VL 7 Flashcards
What is an ecosystem service?
AN ecosystem service is any positive benefit that wildlife or ecosystems provide to people. The benefit can be direct or indirect - small or large
Ecosystem services of insects in agroecosystems
Biological control
Pollination
Decomposition
Food and feed
Biological control
Use of population of one organism to reduce population of another organism
Agents of biological control
Predators, parasitoids, pathogens
life cycles, behavior, habitat preference
Examples of insects that are preyed by ladybugs
Aphid
Scale insects
Mealybugs
Spider mites
Thrips
Whiteflies
Moth eggs
Other soft-body insects
Adults and larvae predaceous, found wherever prey occurs
Life cycle of Colorado potato beetle
Adult Colorado potato beetles hibernate in the soil in and around the field all winter and come out hungry and ready to eat in the early spring, just as the potato plants are coming up
egg -> early larva -> late larva -> pupa -> adult beetle -> mating -> egg
Parastoids - life cycle
Adult female parasitoid -> parasitation of aphid -> parasitoid larva develops, aphid alive -> parasitoid pupates, aphid dies & turn to mummy -> adult parasitoid emerges out the mummy by cutting a hole -> adult female parasitoid
p. 13 (15 on slide)
Natural enemies of aphids
Lacewing larvae
Ladybird beetle larvae and adult
Syrphid fly larvae
Parasitoid wasp
What are 4 implementation strategies in biological control?
Natural biological
Conservation biological control
Classical biological control
Augmentative biological control
Natural biological control
wehere pest organisms are reduced by naturally occurring beneficial organisms without any human interaction
Conservation biological control
where pest organisms are reduced by naturally occurring beneficial organisms, with human actions that protect and stimulate the performance of naturally occurring natural enemies
provide nectar and pollen (flowering insectary strips, border plantings)
Provide shelter and overwintering sites
(grass banks, hedgerows, no-till crop debris, organic mulches, cover crops)
protect habitat from pesticides
Classical biological control
introduction of exotic biocontrol agents for permanent establishment and hence permanent control of targeted pests
e.g.
Ladybug the Rodolia cardinalis, was successfully introduced from Australia to against cottony cushion scale (Icerya purchasi) and saved California citrus industry
Harlequin ladybug, Harmonia axyridis, initially introduced in various areas of the world in as biocontrol agents of aphids but today considered invasive
Augmentative biological control
mass rearing of natural enemies and periodic release
- inundative biological control where effect is due to released organisms alone and no reproduction is expected
- seasonal inoculative biological control where the released organisms are expected to reproduce and provide more long-term (but still non-permanent) control
Release of egg parasitoids in the field or greenhouse
The main advantage of using egg parasitoids as biocontrol agents is that pest can be potentially controlled before any damage is caused to the plants
e.g.
Trichogramma species are commonly produced in Ephestia kuehniella eggs. Parasitized eggs are black in color. Trichogramma species are often shipped and released on hanger cards with glued eggs.
Assessment of biological control
Effectiveness to control pest
Risk assessment on non-target species
Logistic cost (rearing, storage, transportation)
Experimental tests for assessment
Small arena non-choice blackbox test
small arena non-choice behavior test
Large arena ehavior test
field test
p. 28 - 29
flow chart 28 - 29
Environmental risk assessment - direct and indirect effects
direct: Effects on non-target herbivores
indirect: Effects on other trophic levels: intraguild predation, enrichment, apparent competition, vectoring
Integrated Pest Management (IPM)
science-based, sustainable decision-making process that uses information on pest biology, environmental data and technology to manage pest damage in a way that minimizes both economic costs and risks to people, property and the environment
6 IPM Control Methods
Genetic control
Cultural control
Behavioral Control
Biological Control
Physical Control
Chemical Control
Advantage and disadvantage of Predators
Advantage:
prey is killed rapidly
All individuals (male, female, young, adults) actively hunt for prey
Synchronization in predator/pest life-cycles is not a major problem
Disadvantage:
Many preys are needed to sustain each predator
Few predators are highly specific and will not always hunt only the pest insect
Advantage and disadvantage of parasitoids
Advantage:
Survival is high, only one host is necessary for complete
development
Populations can be sustained at low host levels
Narrow host range
Disadvantage:
Only the female is searching for prey
the best searchers tend to lay the fewest eggs
Lack of life-cycle synchronization leads to complete failure of control
