Summer 1995

Focus is produced quarterly by the Cooperative Extension Service
University of Maryland, College Park.

Ellen Varley, editor
Pamela Townsend,
writer/managing editor
Heather Hull, writer
Edwin Remsberg, photographer
Questions, comments or suggestions may be directed to:
Ellen Varley, ev1@umail.umd.edu
phone: (301) 405-4581
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From the Director's Desk

Integrated pest management (IPM) is a "hot" topic in American agriculture. With rising pesticide costs and growing public concerns about pesticide residues in food and contamination of surface- and ground-water supplies, it's only natural that farmers, homeowners, greenhouse growers, golf course managers, and other pesticide users want to reduce their reliance on the chemicals they use to control insects, nematodes, weeds, and diseases.

IPM helps these diverse audiences accomplish this goal. Rather than relying strictly on pesticides to cope with pest problems, they can use a combination of biological, cultural, mechanical, and limited chemical control tactics. This approach minimizes the potential for adverse human health or environmental effects while maximizing economic benefits to both producers and consumers.

Since the early 1970's, the Cooperative Extension Service has taught Maryland residents how to apply and benefit from IPM strategies in a variety of environments. The earliest projects were developed for vegetable and field crops. Since then, projects involving fruits, turf, and ornamentals have been added. Our IPM program is a good example of how university faculty are helping to solve real-world problems through practical, needs-driven research and outreach efforts.

This issue of Focus gives a broad overview of these efforts, highlighting specific research and outreach programs involving fruits, vegetables, turf, field crops, and ornamental plants. It also describes some projects being conducted in special environments, such as greenhouses and zoos. Although the projects described here represent only the tip of the proverbial iceberg, I think they will give you a better understanding of the scope and diversity of Extension's IPM efforts and their relevance to all Maryland residents.

The federal government has set a goal to have IPM practiced on 75 percent of all cropland in the United States by the year 2000. Maryland, Virginia, Pennsylvania, and the District of Columbia have made a commitment to establish voluntary IPM practices on 75 percent of their agricultural, recreational, and public lands. The Cooperative Extension Service is contributing to the achievement of these goals.


Thomas A. Fretz
Dean, College of Agriculture and Natural Resources
Director, Cooperative Extension Service

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Fighting Pests of Field Crops

Since the early 1970's, the Maryland Cooperative Extension Service has educated farmers, industry personnel, and other Maryland residents about the benefits and techniques of integrated pest management (IPM). Some of the earliest efforts which continue today involved field crops: soybeans, alfalfa, field and sweet corn, and small grains. Projects have focused on pest identification, monitoring, and fore-casting; reducing the number and quantity of pesticide applications based on economic thresholds; improving the timing and selection of pesticide treatments; and finding bio-logical, cultural, and mechanical alter-natives to pesticides when possible.

Controlling Corn Rootworm

One project has focused on the western corn rootworm. As its name suggests, this pest feeds primarily on corn roots. A newcomer to Maryland, it poses a major problem for U.S. agri-culture, requiring treatment of more acres than any other insect, according to Betty Marose, Maryland Extension agricultural IPM coordinator.

Marose attributes this high pesticide use to the difficulty involved in predicting corn rootworm populations and the damage they will cause.

Adult beetle counts conducted one year must be used to estimate the size of larval populations and yield losses the following summer. Climatic variation, the presence or absence of other insects, farming practices, and other factors can affect these estimates.

With financial support from the Maryland Grain Producers Association, Marose and several colleagues have conducted research designed to help the agricultural community combat this pernicious pest. Since 1992 they have sampled corn fields and explored techniques for estimating crop losses. They have monitored populations at 68 sites, validating economic thresholds established in the Midwest and modifying them for Maryland. As a result of this work, they have developed sampling techniques that are as effective as older methods and less time-consuming and tedious to perform.

Options for controlling the corn rootworm are currently limited, with crop rotation being the best option because it breaks the pest cycle. "Farmers who rotate corn and soybeans every year don't have problems because corn rootworms aren't found in soybean fields," says Marose. However, farmers who grow corn for more than one year in a row must either monitor pest populations and place sticky traps in their fields or apply pesticides automatically at the beginning of every growing season.

"It's important that we continue our research on this pest," Marose stresses. "If we can get a better handle on population and damage estimates, we can reduce the need for this type of insurance' application of insecticides and replace it with a more targeted approach to control."

Disease Treatment Guidelines

While Marose and her colleagues focus on insect pests, other researchers concentrate on the diseases that affect field crops. For example, Dr. Arv Grybauskas, a plant pathologist with the Maryland Agricultural Experiment Station, studies diseases that affect small grains, including powdery mildew and scab on wheat.

