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Pest Management
Why is pest management
important in the horticulture
industry?
Key Questions
• What are the five major categories of pests?
• Explain best management practices while
maintaining environmental integrity.
• What is complete and incomplete
metamorphosis of insects?
• What is the difference between selective and
nonselective herbicides?
• What are alternative pest control techniques?
• What safety precautions are necessary when
handling, applying, and storing chemicals?
• What is integrated pest management (IPM)?
What are the five major categories
of pests?
• Pest
– Anything that causes injury or loss to a plant
– Can damage plants by: making them less productive,
affecting reproduction, or destroying them
• Host
– plant that provides a pest with food
• Five major categories
1. Insects
2. Nematodes
3. Weeds
4. Diseases
5. Rodents and other animals
1. Insects
• Three distinct body
parts
– Head, thorax,
abdomen
• Three pairs of legs
• Either one, two or no
pairs of wings
Insect-related pests
• Spiders and mites
– Four pairs of legs and two body sections
• Centipedes
– One pair of legs/body section
• Millipedes
– Two pairs of legs/body section
• Sowbugs and pillbugs
– Seven pairs of legs
• Snails, crayfish, and slugs
Insect body
• Cylindrical and segmented
• Made up of:
– External skeleton (body wall)
– Internal muscles and organs
– Respiratory system with
openings in sides of body
wall
– Nervous system consisting of
brain, nerve cord, sensory
nerves in the antennae, eyes,
mouth, and feet
Insect feeding
• Depends on structure
of mouth:
1. Chewing- mandibles
(grubs, beetles,
caterpillars)
2. Piercing and sucking-
elongated beaks with
an injecting organ
(aphids, leafhoppers,
mosquitoes)
Insect feeding
• Variations include:
3. Siphoning (moths and
butterflies)
4. Rasping (thrips)
Beneficial insects
• Help plants grow by
– Improving the soil
– Pollinating plants
– Destroying harmful insect pests
• Examples
– Lady beetle, praying mantis, common green
lacewing
Insect Control Program
1. Identify insect and population/monitor.
2. Determine potential for damage/economic
threshold.
3. Assess potential environmental
issues/hazards.
4. Decide on integrated control measures or
tactics/action threshold.
5. Use control measures.
6. Evaluate the results.
7. Assess resulting environmental
issues/problems.
2. Nematodes
• Appendageless, nonsegmented, worm-like
invertebrates that have a body cavity and
complete digestive tract, including mouth,
alimentary canal, and anus
• Do not have a specialized respiratory or
circulatory system
• Have a well-developed nervous system,
an excretory system, and a set of
longitudinal muscles
• Feed by penetrating root cells with a hollow
stylet mouth structure and injecting enzymes into
cells
– Enzymes digest cellular contents, which are ingested
by nematodes.
– Resulting wounds allow entry of fungi and bacteria.
Symptoms of nematodes
• May mimic problems such as:
– Low or unbalanced fertility
– Sun scald or frost damage
– Poor drainage
– Drought damage
– Insect or mite damage
– Wilt or root-rot fungi
– Herbicide damage
Preventive measures for
nematodes
1. Using disease-free planting materials
2. Proper site selection
3. Using cultural practices to ensure good
growth
Three categories of nematodes
• Ecto-parasitic
– attached outside of host
• Endo-parasitic
– Feed externally on and internally within roots
• Semi-endo-parasitic
– Partially embedded
3. Weeds
• Plants growing out of place or an
unwanted plant
• Grow and persist
• May detract from the color, texture, or
density of the desired plant
Problems with weeds
• Detract from appearance
• Compete for light
• Compete for water
• Compete for nutrients
• Compete for space
Classifications of weeds
• Grasses- monocots
• Broadleaves- dicots
• Other- sedges, rushes, wild onions, wild
garlic
• Categories include
– Annuals (winter and summer)
– Biennials
– Perennials
Other types of weeds
• Moss
– Tangled green mats composed of a branched,
thread-like growth over the soil surface
• Algae
– Group of small, primitive, filamentous, green
plants that manufacture their own food
4. Diseases
• Abnormal conditions in plants that interfere
with their normal appearance, growth,
structure, or function
• Groups of diseases
– Abiotic- noninfectious disorders
– Biotic- caused by parasites or pathogens that
are infectious and transmissible
• Favorable conditions
– Susceptible host
– Causal agent
– Favorable environment
• Methods of control
– Increasing the host’s resistance
– Altering the environment to hinder the
pathogen
– Keeping the pathogen away from susceptible
hosts
Symptoms of disease
• Rotting plant parts, particularly the fruit
• Leaves turning yellow or having an
unnatural color
• Plants wilting
• Plants having twisted leaves or stems
• Buds, flowers, or fruit not developing or
falling off
• Dead plants
Two major types of disease
• Environmental- caused by elements in
plant’s environment that are not right for
the plant
– Nutrient deficiencies
– Damage to plant parts
– Chemical injuries
– Pollution injuries
– Weather-related injuries
– Naturally occurring genetic abnormalities
• Parasitic- caused by microorganisms
– Fungi- small one-celled, usually filamentous,
spore-bearing. Fungi grow on or in plants and
cause plant mildew, plant rusts, and plant
smuts. Spread by wind, water, insects, and in
other ways.
