PLANT DISEASES Flashcards Preview

RHS R2103 > PLANT DISEASES > Flashcards

Flashcards in PLANT DISEASES Deck (38):
1

DESCRIBE THE LIFE CYCLE OF CLUBROOT

1. the resting spores can persist in the soil for 20 years
2. spores germinate after chemical stimulation from the host plant i.e. brassicas
3. mobile zoospores are released which invade the roots via the root hairs
4. roots swell and become distorted
5. resting spores are formed and released into soil as swellings decay

2

DESCRIBE 2 METHODS OF MINIMISING THE EFFECTS OF CLUBROOT

1. ensure soil is removed from boots, tools and tractor wheels
2. increase soil pH by adding lime as clubroot thrives in acid soil
3. avoid planting contaminated seedlings
4. control weeds especially those of the brassica family that act as an alternate host
5. sow resistant varieties

3

NAME 2 PLANTS SUSCEPTIBLE TO INFECTION BY CLUBROOT

1. Brussel sprouts 'Crispis'
2. Cabbage 'Hispi'
3. Capsella bursa-pastoris

4

NAME THE SYMPTOMS OF POTATO BLIGHT ON A NAMED CROP

Named crop: Solanum tuberosum (potato)
Effects:
1. leaves develop dark brown blotches and collapse into rotting mass
2. white fungal growth develops on underside of leaves
3. tubers become reddish brown below skin
4. brown lesions develop on the stems

5

NAME 2 METHODS OF CONTROLLING THE EFFECT OF BLIGHT ON POTATOES

1. use resistant cultivars eg Solanum tuberosum 'Estima'
2. burn any affected material
3. earth up potatoes to prevent spores on soil infecting the tubers
4. implement 4 year crop rotation
5. purchase certified disease free tubers
6. an approved preventative spray can be applied before an attack is detected
7. grow early cultivars

6

DEFINE THE TERM PLANT DISEASE

Damage caused by a viral, fungal or bacterial organism to a plant

7

STATE 2 SYMPTOMS OF GREY MOULD FUNGUS (BOTRYTIS CINERA)

1. fuzzy grey mould on leaves, stems, buds and flowers which may shrivel and die
2. infection of fruit leads to soft brown rotting

8

STATE 2 METHODS TO REDUCE THE EFFECT OF GREY MOULD

1. avoid overcrowding
2. avoid cool, damp conditions
3. remove infected material and dispose of by burning or bringing to municipal composting

9

NAME 4 WAYS CLUB ROOT CAN SPREAD IN A GARDEN

1. infected soil on clothing and equipment
2. importing contaminated plants
3. growing plants in acid, poorly drained soil which favours spread of club root
4. leaving infected material in the ground
5. allowing alternate host weeds to grow

10

STATE DAMAGE CAUSED BY BACTERIAL CANKER ON PRUNUS

1. bacterial canker causes shallow dark depressions on bark of stems and branches
2. brown/black lesions on leaves that die to leave shot hole defects
3. smaller branches become girdled and die back
4. blossom may appear brown and wilted

11

IDENTIFY 4 SYMPTOMS OF HOLLYHOCK RUST

1. hollyhock rust causes orange/brown pustules on stems, bracts and undersides of leaves
2. causes yellow/orange areas on upper sides of leaves
3. pustules turn grey as airborne spores are produced in humid conditions
4. leaves shrivel and fall, staring on lower leaves
5. plants are stunted

12

STATE DAMAGE CAUSED BY ROSE BLACKSPOT

1. blackspot causes purple or black patches on upper sides of leaves
2. yellow discolouration occurs on leaves around the black patches and leaves may drop prematurely

13

NAME 2 TYPES OF DAMAGE CAUSED BY HONEY FUNGUS

1. plants fail to flower or flower profusely just before dying
2. leaves on some branches are smaller and paler than normal
3. deciduous plants display autumn colour prematurely
4. the bark at the base of the stem cracks and bleeds
5. dead and decaying roots with white fungus between bark and wood

14

NAME 2 METHODS OF CONTROL OF HONEY FUNGUS

1. excavate and destroy any infected material by burning
2. place a physical barrier vertically in soil around plant to a depth of 45 cm to prevent rhizomorphs spreading
3. plant resistant species e.g. Ginkgo biloba, Laurus nobilis, Pittosporum, Berberis

15

NAME 4 PLANTS SUSCEPTIBLE TO HONEY FUNGUS

1. Viburnum tinus
2. Betula spp
3. Buddleja davidii
4. Magnolia spp

16

NAME 2 METHODS OF CONTROL OF FIREBLIGHT

1. prune out and burn infected material promptly
2. clean equipment with Jeyes fluid
3. remove Crataegus hedges to stop bees transmitting disease
4. remove secondary blossom (bacterium gains entry to bark via blossom and infection more likely in warmer weather)

17

NAME 2 METHODS TO CONTROL DAMPING OFF DISEASE

1. use sterile growing media and containers
2. sow thinly to avoid overcrowding and maintain ventilation
3. use mains water to irrigate as water butts can harbour infected debris

18

DESCRIBE THE DAMAGE CAUSED BY APPLE AND PEAR CANKER

1. New cankers form from spring onwards with dead, sunken bark.
2. The infection may girdle the stems of younger branches, killing them completely and causing the branches to break off.
3. On older branches concentric rings of damaged bark can be seen.
4. Bark may be shed from trees exposing dead wood beneath and the raised edges of callus can be seen in advanced infections as trees attempt to repair the damage.
5. Developing fruit can be infected causing them to rot and drop.