Grybauskas has developed guidelines for managing powdery mildew with fungicides based on such factors as susceptibility of cultivars, weather, disease severity, nitrogen fertility, and yield potential of the crop. Using these guidelines, producers can determine the risk of potential losses without specialized equipment or knowledge, and make informed decisions about when to use and not to use fungicides.

"Actually," says Grybauskas, "disease management in field crops only rarely involves the use of fungicides." Consequently, the disease management component of Maryland's IPM program is primarily directed toward informing and educating growers about what problems currently exist in their fields and helping them develop long-term management options that will reduce the losses associated with diseases.

For example, the scab disease that affects wheat can't be managed with fungicides. However, because the pathogen that causes scab also is responsible for stalk rots in corn and sorghum, producers can improve their managment of scab by managing the fodder left on the soil surface from the previous crop. And although all wheat cultivars are susceptible, their susceptibility peaks around the time they flower, so producers can reduce losses by growing several cultivars that flower at different times.

A Shared Responsibility

According to a recent survey of more than 125 producers, Extension's field crop program has been very successful. The survey, which compared the pest management practices and pesticide use patterns of producers who employed IPM scouts with those who did not, revealed that producers who hired scouts applied 26 to 45 percent less herbicide on corn and soybeans than those that didn't. They also applied insecticides to only 7 percent of their corn acreage, compared to producers not hiring scouts, who treated 32 percent. Producers who employed scouts reduced their average pesticide costs by $13 an acre and achieved overall economic gains averaging at least $5 an acre on all scouted field crops.

Despite or perhaps because of the success of such educational efforts, the time has come, says Marose, to share some of the responsibility for assisting farmers with others. Although Extension agents used to supervise the scouting of private cropland, she believes a more effective approach is to train independent consultants and agrichemical representatives, who will in turn work directly with farmers.

"Farmers get their information from a variety of sources, and it's essential that all those sources convey the same message," she says. "Extension will conduct research on integrated pest management, publish the results, and train the individuals who provide in-field service. It's the only way we can reach enough growers to have a real impact on pest management practices in Maryland."

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Producing Profitable Produce with Fewer Pesticides

Pesticides are essential to the commercial production of fruits and vegetables in Maryland. However, the potential impact of pesticides on human health and the environment has become an issue of economic, scientific, and public concern. Consumers are increasingly aware of pesticide residues and demand that produce be grown with minimal pesticide use.

The Maryland Cooperative Extension Service has established programs to help growers produce profitable crops and respond to consumer concerns by adopting integrated pest management (IPM) practices.

Monitoring Weather and Targeting Treatment

Richard Heflebower, regional fruit crops specialist, and Robert Rouse, regional fruits and vegetables specialist, pay special attention to helping growers cope with diseases and insects. They monitor weather during the growing season with six weather stations located throughout the state and set pheromone traps to determine insect populations. The data they collect help them predict the timing and severity of insect infestations and disease outbreaks.

"The information is important because it allows growers to develop a sound control strategy," Rouse explains. "They can make an educated decision about what--if any--chemical to use and limit their spraying to the time when it will be most effective."

Rouse, who is located at the Wye Research and Education Center, and Heflebower, who works at the Western Maryland Research and Education Center, also help growers determine when damage has reached an economic threshold. Such thresholds vary depending on the crop and type of damage involved. "For example," says Heflebower, "a grower would need to take immediate and decisive action against an insect that's attacking peaches because people won't buy damaged fruit. If, however, insects are attacking the leaves or trunk, treatment can often wait until after harvest."

Rouse and Heflebower record bi-weekly IPM updates on two toll-free hotlines for fruit and vegetable growers. By calling 1-800-201-PEAR in Western Maryland or 1-800-443-1246 on the Eastern Shore, growers can get information on stages of plant growth, what diseases and pests specific crops are susceptible to at various stages, what types of control methods to use, and how current weather will affect plant growth and disease susceptibility. "This service allows growers to call at their convenience and receive up-to-date information that helps them manage their fruit and vegetable production with greater efficiency," Rouse explains.

Reducing Disease Damage

Maryland growers also receive assistance from Dr. Paul Steiner, an Extension plant pathologist, who concentrates on disease management of fruit crops. "With insects, you can see them and spray them, but with microscopic pathogens, effective disease control measures need to be taken before infection," he says.

After tracking how diseases respond to specific environments, Steiner prepares written recommendations for growers. Control methods often include a combination of practices, such as planting resistant fruit trees or shrubs, removing diseased plants, or altering the micro-environments of trees. Pruning trees to remove excess foliage, for example, will lower the humidity and reduce conditions conducive to disease.

