Whitford, Coordinator, Purdue Pesticide Programs
Gail Ruhl, Extension Disease Diagnostician
Allen Boger, Allen County Extension-Horticulture
Andrew Martin, Specialist, Purdue Pesticide Programs
B. Rosie Lerner, Extension Consumer Horticulturist
Zachary Reicher, Extension Turfgrass Specialist
Robert Corrigan, Extension Urban and Industrial Pest Control Specialist
Cliff Sadof, Extension Ornamental Specialist
Arlene Blessing, Purdue Pesticide Programs
TABLE OF CONTENTS
|Pest Management Strategies||
|Developing A Strategy||
|A Strategy for Lawn Pest Management||
|A Strategy for Pest Control in Home Gardens||
|A Strategy for Pest Control on Landscape Plants||
|A Strategy for Pest Control in the Home||
What activity do these people have in common? They're all using pesticides. However, they may not recognize the products they are using as pesticides.
What are pesticides?
In simple terms, pesticides are chemical compounds used to control pests. Examples include insecticides, which control insects; rodenticides, which control rodents; fungicides, to control the spread of fungal diseases of plants; and herbicides, which control weeds and other plants.
Why are pesticides important?
Pesticides control insect pests and diseases of food and fiber crops, thus improving the quantity and quality of the end products. Some are used to control parasites on farm animals and pets. Others help maintain our health; e.g., disinfectants are used to cleanse kitchens and bathrooms, and repellents are functional in warding off ticks that carry disease.
Are pesticides necessary?
Sometimes pesticides are necessary, but not in every pest situation. Many times, non-chemical control methods may be preferable; other times, it may be possible to employ alternative methods to prevent pest damage. It is prudent to know and understand all available options in a given situation in order to reduce pesticide use.
What is the purpose of this publication?
This publication presents various pest prevention and control programs which can be employed in the home environment. Home, food, health, pet, wildlife, flower and vegetable garden, fruit and shade tree, and turf pest situations are addressed.
The first step in pest management is to identify the pest that is causing the problem. It then becomes essential to learn about the life cycle and behavior of the pest to facilitate the development of a plan to manage it; the goal might be eradication or merely the reduction or suppression of its damage potential.
A good pest management strategy incorporates some or all methods available to manage a given pest. This is called integrated pest management, or IPM. The goal should be to reduce pest populations and damage to economically and aesthetically tolerable levels. Complete eradication may not be possible, practical, or desirable.
Judicious selection of pest control methods should be aimed at reducing or eliminating pesticide use whenever possible. This is important because of concerns about personal and environmental safety. The following methods should be considered in developing a pest management strategy.
Exclusion by Regulation
Government embargoes and quarantines which prohibit the introduction of pests into one country from another--or into one locality from another--are methods of exclusion by regulation. A case in point is the quarantine that prevents pine trees infested with European pine shoot beetles from being transported into Indiana counties known to be free of that insect.
Barriers and devices such as fences, traps, lights, row covers, and noisemakers are examples of mechanical exclusion methods used to keep pests away from garden plants and out of homes. For example, nuisance wildlife such as rabbits can be excluded from gardens and landscape plantings with fencing. Some insects can be kept away from vegetables by covering them with a row cover made from a special kind of fabric. Birds can be banished from fruit crops by covering trees, bushes, or vines with plastic netting.
Rodents and other mammals such as bats can be excluded from homes by permanently closing entrance holes with caulking, steel wool, or structural repairs. Many insects can be kept out by caulking holes and cracks and ensuring that doors and windows are tightly sealed and screened. The use of yellow light bulbs (instead of the more conventional white bulbs) outside entrances will attract fewer kinds of insects. Storing food products and pet food in tightly sealed containers will guard against other insect and rodent infestations.
Glue boards for cockroaches and traps for wildlife are other examples of devices that can be used to keep pests away from homes and plants. The force of water can be used to dislodge insects such as aphids from host plants; such slow-moving insects often simply die before they have a chance to crawl back onto the host.
One word of caution: Some exclusion devices--such as those that produce sounds audible only to insects or rodents, and light traps that electrocute insects--have not been proven effective.
