R2103 1.1 Explain what is meant by physical, cultural, chemical or biological control

Question 1

Two benefits of physical control

Answer 1

1. Most methods once established remain for a long time e.g. fences, netting
2. Usually need little maintenance e.g. plastic sheets

Question 2

Benefits of cultural control

two required

Answer 2

1. Generally environmentally friendly and free
2. Can fit in with daily routines e.g. regular feeding of plants
3. Long lasting effects e.g. removal of alternate host weed species such as sheppards purse

Question 3

Two benefits of chemical control

Answer 3

1. Produces rapid control
2. Products are easily accessible
3. Can target specific pests

Question 4

Two benefits of biological control

Answer 4

1. non-toxic to humans, wildlife and pets
2. Number of predators and parasites increase naturally
3. No build up of resistant pests and diseases
4. A balance population of predators and parasites is reached

Question 5

Limitations of physical control

Two required

Answer 5

1. Barriers and traps and harm other species not just those designed to control
2. Fleece, mesh, netting needs to be in place before damage occurs
3. Fleece, mesh, netting can be expensive
4. Fleece, mesh, netting can be non-biodegradable
5. Physical controls can be labour intensive
6. Squishing / picking off only occurs in your presence
7. Netting can trap wildlife like hedgehogs
8. Yellow sticky traps could also trap beneficial insects e.g. pollinators

Question 6

Limitations of cultural control

2 required

Answer 6

1. May be time consuming
2. May lack rapid action as seen with pesticides
3. More knowledge, planning and research required
4. Selecting plants for disease resistance reduces choices of cultivars
5. Quarantining plants keeps then in pots for longer

Question 7

Two limitations of chemical control

Answer 7

1. Products can be dangerous to humans, animals and plants
2. Products can cause resistant strains of pests, diseases and weeds to develop
3. Contimination of streams and dams
4. Damage to cultivated and wild plants, especially by herbicides
5. Can be expensive
6. Chemical residues can persist on food crops

Question 8

Two limitations of biological control

Answer 8

1. Needs careful introduction and knowledge of life cycles
2. Can be easily affected by pesticides

Question 9

Examples of physical control

Answer 9

1. Plastic sheet - weed supressing
2. Fleece - prevent entry of pests
3. Fences - deter rabbits and deer
4. Beer traps for slugs
5. Rodent traps
6. Copper tape for slugs
7. Sacrificial crops - e.g. row of lettuce between two rows of tomatoes
8. Deterents - onions planted between carrots to deter carrot fly
9. Sticky traps - yellow colour attracts many pests such as white fly
10. Squishing / picking off pest e.g. lily beetles

Question 10

Example of cultural control

Answer 10

1. Crop rotation
2. Using resistant plant varieties
3. Good management and work practices
4. Quarantining new plants to prevent the introduction of pests and disease

Question 11

Example of chemical control

Answer 11

Botantical - Pyrethroids
Based on pyrethrum
Rapid paralysing action but relatively safe
Breaks down easily - storage problems

Question 12

Example of biological control

Answer 12

1. Indigenous e.g. Blue tits eating catapillars
2. Exotic e.g. Wasp Encarsia formosa lays eggs in glasshouse whitefly

Question 13

Minimise risks to people and environment: physical control

Answer 13

Ensure safe removal of infected trees
Ensure safe burning of infected plant material
Ensure all equipment is used correctly

Question 14

Minimise risks to people and environment: cultural control

Answer 14

Check material does not contain pests or diseases

Question 15

Minimise risks to people and environment: chemical control

Answer 15

1. Only use when properly justified
2. Choose least harmful chemical to control organism
3. Read instructions on label
4. Wear correct clothing
5. Apply under dry, wind free conditions
6. Carefully store in secure, safe, dry place away from children and pets

Question 16

Minimise risks to people and environment: biological control

Answer 16

1. Unsuccessful appliation of biological control organisms can lead to a severe pest problem
2. Incorrect introduction of a biological control can kill desirable organisms
3. Choose best predator or parasite for the problem pest of disease concerned
4. Understand both the pests and predator / parasites life cycles in order to achieve reliable control

Question 17

What is physical control?