– Bacteria- small, one-celled organisms with a
primitive nucleus
– Viruses- infective living agents of
microorganisms that do not have an
organized nucleus. Spread by insects,
equipment, and vegetative propagation.
5. Rodents and Other Animals
• Animals pests that eat leaves, stems, fruit,
and roots of plants
• Preventing and controlling animal pests
involves destroying habitat and getting rid
of the animals
Explain best management practices while
maintaining environmental integrity.
• (BMP’s) Best Management Practices
– Those practices that combine scientific
research with practical knowledge to optimize
yields and increase crop quality while
maintaining environmental integrity.
Best management practices used
in horticulture situations:
1. Management of surface and subsurface water
runoff
2. Erosion control
3. Cultural control of pests
4. Soil testing
5. Timing and placement of fertilizers
6. Controlled release fertilizers
7. Irrigation management
8. Biological control of pests
9. Pesticide selection
10. Correct pesticide use
Describe complete and incomplete
metamorphosis of insects
• Metamorphosis- development of an insect
• Complete metamorphosis- insect who life cycle
goes through four distinct stages:
1. Egg
2. Larvae- looks nothing like the adult
3. Pupae- transformation stage
4. Adult
Examples: caterpillars to moths or butterflies, grubs to
beetles, maggots to flies
• Instars- insect growth by shedding of external
skeleton in 4-5 stages
• Incomplete metamorphosis
– Life cycle changes from egg through nymph
to adult.
• Nymph looks similar to adult, only differing in size
and color
– Examples: aphids, leafhoppers, mole crickets,
and chinch bugs
According to Figure 8-6, what are the
differences in complete and incomplete
metamorphosis?
What is the difference between
selective and nonselective herbicides?
• Selective herbicides
– Control a limited number of plant species
• Nonselective herbicides
– Destroy all vegetation
Name at least one trade name of each type of
herbicide.
What are alternative pest control
techniques?
Pests are controlled in the following ways:
1. Cultural practices
2. Biological methods
3. Mechanical methods
4. Chemical methods
5. Genetic methods
Cultural Pest Control
• Uses management techniques to control pests
• Includes
– Primary
• Maintenance programs, Sanitation, Resistant varieties
– Secondary
• Mowing, irrigation, fertilization, pruning, aerification,
mulching, etc.
During evaluation ask:
1. What is wrong?
2. What is the source of the problem?
3. What should be done about it?
Biological Pest Control
• Uses living organisms that are predators
to control pests
• Examples
1. Lady bugs control a range of insect pests
2. Toad frogs eat insects
3. Bacterium Bacillus thuringinensis when
released in fields attack and kill various
species of worms
Mechanical Pest Control
• Uses tools or equipment for control
• Plowing- destroys some pests, particularly weeds
• Mowing- cuts off weeds
• Mulching- covering the ground with a layer of plastic,
sawdust or other material prevents weed growth
How have we mechanically controlled weeds in the greenhouse?
