This appendix is not testable materials but for your additional information.

Controlling a pest is only part of a total pest management program. Pest control is a corrective measure—you use pesticides or other control methods when pests are or are likely to become a problem. Pest management, however, includes preventive measures as well.

The primary goal of a pest management program is to keep the pest population from exceeding a tolerable level. It is nearly impossible to eradicate (i.e., completely get rid of) a pest, and past attempts to do so by using pesticides excessively caused many of the problems we discuss elsewhere in this manual: pesticide resistance, secondary pest outbreaks, and environmental contamination to name a few.

The Decision Making Process

You must make a series of decisions to effectively plan and carry out a pest management program. Perhaps the least effective approach is to rely solely on immediate responses to problems as they arise. At that point, you usually must take direct action, with the use of pesticides often being the only option. We outline the principal elements of your decision-making process below.

Detection

We cannot overemphasize how important it is that you detect pest infestations before they become a problem. If you don’t, control will likely be more costly, less effective, and perhaps too late to prevent damage. To detect pests early, scout or monitor plants frequently, know the common pests that attack the plants, fully understand the pest’s biology, and know the plant’s growth characteristics well enough to recognize abnormalities (e.g., disease symptoms).

Indentification

You must identify an organism to determine whether it is a pest and, if so, to decide whether and how to control it. You usually need to identify a plant disease based on symptoms rather than on the actual pathogen. Be familiar with the common pests of the plants you work with. If you have any doubts, contact your county Extension office. Keep in mind that pests may not be causing the problem. Factors such as improper fertilization also may cause “abnormal” plant characteristics.

Biology

Identification is little more than a tool. Once you have identified a pest, you can get information regarding its biology. Knowing the pest’s life cycle, and how it relates to environmental conditions, is essential in determining if and when a problem might occur and when control measures would be most effective. It makes sense to direct control efforts against the most vulnerable stages of a pest’s life cycle.

Significance of Damage

Almost any level of infestation warrants control for some pests, especially in interiorscapes because of high customer expectations. In most situations, however, you can tolerate some level of pest activity. In these cases, your decision to implement control measures will be based on concerns over plant health, aesthetic damage, or a pest’s impact on the planned uses of a site. Nuisance factors also may influence pest control strategies of managers of landscape plants. For instance, cottony maple scale produces honeydew that drops onto buildings, cars, and sidewalks; in a very short time, a black sooty mold grows on the honeydew. Depending upon the extent of the infestation and the resulting inconveniences,
control measures may be warranted.

Plant Health. Concentrating on plant health gives you more leeway in deciding whether to control pests. For example, you may decide not to treat an infestation of leaf‑eating insects in a landscape planting if you think they are not harming the plants.

Economic considerations come into play when pests seriously threaten the health of landscape plants. The manager then must weigh the cost of pest control against the cost of replacing plants that may die. Within this evaluation, the manager also must include an aesthetic component which compares, for example, the value of a mature shade tree with that of a replacement sapling.

Aesthetic Significance. People buy ornamental plants and, in many cases, care for their lawns primarily to beautify their surroundings. It makes sense, then, that people do not want pests to detract from that beauty. You can look at pest control, then, as being warranted only if you believe a pest will reach the aesthetic injury level. That is the level when it will cause enough damage (i.e., aesthetic damage) to reduce the quality or appearance of a plant. Aesthetic damage, then, is the amount of injury that justifies the cost and effort of control. It is distinct from biological damage. However, whether or not a pest infestation decreases the aesthetics of a planting is a subjective call made by the owner (as evidenced by the widely different views held by lovers and haters of dandelions). This has several implications for the commercial applicator.

First, it greatly increases the range of situations that you might face. There are no standards with regard to pest control based on aesthetics. Even within a plant/pest system, there is likely to be great variability between jobs with respect to the size of the pest population, the age of the plant, and the life stages present in the pest population. Thus, the methods you choose may be different depending on the situation.

You must also keep in mind that, as a commercial applicator, you have a responsibility to let your customers know what level of control you can reasonably expect to attain. Again, because different people see things differently, you are likely to encounter at least some customers who want you to eradicate a given pest. This is rarely possible, and trying to reach this goal can cause a host of other problems. Also, except for cases such as tent caterpillars, where even one nest greatly reduces the beauty of a tree, eradication is usually unnecessary to maximize the aesthetic
value of a planting. Again, you should work with your customers to determine the level of control that is both attainable and acceptable.

