Exam 1

Question 1

Disease Triangle

Answer 1

In order for infection to occur you must have a susceptible host, a virulent pathogen, and the right environment

Question 2

Disease Cycle (monocyclic)

Answer 2

1. Pathogen infects
2. Pathogen grows and reproduces
3. Pathogen makes propagules
4. Propagules dispersed to new host

Question 3

Plant disease

Answer 3

A disorder of structure or function in a plant, affects physiology and morphology, caused by a pathogen

Question 4

Fungi

Answer 4

have hyphae that produce spores

Question 5

Protists

Answer 5

Fungal-like, have hyphae and spores but are in a different kingdom

Question 6

Bacteria

Answer 6

Require a host, do not have a cell wall

Question 7

Nematodes

Answer 7

soil-borne diseases, worm-like

Question 8

Signs

Answer 8

structure of casual pathogen, can be big or small

Question 9

Symptoms

Answer 9

abnormality of plant, includes chlorosis, necrosis, cankers, galls, wilting, blights

Question 10

Koch’s Postulates

Answer 10

1. microbe must be correlated with the disease, constant association with symptomatic host
2. microbe must be isolated from host and grown in pure culture
3. pure culture inoculated into healthy susceptible host must reproduce disease
4. microbe must be recoverable from experiment host

Question 11

Koch’s Postulates (simple)

Answer 11

find microbe + disease, isolate, re-infect, recover

Question 12

Modes of infection

Answer 12

Direct penetration, Penetration through natural openings, Penetration through natural wounds

Question 13

Direct penetration

Answer 13

pathogen (fungi) makes injury

Question 14

Penetration (natural openings)

Answer 14

pathogen (bacteria) enters through stomata, lenticel, or hydathodes

Question 15

Penetration (natural wounds)

Answer 15

pathogen enters via wounds caused by insects/wind/humans, through natural cracks between main and lateral roots

Question 16

Survival outside of host

Answer 16

using survival structures; on/in soil, seeds, vegetative propagative organs, insects, perennial plants

Question 17

Dissemination

Answer 17

via winds, rain splashing/runoff, insects, flooding, contaminated seeds/transplants, animals, tools

Question 18

Monocyclic

Answer 18

one infestation per season

Question 19

Polycyclic

Answer 19

disperses progeny repeatedly throughout season

Question 20

Myxomycetes

Answer 20

slime molds, protist disease

Question 21

Plasmodiophoromycetes

Answer 21

survive winter as resting spores in the soil, disrupt by adding lime and increasing soil pH, protists

Question 22

Oomycetes

Answer 22

type of plasmodiophoromycete, Fungal-like protists