Pest managament Flashcards
Define Integrated Pest management
A pest control strategy that uses an array of complementary methods (mechanical devices, physical devices, genetic, biological, legal, cultural management, and chemical management) in three different strategies (prevention, observation, and intervention) to significantly reduce or eliminate the use of pesticides
How is prevention used to construct an effective I program?
Stops pests from being introduced to a location
Regulations and quarantines are commonly used to prevent introduction
eradication is used to prevent the pest from remaining in the area if pest is already there.
How is avoidance used to construct an effective IPM program?
Keeps a species population below levels where it would be a pest
Pest target is kept healthy so pest damage is below economic threshold
Pest target can be given increased pest resistance through breeding and genetic engineering
Natural enemies can be maintained or increased
Traps can be used to lower pest population
Barriers can be used to separate the pest from host
How is monitoring used to construct an effective IPM program?
Characterized the presence/ absence of the pest and, if present the fluctuations in the pest populations
May include the degree/extent of pest damage to the host
How is suppression used to construct an effective IPM program?
Used to reduce pest populations below the economic threshold of prevention and avoidance tactics fail
Chemical, biological, cultural and other tactics are used to minimize environmental impacts
What are the steps of an IPM program?
Sampling and monitoring
Identification (kind, nature, and severity of pest damage or potential for damage)
Determining need for control (compare cost of treatment with economic benefit of treatment)
Evaluating control options
Implementation
Evaluation and record keeping
How do pathogens, predators, and parasites affect insect pest population development?
Each can reduce pest populations
Pathogen causes a disease to occur in pest
Predators attack the pest and may use it as food
Parasites live on or in the pest and may use t as food
How do host plants affect insect pest population development?
Presence of a host plant increases the possibility of increased pest populations
How does the initial pest population affect insect pest population development?
The higher the initial pest population, the higher the potential for increased pest populations
Initial population of insects or insect density is modified by the spatial distribution of the insects (dispersion), their birth rate (Natality), the pattern of insect growth, and age of the insect population
May or may not lead to higher insect populations
How does temperature affect insect pest population development?
Pests grow and develop in response to thermal inputs
Each organism has a min, max, and optimum temp for growth and development which can change during a life cycle
Often insects grow and develop in response to degree days or the accumulation of heat above a threshold value
How does soil characteristics and conditions affect insect pest population development?
Soil physical properties like moisture, temp, and aeration can be important in the growth and development of some insect populations
How does wind affect insect pest population development?
Wind transports insects to new locations for infestation
Wind damage to immature plants can be misinterpreted as insect damage
How does developmental time and seasonal period of activity of an insect influence their ability to cause damage?
They are related to factors like temp, light, and food supply.
When developmental time and period of activity of the insect coincide with the growth of a host crop, damage may occur
How does the reproduction rate and number of generations per season of an insect influence their ability to cause damage?
The number of eggs (rate) and the number of generations per season combine to improve the survivability of the insect
Some insects produce large numbers of eggs, others produce many generations per season
How does over wintering and over summering strategies of an insect influence their ability to cause damage?
These help to assure that the insect will survive and be competitive
How do feeding habits of an insect influence their ability to cause damage?
Chewing insects remove plant parts where metabolic activities occur or fruiting structures of plants
Piercing-sucking insects remove the internal fluids of the plant, interfering with metabolic activity
Insect activity can also damage plants by vectoring disease
What are the 3 types of metamorphosis?
None/without/simple: egg, young adult with young looking like adult but smaller and feeding on same food source as adult
Gradual/simple: egg, naiad, adult. Naiad look generally like adult but without wings and external genital appendages. Each time naiad goes through feeding stage (instant) followed by a molt it looks more like the adult. All immatures are aquatic and have gills with different food sources for adults and immatures
Complete/complex: egg, larva, pups, adult. Larvae go through series of growth stages and molts but remain worm-like. Food source may or may not be the same. Many species undergo complete metamorphosis
What are the three keys to maximizing disease development and damage to crop?
Environment must be optimum for pathogen growth
Host must be highly susceptible to the pathogen
Pathogen must be abundant , active, and virulent
How do fungi survive between crops, move field to field, and infect plants?
Survival: mycelia, spores, sclerotia in infect plants, debris, soil, insects
Movement: dispersal by wind, water, insects, animals, humans
Infection:
Grow through cell (intracellular mycelium) or between cells (intercellular mycelium)
How do bacteria survive between crops, move field to field, and infect plants?
