Some of the same pests that damage turfgrass can also attack ornamentals. This photo by entomologist Whitney Cranshaw shows the damage that spider mites did to ornamental trees at Chicago's Millennium Park.
Photo courtesy of Whitney Cranshaw, Colorado State University, Bugwood.org.
Pest control of woody ornamentals is a complimentary add-on service for lawn care and lawn maintenance companies. Indications are that it's becoming a more popular service offering, too. In a recent survey by Turf magazine, 13 percent of its readers say that ornamental tree and shrub care is their fastest growing service.
In addition to allowing you to generate more revenue during each stop on a property, adding a new service such as ornamental care can serve to keep possible competitors off of your clients' properties. But the best reason for caring for your customers' ornamentals is also the most obvious: property owners need this service to protect and preserve the beauty and health of valuable plants on their landscapes.
While some of the same pests that damage turfgrass can also damage ornamentals (Japanese beetles and spider mites to name two), adding the service to your company requires becoming educated about a much larger set of pests and their management. It also requires acquiring another professional certification or license.
In other words, you must know what you are doing. You must be able to identify the pests that attack valuable landscape plants, including recognizing the damage that they do to these plants. Then you must determine the best course of action to prevent them from destroying the the health and beauty of the plants.
Guessing doesn't work. Look closely at the damage the pests are doing to the ornamentals, whether it is bore holes to their trunks or leaves that are being munched or are curling or otherwise damaged. Look carefully at the underside of leaves, too.
Some pests, such as mites and thrips, are very small. Use the "beat method" to determine if mites or thrips are investing host plants. Select several plant parts that you suspect are infected and beat them on a piece of white paper. Keep a magnifying lens handy. It will be useful when checking out which of these tiny destroyers are present.
The good, the bad, the harmless
And, yes, due to the incredible variety of ornamentals, you will find lots of small critters, insects and other arthropods. Some are beneficial, some harmless and some merely a nuisance. Those that damage ornaments generally come in two varieties: those that chew and those that suck.
Sucking pests attack all parts of plants. They can be found on leaves, stems, flowers, fruits and even in the soil where they attack the roots of plants. A short list of sucking pests includes mealybugs, scale insects, whiteflies, thrips, bugs (lace bugs, stink bugs, etc.), mites and aphids.
Insects with chewing mouthparts include beetles, caterpillars and sawflies. Beetles can damage any part of a plant, whereas caterpillars are primarily foliage feeders. Often, when you see leaves that have been stripped, it's caterpillar damage. But that's not always the case. Sawflies are foliage feeders, too. Some eat the entire leaf and some "skeletonize" leaves.
Sometimes the best treatment option, assuming the infestation is small and localized, is to prune off the damaged part of the ornamental. More severe infestations often require the use of an appropriate chemical control. Beware that some products are phytotoxic to certain species. Always read and carefully follow label directions. In some instances you may consider treating a small part of the plant before making a more general application to see how the plant responds to the product
Many pests are plant specific or are more prevalent in certain regions of the country. For example, the pests you may encounter, say, in a south Florida landscape, may not be present in the northern part of the state with its more seasonal climate, and certainly not as far north as temperate Indianapolis or Pittsburgh.
Great local info
Fortunately, just about every region of the country has a land grant university with a strong horticulture program that has developed valuable information about localized ornamental pest identification and management. Take advantage of these resources. Get to know and never hesitate to contact your nearest university extension horticultural professional when you encounter unfamiliar plant issues.
Obviously, to make intelligent pest management decisions you need to know about the pests most commonly found in your market, including their life cycles and their habits. In almost all cases infestations are easiest to manage while the pests are in their immature stages. Also, some pests are best treated seasonally. For example, winter is a good time to apply dormant oil to control aphids and scale.
Japanese beetles are chewing insects. As larvae they attack turfgrass roots. As adults they feed on leaves and stems.
Photo courtesy of Clemson University - USDA Cooperative Extension Slide Series, Bugwood.org.
You can use many of the same techniques that you use to manage turfgrass pests to also manage ornamental pests. These techniques fall under the management umbrella known as integrated pest management (IPM).
The U.S. EPA defines IPM as an effective and environmentally sensitive approach to pest management that relies on a combination of common-sense practices. IPM programs use current, comprehensive information on the life cycles of pests and their interaction with the environment. This information, in combination with available pest methods, is used to manage pest damage by the most economical means, and with the least possible hazard to people, property and the environment.
To do this most of you use a combination of cultural and chemical control measures. In rereading the EPA definition of IPM you will note that it does not preclude the use of pesticides; it doesn't even mention them. Given the time and competitive constraints that landscape professionals face, oftentimes the use of a chemical control is the best management strategy. It's up to you to make that decision based upon your horticultural knowledge and your understanding of your clients' expectations.
In other words, what level of pest damage to their woodies will your clients accept? Does it matter where the plants are on their landscapes? Just because you find some pests does not necessarily mean that a treatment is warranted. Of course, there are instances where the best option is to treat preventatively or at the first sign of pest damage that, in your experience, could be the precursor to a full-blown infestation that would threaten the beauty and health of the plant. Knowing this and acting appropriately distinguishes you as a professional and separates you from pretenders and fly-by-night operators.
Unlike agricultural crops where the main consideration for implementing pest management strategies is economic, the main consideration in managing pests on your clients' woody ornamentals is weighted more to protecting and preserving their aesthetic value. This is especially true if they are prized specimen plants in highly visible areas of customers' landscapes.
Admittedly, it's a tall order even for a knowledgeable pro like you, to design a one-size-fits-all pest management program for a landscape that contains many different species and cultivars of woody plants. Pests may affect each species or variety differently. This is a good segue into some common and valuable cultural practices to lessen the likelihood of serious pest pressure.
Remember when your mom taught you to wash your hands and insisted that you do so? Good sanitation is a good practice recommended for woody ornamentals, too. It helps prevent ornamental-damaging health issues, including pest damage. Good sanitation includes pruning dead limbs and raking up dead leaves and other debris where pests overwinter or lurk.
Almost certainly there will be cases where whatever action you take your client will lose a beloved and prized woody. Plants, like people, weaken and die due to a variety of conditions: diseases, pests and, alas, old age, to name just a few. Whatever the ailment and whatever treatment you attempt they perish before their time. It could be they were sited in an unfavorable (to them at least) location on a property. Or, perhaps, they were of a species and variety known to be susceptible to particular pests or ailments. Or, in the case of the introduction of an invasive species such as the emerald ash borer, they succumbed when a new killer arrived in your neighborhood.
In these cases, the best course of action is to explain the reason(s) responsible for the plants' demise and suggest a more appropriate and more pest-resistant species or variety to replace them.
Of course, this isn't a bad time to suggest a landscape renovation featuring the latest, improved, more attractive ornamentals. Your clients count on you to keep their landscapes and lawns healthy and attractive. You're the professional; it's your responsibility
Ron Hall is editor-in-chief of Turf magazine. He has been reporting on the green industry for the past 29 years. Comment on the article or contact him firstname.lastname@example.org.