Planned Use of a Site. Sometimes, a pest problem interferes with the planned use of a site. For example, weeds are unacceptable on golf course putting greens not only because they detract from the appearance but because a poor putting surface interferes with a person’s golf game. Another example would be flowering weeds in the lawn of a family whose child is severely allergic to bee stings—the flowers would attract bees and could therefore prevent the child from playing in the lawn.

Establishing Action Thresholds. You may want to establish a set of guidelines for when control is needed in the different situations you are likely to face. For example, the acceptable levels and types of weeds will likely be different in a play area than on an athletic field, which will in turn be different from what is acceptable in a lawn that surrounds a corporate headquarters. By developing a rough idea of when control is necessary (i.e., an action threshold) in different situations, you can begin to formulate pest management plans for each situation. Each plan should include a goal as well as all appropriate control methods (discussed later) to meet that goal.

The following chart illustrates how the aesthetic value and use of turf influence its maintenance, including pest control. Obviously, areas with high aesthetic value and use would command more management and, therefore, lower action thresholds. This chart also demonstrates how you may need to take both aesthetics and planned use into account in making pest management decisions.

Selection of Methods

If you conclude that a certain pest is likely to cause economic damage, the next step is to decide how to manage the pest. To make the best decision, become familiar with all available methods and evaluate the benefits and risks of each. The methods chosen must be effective, practical, economical, of minimal hazard to people, and environmentally sound.

Evaluation

It is extremely important to evaluate the results of a management program. You can do this by counting pests or assessing plant health and appearance before and after treatment. Record the evaluations for future reference; records can save you from repeating a past mistake or remind you of a successful strategy you used in the past.

Pest Management Methods

We will now discuss various methods of pest management Our intent here is to give you an overview of the alternatives available and to present some characteristics and examples of each.

Prevention

If a pest is completely or nearly absent from a site, do what you can to keep it out. It is often easier to prevent a pest from becoming established than to have to deal with it on a continual basis if it does. Steps that can be taken to prevent pests from infesting a site include:

• Using only certified pest-free seed and planting stock,
• Inspecting incoming plants before using them, and
• Cleaning equipment (e.g., disinfecting pruning tools, cleaning soil off of equipment) between uses and sites.

Resistant Varieties

Resistant varieties have inherent defenses against pests. The degree of resistance to a given pest can range from slight to nearly complete. Note that a resistant variety is resistant to only one or a few pests, not all pests.

Resistant does not mean immune. While a pest may cause some damage to a resistant plant (though less than to a fully susceptible one), it cannot damage a plant which is immune to it. Keep in mind that resistance can break down over time as pest populations evolve to overcome it.

Tolerant varieties can outgrow, repair, or withstand pest damage and often provide all of the necessary aesthetic attributes despite being susceptible to a pest. Beware, however, that pest populations will increase during the season and may pose even more of a problem the next year.

Sanitation

Sanitation is a key to the control of many pests. Removing fallen leaves at the end of the growing season, for example, removes an important source of inoculum for foliar diseases. Likewise, pruning diseased branches from trees can slow or prevent the spread of disease.

Because raw, untreated soil contains numerous plant pathogens and perhaps insect pests as well, interiorscape managers should avoid placing plants, hose ends, or other tools on soil or other contaminated surfaces.

Weed control is important because weeds can be hosts to pathogens and insect pests. Likewise, older plants in an interiorscape might attract pests as their tissues become senescent.

Cultural Control

Cultural control includes practices designed to optimize growing conditions for turf or ornamental plants and/or create unfavorable conditions for the pest. Basically, anything that helps the plant itself will also help it fend off or successfully compete with pests. Proper plant spacing, fertilization, irrigation, and site preparation all help a plant to grow well. As with most organisms, plants are less able to withstand pests and diseases if they are under physiological stress (e.g., do not receive enough nutrients).

Mechanical Control. Cultivation is a form of mechanical control that is effective in controlling germinating weed seedlings. Mowing is another form of mechanical control. Mowing helps maintain grass or ground covers. Repeated mowing helps the grass out compete weeds, prevents the formation of grass seeds that could eventually germinate in unwanted areas, and prevents rodent problems.

Other forms of mechanical control include traps, barriers, and fences that are designed to protect plants from pest mammals.

Site Selection. All ornamental plants, including turfgrass, require certain conditions in order to grow vigorously. If these conditions are not present at the site, the plant is less able to withstand pest damage. We discussed this somewhat in the chapter “Weeds” when we mentioned that weeds can be indicators of growing conditions (e.g., soil pH level, soil compaction). The plants that are currently growing in a site can give you an indication of what growing conditions are like there. Given that information, you can either plant ornamentals or grasses that are well adapted to those conditions or you can try to alter the conditions (e.g., add lime to raise the soil pH) to accommodate the desired plants.