"We may not always be able to totally eliminate a problem, but we can reduce the overall impact," Steiner says, citing an example involving a soil-born fungi called Phytophthora that feeds on the roots of raspberry bushes. This organism thrives in sites that stay wet. Planting bushes on ridges of mounded soil so that roots aren't subject to saturation reduces fungal damage.

Using Computer Technology

Steiner also uses computer technology to help control diseases. During the mid-1980's, he and Heflebower recognized the need for a computer model to combat fireblight, a bacterial disease in fruit. They gathered weather data such as high and low temperatures and rainfall for four years, eventually identifying conditions conducive to the disease. Working with Gary Lightner, a computer program specialist with the U.S. Department of Agriculture in West Virginia, they created a program called "Maryblyt."

To use Maryblyt effectively, growers need to know only the maximum and minimum temperatures, rainfall, and the stage of development of a tree on a given day. With that information, they can predict the risk of infection, the occurrence of infection, and the appearance of symptoms on their own property. They can even get an idea of future risks by entering longer-term forecasts.

"We wanted a program that was both user-friendly and effective for disease management," says Steiner. "This combined approach and the fact that it is based on growth and weather rather than on a calendar, has made it effective--and widely used--in 30 states and 21 countries." With data generated by Maryblyt, growers can make educated decisions about if and when to spray chemicals. "Rather than spraying on a calendar date schedule, growers can spray only when needed and when treatment is most effective," explains Heflebower.

Application Strategies

How pesticides are applied can be as important as when they are applied. Extension experts such as Dr. Galen Dively, an entomologist specializing in IPM, are always searching for ways to use these chemicals as efficiently as possible. Dively, for example, has been examining application strategies for imidacloprid, a new insecticide known commercially as "Admire." This chemical controls the Colorado potato beetle, a major pest of potatoes and tomatoes.

He has found that by applying Admire only to field perimeters or selected rows of crops rather than entire fields, farmers can decrease the rate at which the beetle develops resistance to the product. This treatment approach also reduces the amount of pesticide per acre, lowers environmental risks, and results in substantial cost savings to farmers.

Dively also is conducting research with potatoes and corn varieties that have been genetically altered to increase their resistance to pests. One study involves a transgenic potato called "New Leaf," in which a gene from the bacterium Bacillus thuringiensis has been inserted. This gene produces a protein in the potatoes that makes them resistant to the Colorado potato beetle...and completely safe for people.

"It's an incredible product!" says Dively. "Our only concern is that the beetles will eventually develop a resistance to the protein." By growing a combination of transgenic and unaltered potatoes in the same field, this process can be slowed because it allows for the survival of some susceptible beetles who can mate with any resistant beetles; offspring from such matches are susceptible.

Dively is currently testing mixtures containing different ratios of trans-genic seeds and unaltered seeds. His goal is to identify a ratio that reduces beetle levels enough to prevent economic losses while still maintaining a susceptible pest population.

Programs and Publications

Rouse, Steiner, Heflebower, Dively, and their colleagues share information through a variety of programs and publications, including workshops, farm visits, radio interviews, newsletters, and fact sheets. They also give presentations at industry meetings and annual Experiment Station field days.

Their work appears to be having a positive impact. Fruit growers have told Heflebower that before such educational efforts were introduced they automatically applied pesticides every 10 days rather than risk any pest damage. Now that they understand more about pest problems, environmental factors, and economic thresholds, they don't use pesticides as often. And that means less pesticide residues on produce and more money in growers' pockets.

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Sharing Information

Producers can get useful pest control information by ordering the IPM Scouting Guidelines for Field Crops, a practical publication containing directions on how to apply IPM techniques on the farm.

A 65-minute videotape on corn and soybean IPM for growers, consultants, agribusinesses, and educators also is available. Designed for classroom training as well as individual reference, the video covers all major insects, weeds, and diseases in their natural settings. Funded by the Maryland Department of Agriculture and the U.S. Environmental Protection Agency, the program has received an Award of Excellence from the American Society of Agronomy.

Both the publication and videotpae can be ordered from Betty Marose by calling (301) 405-3929.

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Clinics Promote Information Exchange

"They're like round-table discussions," says Dave Almquist, Talbot County agriculture agent. "They facilitate interaction and the exchange of information."

Almquist is referring to the free plant clinics he and some of his colleagues organize twice a month through the growing season for Extension faculty, IPM field scouts, and representatives of businesses that support Maryland agriculture. These clinics--held in several counties--keep participants aware of what insect, disease, weed, and other crop problems are occurring in their areas and provide them with information on how to deal with these problems.

