Biological Control

Question 1

What is biological control?

Answer 1

The use of natural enemies to reduce damage

Question 2

Give examples of natural predators

Answer 2

ladybirds and their larvae
Nematodes
Lacewings, birds, slow worms, hedgehogs, badgers, toads, frogs, lizards, spiders, centipede, aphid midge, pirate bugs

Question 3

What are the benefits of biological control?

Answer 3

non-toxic to humans and wildlife

Question 4

What are the limitations of biological control?

Answer 4

Careful introduction needed

Knowledge of life cycles needed

Question 5

What are the main problems in biological control?

Answer 5

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

Question 6

give an example of a predator in a glasshouse

Answer 6

Encarsia wasp

Question 7

What does the Encarsia Wasp prey on?

Answer 7

glasshouse whitefly

Question 8

How do you minimize risks in biological control?

Answer 8

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

Question 9

what kind of worm reduced earthworm numbers in New Zealand in the 1960’s?

Answer 9

Flatworm

Question 10

How do you maintain a natural balance in the garden?

Answer 10

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

Question 11

Why shouldn’t you remove rotted/hollow stems and branches from the garden?

Answer 11

they are sheltering sites for parasitic wasps/ predatory beetles and centipedes

Question 12

Why should you pay attention to soil structure? (think of the minibeasts)

Answer 12

full of rotted om so centipedes can locate underground soil pests

Question 13

why should you pay attention to soil pH and nutrient levels?

Answer 13

poorer soil and acidic levels lead to a decline in microbial activity

Question 14

Why is crop rotation important for garden hygiene?

Answer 14

planting the same crop in the same place can encourage soil borne pests and diseases

Question 15

Give an example of a repeat planting disease

Answer 15

club root on brassicas
potato cyst nematode-on potatoes

Planting a young rose where an old specimen was can lead to “re-plant” disease

Question 16

What is a problem with using pesticides?

Answer 16

There can be a build up, and resistance may occur the following year

Question 17

Name some indigenous predators and parasites

Answer 17

birds (blue tits)
hedgehogs
frogs and toads

Question 18

what do blue tits eat?

Answer 18

a pair can consume 10,000 caterpillars and 1million aphids in a year

Also eat scale insects.

Question 19

What do hedgehogs, frogs and toads eat?

Answer 19

beetles, slugs, earthworms, caterpillars.

slugs and ground living insects

Question 20

What do Lacewings eat

Answer 20

their hairy larvae eat aphids and mites

Question 21

What advantages do Lacewings have over Ladybirds?

Answer 21

they can reach prey in folds of leaves

Question 22

Where are Lacewings used commercially?

Answer 22

Greenhouses

Question 23

Where do Hoverflies lay their eggs?

Answer 23

In the centre of aphid colonies, so their larva eat them

Question 24

Which plant encourages hoverflies?

Answer 24

Limnanthes douglasii (Poached egg plant)

They are attracted to the pollen so it encourages more activity in the garden