Diversified Plantings. The pest problems associated with monoculture — the practice of growing only one species or variety of plant in a given area — illustrates the importance of plant diversity. The rapid spread of Dutch elm disease among American elms, which lined virtually every street in many communities, is a striking example of the dangers of monoculture. The fungus that causes the disease could build its numbers to epidemic levels and spread rapidly without any interference. When there is a mixture of plant species, pests of a particular species cannot multiply and spread as rapidly as in a monocultural planting. Moreover, even if plants of a particular species do die as the result of an infestation, other species will remain, lessening the aesthetic impact of the loss.

Water Management. Irrigation can reduce the damaging effects of spider mite infestations during hot, dry summer periods of low humidity and low natural soil moisture. Irrigation does not actually reduce the mite numbers, but allows the plants to better withstand feeding activity, because the root system is able to replace the plant moisture which is lost due to feeding.

Water Quality. Water quality is very important to the overall health of interiorscape plants. Improper salt balances and other problems associated with the water source will stress the plants and make them more susceptible to pests.

Sodium used to replace calcium in hard water can injure plants and break down soil structure. While hard water itself does not harm plants, excess soluble salts need to be leached from the soil occasionally; this can be done by watering to the point where about one tenth of the water drains out of the container.

Most indoor ornamental plants grow best in slightly acid soils, in the range of pH 5.5 to 6.6. (Acids have a lower pH, alkaline substances have a higher pH.) The proper pH, as with proper water quality, is important in avoiding plant stress. Release of nutrients from fertilizers and their availability to plants is control by soil pH. If the pH is too low, conversion of ammonia nitrogen to nitrate is slowed down. If it is too high, the availability of micronutrients is reduced.

Adjust soil pH, if necessary, before planting. Lime will raise the pH. The amount of material needed to reach the desired pH will depend on the starting pH and the amount of organic matter in the soil or planting medium.

Biological Control

Biological control focuses on maximizing the effects of the natural enemies of pests. Thousands of species of insects, mites, nematodes, and pathogens feed on or parasitize pests. You can capitalize on this natural benefit by preserving appropriate habitats, using pesticides that have as little impact as possible on beneficial species, having a diversity of plants, and even introducing natural enemies into a site. Keep in mind that for biological control to be effective, there needs to be a sufficient pest population for the natural enemies to prey upon. As with pesticides, therefore, we cannot expect biological agents to eradicate a pest.

Chemical Control

Pesticides are often used in combination with the other pest management techniques we have already discussed. They should be the last alternative in most management programs, to be used when other management tools are not available or have not adequately controlled the pest. They act quickly and are available in a variety of combinations and formulations such that there are typically a number of effective products available for almost any pest situation. When an infestation is severe and damage is obvious or imminent, pesticides provide the quickest and most effective solution.

There are also disadvantages to pesticide use. The primary concern is toxicity. Each pesticide poses at least some risk to the person using the pesticide and people who enter a site after it is treated. Pest populations may also develop resistance to pesticides, making control more difficult. Finally, pesticides usually provide only temporary solutions; a change in other management practices may be necessary to prevent future problems.

Once you have decided that chemical control is necessary, you will want to choose the best pesticide for the particular situation. Do not buy or use a product unless you answer “yes” to all of the following questions:

• Is the site (e.g., lawn, roses) listed on the label?
• Is the target pest listed on the label or do you have evidence (e.g., Extension recommendations) that the product can control the pest?
• Can the pesticide be applied when you need it? For example, do not use a dormant oil during the growing season.
• Will the pesticide control the particular life stage of the pest? Scale insects that have produced a waxy coating are not very susceptible to many contact insecticides.
• Do you have the necessary equipment to use the product? Some formulations will cause corrosion in different materials used in sprayers (e.g., rubber gaskets). Also be sure you have the label-specified PPE.
• Is the pesticide practical to use for the particular situation? Again, the formulation can be important. Sprays are preferred in some situations while granules may work better in others.
• Did you read the entire label? If there are several products for which you could answer “yes” to all of the questions above, you can choose between them by answering these questions:
• Which product works better? You can use personal experience or that of another person to answer this question.
• Which product works for the necessary length of time? You may prefer a pesticide with a longer residual over one that requires more frequent repeat applications.
• Which product is less toxic to people? You can find this out by comparing the signal words on the pesticide labels.
• Which product poses a lesser risk of exposure? For example, tamper-proof bait stations are designed to keep children and pets from contacting rodent poison.
• Which product is less likely to harm desirable organisms? Remember that some formulations (e.g., ECs) are more likely to cause phytotoxicity than others. The labels will also warn you of any risks to birds, nearby plants, or bees.
• Which product can be used with other pesticides you or your customer uses? If a customer’s dog has recently been treated for fleas with an organophosphate, you might choose to use a product with a different mode of action to treat the customer’s lawn for white grubs. That way, you avoid the risk of the dog suffering an accumulative exposure when it is allowed on the lawn later.

