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Disease Exam Flashcards

1
Q

Plant disease

A

anything that prevents a plant from performing to its maximum potential

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2
Q

Abiotic

A

Caused by conditions external to the plant, not living agents

Cannot spread from plant to plant but are common

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3
Q

Example of abiotic disease

A

nutritional diseases, soil compaction, salt injury, ice, and sun scorch

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4
Q

Biotic Disease

A

Caused by living organisms called plant pathogens

Pathogens can spread from plant to plant and may infect all types of plant tissue including leaves, stems, crowns, roots, tubers, fruit, seeds, and vascular tissues

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5
Q

List 6 types of Plant Pathogens

A
  1. Fungi/Fungal-like organism
  2. Bacteria
  3. Phytoplasmas
  4. Viruses
  5. Nematodes (animal kingdom)
  6. Parasitic Plants
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6
Q

Sign

A

visible portions of a disease-causing organisms

Ex: When you look at powdery mildew, you’re looking at a parasitic fungal disease organism itself

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7
Q

Symptoms

A

The visible effect of disease on the plant.

May include a detectable change in color, shape, or function of the plant as it responds to the pathogen.

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8
Q

Chlorosis (Define)

List two types (Define)

A

A loss of normal plant color

Interveinal: yellowing of leaf tissue between veins

Halo: ring of chlorosis around lesions

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9
Q

Necrosis (define)

List 3 types

A

Dead tissue

Dieback, Lesion, Canker

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10
Q

Necrosis: Dieback

A

whole sections of plant dies

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11
Q

Necrosis: Lesion

A

contained region of tissue that has suffered damage

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12
Q

Necrosis: Canker

A

sunken, swollen, cracked lesion. Used to describe lesions on trunks and branches of woody plants.

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13
Q

Mosaic

A

caused by VIRUS

characterized by yellow flecking and spotting

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14
Q

Ringspot

A

caused by VIRUS

a type of mosaic, but lesions exist as halos around green tissue

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15
Q

Stippling

A

Spot pattern of damaged, chlorotic leaf tissue

*Usually caused by ABIOTIC factors or sucking/piercing insects

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16
Q

Scorch

A

Large necrotic lesions usually caused by bacterial infections or by abiotic factors

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17
Q

Wilt

A

when the above-ground portions of the plant are not getting enough water because the vascular tissue is compromised BIOTIC AND ABIOTIC

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18
Q

Rot

A

Decay of roots or fruit.

Usually caused by fungi and bacteria

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19
Q

Gall

A

Masses of undifferentiated cells. Caused by bacteria and nematodes. Female of nematode lives inside gall. SYMPTOM

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20
Q

Cyst

A

caused by nematodes (2 types). Female nematode is the cyst SIGN

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21
Q

Blight

A

A rapid and complete chlorosis, browning, then death of plant tissues such as leaves, branches, twigs, or floral organs.

Many diseases that primarily exhibit this symptom are called blights.

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22
Q

3 Parts of disease triangle

A

Pathogen, Environment, Host

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23
Q

Fungi

A

Organism is made of cells called hyphae. Masses of hypha is called a mycelium

Multicellular eukaryotes

Heterotrophic: absorptive nutrition

Cell wall made of chitin

Reproduction: spores (sexual or asexual)

24
Q

2 Types of Fungi Sexual Reproduction

A

Heterothallic: can reproduce only with another individual of opposite mating type