19

NAME 2 METHODS TO CONTROL THE EFFECTS OF APPLE AND PEAR CANKER

 Prune out all affected branches and spurs back to fresh green tissue.
 Keep pruning tools clean to reduce the chance of cross infection.
 Ensure that the soil is not acidic as this can encourage the disease.

20

NAME 2 DISEASES MORE PRONE TO OCCUR IN ACID SOIL

1. Apple and pear canker
2. Clubroot

21

DESCRIBE 2 EXAMPLES OF DAMAGE CAUSED BY
STRAWBERRY POWDERY MILDEW

Strawberry powdery mildew causes
1. purple/yellow or reddish coloration of foliage and early leaf drop
2. leaves and fruit covered in powdery white fungus
3. withering and dieback of the plant in extreme cases

22

DESCRIBE 2 METHODS OF CONTROL OF STRAWBERRY POWDERY MILDEW

1. grow resistant cultivars
2. remove and destroy of infected crop waste
3. avoid overhead watering
4. avoid water stress
5. chemicals e.g. myclobutanil prior to the onset of disease

23

DESCRIBE 2 MEANS BY WHICH VIRUSES CAN SPREAD IN A HORTICULTURAL SITUATION

1. sap sucking insect vectors e.g. aphids moving between plants
2. the use of infected plant material when propagating
3. the use of contaminated tools e.g. secateurs

24

DESCRIBE 2 METHODS OF CONTROL OF BACTERIAL CANKER

1. Pruning back infected wood to healthy wood, paint the wound and burn the prunings
2. Pruning should take place in the summer and all pruning tools should be sterilised after use

25

NAME 3 SYMPTOMS OF TOBACCO MOSAIC VIRUS ON A NAMED PLANT

Affected plant : Tomato (Solanum lycopersicum)
1. youngest leaves develop yellow mottling
2.leaves develop blister like lesions, crinkled edges and fern like appearance
3. blossoms become discoloured
4. fruit growth is stunted and fruits are misshapen and blemished

26

NAME 2 METHODS OF CONTROL OF SPREAD OF TOBACCO MOSAIC VIRUS

1. remove the infected plant and dispose of
2. do not put diseased material on compost heap or near other tomato plants
3. avoid all contact with tobacco which harbours the virus
4. ensure hands and equipment are clean

27

NAME 2 VIRUSES THAT CAN AFFECT CROPS

1. Tobacco mosaic virus
2. Potato leaf curl virus

28

NAME 2 BACTERIAL DISEASES OF CROPS

1. Bacterial canker (Prunus spp eg Prunus domestica'Victoria')
2. Fireblight ( Malus domestica and Sorbus spp)

29

NAME 3 FUNGAL DISEASES THAT CAN AFFECT CROPS

1. Strawberry powdery mildew
2. Damping off diseases
3. Honey fungus
4. Rose black spot
5. Hollyhock rust
6. Apple and pear canker

30

NAME 4 SYMPTOMS OF FIREBLIGHT

1. Presence of cankers on branches
2. White, slimy exudation
3. Wood stained red/brown under the bark
4. Burnt appearance of parts of the plant
5. Blossoms wilt and die

31

NAME 2 WAYS FIREBLIGHT IS SPREAD

1. Bees infecting the blossom
2. Insects infecting new shoots
3. Rain splash or wind-blown rain
4. Contaminated tools

32

NAME 2 METHODS OF CONTROL OF FIREBLIGHT

1. Prune back diseased wood to healthy wood and burn the infected material immediately
2. Clean pruning tools between cuts when pruning infected plants
3. Do not use Crataegus monogyna as hedging material
4. Remove secondary blossom

33

DESCRIBE 2 CULTURAL METHODS OF CONTROLLING HOLLYHOCK RUST

1. avoid dense planting and high humidity
2. discard or cut down to soil level after flowering and dispose of leaf material
3. monitor bought in plants carefully
4. do not use seed from affected plants

34

DESCRIBE 2 SYMPTOMS AND 2 CONTROL MEASURES FOR CLUBROOT

Symptoms:
1. stunted growth
2. purplish, wilting foliage
3. swollen roots with loss of finer roots

Control:
1. ensure soil is removed from boots, tools and tractor wheels
2. increase soil pH by adding lime as clubroot thrives in acid soil
3. avoid planting contaminated seedlings
4. control weeds especially those of the brassica family that act as an alternate host
5. sow resistant varieties

35

DESCRIBE 2 SYMPTOMS AND 2 CONTROL MEASURES FOR HONEY FUNGUS

Symptoms:
1. plants fail to flower or flower profusely just before dying
2. leaves on some branches are smaller and paler than normal
3. deciduous plants display autumn colour prematurely
4. the bark at the base of the stem cracks and bleeds
5. dead and decaying roots with white fungus between bark and wood

Control:
1. excavate and destroy any infected material by burning
2. place a physical barrier vertically in soil around plant to a depth of 45 cm to prevent rhizomorphs spreading

36

NAME 2 PLANTS SUSCEPTIBLE TO GREY MOULD

1. strawberry (Fragaria x ananassa)
2. apple (Malus)
3. cucumber (Cucumis sativus)
4. Primula

37

NAME 2 METHODS TO CONTROL GREY MOULD FUNGUS

1. maintain good hygiene
2. remove any dead plant material
3. reduce humidity by increasing ventilation and avoiding overcrowding

38

NAME 2 SYMPTOMS OF DAMPING OFF DISEASES

1. seedlings may fail to emerge
2. seedlings collapse in a mass of whitish fungal growth