Key learning points

1. Plants can be infected by pathogens, such as viruses, bacteria and fungi, that cause diseases.
2. Pests, including insects, can damage plants by feeding on them, and can spread pathogens that cause diseases.
3. Plants have physical, chemical and mechanical defences against pathogens.
4. Examples of physical, chemical and mechanical defences in plants.

Keywords

• Pathogen - A virus, bacterium or other microorganism that causes disease.

• Pest - An insect or other animal that damages plants and can spread plant pathogens.

• Waxy cuticle - Waterproof coating on the surface of a leaf.

• Cell wall - Structure made of cellulose that surrounds plant cells.

• Antimicrobial - A substance that kills microorganisms or stops their growth.

Common misconception