Winter 2000 Newsletters
Integrated Pest Management
What Is It?
Integrated Pest Management (IPM) is an ecologically based and systematic approach to pest control. IPM promotes minimized pesticide use, enhanced environmental stewardship and sustainable systems. IPM uses a combination of pest control practices in concert with naturally occurring controls to prevent, reduce, suppress, eliminate or repel pest populations.
IPM programs are based on information obtained by sampling and monitoring, and this information is used to make management decisions. Pest management tactics may include cultural, mechanical, biological or chemical methods.
IPM principles can be applied wherever pests are found. Programs have been developed throughout the world for use in schools, hospitals, golf courses, restaurants and home gardens as well as for agricultural use. Pests that attack agricultural crops include weeds, mites, insects, diseases and vertebrates such as birds, deer and rabbits.
Agricultural IPM programs use a systematic approach and considers all factors affecting crop health including weather, life stages of pests, natural enemies, plant nutrition, horticultural practices and the development of the crop, to determine if pests approach a level that is damaging to crops.
If pests have not reached this economic threshold, then no treatment is necessary. The goal of IPM is not to completely eradicate pests, but rather to control pest populations in order to prevent both the pest and the pest management practices from having an adverse affect upon the crops, the environment and the cost of running the farm.
Monitoring and Scouting
Monitoring is the first step used by farmers who practice IPM. Monitoring avoids the unnecessary use of pesticides, because a corrective action is taken only when damage caused by the pest reaches an un-acceptable level.
In an IPM program, both the pest populations and the beneficial populations are monitored. Naturally occurring organisms such as ladybugs, preying mantises and lacewing larvae frequently prevent pest populations from reaching damaging levels. Birds are also an effective control.
Farmers have always been record keepers, but IPM requires that they keep track of the fields in new and intensive ways. A whole new profession, called scouting, has arisen. IPM scouts visit the fields on a weekly basis, put out traps, monitor pests and beneficials and advise growers how to proceed.
Cultural Controls
Cultural control is the use of agricultural management practices that will reduce or eliminate pest populations by making it difficult for pests to colonize, develop or survive. The primary requirements needed to support any pest population are food, shelter and water. Any upset to the balance of these will assist in controlling the pest population.
Crop rotation, tillage, field sanitation and flooding are all cultural controls. Farmers may also remove nearby plants that provide an alternate host site for pests or plant crops that act as traps or are beneficial to natural enemies. Altering the date for planting or harvest and the use of seed that is pest resistant or faster maturing may help reduce infestations by allowing farmers to harvest when pests are less abundant.
Mechanical Controls
Mechanical controls include physical barriers that keep pests away, such as netting for birds, electric fences to keep out deer, fine insect screens in greenhouses and floating row covers for vegetable crops. Other examples include reflective mulches, weed reducing mulches and the use of planting distance from roads. These methods control the movement of pests into fields by creating favorable growing conditions for plants and unfavorable conditions for pests.
Biological Controls
Biological controls use the natural enemies of pests against them. Natural enemies of pests include predators, parasites, pathogens and weed feeders. Farming practices which protect natural enemies are emphasized. A common example of biological pest management involves the use of beneficial insects to prey on insect pests. Commercially available insects pathogens can also be employed to kill certain pests, but spare beneficial species. Massachusetts farmers commonly release beneficial insects in greenhouses and orchards, while bacteria-based sprays are used on vegetable crops.
Chemical Controls
In IPM programs, chemical controls or pesticides are used only when necessary, and in conjunction with other pest control practices. Only those pesticides that have the smallest impact on the environment are used. Farmers also select pesticides that do not kill natural enemies. The lowest effective amount of pesticide is applied from carefully calibrated sprayers. The pesticides used today are more effective in smaller amounts and break down faster in the environment.