"The meetings help all of us keep up to date on what's happening out in the field and what we can expect in the coming weeks," Almquist explains. "The participants can then get the information out to farmers on a timely basis."

Each clinic draws an average of 20 people, although attendance varies. "It increases noticeably when producers are facing a major problem of some sort," says Wayne Shaff, an agriculture agent who has been conducting plant clinics in Wicomico County for more than 20 years.

Discussion about such problems often generates new agricultural research projects, according to Carroll County agriculture agent David Greene. "A lot of pest management studies occur as a result of these clinics," he says. "Extension agents and specialists hear first-hand what growers are facing and what they need in the way of solutions."

"There's no question about it," adds Shaff. "These clinics provide a valuable service to everybody."

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Special Schools for Selected Audiences

In addition to their ongoing IPM activities, Extension faculty occasionally offer specialized training for selected audiences.

For example, they worked with the American Society of Agronomy and agribusiness industries to establish the Mid-Atlantic Certified Crop Advisors Program, part of a national effort to develop a voluntary professional certification process for individuals who advise producers on pest, nutrient, and crop management. Agents and specialists determined regional performance objectives, developed an exam, and conducted initial and continuing education programs for the pest management part of the program.

The certification program benefits both advisors and producers, says Betty Marose, Extension agricultural IPM coordinator. Advisors enhance their professional credibility and marketability, and growers know that certified advisors they hire are knowledgeable about the latest information regarding pest and nutrient management.

In 1993 Maryland agents and specialists collaborated with colleagues in Delaware to organize a four-day crop management school for 123 advanced consultants and agribusiness personnel. They provided intensive training on field crops and vegetables that included hands-on learning opportunities dealing with identification of pests and biocontrol agents, pest monitoring, problem-solving, and diagnosis. Tests given before and after the training revealed significant changes in participants' knowledge.

Building on this success, organizers are planning a three-day "school" for December 1995. This training program will provide participants with the information they need to achieve or maintain Certified Crop Advisor status.

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Achieving Low-Input Urban Landscapes

Although most people associate pesticides with food crop production, considerable amounts of pesticides are used by the nursery and greenhouse industries to produce ornamental plants and by homeowners to maintain landscape plants in their yards. In the few instances in which such pesticide use has been examined, a clear pattern of excess has emerged. Studies conducted in Maryland, for example, indicate that as much as 90 percent of the pesticides applied in home landscapes may be unnecessary.

For more than a decade, several faculty members affiliated with the Cooperative Extension Service have focused their attention on the pest problems of ornamental plants, making the University of Maryland, College Park, a leader in urban integrated pest management (IPM). They provide information to homeowners, public and commercial landscape managers, pesticide applicators, and members of the nursery and greenhouse industries through a variety of applied research projects, educational programs, publi-cations, and trade journal articles.

Tracking Greenhouse Pests

One team of campus and field faculty has spent several years developing IPM programs for commercial greenhouse operations. Such programs, which last from the time plants are moved into the greenhouse until they are ready for sale, are based on weekly monitoring, analysis, and feedback, says Stanton Gill, regional Extension specialist for nursery and greenhouse management.

Trained Extension faculty, including Wanda MacLachlan, Bob Stewart, Ginny Rosenkranz, and Russ Balge, and independent "scouts" track pest populations and measure soil pH and soluble salts, root growth and health, and plant height. They fax the data to Gill and his colleagues, plant pathologist Ethel Dutky and Dr. Thomas Blessington, a regional specialist in post-harvest floriculture, for analysis. The three faculty members then send comments and suggestions--emphasizing biological and cultural controls--to growers within the week.

"These growers are working with short-term crops," explains Gill. "They need to respond to problems right away. They appreciate being informed of their options in a timely fashion so that they can decide on a course of action."

Since 1990 Gill, Dutky, and Blessington have designed and implemented greenhouse IPM programs for poinsettia, impatiens, herbs, geranium, chrysanthemum, and ornamental cabbage and kale. These programs have helped growers decrease their use of pesticides while achieving good pest control, maintaining plant quality, and reducing losses.

Taking Aim At Lace Bugs

Other faculty and staff conduct research in public, residential, and commercial landscapes. For example, Dr. Michael Raupp, Extension entomologist and chairman of the Entomology Department, currently is working with graduate student Paula Leddy on a project designed to minimize the problems posed by the azalea lace bug.

"This project has real-world relevance," says Raupp. "The azalea lace bug is one of the most common insect pests in Maryland landscapes because so many people have azaleas in their yards. Information on how to manage this insect using the IPM approach has tremendous value for homeowners and landscapers."

