Pathogenic Plant Diseases

Question 1

The Disease Triangle

Answer 1

Host
Pathogen
Environment

Question 2

How To Remove Host From Triangle

Answer 2

eliminate host
or, select disease resistant species or varieties when planting

Question 3

How To Remove Pathogen From Triangle

Answer 3

eliminating pathogen can be difficult, many spores are ubiquitous
clean greenhouse/nursery
promote complex ecology in landscape
remove diseased material from garden

Question 4

How To Remove Environment From Triangle

Answer 4

alter environmental conditions: temp, humidity, air circulation, soil environment
greenhouses allow you to alter conditions easily

Question 5

Environmental Conditions that lead to disease

Answer 5

crowding in greenhouse
poor ventilation
high humidity
specific temps

Question 6

4 Types of Plant Pathogens

Answer 6

Fungus, Water Mould, Bacteria, and Viruses

Question 7

Examples of Fungus Pathogens

Answer 7

powdery mildew, rust, leafspot/blight, fungal canker, fungal gall, fusarium, rhizoctonia

Question 8

Examples of Water Mould Pathogens

Answer 8

phytophthora and pythium

Question 9

Examples of Bacteria Pathogens

Answer 9

fireblight, bacterial wilt/scabs/leaf spots, wet wood

Question 10

Examples of Virus Pathogens

Answer 10

cucumber mosaic virus, tobacco mosaic virus, aster yellows, impatiens necrotic spot virus

Question 11

Disease Cycle

Answer 11

Inoculation, Incubation, Penetration, Infection, Dissemination

Question 12

Inoculation

Answer 12

contact between plant and pathogen
i.e. spores transported by wind, splashing water, insects, and people

Question 13

Incubation

Answer 13

period of optimal light, temp and moisture before fungal spore germinates

Question 14

Penetration

Answer 14

entry of disease into the tissue
susceptible tissues: thin cuticle, weakened epidermal cells, injury, flowers, stomata

Question 15

Infection

Answer 15

growth and reproduction of pathogen within plant

Question 16

Dissemination

Answer 16

spread of pathogen (pathogen produces reproductive fruting bodies)

Question 17

Horticulture Practices to Reduce Diseases

Answer 17

sanitation, pruning, irrigation

Question 18

4 Fungal Divisions

Answer 18

Zygomycetes
Ascomycetes
Basidiomycetes
Deuteromycetes

Question 19

Zygomycetes

Answer 19

molds (soil born saprophytes)

Question 20

Ascomycetes

Answer 20

yeasts, powdery mildew, dutch elm disease, apple scab, blackspot, powdery mildew

Question 21

Basidiomycetes

Answer 21

mushrooms, smut, and rust

Question 22

Deuteromycetes

Answer 22

verticilium wilt, fusarium wilt, ringworm, athletes foot, cheese, penicillin

Question 23

Conditions Favourable for Fungal Diseases

Answer 23

moisture, poor ventilation, and temperature specific

Question 24

Basic Fungal Lifecycle

Answer 24

spore, hypha, mycelium, fruiting body

Question 25

Fungal Diseases on Surface Tissues

Answer 25

powdery mildew, botrytis, rust, blackspot on roses

Question 26

Systemic Diseases that Cause Wilting

Answer 26

veriticilium wilt and fusarium wilt

Question 27

Water Mould

Answer 27

phytophthora cinnamomi, phytophthora ramorum, and pythium

Question 28

Examples of Bacteria

Answer 28

bacterial canker, bacterial gall, and fireblight