New Frontiers
New pest management strategies are continually being developed. Some recent approaches are the use of Global Positioning Systems (GPS), pheromones and genetic modification. GPS units use computers and technology linked to satellites to determine precise field locations where chemical control is needed and to regulate the amounts of pesticides delivered. Pheromones are chemicals naturally released by animals to communicate with other members of their species. Synthetically produced pheromones, which have been used for years to attract insects to traps for monitoring, are now being used in large doses to confuse insects and prevent them from mating.The ability for a plant to tolerate a pest can be modified by genetically based resistance through traditional plant breeding methods and more recently by genetic modification. Genes of a particular organism are modified to produce a desirable trait, such as crops that are resistant to pests or that produce their own toxins which are harmful to pests.
Information for this article was provided by Craig Hollingsworth and Bill Coli at the University of Massachusetts, Amherst and Brad Mitchell and Trevor Battle at the Mass. Dept. of Food & Agriculture. Additional material came from publications and web sites of American Farm Bureau Federation, UMass, MDFA, Cornell University and the University of Minnesota.
IPM Resources
Massachusetts Department of Food & Agriculture
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University of Massachusetts
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California Foundation for Agriculture
in the Classroom
2300 River Plaza Road
Sacramento, California 95833
(800) 700-AITC
Fax: (916) 561-5697
web site: www.cfaitc.org
- Lessons available on web site, including a 56 page lesson on IPM for grade 4 to 6.
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Books
Amazing Insects (Eyewitness Junior) by Fran Greenaway, 1993. Horn Book, Inc. |
Backyard Bugs by Robin Kittrell Laughlin and Sue Hubbell, 1996. |
The Best Book of Bugs by Claire Llewellyn, 1998. Kirkus Associates |
The Big Bug Book by Margery Facklam, 1994. Horn Book, Inc |
But Will It Bite Me? by Edith G. Bailes, 1984. Cardamon Press. |
Common Sense Pest Control by Olkowsky, Darr and Olkowsky, 1991. Taunton Press. |
Guide to Observing Insect Lives by Donald W. Stokes, 1984. Little Brown and Co. |
The Insect Book: A Basic Guide to the Collection and Care of Common Insects for Young Children by Connie Zakowski, 1996. |
Insect Invaders by Howard & Margery Facklam, 1995. Twenty First Century Books. |
Insect Wars by SaraVan Dyck, 1997. The Horn Book, Inc. |
Insects Around the House and Insects in the Garden by Dorothy M. Souza, 1991. |
The Practical Entomologist by Rick Imes, 1992. |
What About Ladybugs? by Celia Godkin, 1995. Horn Books, Inc. |
What Bit Me? by Dorothy M. Souza, 1991. The Horn Book, Inc. |
Information for this newsletter was taken from the sources listed above .
IPM Facts
- UMass Extension has been developing IPM programs since 1978. The Massachusetts Dept. of Food & Agriculture encourages all farmers in the state to practice IPM. In Massachusetts, IPM programs have demonstrated that it is possible in some crops to reduce pesticide use by between 25% and 70% with no loss of yield or quality.
- Private-sector knowledge and adoption of IPM has consistently increased over the past decade. Currently, over 40% of the Massachusetts cranberry acreage, 30% of apple acreage, over 50% of potato acreage and about 25% of sweet corn acreage is grown using IPM strategies.
- IPM programs in Massachusetts have been responsible for economic development in the form of nine private-sector IPM businesses employing fourteen people.
- Some Massachusetts apple growers practice a set of biologically-intensive management practices that eliminate all pesticide sprays after early June. They have been able to use 50% fewer pesticide sprays and a new, ecologically-based, control for fly speck, a serious apple disease, cut the use of fungicide by 50%.
- Recent demonstration projects have been successful in reducing overall pesticide use in strawberries by between 25% and 40% with no adverse affect on yield.
- Synthetic pesticide reductions by farmers participating in Massachusetts IPM programs include 85% for cabbage, 80% for potato, 50 % for sweet corn, 30 % for cranberries and 27% for poinsettia crops.