Leddy has been studying and comparing azalea lace bug populations and damage in different types of home landscapes in the Montgomery and Prince George's County communities of Takoma Park, University Park, and College Park. She has found that azalea lace bug populations are smallest in architecturally complex landscape--those that include a variety of trees, shrubs, annuals, perennials, and ground covers. Conversely, populations tend to be quite large in architecturally simple landscapes that contain nothing but azaleas and perhaps some turf.

"Complex landscapes provide favorable habitats for natural enemies of the azalea lace bug--especially tree crickets and hunting spiders in the family Clubionidae," she explains. They keep lace bug populations low."

By designing landscapes favorable to lace bug predators, home gardeners and landscapers should be able to minimize damage caused by this pest while reducing their use of chemical pesticides. Leddy hopes to have specific landscape design recommendations available by this fall as part of her PhD dissertation.

Battling Boxwood Leaf Miners

Another of Raupp's graduate students, Gabe D'Eustachio, is working on a project involving boxwoods at Pennsylvania's famed Longwood Gardens.

"The American boxwood is one of the most prized and revered ornamental shrubs," says Raupp. "It has a long history dating back to English formal gardens of an earlier era and is still an important component of modern American landscapes."

Over the years, he adds, the boxwoods at Longwood have been damaged by the boxwood leaf miner, a small fly that lays its eggs in boxwood leaves. When the eggs hatch, the maggots "mine" the leaf, eating tissue between leaf surfaces. Their feeding causes blisters, discoloration, and the loss of many leaves.

Chemical pesticides are effective only during a specific time in the leaf miner's life cycle. To maximize such effectiveness and prevent unnecessary spraying, D'Eustachio has developed a model based on heat unit accumulation or "degree days" that landscape maintenance personnel at Longwood and elsewhere can use to determine the optimum treatment time.

He also is working with staff at the National Arboretum in Washington, D.C., to develop resistant boxwood cultivars. "Our goal," he says, "is to eventually replace existing cultivars with those more resistant to leaf miners and other pests so that chemical controls can be eliminated or at least greatly reduced."

Short Courses & Conferences

Information gleaned from research and demonstration projects is made available to members of the greenhouse and landscape industries and the general public through such programs as the Advanced Landscape IPM Short Course and the Greenhouse Management Short Course.

The Advanced Landscape IPM Short Course is offered each January. Designed for professionals in the nursery, landscape maintenance, and arboricultural industries, the five-day program has been organized since 1988 by Extension entomologist Dr. John Davidson. It features a combination of lectures and laboratory sessions, although a lecture-only option is available. Davidson thinks the labs add a valuable element to the learning experience. "Spending several hours in a lab looking at actual specimens of over 50 pest and beneficial insect species, as well as various plant diseases, adds a valuable element to the learning experience," he says. "And as far as I know, we're the only program in the country to provide this in-depth opportunity to landscape industry personnel."

That may be why participants come from as far away as Florida, California, and Oregon and represent prestigious organizations and well-known cultural and historical sites. This year's class, for example, included representatives from the Chesapeake Bay Foundation, the Office of the Architect of the U.S. Capitol, and the Biltmore Company in Asheville, N.C. Several participating public institutions, including the Chicago Botanic Garden, are developing similar training programs based on this Extension short course and incorporating some of its materials.

Although the acronym IPM is not included in the title of the Greenhouse Management Short Course, the subject is dealt with thoroughly. "We introduce IPM concepts throughout the program, which covers all aspects of greenhouse operation," explains organizer Stan Gill. "For example, the impact of ventilation, fertilizer injector calibration, and other engineering issues on disease management is discussed. One of our goals is to encourage greenhouse growers to adopt IPM practices."

Like the landscape IPM short course, the greenhouse short course features both lectures and hands-on laboratory sessions. It also includes visits to area greenhouses, where participants can observe the application of various management practices.

For the past four years, the Greenhouse Management Short Course has been held at central Maryland locations. Now, says Gill, it's time to take the show on the road; the course was offered in southern Prince George's County in June and will be held at an Eastern Shore location in the fall. "We want to give as many growers as possible the opportunity to benefit from this program," he explains.

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Community Cuts Chemical Use

Residents of Kettering, a 500-acre residential community in southern Prince George's County, have reduced their use of pesticides and fertilizers (nutrients), thanks to a program sponsored by the Prince George's County Department of Environmental Resources with support from the Cooperative Extension Service. Called the "Kettering Community Demonstration Project," the program was designed to reduce chemical contamination of the local watershed. Kettering was selected as the project site because it had a natural drainage basin that allowed experimenters to monitor chemical contamination in water.

