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Flashcards in PLANT DISORDERS Deck (25):
1

DESCRIBE 3 EFFECTS OF PROLONGED DROUGHT ON A CROP

1. reduction in foliage size
2. dry, brown , crisp leaves
3. reduction in crop yield and new growth
4. increased susceptibility to pests and diseases
5. early bolting (e.g. lettuce) and excessive flowering.
6. wilting of the plant from the top down

2

LIST 4 PHYSIOLOGICAL DISORDERS AFFECTING PLANT GROWTH

1. nutrient deficiency and toxicity
2. wind or frost damage
3. water-logging
4. high or low temperatures
5. high or low light levels
6. bolting
7. blindness
8. drought

3

DEFINE PHYSIOLOGICL DISORDER IN PLANTS

A problem or physical damage caused by growing conditions ( environmental or abiotic factors) of a plant rather than pest or disease.
any non living detrimental effect on a plant not caused directly by pest or disease

4

DESCRIBE 3 SYMPTOMS OF A PLANT GROWN IN CONDITIONS THAT ARE TOO SHADY

1. growth will be etiolated
2. growth is toward light
3. thin stems and small, yellow leaves
4. plants fail to flower/fruit or only produce few flowers/fruits
5. variegated foliage tends to revert to greener form

5

NAME THE SYMPTOMS AND AVOIDANCE METHODS OF WATERLOGGING

waterlogging
symptoms
- wilting
- yellow or brown leaves
- brown and rotting roots
- stunted plant growth
- plant death
- fungal infection
avoidance methods
-avoid compaction of wet soil
-improve drainage and structure with organic matter and grit
-use raised beds
-spike lawns and add sand

6

NAME THE SYMPTOMS AND AVOIDANCE METHODS OF WIND DAMAGE

wind damage
symptoms
- scorched leaves around edges
- torn leaves
- blossoms blown off
- stems damaged
avoidance
-provide protection with natural or artificial windbreak or hedge

7

NAME THE SYMPTOMS AND AVOIDANCE METHODS OF FROST DAMAGE

frost damage
symptoms
-affects exposed parts of plants
-leaf scorch: turning brown and spotted between veins
-blossoms turn brown and drop off
- stems of tender plants turn black and collapse
- bark split
-root heave
avoidance
-select hardy plants
-select suitable planting position, e.g. against warm wall
-cover plants with horticultural fleece
- harden off seedlings

8

EXPLAIN LIME INDUCED CHLOROSIS

iron deficiency in acid loving plants grown in calcareous (alkaline) soils leading to yellowing of the leaves ( iron needed in synthesis of chlorophyll)

9

NAME 2 DEFICIENCIES WHICH OCCUR IN ACID SOIL

1. magnesium which is leached out
2. calcium in non calcifuge plants
3. phosphorus
4. molybdenum

10

STATE HOW PLANT GROWTH IS AFFECTED BY ROSE BALLING

- bud becomes soft and slimy to touch
- outer petals harden and encase the bud which cannot open
- bud may drop off
- becomes susceptible to grey mould

11

STATE HOW PLANT GROWTH IS AFFECTED BY FASCIATION

- stems become flattened and elongated
-stems appear to consist of several fused shoots
- flower heads become flattened and misshapen and develop numerous flower heads
- susceptible plants: Digitalis, Veronicastrum, Euphorbia, Forsythia

12

NAME 3 CAUSES OF FASCIATION

1. random genetic mutation
2. physical damage to plant at tip
3. viral or bacterial infection

13

DESCRIBE METHODS OF CONTROLLING HIGH TEMPERATURE DAMAGE

1. Use shading under glass by installing blinds or paint wash
2. Increase the humidity by damping down the floor in a greenhouse

14

DESCRIBE LIME INDUCED CHLOROSIS

1. yellowing of the leaves
2. interveinal chlorosis
(due to reduced iron absorption in alkaline soil leading to lack of chlorophyll)

15

DESCRIBE 2 METHODS OF AVOIDING LIME INDUCED CHLOROSIS

1. lower the pH of the soil by the use of acidic ameliorants e.g. sequestered iron that makes iron more freely available to plants
2. avoid irrigating containerised plants with alkaline/hard water
3. avoiding the excess use of fertilisers high in phosphates.

16

DESCRIBE 2 EFFECTS OF HIGH TEMPERATURE DAMAGE TO PLANTS

1. sun scald on susceptible stems, foliage, flowers and fruit
2. greenback on tomatoes
3. heat damage to surface roots or exposed plants
4. strangles on exposed root vegetables.
(note high temperature damage not the same as drought)

17

NAME 2 PLANTS SUITABLE FOR ACID SOIL

1. Camellia japonica
2. Pieris japonica
3. Rhododendrum hirsuta

18

NAME 2 PLANTS SUITABLE FOR WATERLOGGED SOIL

1. Caltha palustris
2. Myrica gale
3. Houttyunia cordata
4. Cornus alba
5. Hydrangea paniculata
6. Hosta

19

NAME 2 SHADE TOLERANT PLANTS

1. Viburnum davidii
2. Alchemilla mollis
3. Anemone x hybrida 'Honorine Jobert'
4. Hedera helix
5. Hosta sieboldii
6. Fatsia japonica
7. Viburnum tinus 'Eve Price'

20

NAME 2 DROUGHT TOLERANT PLANTS

1. Lavandula angustifolia
2. Ceanothus
3. Buxus sempervirens
4. Hylotelephium spectabile

21

NAME 2 METHODS OF AVOIDING ROSE BALLING

1. use resistant cultivars
2. avoid overhead watering
3. improve air circulation by pruning

22

STATE 2 EFFECTS OF LOW TEMPERATURE ON PLANT GROWTH

1. seeds fail to germinate
2. poor growth and flowering
3. poor pollination
4. poor yield of fruit

23

DESCRIBE THE EFFECTS OF SOIL pH ON GARDEN PLANTS


1. pH levels affect the uptake of nutrients
2. Most nutrients are available at a pH of 6.5
3. Iron may be unavailable to acid loving plants if grown in an alkaline soil
4. Iron is required for the manufacture of chlorophyll. A loss of chlorophyll will reduce the rate of photosynthesis and can cause lime-induced chlorosis
5. Soil fauna e.g. earthworms and microbial activity is reduced in acid soils which can affect plants as soil aeration is reduced
6. The colour of Hydrangea flowers are affected by soil pH

24

STATE ONE METHOD OF MAKING ACID SOIL MORE ALKALINE
AND ONE METHOD OF MAKING ALKALINE SOIL MORE ACID

1 Making acid soil more alkaline:
- add ground limestone (calcium carbonate)
-use mushroom compost

2. making alkaline soil more acidic
- add sulphur( which is converted to sulphuric acid by soil organisms)
- apply farm yard manure
- use pine needles as mulch

25

DESCRIBE HOW PLANTS ARE AFFECTED BY GROWING IN INAPPROPRIATE SOIL pH

- the solubility of minerals is dependant on soil pH
- in acid soils ( pH 4-5) aluminium, iron and manganese solubility can lead to toxicity
- in alkaline soils solubility of minerals eg iron, manganese and zinc is restricted leading to deficiencies
- iron deficiency leads to interveinal chlorosis