- New federal policy goals aim to reduce pesticide use and to ensure adoption of IPM practices on 75% of U.S. farms by the end of the year 2000. In Massachusetts, 8,937 people have attended educational programs and been trained in IPM methods.
Understanding Biological Controls
Biological control can be an effective way of sidestepping the use of chemical pesticides, thereby protecting the soil and water and saving many beneficial insects. But it takes plenty of detective work to find and cultivate the right enemy, and then make sure that the enemy does not itself become a pest.
Predators, parasites, and pathogens are natural enemies used as biological controls. Predators of insects and mites include beetles, true bugs, lacewings, flies, midges, spiders, wasps and predatory mites. Some predators are specialized in their choice of prey, others are generalists; and some will prey on other natural enemies as well as pests.
Lady beetles are voracious predators. The convergent lady beetle larva eats its weight in aphids every day and consumes as many as 50 aphids a day as an adult. The seven-spotted lady beetle adults may eat several hundred aphids per day and each larva eats 200 to 300 aphids as it grows. Once the adults and larvae have eliminated an aphid colony, they will search for additional food, often leaving the area where they have been released.
Parasites live on or in other organisms, feeding upon them, and frequently destroying them. Insect parasites are usually flies or wasps. In some parasites, the immature form feeds on or within a single insect host; other parasites are free-living adults. Most parasites only attack a particular life stage of one or several related species. The life cycles of the pest and parasites can coincide, the pest’s life cycles may be altered by the parasite to accommodate its development.
Pathogens are disease causing organisms such as bacteria, viruses and fungi that affect insects, plants and animals. The pathogens that are selected as biological controls are very specific and affect only one type of pest. Microbial products do not directly affect beneficial insects, and none are toxic to wildlife or humans.
Some pathogens have been mass produced and are available commercially for use in standard sprays. The bacterium, Bacillus thuringiensis or Bt, and several related strains of bacillus have been produced for use by gardeners and growers. Each strain affects a different group of beetle, moth or even mosquito. For example, when the larvae of the Colorado Potato Beetle feed on this bacterium, the gut of the larva is paralyzed, resulting in death from starvation.
IPM History
The use of natural enemies to reduce the impact of pests has a long history. Ancient Chinese farmers used ants as predators for pests on citrus trees and controlled grasshoppers by herding them into pits. By 500 A.D. the Chinese employed full time locust control officers.
New pest control methods introduced between the mid 18th & 19th century included nicotine extract to control aphids, petroleum oils to suffocate insect eggs, minerals such as copper, lead and arsenic and botanical extracts such as rotenone and pyrethrum, which were used against plant diseases and insects. In 1874, DDT was synthesized by a German chemist.
The first U.S. biocontrol project was instituted in 1888, and involved using vedali beetles against citrus pests. The golden age of pesticides began in the 1940's and continued through the 1960's. New classes of organophosphates and carbonates led farmers to rely on "preventative" calender-driven spraying programs whether pests were present or not.
In the 1950's, scientists in Canada and the U.S. began work on strategies toward "harmonizing" control of pests. In 1962, Rachel Carson’s Silent Spring drew public attention to the hazards of pesticides. In the 1960's and 1970's there was also a realization that insects, fungi and weeds were becoming pesticide resistant. They also discovered that chemical pesticides persist in soils and in animal fatty tissue.
In 1970, the U.S. Environmental Protection Agency was founded and a year later the EPA began funding IPM research at land-grant universities. In 1978, the first New England grant for an IPM project was given to UMass for a pilot study of IPM in Massachusetts apple orchards.
Since 1978, the IPM program at the University of Massachusetts has worked in conjunction with the Mass. Dept. of Food & Agriculture and farmers throughout the state to implement IPM programs in a variety of agricultural areas and also to develop new strategies.
Information for this article was taken from "Vigorous Farms in a Safe Environment" by William Coli of UMass.
What A Pest!