Bob Stewart, an area Extension agent in commercial horticulture, conducted an information program with Steven Paul, public education coordinator of the Department of Environmental Resources. Stewart served as an instructor, working directly with homeowners and commercial lawn care and landscape companies. In addition, he developed flyers, gave community lectures, and produced a newsletter to get the word out about reducing reliance on chemicals.

He encouraged commercial companies to identify pest problems and get positive pest identifications before applying pesticides. "Prior to the Kettering project, commercial companies were using pesticides to solve problems that weren't even pest related," he explains. "Once they began limiting pesticide applications to specific, identifiable pest problems, 50 percent of the areas that would have been sprayed with chemicals were left untouched."

Stewart also worked with residents to reduce nutrient applications, encouraging them to base their fertilizer decisions on soil test recommendations. "A fairly large amount of fertilizer use in the area was unnecessary," he says. "Generally, we found that if homeowners cut back on their nutrient use by 25 percent they could still achieve and maintain the same quality of landscape."

Demonstration Gardens: Seeing is Believing

Extension agents, specialists, and volunteers are cooperating with the Montgomery and Howard county governments to encourage the adoption of integrated pest management (IPM) practices. Their goal, says Dr. Lee Hellman, pest management specialist, is to make IPM the pest control choice at sod fields, golf courses, schools, parks and other public grounds, and private residences.

One of the ways they are accomplishing this goal is through the establishment and maintenance of demonstration gardens.

The garden in Montgomery County is called Project Earth Garden. Now in its second year, the 30- by 150-foot garden is located outside the county Extension office in Derwood. It includes resistant cultivars of flowers and vegetables, plants that attract insect predators, and turf plots showing the impact of different mowing heights on turf weeds and diseases.

Informational signs are currently being revised and a garden brochure developed, according to Steve Dubik, Montgomery County Master Gardener coordinator. "We try to keep improving the educational value of the garden," he says.

Following their colleagues' lead, Howard County Extension professionals and volunteers are working with the county's Parks and Recreation Department to establish a demonstration garden in David Forest Park in Ellicott City. The initial phase of the collaborative project involves revising an existing garden to illustrate IPM concepts. Planting was completed in early June. Master Gardeners will maintain the garden, with help from local girl scouts. Eventually, they hope to add turf plots and establish a backyard wildlife demonstration area, according to Georgia Eacker, coordinator of Howard County's Master Gardener program.

"Demonstration areas are a great way to educate people," she says. "If people can see for themselves how IPM techniques work, they'll believe what we tell them."

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IPM on the Home Front

Helping Maryland residents cope with plant pests and diseases is one of the major functions of specialists at Extension's Home and Garden Information Center (HGIC). In fact, nearly half the 250,000 questions received at the center since it opened in 1989 have involved pest control issues, says center head Dr. David Clement.

He and his colleagues take advantage of such questions to educate callers about the practice of integrated pest management (IPM), encouraging greater use of physical, cultural, and biological control methods. "We're not telling people never to use chemicals," explains Clement. "But we are telling them to use them wisely and judiciously."

Volunteers Share Knowledge

HGIC faculty and staff receive help in their educational efforts from some 500 volunteer 'Master Gardeners' in six counties and the city of Baltimore.

"IPM philosophy is incorporated into all aspects of the training we provide these volunteers," says Jon Traunfeld, who coordinates the state's Master Gardener program. Master Gardeners then share the information they receive with other Maryland residents through exhibits, newsletters, plant clinics, and--in Montgomery County--through a program called Project Earth Garden (see article on demonstration gardens, pg. 8).

"They're an essential element of the urban IPM program," emphasizes Traunfeld. "They help us reach a much greater number of people than we could hope to without them."

From Boxwoods to Birch Trees

To help get their message across, both faculty and volunteers provide home gardeners with fact-filled publications, including a new series on IPM control methods for some popular Maryland plants. Three of the publications--on boxwoods, birch trees, and azaleas and rhododendrons--are already available. Several more on common home garden fruits and vegetables are in various stages of development.

"The goal of the IPM series is to help home gardeners diagnose insect and disease problems themselves," says Mary Kay Malinoski, a HGIC entomologist and co-author of the documents. To this end, each publication contains a list of symptoms and possible causes, as well as detailed descriptions of specific diseases and insect pests. Illustrations support the text where appropriate.

"As you'd expect," says Malinoski, "control methods focus on physical, cultural, and biological techniques, such as the relocation of a plant, increased watering during drought, removal of fallen leaves that may harbor pests, and the introduction of natural predators. Chemical pesticides are recommended only when other methods fail."