It is important to select species and cultivars of crops and ornamental plants recommended for the locale. Neighbors and professionals in the community should be consulted to determine which kinds of plants grow best and without significant pest problems. Avoid those that are known to have a questionable history and those recognized as marginally hardy. Cold temperatures can predispose tender woody and perennial plants to pest damage; choosing a hardier variety would be an example of cultural control through plant selection.
The European white birch tree is a beautiful tree and a popular choice for the residential landscape. However, it does not grow well in Indiana's climate; summer soil temperatures are too high, causing an unhealthy root system. The weakened tree then becomes susceptible to bronze birch borers that damage and usually kill it. Maintaining a European white birch tree in Indiana nearly always requires annual applications of an insecticide to control the borers. The frustration, expense, and hard work can be avoided by selecting a river birch, which is not susceptible to the borer, thereby eliminating the need for pesticide application. This, too, would constitute cultural control by plant selection.
Some plant cultivars resist or tolerate pest damage. Examples include tomato cultivars that are resistant to wilt diseases, apple cultivars resistant to scab diseases, and plants bred to produce more surface hairs that will discourage insect feeding. Cultivar selection should be based on the plants' known resistance to common pest problems, thus limiting loss potential and reducing the likelihood that a pesticide application might be needed.
There are recommended planting intervals for most crops, and it is wise to recognize their importance. Careful selection of planting dates enhances crops' defenses against disease and insect infestations. Planting too early in the spring can result in plants weakened by cold, wet soil conditions; and late spring frosts can damage or kill crops planted too early. Root and seed rots usually can be avoided by choosing later planting dates that lend more favorable soil conditions. Certain insect pest problems can be avoided by choosing appropriate planting dates. Growing a combination of early, mid, and late season crops may decrease the potential for losses due to pests, based on the resulting staggered dates of maturity; i.e., a pest present at a given time wouldn't be apt to affect all three stages of growth. Careful selection of planting dates is a form of cultural control.
If space permits, crops should be rotated to different areas of the garden each year to prevent buildup of pests in the soil.
Sanitation is perhaps the most important cultural practice that can be used to help manage pests. It consists of removing plants or plant parts suspected of harboring insects or disease. For example, affected leaves, twigs, and branches of dogwoods infected with anthracnose should be removed and destroyed to help prevent the disease from spreading. Another example is the removal of certain plant parts that may be diseased, such as fallen rose leaves that are infected with black spot. It is important to always buy healthy seeds and plants known to be free of insects and disease. Examine 'gifts' from neighbors and tactfully decline those which obviously display pest symptoms. Remove garden weeds before they mature and produce seeds, and add them to your compost pile.
Sanitation is also important at the end of the growing season. Plant residue from annual crops, as well as the tops of herbaceous perennials, should be removed from the garden in the fall. Those not infested with insects or infected with disease can be added to a compost pile.
Other examples of cultural control through sanitation include removal of dead or diseased limbs from trees and shrubs; garbage management to discourage flies and rodents; careful attention to pet food areas; scrupulous cleanup of food crumbs in the home; and elimination of paper bags, newspapers, and other materials that provide food and shelter for pests such as cockroaches and rodents.
Other Cultural Methods
Good cultural practices include providing plants the best possible growing situation: proper spacing, watering, and fertilization. Weed control and the timely harvesting of produce also help to maintain healthy plants. The control of weeds with organic mulch is a good cultural practice, and mulch also contributes to plant health by moderating soil temperatures and conserving moisture.
Manipulation of a pest's environment also can be an effective method of cultural control. For example, venting the crawl space beneath a house will allow the space to dry, rendering the area unfavorable for the development of allergy-causing mildews and wood destroying organisms such as termites and decay fungi.
Pesticides can consist of one or more active ingredients, and the active ingredients can be either organic or inorganic. Organic compounds are based on carbon chemistry and are formulated from molecules that contain carbon, hydrogen, and oxygen. Some organic compounds used in pesticides occur naturally and are obtained from plants or bacteria; these are called natural, biological, or botanical pesticides.
