horticulture science lesson 31 understanding integrated pest management

Horticulture Science Lesson 31

Understanding Integrated Pest Management

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Interest ApproachBegin the lesson by having students read a newspaper article about pesticides found in a groundwater supply. Ask students for ways they believe this problemcan be stopped. Indicate that chemical pesticides are useful tools for horticulturists, but pesticides must be used wisely. Tell them that there are many other means by which to control the pest populations.


Student Learning Objectives• Explain integrated pest management.

• Identify and describe the types of pests.


Student Learning Objectives• Identify the basic elements of an integrated pest management program.


Terms• annual weed• bacteria• best management practices (BMPs)

• biennial weed• biological control• broadleaf weeds• causal agent• chemical control


Terms• cultural/physical control• disease triangle• economic injury level• economic threshold• fungi• grass weeds• infectious diseases• insects


Terms• integrated pest management (IPM)

• mites• nematodes• noninfectious diseases• parasitic plants• pathogens• perennial weed


Terms• pest• pesticides• plant disease• sanitation• scouting• viruses• weeds


What is integrated pest management?

• Integrated pest management (IPM) is a pest management strategy that uses a combination of best management practices (BMP) to reduce pest damage with the least disruption to the environment.

• Best management practices (BMPs) are those practices that combine scientific research with practical knowledge to optimize production and increase crop quality while maintaining environmental integrity.



• IPM provides protection against hazards to humans, domestic animals, plants, and the environment.

• Studies have shown that no single control measure works consistently over a long period of time.

• A reason for this is that pests can develop resistance to certain control measures.



• The goal of IPM is to keep pest populations below the economic or aesthetic injury level.1. Economic injury level is the point at which the cost of pest control equals the revenue loss caused by a pest. – It is determined by estimating the potential

yield loss, the value of the crop, and the cost of treatment.

– Economic injury level also clearly defines how much damage can be tolerated.



2. Economic threshold is the number of insects per plant or the amount of damage to the plant that economically justifies the use of control measures. – If a control is applied when a pest population

reaches the economic threshold, the population will be suppressed before it reaches the economic injury level.



• The key to a successful IPM program is scouting, which involves regularly monitoring pest populations and crop conditions.

• A scout collects data about which pests are causing damage, what stage of life each pest is in, and whether the pest population is increasing or decreasing.

• Knowing how to identify key pests and their biological characteristics is important.



• The weakest link in each pest’s biology must be found if management of the pest is to be successful.



• Benefits of IPM help sustain the ability of the earth to meet the needs of an increasing human population.1. The benefits to horticulture vary with the crop and the extent to which pests interfere with economical production. – Careful planning is required to make effective

use of IPM.



• The benefits of IPM to the horticulture industry:

a. There are reduced pesticide costs in addition to fewer pesticides used with IPM. b. Application costs are reduced due to time, and the cost of labor for pesticide application is reduced.c. Less pesticide resistance develops within populations of insects, weeds,

and diseases.



2. IPM also benefits the environment, which is made more sustainable and friendly to people.

• Benefits of IPM to the environment:a. Reduced contamination and degradation of the environment occurs through the use of IPM. – Pesticide residues do not build up in soil, water, and other

natural resources.b. Cancer-causing residues are present in smaller amounts or are not on food at all. – Less pesticide residue on food products means a

decreased chance of people ingesting pesticides.


How are the types of pests identified and described?

• An understanding of the major pest groups and their biology is required to ensure success in reducing crop losses due to pests.

• A pest is a living organism that can cause injury or loss to a plant.

• Pests include insects, diseases, weeds, mites, nematodes parasites, and animals.



• Insects are a group of animals with an exoskeleton and three body parts.

• Most insects have six legs and four wings. • More than 800,000 kinds of insects have

been identified. • Insects are capable of producing large

numbers of offspring in a short time and can cause economical loss by feeding on horticultural crops.



1. Insects have either chewing or sucking mouthparts. – Damage symptoms caused by chewing

insects are leaf defoliation, leaf mining, stem boring, and root feeding.

– Insects with sucking mouthparts produce distorted plant growth, leaf stippling, and leaf burn.



2. As an insect grows from an egg to an adult, it passes through several growth stages, which is called metamorphosis. – Two types of

metamorphosis exist: incomplete and complete.



a. Incomplete metamorphosis consists of three life stages: egg, nymph, and adult. • As a nymph, the insect

grows and passes through several instars between molts.

• Each time the insect molts or sheds its exoskeleton, it passes into the next instar.



• b. Complete metamorphosis consists of four life stages: egg, larva, pupa, and adult. • The larva stage is

the period when the insect grows.

• The pupa is a resting period where a dramatic morphological change from larva to adult occurs.



• A plant disease is defined as a disturbance to the normal growth and development of a plant. – Diseases are generally classified as being

infectious or noninfectious. • Infectious diseases are caused by living

organisms such as bacteria, fungi, or virus, which are often referred to as disease pathogens. – An infectious disease can be spread to other

plants.



• Noninfectious diseases are caused by environmental imbalances and cannot be spread to other plants.– Noninfectious disease examples include over

watering, nutrient deficiencies, and air pollution damage.

– Plants are most susceptible to disease when they are under some type of stress.

– The stress is usually associated with environmental factors.



1. The occurrence and severity of infectious plant diseases is based on three factors.

• A susceptible plant or host must be present. • The causal agent or organism that

produces a disease must be present. • Environmental conditions conducive to the

causal agent must occur. – The relationship of these three factors is known

as the disease triangle. – Disease control programs are designed to affect

each or all of these factors.



