Review Chapters 10-15 Flashcards
ecological pest issues
Significant alteration of habitats
Modifications to soil, water, and topography
Displacement of natural flora and fauna
Native species replaced with non-native species used for food and fiber
cultural control
purposeful manipulation of the environment to reduce
rates of pest damage
ecological management
understanding pest ecology as it relates to the deired commodity -> food, space, shelter. the goal of which is to find weak links in the insect seasonal cycle and exploit them
Ecological management-food
food is usually the easiest to take advantage of
insects have varied food requirements
some food changes seasonally
food sources usually provide nutrition and shelter
Categories of Ecological Management
- Reducing the average favorability of the ecosystem
- Disrupting the continuity of requisite food sources
- Diverting pest populations from the commodity
- Reducing the impact of insect injury
* One or more approaches can be used at a time
sanitation
remove debris from habitat reduces survival and reproductive rates
crop residue destruction and utilization
Destroy/remove crop residues to reduce infestations
Burning
Tilling
Mowing
Livestock grazing
Downside is bad soil health
sanitation in logging
burning and pruning
sanitation in homes
removal of leaf litter and brush piles in backyards, removal of containers that hold standing water, elimination of animal waste, efficient storage
habitat modification
Certain insects may feed on alternate host plants
* Typical for when crop plants aren’t in season
* Alternate habitats and food sources can be destroyed or limited
* Reduce habitat and food = reduce pest
* Destroy volunteer plants
* Suppression of grasshoppers
obscuring host presence
pest cant find host plant ex: plastic soil mulch, metalized plastic sheets to reflect UV rays, hiding crops
tillage
Seedbed preparation
* Weed control
* Destroy alternate pest habitats
* Change soil environment
* Soil texture, moisture,
temperature, etc.
* Understanding soil types
* Life stages occur in the soil
* Informs timing and depth of tillage
irrigation
management of water
chemigation
uses irrigation system to dispense insecticides and other pesticides over area not ecologically friendly
Continuity disruption
reduces continuity in space, change crop layout over seasons or plant life
crop spacing
space crops for maximum production. close enough for as much production as possible but far enough for space to grow. plants that are too close togeather aid in insect movement
crop rotation`
most important method for discontinuity. rotates locations for specific annuals each year. improves soil structure. works best when pet has narrow host range, eggs are laid before new crops are planted, and the feeding stage is not very mobile
crop fallowing
Typically used in dry regions
* Keep area weed free the previous season, stores precipitation
* Moisture stays in the ground, higher productivity for next crop
* Precipitation from 2 growing seasons allows biennial crops to thrive
methods of diverting populations
Trap cropping
* Strip harvesting
* Intercropping
* Push-pull polycropping
trap cropping
Plant small areas of a crop or other species new the protected crop. Favorability of alternate environment (trap) lures the pest to move into the trap area and stay away from the protected plant
Strip harvesting
Similar to trap cropping, but trap is created in a main crop
* Harvest different areas at different times
* Insects in the crop are not forced to search for replacements in adjacent
crops
* Protects crops near by
Intercropping
Grow dissimilar crops in the
same location
Push-pull cropping
Goal: pest reduction on the protected host or resource
* Pests are repelled away (push) from resource using stimuli that mask
host appearance or have a repellant
* Pests are simultaneously attracted (pull) using highly apparent and
attractive stimuli
* Trap crops
impact of insect injury
Options for reducing the amount of damage done to the plant
modify host tolerance
modify harvest schedules
Most commonly used chemical for quality of human life
conventional insecticide
retail sale of pesticides are $_ billion
$14 Billion
Percentage of retail sale for conventional insecticides
66% agriculture
24% home and garden
10% industry and government
Percent of US household gardens use pesticides
85%
insecticide
insect killer
herbicide
weed killers
acaricide
mite and tick killers
fungicide
fungus killer
nematicide
nematode killer
what are economic poisons used for
controlling, preventing, destroying, repelling, mitigating pests
How are insecticide names formatted
common name, trade name(brand), chemical name
What do chemical formulas represent
composition of chemical compounds, components of single molecules, characterization of insecticides, molecular and structural formulas
Mode of action
the way in which the insecticide causes damage to the insect
stomach acids
fatal when eaten
contact poisons
fatal when come into contact with - walked on/touched
fumigants
becomes a gas above 5 degrees celcius
inorganic
no carbon
organic
has carbon atoms. most insecticides are organic, but divided into natural and synthetic
What are Natural insecticide separated into
plant based & mineral oils
what are synthetic insecticides separated into
inorganic and organic
How are natural insecticides made
refining natural substances
how are botanical insecticides made
plants
how are mineral oils made
refining petroleum
what are botanical insecticides used for
wide usage
what are mineral oils used for
fruit tree insects and mosquito larvae
4 major groups of active ingredients
organophosphates, carbamates, pyrethroids, neonicotinoids
Most precise method of grouping insecticides
active ingredients
how do active ingredients get grouped
chemical makeup
What are pyrethoids
fast developing group of modern insecticides replacing older ones
very effective
safer for humans
highly toxic to insects in small dosages
what are third generation pyrethoids used in
cotton, corn, soybeans
what are third generation pyrethoids useful against
above ground insect pests
what are more potent, third generation pyrethoids or fourth
fourth
application of fourth generation pyrethoids against third generation
1/10th of 3rd generation
Carbamates
useful against broad spectrum of insects
wide application in agriculture
environemntally persistant
toxic to pollinators and parasitoids
highly toxic to humans
Organophosphates
nazi made
derived from phosphoric acid
very toxic to insects
unstable in light and breaks down into non toxic substances
most widley used group of insecticides used today
organophosphates
Organophosphate - Aliphatic Derivatives
Includes straight carbon chains
Tepp (Aliphatic Derivative)
oldest and most toxic. used for fly control.