The organic active ingredient in pyrethrin insecticides is obtained from a certain chrysanthemum flower. Pyrethrins often are used to control flying and crawling insects in the home, as well as on pets and garden plants.
Inorganic compounds do not contain carbon but are derived from mineral sources. Some inorganic compounds used in pesticides also occur naturally. An example is a copper-based product used for algae control in ponds.
Pesticides containing synthetic (manufactured) compounds comprise the largest number of products used to control pests. Most synthetic pesticides consist of organic compounds, and these represent the group that most people consider when contemplating the use of pesticides.
Many synthetic pesticides have a mode of action similar to that of natural pesticides. Both natural and synthetic pesticides can vary in their toxicity to people and pets. Don't assume that just because a pesticide is `natural' it is not toxic; conversely, some natural pesticides can be quite toxic. Always read the product label and follow the precautions stated. Follow all instructions carefully.
Some pesticides control pests without killing them. Following are examples of pesticides that provide pest control alternatives.
Topical products which lessen human attractiveness to ticks, chiggers, mosquitoes, biting flies, etc., are called repellents. They help make outdoor activities more enjoyable and contribute to the prevention of diseases transmitted by certain insects. Lumber treated with wood preservatives extends the lifetime of outdoor structures and furniture by repelling wood destroying organisms. Repellents can be used to discourage deer from feeding on the bark of valuable trees.
Chemicals used to lure pests into a trap are called attractants. For instance, an insect sexual attractant (called a pheromone) may be used inside a plastic bag, luring Japanese beetles inside. When the bag becomes filled with beetles, it can be tied off and discarded. However, Japanese beetle traps should be used with caution; since they work by attracting the beetles, one might end up with more beetles--instead of fewer--if they were the only person in the neighborhood using the traps. Everyone in the neighborhood should use them simultaneously to be effective; and it is important to place the traps far away from potential host plants.
Other examples of attractant devices are yellow jacket traps, glue boards for cockroaches, and traps used to monitor the presence of other insects.
Pesticides developed to adversely affect the growth of specific insects are categorized as growth regulators. They work by preventing the immature stages of certain insects from maturing into adults, or by rendering adults sterile or killing them. Some flea and roach products are growth regulators.
Insects that contact desiccants usually die. For example, a silica material called diatomaceous earth, commonly used in swimming pool filters and also helpful in managing garden slugs, is abrasive to the outer covering of some insects; the abrasive action dehydrates the pest, resulting in death.
Some people try to formulate their own pesticides, using household products. This can be a dangerous practice. Many household chemicals are toxic, and mixing several of them together can result in combinations that are injurious to people, pets, and plants. This is especially true when the concoctions are applied to food crops. Remember that home remedies have not been tested and registered by the Environmental Protection Agency. Don't gamble with them!
Although it is extremely important to remember that total eradication of a pest population is not the goal in most cases, it is equally important to recognize that sometimes it is. Eradication is by all means desirable when termites are damaging a structure or when pests present the possibility of disease transmission to people or pets.
A preferred strategy in most pest control situations is to think in terms of reducing pest activity to a level which poses only minimal potential for damage to or annoyance of the host, be it plant, animal, or structure. For instance, it is not necessarily desirable to kill all spiders in the home environment; most of us are willing to tolerate a spider here and there, but we're not willing to share our kitchens with even a single German cockroach or mouse.
Effective pest management and reduced use of pesticides are compatible. Pesticides used correctly and judiciously are good tools for pest control. However, they should not be used if non-pesticidal approaches can solve the problem.
Selection of the most appropriate pest management method in a particular situation should be preceded by accurate pest identification and a survey of the site to determine the exact location and extent of the pest population. Pest management based on limited pesticide use requires learning as much as possible about the pest and how it survives in the home, lawn, or garden. In some cases, successful pest management strategies require patience, persistence, and long-term commitment.
Persistent pest problems may necessitate consulting a pest management professional who is properly trained to identify pests and provide the safest, most cost-effective approach for control or elimination.
Select grass species and cultivars that are insect and disease resistant. Chose those that are best adapted to grow under the sun or shade conditions of the landscape. The amount of maintenance which will be required and the intended use of the turf also should be considered in the selection process.
