is the likely culprit for many trees, especially seedlings and shallow rooted and recently planted trees and shrubs that lack extensive root systems which cannot absorb water from deeper in the soil profile.

Some trees in the landscape, primarily oaks, are also affected by a biotic agent that causes leaf scorch. Bacterial leaf scorch of shade trees (BLS) is caused by the bacterium Xylella fastidiosa. Like leaf scorching due to other biotic agents, leaf scorch caused by Xylella is not clearly defined; scorch symptoms are often irregular in shape, and frequently a dull red “band” is apparent between healthy and scorched (necrotic) tissues.

Reprinted with modifications from "Leaf Scorching in Shade Trees – Biotic or Abiotic?" by Ann B. Gould, Ph.D., Specialist in Plant Pathology, Rutgers University in the September 20, 2007 edition of the Plant and Pest Advisory, Landscape, Nursery, and Turf Edition, from Rutgers University.

Sunday, September 7, 2008

Turf - Act Now to Renovate Turf While there is Soil Moisture

Now is a good time to renovate turf as we have some soil moisture. Some thoughts on this topic follow.
  • While there is adequate soil moisture, plan to do turf renovations.
  • Early September is a great time period to plant as you can get seed germinated and established before colder weather in October. In particular, tall fescues will benefit from earlier planting.
  • Now is the time to add your first fall fertilizer at 1 lb. of N per 1000 sq. ft.
  • Now is the time to add lime if soil tests indicate that soil pH has dropped below 6.0
  • Core aeration is a recommended practice for turf areas that have been compacted, have built up thatch, or that would benefit from compost topdressings. September is the ideal time to do this as long as there is soil moisture.
  • To do a renovation, ideally you should do the following: apply any lime or fertilizer, core aerate, apply compost topdressing, drag if needed, overseed 1/3 third of your seed, and slit seed the remaining 2/3 of the seed 1/3 in one direction and 1/3 perpendicular to that direction.
  • Choose well adapted, disease resistant turf varieties. For most applications, turf-type tall fescue is the choice for this area.

Gordon Johnson, Extension Horticulture Agent, UD, Kent County.

Hanna - A Drought Breaker?

Tropical storm Hanna brought welcome rain to Delaware on Saturday. Was it enough to break the drought? Some areas received just a little over an inch, others close to two inches. Many plants were severely drought stressed before the rain. Most deciduous woody plants will not put out new leaves because it is late in the season. The same goes for many perennial plants. Evergreen species should benefit significantly. Turf should recover but some areas will have thinned out. Nursery and greenhouse growers can breath a sigh of relief for the fall sales season as customers should be looking for plants now that there is some soil moisture (and they will be looking to replace drought damaged plants). The following are rainfall totals for the area.

Blackbird 1.92 inches
Smyrna 1.44 inches
Dover 1.30 inches
Kitts Hummock 1.22 inches
Harrington 1.10 inches
Milford 1.39 inches

Gordon Johnson, Extension Horticulture Agent, UD, Kent County

Saturday, September 6, 2008

Greenhouse - Scouting Poinsettias for Whiteflies

The following are some guidelines for scouting poinsettias for whiteflies.

Scouting your poinsettia houses is critical. Small populations of whiteflies caught early, especially if it is a Q-biotype sweetpotato/silverleaf population, will be much easier to manage than those that get out of hand. Remember that, on average, one female can lay more than 200 eggs in her lifetime and a whitefly population can increase 10 times in 4 weeks!

Some poinsettia whitefly scouting tips and pointers:

1) Smaller houses (less than 4000-6000 ft2) can be scouted as a unit; larger houses should be broken into sections. ?? Inspect, or scout, about 10 plants per 1000 ft2.

2) Scout weekly, and try to scout on the same day each week.

3) To look for whitefly eggs, crawlers (1st instar), nymphs (2nd – 3rd instars), and pupae (4th instar), inspect the undersides of the leaves. Check at least 3 leaves per plant, and make sure to check leaves from different areas of the plant – top, middle, and bottom. 6

Eggs are small and spindle-shaped and are typically laid in circular or crescent-shaped patterns, though they can be scattered across the leaf underside singly or in clusters. You will often see eggs in clusters of white-gray dusty patches. Eggs are small, and magnification is often needed to be able to observe them (a 10-20x handlens is fine).

Nymphs can be seen with the naked eye, though the smallest instars (stages) are often difficult to observe. Nymphs are somewhat oval in shape and lightly colored. Older nymphs will be larger in size.

Pupae are easily observed with the naked eye. Some mistake these for the ‘eggs’. A hand-lens is helpful to determine whether the pupae are greenhouse or sweetpotato/silverleaf whiteflies.

To simplify things, your observations can be recorded as ‘small’ (1st and 2nd instars), ‘medium’ (3rd instars), and ‘large’ (pupae, 4th instars), or for less detail, record all 1st-4th instars as ‘immatures’.

Record any whitefly adults seen when scouting for eggs, nymphs and pupae. Adults can also be monitored with sticky cards or tape. Use 1 trap per 1000 ft2 and place immediately above the canopy, and place extra cards near doors and vents. If this seems too many, set at least a few in the older crops and where whiteflies are most suspected or have been seen.