Malathion (aliphatic Derivative)
effective against many insects
agricultural and home use.
used against lice, fleas, mites
Organophosphate - Phenyl Derivatives
greater stability. residues last somewhat longer in environment
Organophosphate - Heterocyclic derivatives
difficult to measure residue. limited for use on food for human consumption
Neonicotinoids
nicotine. used on aphids, leafhoppers, whiteflies, termites. low toxicity to mammals
Phenylpyrazoles
made only of fipronil which acts as a potent blocker of
the GABA-regulated chloride channel
pyrroles
contact and stomach modes of action, only chlorfenapyr
pyrazoles
contact and stomach modes of action, tebufenpyrad and
fenpyroximate
pyridazinones
rapid knockdown and long residual properties, only
pyridaben
Pyradine Azomethines
only pymetrozine, precise MoA unknown
Oxadiazines
only indoxacarb, sodium channel blocker
Insect Growth Regulators
generation 3 insecticide. disrupts growth process.
Repellants
chemical that causes insect to move away from source
Chlorinated Hydrocarbons
First widely used synthetic organic insecticides. not used in US because of safety concerns. (DDT.)
DDT & relatives of DDT
Banned. residue in human bodies.
HCH & Lindane
kills more insects than DDT. strong odor and flavor that lingers on food products
Cyclodines
not used in us. More toxic than DDT and more dangerous to apply
Botanicals
derived from plant products. used longer than other types of insecticides
synergists
increase toxicity of the insecticide directly
adjuvants
auxiliaries, serve to carry the insecticide or are added to improve adhesion, mixing, surface tension, or smell
Insecticide formulations
mixture of active and inert ingredients. Some are ready to use directly, others need to be diluted in water or oil
Insecticide toxicity
refers to toxicity of substance inherent poisonus potency under given set of laboratory conditions.
Mode of action
involves all the anatomical, physical, and biochemical
responses to a chemical, as well as its fate in the organism
Nerve Poisons
affects nervous system.
Metabolic Poisons
disrupts wide range of metabolic processes usually in mitochondria
Alkylating Poisions
replace active hydrogen in biologically significant compounds in alkyl group
Muscle Poisons
direct influence on muscle tissue
Physical Toxicants
blocks metabolic process by physical means.
Toxicity to humans
Insecticides also cause acute poisoning in humans
* Illness or death from a single exposure
* Chronic poisoning occurs with long-term exposure
* Many laws to regulate insecticide use
Biopesticides
made from natural materials (plants, animals, microorganisms, certain minerals)
Bio-pesticides vs insecticide characteristics
- Unique mode of action (MOA)
- Narrow pest range
- Low use volume
- Natural occurrence
Are insecticides or bio-pesticides less harmful and persistent for the environment
bio-pesticide is less harmful and persistent in the environment than synthetic insecticides
What does specificity of bio-pesticides do
targets one specific group of pests
Do Insect Growth Regulators use specificity?
yes.
Do insect growth regulators effect natural enemies
no
What does the Environmental Protection Agency do
regulates and registeres insecticides
what are the classes bio-pesticides are registered under
- Microbial pesticides
- Biochemical pesticides
- Plant-incorporated protectants
Microbial pesticides
sprayed or delivered like conventional insecticides. active ingredients are bacteria, viruses, fungi, and protozoa.
