PLANT DISORDERS Flashcards
DESCRIBE 3 EFFECTS OF PROLONGED DROUGHT ON A CROP
- reduction in foliage size
- dry, brown , crisp leaves
- reduction in crop yield and new growth
- increased susceptibility to pests and diseases
- early bolting (e.g. lettuce) and excessive flowering.
- wilting of the plant from the top down
LIST 4 PHYSIOLOGICAL DISORDERS AFFECTING PLANT GROWTH
- nutrient deficiency and toxicity
- wind or frost damage
- water-logging
- high or low temperatures
- high or low light levels
- bolting
- blindness
- drought
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
DESCRIBE 3 SYMPTOMS OF A PLANT GROWN IN CONDITIONS THAT ARE TOO SHADY
- growth will be etiolated
- growth is toward light
- thin stems and small, yellow leaves
- plants fail to flower/fruit or only produce few flowers/fruits
- variegated foliage tends to revert to greener form
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
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
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
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)
NAME 2 DEFICIENCIES WHICH OCCUR IN ACID SOIL
- magnesium which is leached out
- calcium in non calcifuge plants
- phosphorus
- molybdenum
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
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
NAME 3 CAUSES OF FASCIATION
- random genetic mutation
- physical damage to plant at tip
- viral or bacterial infection
DESCRIBE METHODS OF CONTROLLING HIGH TEMPERATURE DAMAGE
- Use shading under glass by installing blinds or paint wash
- Increase the humidity by damping down the floor in a greenhouse
DESCRIBE LIME INDUCED CHLOROSIS
- yellowing of the leaves
- interveinal chlorosis
(due to reduced iron absorption in alkaline soil leading to lack of chlorophyll)
DESCRIBE 2 METHODS OF AVOIDING LIME INDUCED CHLOROSIS
- lower the pH of the soil by the use of acidic ameliorants e.g. sequestered iron that makes iron more freely available to plants
- avoid irrigating containerised plants with alkaline/hard water
- avoiding the excess use of fertilisers high in phosphates.
DESCRIBE 2 EFFECTS OF HIGH TEMPERATURE DAMAGE TO PLANTS
- sun scald on susceptible stems, foliage, flowers and fruit
- greenback on tomatoes
- heat damage to surface roots or exposed plants
- strangles on exposed root vegetables.
(note high temperature damage not the same as drought)
NAME 2 PLANTS SUITABLE FOR ACID SOIL
- Camellia japonica
- Pieris japonica
- Rhododendrum hirsuta
NAME 2 PLANTS SUITABLE FOR WATERLOGGED SOIL
- Caltha palustris
- Myrica gale
- Houttyunia cordata
- Cornus alba
- Hydrangea paniculata
- Hosta
NAME 2 SHADE TOLERANT PLANTS
- Viburnum davidii
- Alchemilla mollis
- Anemone x hybrida ‘Honorine Jobert’
- Hedera helix
- Hosta sieboldii
- Fatsia japonica
- Viburnum tinus ‘Eve Price’
NAME 2 DROUGHT TOLERANT PLANTS
- Lavandula angustifolia
- Ceanothus
- Buxus sempervirens
- Hylotelephium spectabile
NAME 2 METHODS OF AVOIDING ROSE BALLING
- use resistant cultivars
- avoid overhead watering
- improve air circulation by pruning
STATE 2 EFFECTS OF LOW TEMPERATURE ON PLANT GROWTH
- seeds fail to germinate
- poor growth and flowering
- poor pollination
- poor yield of fruit
DESCRIBE THE EFFECTS OF SOIL pH ON GARDEN PLANTS
- pH levels affect the uptake of nutrients
- Most nutrients are available at a pH of 6.5
- Iron may be unavailable to acid loving plants if grown in an alkaline soil
- Iron is required for the manufacture of chlorophyll. A loss of chlorophyll will reduce the rate of photosynthesis and can cause lime-induced chlorosis
- Soil fauna e.g. earthworms and microbial activity is reduced in acid soils which can affect plants as soil aeration is reduced
- The colour of Hydrangea flowers are affected by soil pH
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
- 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
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
