During the last fifty years, the landscape industry has become more and more dependent on the use of pesticides as the first choice of dealing with many problems. So much so that many of us have never learned other methods of creating and maintaining a healthy landscape.

When I started out working for tree care companies in the mid 1970s, gypsy moths were the major pest, and we would spray all trees and shrubs on the properties with the most powerful insecticides available. That approach certainly killed many caterpillars and saved many trees, but it also killed many beneficial insects and caused environmental concerns. Many clients would ask us to also spray their crabapples for disease, cherry trees for scale, and hemlocks for mite. We were very efficient and added fungicide, other insecticides, and miticides to the mix and sprayed everything.

By the mid 1980s those cover sprays evolved into spot treatments based on calendar dates, which helped reduce the amount of pesticides used. In the 1990s some companies were adding integrated pest management (IPM) services for their clients. As defined by the Southeast PA IPM Research Group, “IPM is a pest population management system that utilizes all suitable techniques (biorational, chemical, cultural, fertilization, irrigation, monitoring with sex pheromone traps, resistant plant varieties, etc.) and information to reduce or manipulate pest populations that are maintained at tolerable levels (meaning a few pests will still be around) while providing protection against hazards to humans, domestic animals and earth’s environment.”

In reality, many landscape IPM programs just include monitoring and spot treatments as required, usually with traditional pesticides. This technique is focused on pest control by reacting to the pest. It certainly is an improvement and has reduced pesticide usage even more, but we are treating the symptoms without addressing the cause of the problem. However, times are changing, and due to public demand as well as new regulations, we have to become knowledgeable in other techniques to care for plants. In fact, those who continue with business as usual may find themselves out of the business before long.

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In the past couple of decades, science has provided us with new insights into the biological workings of plants that are helping to reduce the amount of pesticides and salt-based fertilizers that were considered necessary for landscape maintenance. A great deal of research and fieldwork has demonstrated that, just as in humans, when stress factors are reduced plants become healthier, and more energy can be devoted to defensive measures. Programs that address these issues have been called plant health care (PHC). This is a proactive program that comes from a completely different mindset. The Southeast PA IPM Research Group defines PHC as “a process of scheduled preventative maintenance based on monitoring and use of cultural and chemical tactics, to enhance plant vitality. The plant and its requirements become the central focus of our activities, rather than responding to symptoms caused by pest presence, physical agents, or nutritional deficiencies. A plant health care practice addresses the basic causes of the reduction in plant health and provides corrective measures to promote plant health.”

On paper there are many similarities between IPM and PHC programs; the game changer is shifting the emphasis from pest management to plant health. Healthy strong plants are better prepared to withstand many pest problems. As stated before, when plants are stressed due to environmental and/or cultural pressures they divert energy from growth and defense to survival. In many cases, pests are able to detect these chemical changes in the stressed plant and move in for the attack. Some common examples include the following:

  • Stressed birch trees are targeted by bronze birch borers.
  • Kentucky bluegrass, when fertilized, closely mowed, and improperly irrigated, encourages that buildup, which is idea for infestations of billbugs, chinch bugs, and sod webworms.

In cases like these, the pests are secondary problems and only treating for them is a band-aid approach. Good PHC programs may begin by treating emergency problems and then are followed up by actions to rectify the cause.

Landscape contractors are always asking me, “How can I kill pests organically?” My answer surprises many of them: “Let’s start at the beginning and talk about the importance of soil health.” Understanding the associations between soil health and plant health is the key to setting yourself apart from your competition.

In my case, I had become proficient in IPM and kept many pests under control while using much fewer pesticides than in the past. But, many plants still did not look vital and healthy even when traditional fertilization was part of the program. I knew enough about soil compaction to realize it is a major part of the problem, but I knew of no economical way to improve soil structure in existing plantings or turf areas. I began to learn more about soils and what grabbed my interest the most was the dynamics of soil biology. Good, healthy soil is teeming with life, not just earthworms and insects, but also billions of microbes. Many of them promote root growth, nutrient and water uptake, and will defend plants against diseases and other pests. You can almost say that the soil is the digestive and immune systems for plants.

When we use salt-based fertilizers, we bypass this system. It’s almost like someone being fed intravenously; he’ll get the basic nutrients and will survive but in a weakened state. Now, he needs antibiotics because his immune system is not working as it should be. When plants are weak, we need more pesticides to control more frequent disease and insect attacks.

Microbes in the soil provide plants with more than basic nutrients. They also deliver enzymes, proteins, and hormones that are necessary for plant vitality. They help improve soil structure and increase water retention while improving drainage. Microbes also form protective layers around roots to defend against pathogens. Science is just beginning to understand the millions of biological activities that occur in the top six inches of good soil and their impact on plant health.

Key Components of PHC Programs

Whether your business is a nursery, landscape contracting, or maintenance, the following aspects need to be understood in order to implement successful PHC programs.

Client expectations need to be defined not only to offer the best service but to achieve the best results. Client education is essential, as many people do not have horticulture backgrounds and may have unrealistic expectations. Using your knowledge in a professional manner to help clients meet their goals is the sign of a successful businessperson.

Site considerations such as hours of sun, temperature range, soil type, slope and drainage, irrigation, plant types, site usage, and many other factors come into play when designing a PHC program. When you understand the site you are working with, you will have a much greater impact on preventing pest problems.

Cultural control strategies will greatly reduce stress factors. It’s really sad to have to tell a new client that their trees were planted too deeply, the wrong grass seed was used, or the plant they just installed should never have been planted there in the first place. Proper pruning, mowing height, irrigation, and nutrient management are additional procedures that will improve plant health.

Pest Control

Even with best management practices there will be times when pests will cause problems and have to be controlled. There are many options we can choose from. Do we need to exterminate the pest or manage an acceptable balance? There are times when extermination may be the best option and a strong pesticide may be required to remedy the situation. An organic-based PHC program does allow for this. But bringing out the big hammer should be the exception rather than the rule.

When soil health and sound cultural practices are maintained, there is little need to pull the pesticide trigger. When this is necessary, consider using EPA minimum risk pesticides and/ or biorational controls. In 1996, the EPA exempted pesticide registration on products containing only ingredients listed by the EPA as posing little or no risk. Manufactures of these products may legally claim pests that are controlled by the product. Depending on state laws, an applicator license may or may not be required to apply these products professionally. 

Biorational controls are designed to have little or no impact on beneficial insects and the environment. They may include horticultural oils and insecticidal soap, bacteria such as Bt, the attraction and release of predators, and other options. Some are EPA-registered pesticides requiring an applicator license.

The benefits of an organic-based PHC program are numerous. We, our workers, and our clients are exposed to less pesticides, and nutrient runoff into our waterways is reduced. At the same time, we are able to provide vibrant lawns and landscapes at competitive pricing. Public pressure, government regulations, and good business practices are all telling us to go green. Now is the time to get serious about promoting our profession as being environmental stewards. We take pride in the work we do to enhance the beauty of outdoor spaces for our clients. Take the lead and separate your business from your competition by implementing an organic-based PHC program.

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