Microbial pesticides - bacteria
spore forming bacteria are most commonly used as insecticides
what is BT
Bacillus Thuringensis. (BT crops are crops that have been genetically modified to resist pests through bacteria.
What is BT most commonly used for
moths, mosquitos, beetles
Viruses
believed to have management potential
fungi
naturally occuring
protozoa
single celled organisms that parasitize organisms and kill insects when ingested.
Biochemical pesticide -Insect Growth Regulators
disrupts the normal growth and development of immature insects. Usually the juvenile hormones
Biochemical pesticide - Repellants
attracts pests to sides where they are killed or repels away from source
Plant oils used as repellants
cedarwood, citronella, eucalyptus, jojoba, lavandin, linalool
Attractants used in repellants
cinnamaldehyde (cinnamon), citronellol (citronella), eugenol, methy, geraniol.
Suffocating agents
oil that blocks respiratory system/breaks down cuticle and suffocates soft bodied insects
dessicants
disrupts the waxy outer layer of the cuticle causing water loss and resulting in death
coatings
makes a nontoxic physical barrier between an insect pest and leaf surface
pheromones
volatile chemical attractants involved in finding insect mates
Plant-Incorperated Protectants (PIP)
Pesticidal substance that plants produce and are added to the plant and makes plants that are resistant to certain insects. (BT crops)
gene stacks
produce plants resistant to multiple pest species
resistant plants
reduces pesticide dependancy, decreases risk of insecticide dependancy
phenotype
visual expression of genetic crosses
Earliest resistant plant
wheat variety resistant to hessian fly in 1831
what saved US wine industry
grapevines resistant to grape phylloxera
What university started modern research of plant breeding for insect resistance in 1920
Kansas State University
What saved apples in 1831
winter majetin apples resistant to wooly apple aphid
what are host plants? why are they important for insect species
general habitat for plant. insect lives, survives. and reproduces on plant.
Requirements for Insect Host plant
- General habitat
- Finding the host plant
- Accepting the plant as proper host
- Sufficiency of the plant for survival and successful reproduction
why do host plants market themselves for insects (why do plants try to attract insects)
pollination
in what ways do plants select for & attract insects
- Morphological characteristics
- Physiological characteristics
* Includes primary (growth and reproduction)
and secondary (nonessential to primary
metabolism) metabolites
* Token stimuli - Host-plant selection
* Involves primary and secondary metabolites
FLORAL STRUCTUES EVOLVE FOR POLLINATORS!!!
Resistance-Non-prefence resistance
plant characteristics lead insects away from particular host
Resistance-Allelochemical nonpreference
chemically attract less or leads away
Resistance-morphological nonpreference
plant structural characteristics disrupt normal behavior of insect
Resistance-Antibiosis
impairs insect meabolic processes often by consuming plant metabolies
Resistance-tolerance
plats can still produce a good yield in spite of pest injury levels
Resistance-Ecological resistance
not considered true resistance because it relies on environmental conditions instead of genetics
Forms of ecological resistance
Host evasion, Induced Resistance, Host escape
Ecological Resistance-Host Evasion
plant passes through suseptible stage quickly/ at a time where injurious insects are reduced
Ecological Resistance- Induced Resistance
temporary resistance derived from plant condition or environment. (fertilization, changes in soil moisture compounds produced when plant becomes diseased or attacked by insects)
Ecological Resistance- Host Escape
Presence of an uninfected plant doesn’t mean its resistance. escape can occur
Epidemiological Resistance-Virulent Genes
allows pests to overcome resistance and attack plant again
Epidemiological Resistance-Biotypes
different populations of insect species that vary in virulence to cultivar - like aphids
Resistance- Vertical resistance
plant cultvar reistant to one or a few pest genotypes
resistance- horizonal resistance
cultivars that express resisistance against broad range of genotypes
Mode of inheritance- Oligogenic resistance
major gene resistance conferred by one or a few genes
Mode of inheritance- polygenic resistance
conferred by many genes, each contributing to the resistance effect
Mode of inheritance-Cytoplasmic resistance
Conferred by mutable (capable of mutation) substances in cytoplasm
Factors mediating expression: physical and biological
physical: temperature, light intensity, soil fertility
biological: biotipes & plant age
Traditional form of breeding plants
identify preferred trait, fertilize plants, observe plant baby grow,
Marker-assisted breeding
using genetic marker to show location within plants genome that possesses insect-resistant characteristic
Recombinant DNA (rDNA)
process of inserting new DNA along DNA strand with cutting and splicing
Restriction enzyme
chemicals used to cut DNA into reproducible pieces at specific locations