Survival: in infected plants, debris, soil, insects
Movement: dispersal by water, insects, animals, humans
Infection: invade plant tissue through the cells (intracellular) or between cells (intercellular)
How do viruses survive between crops, move field to field, and infect plants?
Survival: in living tissue, insects, nematodes
Movement: dispersal by insects, humans
Infection: invade plant tissue through the cells (intracellular)
How do nematodes survive between crops, move field to field, and infect plants?
Survival: eggs in soil, eggs and nematodes in roots, some larva and adults in seeds or bulbs
Movement: dispersal by water, animals, humans
Infection: invade plant tissue through the cells (intracellular) or between the cells (intercellular)
How does weed growth rate affect the competitive ability of weed populations?
High growth rate makes it more possible for the weed to intercept light and shade the crop, and to have a large root system which will extract water and nutrients needed by the crops
Early emergence also increases competitiveness
How does weed seed production affect the competitive ability of weed populations?
High seed production increases the likelihood that the weed will remain at competitive populations in the field
How does weed seed dormancy affect the competitive ability of weed populations?
Seed dormancy will ensure the weed will survive in the field for years allowing it to reappear at competitive levels when the dormancy is broken
How does weed reproduction method affect the competitive ability of weed populations?
Weeds reproduce by seed and vegetative growth
Seed variability, seed dormancy, and seed numbers are important for weeds that produce seeds
Vegetative reproduction is common for perennial weeds where they reproduce from stolons, rhizomes, bulbs, aerial bulblets, comes, tubers, or tap roots (these asexual reproductive parts are hard to control culturally)
How does weed life cycle affect the competitive ability of weed populations?
Weeds that germinate before crop plants germinate and grow rapidly while the crop is small are more competitive.
Weed survival depends on the ability of the weed to complete its life cycle, including production of viable seed that remain viable in the soil for extended periods, and/or maintenance of vegetative reproductive structures
What are advantages/disadvantages to direct observation?
Advantage: no equipment needed, good for small plants
Disadvantage: careful observation a must, more difficult in dense plant stands
What are advantages/disadvantages to sweep net and drop cloths?
Advantage: inexpensive, can be used to sample many pests
Disadvantage: sweeping efficiency varies from person to person, insects per sweep is not a direct measure of population per area
What are advantages/disadvantages to insect traps?
Advantage: trap specific insects of interest
Disadvantage: only trap insects that will move to the trap
How are heat units calculated?
Air temp is used to calculate heat units
Heat units that accumulate in a day equal the average temp that day minus some base temp (unless there is a temp max)
If there is a temp max, the heat units for that day would be the temp max minus the base temp
How are weed samples obtained, prepared, and shipped for evaluation?
Collect the whole weed, including the root system
Blog any excess moisture off the weed, place it in a plastic bag, seal the bag, and refrigerate.
Send weed sample to lab ASAP
How are insect samples obtained, prepared, and shipped for evaluation?
Collect the insect, place it in a vial with rubbing alcohol, and tightly seal vial.
Ship to lab for identification
How are diseased plants samples obtained, prepared, and shipped for evaluation?
If possible, collect the whole plant, including root system. If it’s not possible to collect the whole plant, collect affected part and put in plastic bag.
Shake soil from roots, but do not wash roots. Enclose roots in plastic bag and then enclose the whole plant in a second plastic bag.
Do not add moisture, refrigerate prior to shipment. Ship ASAP
How are soil samples for nematode analysis obtained, prepared, and shipped for evaluation?
Collect soil samples similar to routine soil samples for soil fertility testing.
There is considerable spatial variability in nematode populations, so fields should not be too large (<50 acres) for a sample.
There are specific, optimum dates for sample collection for some nematodes to improve the interpretation of potential damage
Soil samples should be placed in plastic bags and sealed. Soil should not be dried out and should be protected from sun, freezing, and heat.
It is best to store sample on ice (refrigerate) and ship to lab within the next day or so.
What factors can help identify a pest?
Crop grown
Time of year
Symptoms/ pattern of damage
Distinguishing characteristics of pest
Distribution in field
What pest characteristics can be used to identify pests and insects?
