Plant Diseases

Question 1

Plant Pathogens

Answer 1

Plants are vulnerable to viruses, bacteria, and fungi but they are also attacked by pests that cause a lot of damage. Insect pests may both destroy plants directly and act as vectors of disease.

Question 2

Physical barriers

Answer 2

Plants have number of physical barriers that reduce the invasion of pathogens:

• The cellulose walls that strengthen plant cells also help to resist invasion by microorganisms
• The tough waxy cuticle on the surface of the leaves acts as a barrier to the entry of pathogens.
• Bark on trees, and a layer of dead cells on the outside of stems, form a protective layer that is hard for pathogens to penetrate.
• Leaf fall - deciduous trees lose their leaves in autumn.

Question 3

Chemical barriers

Answer 3

Many plants produce antibacterial chemicals that protect them against invading pathogens, and these are very effective at preventing bacterial diseases n many plants.