Grasses recommended for Indiana lawns include the 'cool season' Kentucky bluegrasses, turf-type perennial ryegrasses, fine fescues, and turf-type tall fescues.
In southern Indiana, the 'warm season' zoysia grasses may be desirable, although they are slow to green up in the spring. Other species recommended for southern Indiana include the turf-type tall fescues for sunny areas, and mixtures of Kentucky bluegrasses, turf-type perennial ryegrassess, and fine fescues for lightly shaded areas.
In northern and central Indiana, Kentucky bluegrasses and turf-type perennial ryegrasses perform best in sunny locations; the turf-type tall fescues are worthy of trial for high traffic areas; and fine fescues are good to include in mixtures for lightly shaded areas.
Always blend two or three cultivars of each species included in a mixture of seed for lawn turf to provide better disease resistance and adaptation to the site. Planting a single cultivar invites problems.
Homeowners with many large trees in their landscapes often become frustrated because it is difficult to grow a beautiful lawn in heavy shade. The grass plants gradually disappear and weeds, moss, and algae take over. Designing a woodland garden for such problem areas would be a better choice than chemical control of pests. Use ground covers, perennial flowers, and shrubs that are adapted to heavy shade. Combine these with mulch, decks, outdoor furniture, and other accessories to create a pleasant retreat. Consult landscape architects and designers for assistance in making the project a success.
Lawns in the northern half of Indiana should be seeded with cool season grasses between August 15 and September 15, and those in the southern half between September 1 and September 30. Cool season grasses also can be seeded in the spring, although more irrigation and more herbicides for weed control may be required. Zoysia grass is usually started from plants rather than seed; the 'plugs' or 'sod strips' of zoysia grass should be started in late spring.
Fall applications of fertilizers are best for cool season grasses. Two-thirds of the annual nitrogen requirement for a lawn should be applied in the fall, followed by the remainder in mid to late spring. Fertilizers should not be applied too early in the spring because they will promote lush growth that is more susceptible to disease. Zoysia grass should be fertilized only in late spring or summer.
The grass species in a lawn should determine the mowing height. Kentucky bluegrass, turf-type perennial ryegrass, and fine fescues should be mowed at least 2.5 inches high. A mowing height of at least 3 inches is best for turf-type tall fescues.
Mow often so that no more than 1/3 of each leaf blade is removed each time the grass is cut. This may mean mowing several times each week in the spring and fall, but usually only weekly or biweekly in the summer. Lawns should be mowed about 1/2 inch higher in summer to help grass plants tolerate heat and drought stress. Always mow with sharp blades. Leave the clippings on the lawn unless they are needed for mulch or compost. This important practice will return nutrients to the soil to be taken up by the grass plants; it will not increase the buildup of thatch. When too many clippings remain on the surface of grass plants after mowing, spread the clippings uniformly with a rake or recut the lawn. Frequent mowing when the lawn is dry helps disperse the clippings properly.
It is best to water between 4 and 8 A.M. because the evaporation rate is low early in the morning, allowing most of the water to soak into the soil; and in urban areas this is when municipal water pressure is highest. Midday watering is not advised due to the likelihood of rapid evaporation. Watering late in the evening is not advisable because flowers and other landscape plantings are more likely to stay wet, making them more vulnerable to disease.
The thatch layer in lawns is composed of dead and living shoots, stems, and roots of grass plants. These parts of grass plants resist decay and accumulate on the soil surface, forming thatch. A small amount of thatch is desirable; however, the accumulation of more than 1/2 inch of thatch limits water and air movement, reduces the effects of fertilizer and pesticide applications, promotes shallow rooting, and increases disease and insect damage. Excessive thatch buildup can be managed with proper applications of moderate amounts of fertilizer and water.
Removal of excessive thatch is difficult and expensive. It may require the use of aerification equipment or, at worst, the physical removal of the sod (including the thatch layer) and the reestablishment of a new lawn. Power rakes (dethatching machines) are effective in minimizing thatch, but they are not effective in removing excessive layers of thatch.