Avoid, or at least greatly reduce, using sticky cards in greenhouses where you are employing a biocontrol insect; the cards will trap the beneficials as well as the pest. Keep records of what life stages are found and where. This will help in your management decisions and can also provide a history that can be useful in upcoming seasons.

By identifying hot spots, a spot or area treatment can be applied, instead of treating the whole crop and, by knowing the predominant life stages of the whitefly pest, you can adjust your management strategy to optimize control.

Choose an insecticide that is effective for the life stage that is present. Use the information generated by scouting to determine whether or not you are above or below your action threshold (whether it is necessary to apply a treatment to manage the whiteflies).

To avoid the buildup of a whitefly population, the threshold early in the season should be lower than the threshold later in the season. As a guideline, treat when you find above ~ 0.2 immatures per leaf scouted through October. Later in the season, treat when above ~ 2 immatures per leaf scouted. (For the area scouted, calculate the average number of immatures found per leaves inspected). Keep in mind that these are guidelines, and thresholds will vary depending on the practices of each operation as well as the demands of each customer.

Houses that are not thoroughly scouted should consider using higher thresholds. Don’t stop after treatment; scouting after pesticide application is important too! Make sure that your management practices are working.

Reprinted from "Whitefly Watch: Don’t Forget to Scout!" by Nora Catlin, Cornell Cooperative Extension of Suffolk County, NY in the October 2006 edition of the Northeast Floriculture IPM Notes.

Landscape, Nursery, Turf, and Greenhouse - Water Absorbing Polymers II

The following is more information on water absorbing polymer use in horticultural applications during establishment.

Hydrogels have been used in field establishment of revegetation projects, as well as perennial, and annual establishment and production. Plants installed in media with hydrogels have had different responses. For instance, plants requiring more moisture than is readily available seem to benefit from hydrogel additions, but negative responses can occur if the hydrogels are used in environments that are naturally moist and xeriphytic plants are planted. Plants also have unique responses for different growth stages, so amounts of hydrogel required may vary as a plant develops.

Research on plant establishment in dry conditions has shown benefits for using these hydrogels (water absorbing polymers). Pinus halepensis (Aleppo pine) doubled its survival rates in 0.4% hydrogel soil compared to no hydrogel amendments. The hydrogel also prolonged water availability for plant use when irrigation was stopped. The hydrogel media also allowed for 19 days to pass before plants started to die whereas in the control with no hydrogel plants started to die after five days of drought. Pinus pinea (umbrella pine or Italian stone pine) seedlings survived 1.4 to 2.0 times longer with applications of hydrogels compared to the trials with no hydrogels in the field production. Pinus halepensis also had increased adventicous root growth along with increased overall plant mass when the hydrogel was added to the media. Research has shown that Quercus rubra (red oak) and Nyssa sylvatica (black gum) had increased root regeneration when rooting hormones were added to the polymers for transplant aids. Dehgan and others (1994) noted that foliage plants like Photinia x fraseri (Fraser photinia) responded in increased mass to the incorporation of hydrogels into media.

Hydrogels usually have some effect on plant establishment, with the greatest benefit for moisture loving plants planted in dryer conditions. Festuca arundinacea ‘Rebel’ (Tall fescue) benefited from pre-seeding incorporation of hydrophilic polymers into the soil. Pyracantha cocinnea (scarlet firehorn) and Rhododendron sp. (azalea) had increased survival and increased dry weights in container production when a hydrogel was incorporated into the media. Drought sensitive annuals, such as Petunia parviflora (petunia), responded well to hydrogels in dry conditions and increased flower numbers and dry weights.

Not all plants respond the same to hydrogels. One issue is that thay retain fertilizer salts. This can actually reduce plant growth. In container production of Betula pendula (European birch), hydrogel incorporation into the media has shown a reduction in overall plant mass and also decreased the amount of water available to the plants. After further investigation, the lack of water availability was attributed to the amounts of soluble salts in the media. Another research project found that Codiaeum variegatum (croton), Dieffenbachia sp. (dumb cane) and Hibiscus rosa-sinensis (hibiscus) showed no visible size differences when hydrogels were used compared to not being used. Annuals requiring dry regimes such as Catharanthus roseus (vinca) do not respond well to extra water being held by the soil.

Extracted from "Hydrophilic Polymers – Effects and Uses in the Landscape" by Daniel Peterson in the Restoration and Reclamation Review Student On-Line Journal, University of Minnesota, St. Paul, Minnesota (USA), Department of Horticultural Science

Friday, September 5, 2008

Landscape and Turf - What are Those Wasps

Cicada killers often will cause concern by homeowners because of their size. Another wasp that is found in turf and landscapes this time of year is the Scoliid wasp. The following is some information and photos.

The cicada killer wasps have started to decline in numbers; however, another wasp is starting to appear. This wasp is a scoliid wasp and is a parasitoid of green June beetle larvae. It has a gun metal blueblack body with a rust colored abdomen with two yellow spots. Adult wasps may be found feeding on flowers and is nonaggressive. This wasp flies over turfgrass in zigzag patterns searching for entrance holes for the grub entrance holes and other cues. Females can sting but requires provocation; thus no treatment is warranted.




Scoliid wasp photos by Brian Kunkel, UD Ornamental IPM Specialist.

From the August 29, 2008 edition of the Ornamentals Hotline from UD Extension.