Audiotapes Planned

Malinoski and other specialists at the HGIC plan to take IPM education one step further with the creation of prerecorded audio tapes that, like the publication series, will help home gardeners diagnose and treat a variety of plant problems. The audio tapes will be accessible on the center's new toll-free phone system, which is currently being upgraded and expanded to handle increased demand.

Although it will take a while to prepare the audiotapes and add them to the system, Clement hopes to have material on mowing, turf pest control, and other lawn-care topics available this summer. "We're committed to using the technology available to us to provide information to as many people as possible," he says.

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Tackling Turf Troubles

Grass doesn't produce fragrant, showy flowers for spring bouquets or yield tasty fruits and vegetables for human consumption. It does, however, form the backbone of most residential landscapes and provide the playing field for many popular sports.

Patchy, weed-infested turf can detract from the appearance of a home yard and cause economic losses at sports clubs and golf courses. It's not surprising, therefore, that people devote a great deal of time, effort, money and pesticides protecting grass from damage caused by insects, weeds, and diseases. However, growing concerns about the health and environmental effects of such chemicals are causing homeowners, turf producers, golf course superintendents, and lawn-care companies to look for effective alternatives.

Faculty affiliated with the Maryland Cooperative Extension Service are investigating ways to help these diverse audiences maintain grass using integrated pest management (IPM) practices. Leading the way are turf management specialists Dr. Tom Turner and Dr. Peter Dernoeden and pest management specialist Dr. Lee Hellman.

Evaluating Seed and Sod

Turner concentrates his research efforts on identifying turf varieties that are resistant to insect and disease damage. "The cornerstone of any turf IPM program is the development and identification of genetically resistant material because resistant grasses don't require as much pesticide," he explains.

Turner has evaluated 750 cultivars of the turf species used in Maryland, exposing them to various forms of environmental stress. "We let diseases and insects attack them," he says. "Varieties that are resistant to damage are placed on a list of recommended cultivars. Those that aren't resistant don't make the list."

The list has several uses. It helps homeowners choose the best grass seed for their property and is used by the Maryland Department of Agriculture (MDA) in their seed and sod certification program. Only cultivars on the Extension list may be sold as MDA-certified, so consumers can be confident of getting grass suited to Maryland conditions.

Turner also evaluates the suitability of various turf varieties for specific uses, such as golf courses. He and research assistant Greg Goudeau are currently examining the resistance of several cultivars to insects, weeds, and diseases under golf course conditions, which include mowing heights of 1/2 inch or less. "That's much shorter than we'd recommend for home lawns because it creates an environment conducive to a variety of problems," says Turner. "By determining which cultivars are resistant to problems under such conditions, we're giving golf course superintendents the information they need to develop an effective IPM program."

Cultural Approach to Disease Control

Turner's colleague Denoeden has focused much of his attention on the impact of various cultural practices on turf weeds and diseases. His studies have revealed ways to maintain effective weed control with reduced herbicide rates and have shown how increasing mowing height greatly reduces weed and disease problems in lawns. Dernoeden also has evaluated the use of low maintenance grasses, which require less mowing, water, fertilizer, and pesticides.

Under Dernoeden's guidance, Dr. Michael Fidanza has developed a model that can be used to forecast a common fungal problem called brown patch disease with a high degree of accuracy. This accomplishment has important implications, says Dernoeden, because 25 percent of all fungicides applied during the summer to golf courses in the Baltimore/Washington corridor are designed to prevent brown patch.

Fidanza also found that dawn irrigation reduced the occurrence of brown patch while night watering increased it, and that slow-release nitrogen fertilizer applied in the fall deterred development of the disease compared to the use of quick-release nitrogen sources in the spring.

Holistic Approach

Hellman, a pest management specialist, rounds out the trio's work by evaluating the effectiveness of insecticides and searching for biological alternatives, such as bacteria and parasitic nematodes. He currently is studying the role of endophytes, fungal organisms in grass that are toxic to insect pests. The presence of endophytes is especially important in grasses, such as fine fescues, that have little resistance to insects.

Hellman also is working with graduate student Judy Wells to develop an IPM plan for both turf and ornamental plants in the new Haupt Gardens behind the Smithsonian "castle." Such a comprehensive project makes sense, says Hellman, because turf pests don't exist in a vacuum. "It's important to focus on the landscape as a whole because there's so much interaction," he explains. "For example, trees can create excessive shade and reduce air circulation, causing grass to retain moisture and become more susceptible to insects and disease. We need to deal with the whole environment."