By answering these questions before you choose a product, you will be more likely to make an effective application with the least possible risk to you, your customer, and the environment.

Integrated Pest Management

Integrated pest management (IPM) is a decision-making process that considers all available control methods. It encourages the use of all available techniques where practical and does not rely on a single-method approach. A sound IPM program can help ensure that you apply pesticides only when necessary.

IPM is by no means a new concept. Some forms of IPM have been practiced for centuries. The significance of today’s IPM is that it is based on a scientific and systematic approach. You must be familiar with the site, the pest, and all available control tactics to develop and implement an IPM program. The principles of pest management we have discussed thus far are, in effect, principles of IPM.

IPM means different things to different people. It is unlikely that any one definition will satisfy everyone. For the purposes of this discussion, we will consider IPM as:

An ecological approach to pest management in which we combine all available necessary techniques into a unified program. Our goal is
to manage pest populations in a way that avoids aesthetic damage and minimizes adverse side effects.

The principal features of the definition are boldfaced.

IPM is an ecological approach, an approach based on a thorough understanding of both the site and the pest, and of their interactions with each other and the environment. Such understanding requires a significant amount of reliable information.

An IPM program considers all available techniques, both chemical and nonchemical. These control tactics are, however, applied only when necessary. An important part of any IPM program is determining when control is, in fact, necessary. It requires you to check sites carefully and on a regular basis.

IPM is a unified approach that integrates all beneficial control measures into a comprehensive pest control program.

By definition, an IPM program manages pest populations. This involves prevention as well as control to avoid aesthetic damage or to keep pests within population levels that your customer will find tolerable. This concept has definite implications for the desired level of pest control; if it is both unnecessary and unrealistic to eradicate a pest, you can reduce your control efforts, particularly the amount of
pesticides you use.

Finally, IPM programs are designed to minimize adverse side effects which might result from pest control measures. Adverse effects can range from killing desirable plants to harming ourselves, others, and the environment. For information on IPM programs in Wisconsin, contact your county Extension office or the UW-Extension IPM program.

An Example of the IPM Approach

We will use the example of pest management in turfgrass culture to demonstrate the IPM approach.

If possible, the IPM approach starts with site selection and preparation. Correct drainage problems. For example, you can modify the grass root zone by adding good topsoil or by incorporating soil amendments such as peat humus and/or, rarely, sand (you must achieve at least 60% sand to get a beneficial effect).

Select the best grass species for the environment and the intended use of the turf area. Seed or sod cultivars selected should be resistant to anticipated diseases. When possible, use blends of several superior cultivars or mixtures of two or more grass species to reduce the disease potential associated with establishing a monoculture of a single cultivar. Fescues are more tolerant of shade, acid soil, and low fertility than
Kentucky bluegrass.

A management plan geared to maintaining vigorous, competitive turfgrass is part of the IPM approach. Attention is focused on mowing practices, fertilization, irrigation, thatch control, relieving soil compaction, and other management practices. Timing of operations is yet another consideration. Turfgrass establishment is more rapid and weed problems are reduced when seedings are made in late summer compared to spring seeding. Time irrigation and fertilization schedules so as not to encourage certain diseases or weeds which weaken stands of turfgrass.

One of the most important aspects of a turfgrass IPM program is periodic scouting of the turf area to detect and determine the extent of developing pest problems. Establish a threshold level of pest incidence — an allowable pest level which, if not exceeded, is not detrimental to the turfgrass. The threshold level depends on turf use. Very few pests are tolerated on golf greens while more are tolerated on rough turf such as roadsides. You must correctly identify the pest before trying to control it; most pesticides only affect certain pests, and even cultural controls will vary in effectiveness depending on the life cycle of the weed (e.g., annual vs. perennial).

Timing of pesticide applications is important. You should consider the stage of development of the pest as well as periods when the possibility of adverse effects to the environment are at a minimum. As an example, the potential of injury to garden tomato plants by herbicides used to kill dandelions in lawns is lowest in early May before tomatoes are transplanted in the garden (or in fall after the first frosts) as compared to 2,4‑D application made in mid‑summer.