2. Fungi are a principal cause of plant disease.

• Fungi are organisms that lack chlorophyll. – They absorb nutrients from living or dead

organisms. – Their bodies consist of threadlike vegetative

structures known as hyphae. – When hyphae are grouped together, they are

called mycelium. – Fungi can reproduce and cause disease by

producing spores or mycelia. – The fungus can produce spores asexually or

sexually.



3. Bacteria are one-celled or unicellular microscopic organisms. – Bacteria can enter a

plant only through wounds or natural openings.



4. Viruses are composed of nucleic acids surrounded by protein sheaths. – They are capable of altering a plant’s

metabolism by affecting protein synthesis.– Plant viruses are transmitted by seeds,

insects, nematodes, fungi, and mechanical means.

– Viral diseases produce several symptoms including ring spots, stunting, malformations, and mosaics.

– A mosaic symptom is a leaf pattern of light and dark green color.



• Weeds are plants that are undesirable and are often considered out of place.– Weeds compete for space, nutrients, water, and

light that the crop plants need to grow. – They also harbor insect pests. – Weed life cycles are annuals, biennials, and

perennials. – They are also classified as broadleaf or grass

weeds.1. An annual weed is a plant that completes its life cycle within one growing season.



2. A biennial weed is a plant that will live for two growing seasons. – Vegetative growth occurs in the first year

where the plant produces leaf, stems, and root tissue.

– During the second year, the plant flowers and produces seeds.

3. A perennial weed can live for more than two growing seasons and may reproduce by seed and/or vegetative growth.



4. Broadleaf weeds have a broad leaf associated with dicot plants. – Examples are dandelions, ground ivy,

plantain, and spurge.5. Grass weeds include monocots such as crabgrass, nimblewill, and quackgrass.



• Plants suffer from a variety of other pests including mites, nematodes, parasitic plants, and animals.1. Mites are small organisms with an exoskeleton, two body parts, and eight legs.2. Nematodes are tiny hair-like roundworms that feed on the root of plants. – They may live in the soil or water, within insects, or as

parasites of plants or animal– Nematodes are quite small and

produce damage to plants by feeding on roots, stems, or leaf tissue.



3. Some plants, such as dodder and mistletoe, are parasitic. – Parasitic plants extract water and nutrients

from other plants and give nothing in return.4. Animals including deer, mice, rabbits, and voles cause severe physical damage to plants, which often causes plant death.


What are the basic elements of an integrated pest management

program?• For successful management of pests, the

IPM program must be a year-round program.

• Also, IPM control measures for a specific crop, poinsettias for example, should begin before the plants enter the greenhouse.

• The strength of IPM is the combination of control measures used.

• Four broad areas of control include sanitation, cultural/physical control, biological control, and chemical control.



program?• Many pest problems can be greatly

reduced, if not eliminated, with sanitation.

• Sanitation is simply the effort made to keep a greenhouse or garden clean.

• Many insects and diseases can be found in plant debris.

• Sanitation involves the removal of weeds from the immediate area around crops.



program?• Cultural/physical control methods are

those methods that physically prevent activities of pests. – Used alone they probably will not provide

complete control of pests and reduce certain problems.

– Cultural/physical controls are also safe to humans and relatively easy to implement.

1. Stop the introduction of pests to the greenhouse when possible.2. Remove and destroy heavily infested and diseased plants.



program?3. Maintain optimal cultural requirements for each crop (growing medium, watering, fertility, temperatures, etc.) to promote healthy growth. 4. Fungal diseases can be reduced by providing good air circulation around the plants.5. The yellow sticky traps used as monitoring tools also serve as a means of physical control.



program?• Biological controls involve the use of

living organisms to control pests. – They maybe microbial organisms, parasitic

organisms, or predators. – Biological control organisms for greenhouse

use are found in nature and are considered environmentally safe.

1. A bacterium, Bacillus thurengiensis, effectively controls caterpillars. – Aphids and whitefly can be controlled to an

extent by species of bacteria and fungi. – The bacteria and fungi are natural diseases of

those insects.



program?2. Parasitic organisms help to control some pests. – The parasites are natural enemies of the pest and live

off the pest organism. – An example is a tiny parasitic wasp that lays its eggs

on the whitefly larva that feeds on plant leaves. – The eggs hatch with the wasp larva inside the whitefly

larva. – The wasp larva proceeds to eat the whitefly larva. – The wasp matures, emerges from what is left of the

whitefly, mates, and looks for whitefly larva on which to lie the next generation of eggs.



program?3. Predatory organisms can be released to devour certain plant pests. – A beetle attacks whitefly larva and adults. – A mite is used to control thrips. – Ladybugs eat aphids. – As with parasitic organisms, chemical

pesticides should not be used with predatory organisms.

– Also, predatory and parasitic organisms should be released when pest populations are small.



program?• The use of chemicals to control pests and

diseases is chemical control. – The chemicals used are called pesticides.– Although once used almost exclusively,

control of pests with the use of pesticides is now viewed as only one component of an IPM program.

– In fact, use of chemical pesticides is now often done only when absolutely necessary.

– Application of pesticides must be done safely to reduce potential injury to people and the environment.


Review/Summary• What is integrated pest management?

• How are the types of pests identified and described?


Review/Summary• What are the basic elements of an integrated pest management program?
