Biological Control Flashcards
What is biological control?
The use of natural enemies to reduce damage
Give examples of natural predators
ladybirds and their larvae
Nematodes
Lacewings, birds, slow worms, hedgehogs, badgers, toads, frogs, lizards, spiders, centipede, aphid midge, pirate bugs
What are the benefits of biological control?
non-toxic to humans and wildlife
What are the limitations of biological control?
Careful introduction needed
Knowledge of life cycles needed
What are the main problems in biological control?
if you don’t apply correctly, you can end up with a severe pest problem
Incorrect introduction can kill off the organisms you want to keep
give an example of a predator in a glasshouse
Encarsia wasp
What does the Encarsia Wasp prey on?
glasshouse whitefly
How do you minimize risks in biological control?
understand the life cycles of the pests and predators to achieve reliable control.
Chose the most suitable predator or parasite for the pest or disease
Make sure the animal your using isn’t susceptible to attack from other predators you’re using
what kind of worm reduced earthworm numbers in New Zealand in the 1960’s?
Flatworm
How do you maintain a natural balance in the garden?
Don’t remove rotting/hollow stems of herbaceous perennials or branches of decaying wood.
Ensure good soil structure
Pay attention to soil pH
Crop rotation
Why shouldn’t you remove rotted/hollow stems and branches from the garden?
they are sheltering sites for parasitic wasps/ predatory beetles and centipedes
Why should you pay attention to soil structure? (think of the minibeasts)
full of rotted om so centipedes can locate underground soil pests
why should you pay attention to soil pH and nutrient levels?
poorer soil and acidic levels lead to a decline in microbial activity
Why is crop rotation important for garden hygiene?
planting the same crop in the same place can encourage soil borne pests and diseases
Give an example of a repeat planting disease
club root on brassicas
potato cyst nematode-on potatoes
Planting a young rose where an old specimen was can lead to “re-plant” disease
What is a problem with using pesticides?
There can be a build up, and resistance may occur the following year
Name some indigenous predators and parasites
birds (blue tits)
hedgehogs
frogs and toads
what do blue tits eat?
a pair can consume 10,000 caterpillars and 1million aphids in a year
Also eat scale insects.
What do hedgehogs, frogs and toads eat?
beetles, slugs, earthworms, caterpillars.
slugs and ground living insects
What do Lacewings eat
their hairy larvae eat aphids and mites
What advantages do Lacewings have over Ladybirds?
they can reach prey in folds of leaves
Where are Lacewings used commercially?
Greenhouses
Where do Hoverflies lay their eggs?
In the centre of aphid colonies, so their larva eat them
Which plant encourages hoverflies?
Limnanthes douglasii (Poached egg plant)
They are attracted to the pollen so it encourages more activity in the garden
