W12: Biocontrol (Classical Biocontrol Introduction) [Dr. Nic] Flashcards
Types of biocontrol? BC^3(4)
- Bioherbicides/Biopesticides.
- Conservation biological control.
- Competitor-based biological control.
- Classical biological control.
Bioherbicides?
= weed control products that are derived from living organism, including any natural products they produce during their growth, that suppress weed population.
Pros of Bioherbicides? (8)
- Low development cost.
- Low cost of regulatory approval.
- Good public acceptance.
- No chemical residue.
- Narrow host range.
- Approved for organic farming.
- No evolved restriction yet.
- Low mammalian & ecotoxicity.
Cons of Bioherbicides? (9)
- Narrow host range.
- Short shelf life.
- Special storage conditions.
- Quality control issues.
- Relatively expensive.
- Slower than chemical herbicides.
- Required microenvironment for infectivity.
- Special formulation & application technology.
- Efficacy is poorer than chemical herbicides.
Pros of Biopesticides? (4)
- Potent insecticidal activity.
- Specific host range.
- Harmless to humans & other mammals.
- Biodegradable.
Cons of Biopesticides? (4)
- Susceptible to proteases in leaf exudates.
- Needs to be reapplied for full effect.
- Easily removed from plant surface by wind & rain.
- Rapidly inactivated by UV light, heat & extreme pH.
Conservation biological control?
= pest management strategy that focuses on enhancing & preserving the natural enemies of pests, such as parasitoids, predators & pathogens.
Eg of Conservation biological control?
Cultivating flowering plants along field edges to attract & sustain natural enemies like ladybugs which prey on aphids.
Competitor-based biological control?
= pest management strategy that involves using competitive relationships among organisms to suppress pest populations.
Eg of Competitive-based biological control?
Certain nematodes can outcompete harmful nematode species in the soil that damage crops.
Classical biological control attributes? (3)
- Based on the premise of ERH.
- Reunite the invasive organism with its natural enemy.
- Host-specific natural enemies to bring about the long-term/sustainable control of a target weed.
Biocontrol Graph?
Explain Eg of Classical biological control? (2)
- Redwater fern was introduced to Colesburg in 1980 and rapidly spread through humans and other means (faeces).
- Weevil introduced fed on red water fern to kill it (host-specific).
Biological control of alien invasive weeds?
= the use of host-specific natural enemies to bring about the long-term/sustainable control of the target plant.
Impacts of invasive Prosopis trees on native species? (2)
- Invasive Prosopis trees caused a decline in native tree density.
- Poor households relying on ecosystem services are most negatively impacted by weeds.