Pesticides are useless on neglected or poorly managed lawns. When more than 5 percent of a lawn consists of weeds and dead grass, complete renovation is required. The homeowner may choose to do the renovation with the aid of information available from the local Cooperative Extension Service; in some cases, however, it may be better to employ a professional firm to renovate the lawn. In either case, lawn renovation is a major undertaking that has to be done properly and completely. The optimum time for renovating a lawn is late summer. Preparation should begin in August so seed can be planted in the fall according to recommendations for the geographical area.
First, the pest must be positively identified, followed by the selection of a pesticide product suitable for both the pest and the site to be treated. The pesticide label must be read carefully and followed explicitly. If any part of the label is unclear to the applicator, it is important that a professional be consulted for clarification. Children and pets must be kept well away from the area during treatment; and in the case of lawn spray applications they must be kept away until the pesticide has dried completely. When granules are applied to lawns, they should be watered thoroughly into the soil and the grass allowed to dry. Some pesticide labels state specific periods of time during which people must stay off a treated lawn. Consideration of neighbors should be exhibited by posting `keep off' signs which indicate that a pesticide application has been made to the area.
Grubs hatch during mid July in southern Indiana, late July in the central part of the state, and early August in the north. Egg hatch is the optimal time for grub control applications because newly hatched grubs are very susceptible to insecticides and because only minimal turf damage will have occurred. Waiting until severe damage is apparent before treating means killing larger, hardier grubs in an already stressed turf.
On the other hand, not all turfgrass will be infested with grubs every year. Responsible use of chemicals dictates that they be used only when and where needed. So, how does one know if treatment is required, before it is too late? The answer lies in monitoring. To monitor for grubs, cut a small section of turf at several locations during peak egg hatch (use a knife for this sampling). Search through the soil just below the thatch for tiny white grubs. Grubs in low concentrations (4 or less per square foot of turf) seldom cause any damage and do not merit concern; slightly increased irrigation will rejuvenate the turf with no apparent or lasting damage. Larger numbers (8 or more grubs per square foot) require immediate treatment to prevent damage. Concentrations of 4-8 per square foot call for individual judgment. Points to consider are (1) whether slight grub damage in the affected area would be tolerable and (2) whether more irrigation to the area might negate the effects of minimal root pruning by grubs; if the answer to the latter is yes, the homeowner might elect to forego the cost and energy of an insecticide application.
However, if treatment is required, it is important to irrigate, apply the product correctly (calibrate equipment properly), and follow all label directions during application. Regardless of whether or not the decision is to treat, the area should be monitored again the following week as well as throughout late summer and fall.
Most lawn diseases go essentially unnoticed in the early stages; and once they have advanced to the point of recognition it is very unlikely that control can be accomplished, even with pesticides. Although small damaged areas sometimes respond to good maintenance practices such as fertilization and watering, complete renovation usually is a wiser choice for larger areas.
The best control for lawn weeds is to mow and fertilize appropriately. A dense lawn, mowed as needed and at the proper height, will prevent many annual weeds from becoming a problem. When a weed does create a problem, a positive identification becomes the first step in achieving control. Then, if chemical control is determined to be the best approach, comes product selection, followed by application according to label directions. It should be noted that some perennials are difficult or impossible to control; in those cases, a licensed professional lawn care company may need to be employed.
If a fungal disease is identified, a fungicide registered for controlling it on the host plant must be applied on a regular basis (usually every 7-14 days). Very thorough coverage of the leaf and stem surfaces of the entire planting is necessary since most fungicides available to homeowners are not curative, but preventative; i.e., they must be applied to healthy leaves to prevent invasion by the fungus.
Black plastic can be used as a ground cover to conserve moisture and control weeds. It will warm the soil in the spring but may retain too much heat for some plants in summer. Plastic mulches should be used only with plantings of annual vegetables and flowers; in landscape beds, it can prevent water and air from reaching the roots of trees and shrubs. It also may encourage shallow rooting, leaving the plants more susceptible to cold injury.
An insecticide application may be necessary when plants are in danger of being severely damaged or destroyed. But before using a pesticide the home gardener should understand that
Most plants can be pruned in late winter or early spring, but trees and plants that flower in the spring should be pruned after the blooms fade.
