Plant disorders Flashcards
What is meant by the term plant disorder?
Physiological disorders
Disorders not caused by pests or disease but by some problem in the environment in which the plant is being grown.
How are plants affected by frost
Frost causes cells to freeze, contents expand, cell ruptures and is killed. Plants blacken and die. This happens to non hardy plants as a matter of course.
Damaging to young shoots and tips and buds reducing production of flowers and fruit.
State one method of avoiding frost damage
Provide protection such as straw, fleece,cloches etc or bring tender plants under cover.
Describe how plants are adversely affected by shade.
Etiolation with long weak stems, small sparse leaves, pale yellow.
How to avoid problems associated with shade
Grow plants that are suitable for the position they are going to occupy.
Describe how plant growth is adversely affected by drought.
Foliage will start to wilt and turn brown. Then they may fall and plant eventually die.
Some run to seed.
Fruit will fail to set
Date how to avoid problems from drought.
Mulch
Water regularly
Increase water holding capacity of soil (long term)
Describe how plant growth is adversely affected by water-logging.
Leaves turn yellow and wilt
Growth stunted
Roots rot
State one method of lessening the affect of water-logging on plants
Improve the structure of the soil.
Drainage
Describe how plant growth is adversely affected by high/low temperature damage
Low temperatures tend to cause slow growth
High temperatures scorch leaves and drought may be caused
How to avoid damage from high/low temperatures?
Mostly a problem in greenhouses. Shade from strong sunlight.
Describe how plant growth is adversely affected by soil pH including lime induced chlorosis(iron deficiency/too alkaline)
Roots unable to absorb a balance of nutrients
Iron is not available to the plant (needed to produce chlorophyll) so leaves turn yellow or brown in margins and between veins.
Poor quality fruit and quantity
Describe how plant growth is adversely affected by fasciation.
Apical meristem becomes flattened and elongated and has appearance of many shoots together.
Can be caused by aphids or mechanical means.
Not necessarily fatal.
State new method of avoiding or dealing with fasciation.
Cut out the damaged part of plant.
Describe how plant growth is adversely affected by rose balling.
Outer petals of rose bud die and become stiff so inner petals cannot emerge. Buds go brown and drop off or can become covered in grey mould.