Type and number of legs: mites vary (0-8), insects have 6. Legs can be segmented
Type of mouth parts: piercing-sucking features or biting/chewing features
Wing characteristics
Life cycle
What are cotyledon features to evaluate when differentiating weeds
Above ground vs below ground cotyledons
Presence/absence, number, and orientation of lobes
Length and width; length vs width
Thickness
Margins parallel or other
Venation
Pubescence
Color
Shape
Odor
How are arrangement, shape, and vein pattern on leaves evaluated to differentiate weeds?
Leaf arrangement (attachment to stalk): alternate, opposite, whorled
Leaf morphology evaluation includes
Types: simple, compound (trifoliate, dissected, leaflet numbers, and types)
Margins (entire, toothed, loved, undulated, hairy)
Shapes (length, width, length vs width, linear, elliptic, oval)
Surface (upper, lower, smooth, hairy, projections, waxy, granules, glands)
Hair (short, stiff, long, soft, shaggy, appeased, position on leaf, star shaped, unbranched, dense)
Vein and mid vein characteristics
Color
Odor
Juice when crushed/broken
How are ligules and audibles evaluated to differentiate weeds?
Aruicles: Presence/absence
ligule:
Presence/absence
Membranaceous
Shape (obtuse, truncate, acute)
Fringe of hairs
Margins (ciliate, notched/toothed, smooth
What are the different stem shapes?
Tuber: enlarged underground stem that has nodes
Rhizome: underground stem that can have buds that sprout forming new shoots
Stolen: above ground stem with buds that sprout forming new shoots
Bulb: underground stem with fleshy leaves that store food
Corm: fleshy underground stem with papery leaves
Grass stems are flattened or round
Broadleaf stems are erect, twisted, or growing along the ground
What are the different types of root systems?
Tap root: main root enlarging and growing downward
Fibrous roots: thin, thread-like roots, usually without a primary root present
Adventitious root: root growing from something else other than root tissue (stem, etc)
Tuberous root: root enlarged for storage of food reserves
Aerial root: adventitious root produced above ground, often for climbing
What non-pest factors can cause plant damage?
Wind lodging: plant parts are rubbed together or broken off by wind
Sandblasting: sand size particles carried by wind that damages plants
Temp extremes: high temps cause enzyme systems to alter or inactivate. Low temps cause ice to form between plant cells and then within cells disrupting them
Rain, hail, and ice: snow hail and ice can break plant parts due to weight or impact on plant branches or growing points. Rain can increase the possibility of lodging
Moisture extremes
Sunlight
Pesticides phytotoxicity: pesticides can damage nontarget crops/plants
Nutrient deficiency/toxicity
Soil compaction
Lightning
Mechanical/ animal
What are advantages/limitations to using hand lens for diagnosis?
Advantage: easy to use, several samples can be viewed
Limitation: must record observations in data book, requires clear wording
What are advantages/limitations to using digital camera as a diagnostic tool?
Advantage: easy to use, several samples can be recorded, record of specimen for future use
Limitation: lens may not be correct for good image, may be difficult to acquire images from some perspectives, need correct lighting
What are advantages/limitations to using picture references as a diagnostic tool?
Advantage: easy to use
Limitation: does not show variability in pest characteristics
What are advantages/limitations to using dichotomous key as a diagnostic tool?
Advantage: logical process leading to a result
Limitation: may lead to erroneous conclusions, need several specimens, verification using another method is recommended
Distinguish action threshold from economic injury level
Action threshold (AT) is that pest population and/or associated injury when pest control will prevent the economic injury level (EIL) from being reached.
EIL: the point where pest management costs equal loss in income due to the damage from the pest
Above EIL, income loss will occur unless the pest is controlled
How is economic injury level calculated?
EIL= C/ (VID)
C: cost of pest management alternative $/acre
V: value of the part of crop sold $/lb
I: injury amount % loss/pest/acre
D: damage per injury amount lbs/acre/% loss
When is treatment cost effective?
When EIL<1
C< VID
Cost of treatment is less than income lost from pest damage
What information can be used to make the best pest management decisions?
Current crop pest data from monitoring and scouting
Pest history
Pesticide history
Cropping history
Fertility level
Soil, weather, and crop conditions
Future cropping plans
Crop biotech traits
Refuge locations
Distinguish genetic resistance and transgenic resistance
Genetic resistance is created through breeding crops to develop crops which are resistant to a pest (plant can exclude or overcome pest)
Transgenic resistance of a crop to a pest is resistance obtained from the genetic material of another species of plant/animal
How do Bt modified crops affect pest management?