Sharing Research Results

Hellman, Turner, Dernoeden, and their colleagues share their research results with Extension faculty, members of the turf industry, public and private grounds managers, regulatory agency representatives, and the general public through lectures, workshops, seminars, and other programs, including a four-day Advanced Turfgrass IPM Short Course, a three-day annual Turf Conference, and occasional field day events. More than 2,000 people in the turfgrass industry have benefited from such programs since 1992. As one lawncare company employee said of the special IPM short course, "I feel that concepts regarding IPM were well presented by all faculty--excellent information."

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Zeroing in on Zoo Pests

What happens when a pest problem occurs in a zoo? The use of pesticides can be potentially harmful to animals and plants in exhibit areas. Integrated pest management (IPM) programs at area zoos has allowed someone to inspect for potential problems and then contact Cooperative Extension Service specialists who recommend biological and cultural methods of addressing the problem.

"It's a continual process," says Stan Gill, regional Extension specialist, nursery and greenhouse management. "There is always a problem that needs regular monitoring."

'Scouting' at the National Zoo

In the planning stage of their "Amazonia" rain forest exhibit, for example, officials at the National Zoological Park in Washington, D.C., became concerned about potential disease and insect problems. They contacted Ethel Dutky, director of the plant clinic at the University of Maryland, College Park, who had worked with the zoo before.

Dutky worked closely with Stan Gill and Dr. Tom Blessington, a regional Extension specialist in post-harvest floriculture. The three requested and received a grant from the Smithsonian Institution to fund a scout who would monitor the exhibit and report weekly on any potential pest problems.

From May 1993 until May 1994, the scout identified pest, disease, and cultural problems; collected plant and soil samples; took light readings; released pest parasites; and evaluated the success or failure of controls. He reported his findings to the Central Maryland Research and Education Center (CMREC) for evaluation by the Extension specialists. The scout shared their evaluations and suggestions to zoo staff.

One pest found in the Amazonia exhibit was the "spiralling whitefly." This insect was feeding on leaves of large trees and producing a white wax in fine, spiralling filaments that fell onto ponds and walkways.

Pesticides were rejected as a control option because they might harm the fish, frogs, turtles, and other animals in the exhibit. Instead, Dutky, Gill, and Blessington recommended a combination of several control methods, such as horticultural oil, insecticidal soap, and non-toxic sprays, that would have only a minimal effect on mammals, fish, reptiles, and birds.

Another pest that posed a challenge for the team was brown soft scale, a small insect that feeds on and damages plants. "We were limited as to what we could use to control this insect because we had to avoid posing a threat to animals in the exhibit and the people that tour it," Gill explains.

He and his colleagues contacted Texas A&M University and learned of a wasp that attacks only brown soft scale insects. Such wasps were released in the exhibit and the brown soft scale were soon eradicated.

The IPM program was so successful that after one year of implementation, the scout was hired as an independent contractor by the zoo.

"This program really says a lot of positive things about what zoos are doing to control pests," says Dutky. "It also gave those of us involved a chance to work on something separate from direct horticultural study."

Although the grant has expired, she and her colleagues are contacted by the scout when something unusual comes up. They also are training other scouts to ensure that IPM programs remain an option for zoos.

Zoo Training in Philadelphia

A similar project is currently underway at the Philadelphia Zoological Park. Dr. Mike Raupp, professor of entomology, Paula Leddy, a graduate student, and other University of Maryland entomologists are developing an IPM program that focuses on the total zoo environment. "Our main objective is to enhance implementation of IPM in the Philadelphia Zoological Park through a series of educational programs developed for park supervisors and technical staff," says Raupp. Some of those educational programs include formal classroom and laboratory sessions at the University of Maryland and hands-on field work at the zoo. Training and reference materials, including IPM manuals, are being developed for use by park personnel to implement programs on a continuing basis.

Raupp coordinates the training program, the scouting process, and the release of biological control agents similar to the ones used in the "Amazonia" exhibit at the National Zoological Park. As in Washington, D.C., parasitic wasps are controlling soft and armored scale insects that destroy foliage.

"Studies document dramatic reductions in the quantities of pesticides used and number of plants treated without sacrifice to the appearance of the plants following the implementation of IPM programs in ornamental landscapes," says Raupp. "Projects such as those at the National and Philadelphia zoos demonstrate that this approach can work equally well in a zoo environment."

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Read On...

The following publications contain information on managing insects, weeds, and diseases in a variety of settings. Some are sold at the price listed; others are free on a single-copy basis to Maryland residents. All are available from local Cooperative Extension Service offices and Extension's Home and Garden Information Center.

IPM Series:

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