Plant Disease - B3

Question 1

Name three ways to detect plant disease.

Answer 1

Stunted growth.

Spots on leaves.

Areas of decay (rot).

Malformed stems or leaves.

Discolouration.

The presence of pests

Question 2

Name two symptoms of plant disease caused by deficiency.

Answer 2

Stunted growth is caused by nitrate deficiency.

Chlorosis is caused by magnesium deficiency.

This is because nitrate ions are needed for protein synthesis and therefore growth and magnesium ions are needed to make chlorophyll.

Question 3

Name three ways a plant can be infected.

Answer 3

Tobacco mosaic virus (TMV) - as a viral disease.
Black spot - as a fungal disease.
Aphids - as insects.

Question 4

Name three ways a plant defends itself against diseases.

Answer 4

Tough waxy cuticle on leaves,

Layers of dead cells around stems (bark on trees) which fall off.

Impermeable cellulose cell walls

Antibacterial chemicals, poisons to deter herbivores,