Plant disease + infection Flashcards
Examples of plant disease
Tobacco mosaic virus
Rose black spot
Tobacco mosaic virus
A virus that effects plants eg tomatoes
Symptoms of TMV
Leaves discolour in a yellow mosaic pattern = reduced rate of photosynthesis
So plant growth reduced
Rose black spot
Fungus that effects roses
Rose black spot symptoms
Causes leaves to develop purple and black spots
Turns yellow then falls off :(
Reduces rate of photosynthesis to fall
So stunted growth
How does rose black spot spread?
A fungus so by spores
In water or in the wind
How to reduce spread of rose black spot?
Use chemicals that kill fungi (fungicides)
Remove and destroy infected leaves
Types of plant Defences
Physical
Chemical
Mechanical
Physical responses
Cell wall + waxy cuticle difficult for microorganisms (pathogens) to penetrate and attack
Dead cells around stems (bark) barrier to microorganisms (pathogens)
How does bark work?
As it ages, eventually falls off then replaced by new bark underneath
Chemical responses
Antibacterial chemicals to kill bacteria
Release poisons to deter herbivores eating it
Mechanical responses
Sharp thorns stop herbivores eating it
Hairs which irritate herbivores mouths
Leaves that move when touched to scare away herbivores
Mimicry
Mimicry
Appearing to be another plant that’s dangerous to avoid being eaten eg looking like a stinging nettle despite not stinging
What does a plant need to protect itself from?
Herbivores eating it
Insects eating it
Microorganisms penetrating it
Plants being attacked by insects
Aphids extract sugars which stunt its growth