Predators attack, kill, and eat multiple numbers of pests. Parasites lay an egg in or on a pest; and when the egg hatches, the new parasite consumes and usually kills the pest as it matures. Pathogens are free-living microscopic organisms (bacteria, fungi, viruses, etc.) that invade the pest and cause a disease that weakens or kills it.
Proper and complete identification of the pest is critical. For example, identifying an insect pest as a cockroach is not sufficient. German, America, Oriental, woods, and brown-banded cockroaches have very separate and distinct biologies and behavior patterns; and a thorough understanding of those characteristics is essential in the development of a sound management strategy. It is from such information that one can determine how, when, and where to inspect for the pest. County Extension and Purdue Plant and Pest Diagnostic Laboratory personnel are available to assist Indiana homeowners with pest identification. They can provide information on the pest and how to manage it--and they also can advise the homeowner as to whether or not a pest control professional should be consulted.
Pesticide treatments around the perimeter of a building can be effective for some pest problems. In many cases, pest management professionals are better trained and equipped than the homeowner to make perimeter treatments. Perimeter treatments should be used only when needed, not as a cure-all for keeping insects out of the home. It is more important to identify and correct food, water, and shelter conditions that favor pests, both inside and out.
Eliminating Breeding Places for Mosquitoes
The most effective method of mosquito control around the home is to prevent or eliminate breeding sites:
Publications on pest control in lawn, landscape plant, fruit and vegetable, and residential situations may be obtained through county offices of the Purdue University Cooperative Extension Service. County Extension Educators have access to a current list of publications available and are eager to assist homeowners in acquiring information pertinent to their specific pest control problems.
Garden Path, a newsletter that presents homeowners with timely information
on many aspects of insect and disease control and other horticultural topics,
is available through the Purdue University Plant and Pest Diagnostic Laboratory,
915 W. State Street, West Lafayette, IN 47907-2054. Those interested
in subscribing may call (765) 494-7071. Questions from subscribers, with appropriate
specialists' replies, are featured in each issue.
*The Indiana Master Gardener Volunteer Educator Program,
conducted through participating county Extension offices, provides an intensive
education in horticultural principles to those with an interest in helping
teach gardening information. Interns are schooled in subjects such as plant and
soil science, plant problem diagnosis, pesticide safety, and vegetable, flower,
fruit, and landscape gardening. After completing their training, interns must
volunteer one hour of community education for each hour of training received.
Interested parties should write the Master Gardener State Coordinator, 1165 HORT, Purdue University, West Lafayette, IN 47907-1165, or call (765) 494-1311. Information can also be obtained through county Cooperative Extension Service Educators.
* Purdue University's Plant & Pest Diagnostic Laboratory staff--experts in the areas of entomology, botany and plant pathology, horticulture, forestry and natural resources, and agronomy--are available to assist the homeowner in identifying pest problems and for advice on appropriate remedial procedures. Write the Director, Purdue University Plant and Pest Diagnostic Laboratory, 915 W. State Street, West Lafayette, IN 47907-2054, or phone (765) 494-7071. Form PPDL-3 is available through county Extension offices. The form must be properly and completely filled out and must accompany all samples submitted to the laboratory. Directions for completion are found on the back of the form.
Pesticides in the Home, Lawn, and Garden (PPP-29), is a companion to PPP-34. It addresses information all homeowners should know about using over-the-counter pesticides. Features include pesticide safety, pesticide labels, definitions of words commonly found on pesticide labels, and pesticide disposal.
PPP-29 and PPP-34 are available through the Purdue University Media Distribution Center. Call (888) 398-4636.
The information given herein is supplied with the understanding that no discrimination is intended and no endorsement by the Purdue University Cooperative Extension Service is implied.
It is the policy of the Purdue University Cooperative Extension Service, David
C. Petritz, Director, that all persons shall have equal
opportunity and access to the programs and facilities without regard to race, color, sex, religion, national origin, age, marital status,
parental status, sexual orientation, or disability. Purdue University is an Affirmative Action employer.