Transgenic Crops
resistant plants typically have the BT gene
Engineered Resistance management strategies
- Mixes of resistant and susceptible plants in the plant stand, elaving a
refuge for some individuals - Sublethal doses that make insects more culnerable to other
environmental factors - Expression of the resistance favor only in the plant part needing
protection (usually reproductive structures)
What is Insect Resistance Management
trying to use strategies to be proactive about trying to prevent insect resistance
What is a Refuge Strip in Insect Resistance Management
strip, block, or mix of crop that doesn’t contain BT. helps maintain population of insects that aren’t exposed to BT proteins
Risks and benefits of transgenic crops (BT)
Benefits:
* Insect resistant plants
* Effective
* Reduces amount of chemical pesticides needed
* Risks:
* Potential environmental risks
1. Unintended cross-pollination, weediness of transgenic crops
2. Loss of biological diversity
3. Pest resistance to transgenic crops
4. Increased herbicide use with herbicide-tolerant crops
5. Adverse impacts on non-target species
What do insecticide generations effect
1st generation: stomach poisons
* 2nd generation: contact poisons
* 3rd generation: insect growth regulators
(IGRs)
Insect growth regulators
chemicals that alter normal growth and development of insects by disrupting endocrine system (Juvenile hormones)
What part of insect lifecycle is most vulnerable to IGR
Larvae & Pupae and molting
Hormone mimic
plant compounds that produce results in insects similar to increasing the concentration of Juvenile hormone
Categories of IGR
Chitin synthesis, Juvenile hormone, Molting horone
what does chitin systhesis do
eggs hatching
What does juvenile hormone do
effects juvenile insects growing
what do molting hormones do
effects molting
Types of pheremones
Sex, alarm, trail-making, aggregation, epideictic
Sex pheromones
most common and most research
Alarm pheromones
social insects like bees and ants
trail making pheromones
foraging ants and termites
aggregation pheromones
beetles, cause insects to aggregate or
congregate at food sites, reproductive habitats, hibernation sites, etc.
Epideictic pheremones
spacing pheromones that cause dispersal away
from crowded food sources
what are pheromone traps usually on
sticky traps
Pros of pheromones used for sampling
sampling and detection, attracts insects to trap, reduces reliance on chemical insecticides
How are pheromones used for attract and kill
insects attracted to source (typically by sex pheromones), killed by various means
Mating disruption
causes confusion or decoy. air filled with sex pheromone and makes insects unable to locate mates
Traditional bait
attract and kill. food lures.
Deterrents
prevents feeding or oviposition by insects
DEET
most common repellant ingredient
What do traditional repellants target
mosquitos, biting flies, fleas, ticks, mites
plant allomones used as repellants
natural substance derived from plant and animals. most served as repellants from the aspect of host plant resistance
epideictic pheromones used as repellants
future use due to current research. used by insects to deter other insects from area
Behavior modification
attractants and repellants combined with other methods like killing agents/insectidices
autocidal control
insects are
used against members of their
own species to reduce population
levels. ->sterile insect technique
goals of genetic control
- Produce sterility of
progeny - Reduce fecundity
- Reduce survival in
otherwise favorable
environments
Sterile insect technique are used in what bugs
originally screw worms
Sterile insect technique theory
Lower population numbers by preventing viable offspring
Reproduction penalty placed on the population would be so great that it
could not be overcome
Population numbers drop
sterile insect tehnique vs other tactics
more effective
insecticides need more applications
SIT as a reduction effect in next generation
Chemosterilants
chemicals that are capable of sterilizing insects. both males and females have similar effect to insecticides
Radiation in Sterilizing insect technique
X-rays used to cause steralization. pupae close to adult emergence makes sterile adults
Groups pf chemosteralization
- Alkylating agents
- Phosphorous amides
- Triazines
- Antimetabolites
Total population management
area-wide programs that attempts to
use all available means to eradicate a pest
area wide management
Area wide management attempts to account for migration and other
insect movement
Screwworm
eats livestock still alive and causes a lot of money loss. used Sterile insect technique
How did they get rid of screwworm
sterile insect technique released in 1958 in South East USA. Complete eradication in Florida
Pests Sterile Insect Technique is being used for
tropical fruit flies. Screwworm
Sterile insect Technique requirements and limitations
Economical mass rearing of insects
* Need to release millions of insects
* Releases are usually weekly over a several month period
* Only successful when the insects that are being released aren’t also
causing damage