Chemical Pest Control
• Uses a pesticide, which is a chemical to
control pests
• Chemicals are often mixed with a
surfactant, which is a material to help
disperse, spread, wet or emulsify a
pesticide formulation
Types of Chemical Pesticides
• Insecticide
– Controls insects
– Material that does the killing is called the active
ingredient
– Can be in form of dusts, granules, powders, or
solutions
– Classified by how they get into insect’s body
• Stomach poisons- eaten, work on chewing insects
• Contact poisons- absorbed thru skin, must contact
• Systemic poisons- inside plant, applied to soil or leaves and
taken up into plant, insect poisoned when it bites into plant
• Fumigants- gas form, enters insect thru respiratory system,
must be used in closed places
• Nematicide- controls nematodes
• Herbacide- control weeds
– Classified by
1. Type of action
2. Chemical composition
3. Method of application
4. Species of plants affected
- Examples:
- Selective- control limited # of weeds
- Nonselective- kills all vegetation
- Contact- kills only portions of plant it contacts
- Systemic- absorbed into plant’s vascular and root
system and destroys entire plant
– Methods of Herbicide application
1. Preplant- applied before planting
2. Preemergence- applied after planting but before
crop emergence
3. Postemergence- applied after crop emergence
- Performance of herbicides depends on:
1. Temperature
2. Rainfall
3. Humidity
4. Maturity of crop and weeds
5. Soil characteristics
6. Chemical concentration
• Fungicide- controls disease caused by
fungi. The best fungicides are systematic.
• Bactericides (germicides)- controls
bacteria
Genetic Pest Control
• Utilizes biotechnology by gene transfer or
genetic manipulation to make plants resistant to
specific pests
• Biotechnology- mgmt of biological systems for
the benefit of humanity
• Organismic biotechnology- deals with intact or
complete organisms
• Molecular biotechnology- involves changing the
structure and parts of cells
• Transgenic organism- carries a foreign gene that
was inserted by laboratory techniques in all its
cells
What safety precautions are necessary when
handling, applying, and storing chemicals?
• Application of pesticides can be
dangerous. They may:
1. Injure people
2. Injure animals
3. Pollute the environment
4. Contaminate water and food
Safety guidelines to follow are:
1. Use only approved pesticides.
2. Read the label before application.
3. Use the pesticide with lowest toxicity.
4. Use the right equipment.
5. Mix according to the directions on the pesticide
label.
6. Apply evenly.
7. Avoid vapor damage.
8. Clean up.
9. Store properly.
10. Know the correct emergency measures.
Techniques for storing pesticides safely:
1. Storage area should be located where cleanup
materials are close at hand.
2. Keep pesticides in original containers with labels in
place.
3. Never store pesticides near food, medicine, or
cleaning supplies.
4. Do not store flammable materials with pesticides.
5. Organize materials to be accessible and visible.
6. Mark each container with the date or purchase.
7. Routinely check containers for damage or leaks
8. Dispose of unwanted or outdated materials and
containers according to label recommendations.
What is integrated pest
management (IPM)?
• IPM- Pest mgmt strategy that uses a
combination of BMPs to reduce pest
damage with the least disruption to the
environment
• Goal
– Keep pest populations below economic or
aesthetic injury level
• Ecologically based strategy that relies on
the following factors to control pests:
– Weather
– Pest diseases
– Predators
– Parasites
Phase I of IPM
• involves pest ID, monitoring, and action
thresholds
– Action threshold- predetermined level at
which pest control is needed
Phase II of IPM
• Involves evaluating all possible control
measures
• Control options may include:
– Chemical
– Biological
– Mechanical
The basic elements of an IPM
program include:
• People- system devisors and pest managers
• Knowledge and info needed to devise the
system and make sound decisions
• Program for monitoring the ecosystem elements
• Pest densities at which control methods are put
into action
• Techniques used to manipulate pest populations
• Agents and materials
Scouting
• Monitoring plants regularly to determine
current levels of pest activity
• Scouts check:
– To identify the presence of a pest
– The stage of development
– Amount of damage done
Environment and IPM
• IPM incorporates the changing or
amending of any or all parts of the plant
ecosystem to lower pest populations
• Ecosystem includes
– Biotic factors- living plants and animals
– Abiotic factors- soil and water
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