Pathogens And Plant Disease

Question 1

Define pathogen

Answer 1

Any microorganism that causes disease

Question 2

Define vector (oh yeah oh yeah)

Answer 2

Any agent that carries and transmits an infectious pathogen into another living organism

Question 3

How are pathogens transmitted?

Answer 3

• direct contact
• air/droplet infection
• contaminated water
• contaminated food
• touching surfaces

Question 4

What are Bacteria

Answer 4

• single celled prokaryotes
• living cells, can be killed by antibiotics
• can reproduce by binary fission anywhere moist in host
• produce toxins that damage cells and tissues
• eg. E.coli and salmonella

Question 5

What are viruses?

Answer 5

• not cells but consist of genetic material + protein coat
• reproduce rapidly INSIDE host cells using host DNA, produce 1000s of copies until cell bursts open, it is this cell damage that makes you feel ill
  Eg. Covid 19, HIV

Question 6

What are Protists?

Answer 6

• single celled eukaryotes
• reproduce in blood
• can be parasitic meaning they live inside or on another organism, causing harm
• cause chills and fever
• Eg. Malaria

Question 7

What are fungi?

Answer 7

• Eukaryotes
• Have thread like structures called hyphae which produce spores, allowing them to easily spread
• Cell wall of fungi is made of CHITIN
• use SAPROTROPHIC NUTRITION - secrete enzymes to digest food and absorb it
  Eg. Athlete’s foot

Question 8

What are symptoms of plant disease?

Answer 8

• stunted growth
• spots on leaves
• areas of decay (rot)
• abnormal growths
• malformed stems or leaves
• discolouration
• presence of pests

Question 9

Why is it important to control plant disease?

Answer 9

• crops get destroyed
• they are hard to control
• cause knock on effects up the food chain

Question 10

How to control TMV?

Answer 10

• remove infected plants
• remove weeds (they may carry TMV)
• burn removed infected plants

Question 11

How to control black spot fungus?

Answer 11

• removal of ingmfected plant
• burn infected plants

Question 12

What are signs of an aphid infestation?

Answer 12

• decreased growth rate
• mottled yellow leaves
• low yield
• wilting
• death
• mold growths

Question 13

How to control aphids?

Answer 13

• squash colonies
• encourage or release predators
• use insecticide (may harm pollinators)

Question 14

What happens if a plant has a nitrate deficiency?

Answer 14

• nitrates needed to make amino acids used during protein synthesis for growth
• stunted growth

Question 15

What happens if a plant has a magnesium deficiency?

Answer 15

• magnesium needed to make chlorophyll, so lack of chlorophyll (chlorosis)
• yellowed leaves

Question 16

Hoe to know if a plant has a pathogen, pest or disease?

Answer 16

• take infected plant to lab
• use testing kits containing monoclonal antibodies
• reference to garden manuals or websites