Can be used in place of insecticides which reduces insecticide use in the crop. Refuge areas of the same crop not containing Bt must be planted nearby to reduce genetic alteration in the target insects that would make them tolerant of Bt toxin
How does glyphosate resistance affect pest management?
A crop with glyphosate resistance can be sprayed with glyphosate without being damaged.
How does glufosinate resistance affect pest management?
Glufosinate herbicide can be used on glufosinate resistant crops without being damaged.
What are the advantages/ limitations to incorporating multiple traits into crops through transgenic techniques?
Advantages:
- Chemical applications reduced/eliminated if genetically engineered crop controls pest
- multiple pests can be controlled at the same time
- fewer trips across the field with implements or aerial applications
- eliminates environmental problems and pesticide carryover if pesticides are not used
- less management required (fewer chemical applications)
Limitations:
- yield may be less
- cost of seed and technology fee
- pests may develop resistance
Describe the concept of critical weed free period
The time during the growing season when the crop must be kept free of weeds. If the crop is not weed free during this period, yield and/or crop quality will decrease. The time during the growing season is often defined in terms of crop development
Identify biological control agents
Lacewings
Ground beetles
Lady bugs
Minute pirate bugs
Damsel bug
Parasitic wasp
Predatory mites
Spiders
Syriphidfly larvae
What are the advantages/ limitations to using biological control agents in crop production?
Advantages:
- used to control a specific pest or group of pests
- agents that are not indigenous to the crop or location usually offer the best pest control
Limitations:
- lack of broad spectrum control
- potential damage to non-target organisms
- cost
What is mode of action and how does it affect pesticide selection?
Mode of action: the way the pesticide kills/ damages pest
Using the same mode of action repeatedly can lead to pest resistance to pesticides and lack of efficacy. Varying mode of action reduces potential for pest resistance.
Distinguish contact and systematic pesticides
Contact pesticides exert their pesticidal action at the point of contact with the plant or pest
Systematic pesticides move in the plant to the site of pesticidal action
What factors increase the risk of crop injury from pesticides
Application near a sensitive crop
Improper aerial application
Wind
High temp which increases volatilization
Use of small droplets, high pressure, higher boom height, lower spray viscosity
What are advantages/ limitations to ground application methods?
Advantages: less drift, cost-effective for smaller areas
Limitations: slow, timeliness, soil compaction, crop plant physical injury by equipment
What are advantages/ limitations to aerial application methods?
Advantages: large area sprayed quickly, timeliness, use where ground rigs can’t go(wet areas, closed canopies) no physical damage to crop or soil
Limitations: more drift, costly for small areas, increases public concern, weather
What are the different mode of action groups and what plant injury symptoms do they cause?
Photosynthesis inhibitors:
Contact burn of existing leaves, chlorosis of oldest leaf margins of seedlings if soil uptake
Cell membrane disrupters:
Contact burn of existing leaves, chlorosis of veins if soil uptake
Growth regulators:
Distorted growth of new leaves, callus growth on stem
Pigment inhibitors:
Bleaching (white) of existing leaves
Seedling growth inhibitors:
Clubbed root tips or leading out underground, wrapped leaves, buggy whipping
Amino acid synthesis inhibitors:
Chlorotic new growth to death depending on rate, white flash in corn
Nitrogen metabolism inhibitors:
Chlorosis of entire plant in 4-5 days
Lipid synthesis inhibitors:
Growing point rots, new leaves pull out easy, white flash in corn
What insect stage is most sensitive to insecticides?
Early stages (larva, pupa),
early vs late in stars
eggs just before hatching
Describe the types of insecticide activity
Contact:
Enters the insect when insect comes in contact (touch, ingestion, inhalation) with chemical
Stomach poisoning:
Stomach poisons are ingested by insect
Systemic:
Absorbed by plant or animal which is then ingested by the insect
Ovicidal:
Kill insect eggs
Juvenile hormone (insect growth regulators): Kill pest when applied at the proper point in the metamorphosis
How is pesticide dosage determined?
Determine rate:
Correct amount of active ingredient (ai) to apply from the label by considering weeds present, soils, and other factors
Determine Concentration:
Actual amount of active ingredient in pesticide
*make sure units (lbs ai/ac, kg ai/ha, oz ai/1000 ft2) are the same as for concentration and rate!
Dosage= rate/concentration