Answer 17

Physical or mechanical control methods involve using barriers, traps or physical removal to prevent or reduce pest and disease problems

Question 18

What is cultural control?

Answer 18

Is a procedure or manipulation (sound husbandry) of the growing environment, that results in weed, pest or disease control.

Question 19

Crop rotation

cultural control

Answer 19

1. Makes sure the same crop is not planted in the same place every year
2. Breaks the life cycle of pests and diseases. Prevents numbers increasing, especially if they are able to overwinter in the soil
3. Group similar crops together - Leaf crops > Root crops > Legume/other(potato here)
4. Good for soil - avoids nutrient shortages. Legumes provide nitrogen in the soil which is needed by leaf crops
5. Not so good against pests and diseases which are unspecific
6. Pests examples - potato cyst nematode, club root in brassicas
7. Benefical change in fungal and bacterial population in the soil

Question 20

Disease resistant plants

Cultural control

Answer 20

1. Resistance can occur naturally and scientists can use these in a breeding program.
2. Disease can mutate so resistance may not last
3. Informed planting - ‘right plant, right place’
4. Cornus alba - better in water logged winter soil than a Mediterranean species

Question 21

Methods of good management and work practice

Cultural control

Answer 21

1. Keep tools and containers clean so infections cannot spread
2. Cut out infected material and burn or take to rubbish dump
3. Prevent injury to plants by making pruning cuts clean and providing wind breaks
4. Good ventilation is important. Reduces spread of diseases
5. Keep greenhouse humidity and temperatures at suitable levels so fungal infections don’t develop
6. Make sure soil is well-drained to help stop the growth of soil borne plant disease that attack plant roots
7. Hoeing also brings pests to surface to dry out or be eaten by birds
8. Covering and regular clearing of water tanks to prevent breeding of fungi

Question 22

Quarantining plants

Answer 22

1. New material should be kept seperate from other plants
2. Even plants can occasionally harbour pests

Question 23

Types of chemical controls? (8)

Answer 23

Usually called ‘pesticides’ and include:
1. Weedkillers (herbicides)
2. Slug pellets(molluscicides)
3. Fungicide sprays
4. Animal repellents
5. Hormone rooting powders
6. Insecticides
7. Plant growth regulators
8. Lawn sand treatment

Question 24

Main classes of pesticides (3)

Answer 24

1. Plant derived pesticides (botanicals) e.g. Pyrethroids, rotenoids, nicotinoids
2. Inorganic (synthetic insecticides) only maybe those based on bifenthrin for amateur use.
3. Insecticidal soaps and fatty acids. Widely used where biological controls are used. generally less toxic to humans and short lived on the environment.

Question 25

Deciding on pestcide to use (3)

Answer 25

1. The type of plant that needs controlling
2. The type and value of the crop
3. The presence of any benefical insects

Question 26

Four main types of pesticide action

Answer 26

1. Contact - sprayed onto pests and absorbed.
2. Stomach - e.g. slug bait
3. Systemic poisons - sprayed on plants and absorbed by tissues. Pests eat the plant and absorb poison.
4. Suffocation - oils block the breathing pores

Question 27

Fungicides

Answer 27

1. Either kill fungal spores or prevent them from germinating
2. Regular use can cause resistance

Question 28

Controlling risks of applying chemical control (6)

Answer 28

1. Only use when properly justified
2. Choose least harmful chemical to control organism
3. Read instructions on label
4. Wear correct clothing
5. Apply under dry, wind free conditions
6. Carefully store in secure, safe, dry place away from children and pets

Question 29

What is biological control

Answer 29

use of natural enemies to reduce damage caused by pest or disease

Question 30

What is chemical control

Answer 30

Use of a chemical substance intended to prevent or kill a destructive weed, pest or disease