Plant disease Flashcards
what could plant pathogens do?
kill or reduce the growth of many plants, which in turn can reduce biodiversity.
what are the symptoms of Chalara ash dieback?
leaf loss
die back of new shoots
bark lesions
describe the 4 steps in the identification of pathogens:
1- scientists will visit the location.
2- look at other factors that might cause similar symptoms. For example, damage to leaves might be caused by a pathogen or grazing animals.
3- identify any environmental causes such as pollution that might be affecting the plants.
4- photograph the symptoms and take samples for laboratory analysis.
what do scientists do once an infection has been identified?
look for any patterns in the distribution of infected plants
what can pests do to plants?
can weaken and damage the plant
how could farmers identify the cause of their plans’ decay? (2)
use gardening manuals and the internet to identify plant diseases.
compare the symptoms of their plants with images of other infected ones
what are the 4 physical defences of plants?
bark
waxy cuticles
thorns and hairs
drooping leaves
describe how ‘bark’ acts as a physical barrier: (2)
plants are covered with a thick bark.
which is an external layer of dead cells which forms a physical barrier against infection
describe how ‘waxy cuticles’ acts as a physical barrier: (2)
Leaves are covered with waxy cuticle which also helps to prevent their cells from becoming infected
prevents excess water gain which could result in the leaf harbouring bacteria
describe how ‘thorns and hairs’ acts as a physical barrier: (2)
thorns prevents plants from avoid being eaten and hairs make pest movement more difficult
-adaptations protect plants from damage from pests and from disease from pathogens carried by pests.
describe how ‘drooping leaves’ acts as a physical barrier: (2)
-evolved to close its leaves and then point its stems towards the ground when touched by an insect as it lands on it.
-movement is a defence mechanism which acts to dislodge any insect that rests on it.
describe how ‘poisons’ act as a chemical barrier:
-what do these poisons NOT do?
poisons deter herbivores from eating them.
do not defend plants from infection by pathogens.
describe how ‘toxins’ act as a chemical barrier: (2)
plants release a toxin into the air when attacked by aphids.
-acts as a warning to other aphids, causing them to fly away.
describe how ‘antibacterial chemicals’ act as a form of chemical defence:
they kill bacteria that were not stopped by physical defences.
what are the three chemical defences?
poisons
toxins
antibacterial chemicals