Homothallic: can reproduce with another individual or itself

25
Another name for spores
conidia (produced by conifiophores)
26
Environmental factors for fungi
Temperature: Warm, Cool, Disease is favored by conditions that provide it with an advantage over the host Moisture: most fungi require water to INFECT about 90%
27
Fungi: Biotroph
Leach nutrients off living plant Infection is specialized through mechanical insertion or through natural openings growth intercellular
28
Fungi: Necrotroph
Eats and kills everything Host cells killed rapidly with toxins and enzymes -pathogen kills host first then feeds Infection occurs at wounds or natural opening Growth is inter- and intracellular
29
Fungi: Hyperplasia
fungi makes plant create more cells than it needs
30
Fungi: Hypertrophy
tissue malformation of one cell "smut"
31
Bacteria
Prokaryote The most primitive of life and very small organism Known as prokaryote because of lack of membrane-bound organelles A single circular chromosome Can contain from several to hundred of accessory DNA segments, called plasmids Many navigate by chemotaxis (opposite chemicals attracting) Call walls made of peptidoglycan
32
3 Different types of bacteria
Bacilli (rod-shaped) Cocci (spherical) Spirilla (spiraled)
33
Bacteria Reproduction
Sexual and Asexual Asexual: Binary Fission Sexual: transformation and conjugation (picking and sharing DNA fragments)
34
Plasmid
circular segment of accessory DNA
35
Bacterial Leaf Spots
Typical leaf spots caused by bacteria appear as water-soaked brown to black lesions often outlined with a yellow halo Necrotic spots can be angular "V" shape
36
Symptoms of bacteria
``` leaf spots bacterial leaf scorch bacterial blights bacterial wilts Rot and galls ```
37
Virus
Open system DNA or RNA wrapped in protein coat called capsid Vector-borne Protein coat intersects with cell membrane and virus is absorbed Genetic material is incorporated into host genome Need a living host cell in order to reproduce
38
Virus Symptoms
Mosaic Ringspot Rosette Discoloration
39
Oomycetes
Water molds: use water as transport method Primarily parasites of vascular tissue Kingdom: Chromista
40
Oomycetes Reproduction
Sporangium: Zoospores Oogonium (female) and antheridium (male) Oospores (reproductive organ)
41
Symptoms of Oomycetes
Root rot Blight Canker
42
Nematodes
Most numerous multicellular organisms on Earth Multicellular with a "tube in a tube" body structure Feed through a stylet, the feeding strategies vary
43
Life cycle of Nematodes
6 Stages of Growth: egg, 4 juvenile stages, and an adult phase Nematodes can go from egg to egg-laying in 21 days Males are long and slender Females, after mating, fuse their mouth parts to the root tissue, swell with eggs, and burst from the pressure of the developing eggs
44
Signs and symptoms of nematodes
patches or spots galls cyst
45
Disease cycles
The chain of events involved in the disease development includes inoculation, penetration, infection, penetration, infection, incubation, reproduction, and survival.
46
1st stage of disease cycle
Inoculation: the introduction of the plant pathogen to the host.
47
2nd stage of disease cycle
Penetration: wound sites and natural plant openings, such as stomata and hydathodes, facilitate the entrance of some plant pathogens
48
3rd stage of disease cycle
Infection: pathogens invades the plant tissue and establishes a parasitic relationship between itself and the plant
49
4th stage of disease cycle
Incubation: once inside the plant, pathogens may undergo an incubation period and remain latent for a period before initiating disease
50
5th stage of disease cycle
Reproduction: plant pathogens can reproduce sexually and asexually. It is dependent on the pathogen
51
6th stage of disease cycle
Survival: Plant pathogens have evolved so they can survive prolonged periods of unfavorable weather conditions.
52
Nitrogen Deficiency
Utilization: key element in every biological molecule, especially chlorophyll Symptoms: chlorosis in the older leaves, leaf drop N is mobile (older parts of plant) Looks like: viruses, root rots, early stages of wilt, downy mildew
53
Potassium Deficiency
Utilization: chilling tolerance, disease tolerance, enzyme cofactor Symptoms: stunting, darkening of leaves, scorching of leaf margins, leaf cupping, chlorosis, necrosis K is mobile (older parts of plant) Looks like: viruses, bacterial leaf scorch, root rots
54
Magnesium Deficiency
Utilization: integral in chlorophyll molecule, enzyme cofactors Symptoms: interveinal chlorosis beginning in old leaves Mg is mobile (older parts of plant) Looks like herbicide damage, viruses, powdery mildews, downy mildews
55
Iron Deficiency
Utilization: Enzyme cofactor, crucial in chlorophyll production, transport other elements Symptoms: Chlorosis beginning in the youngest leaves, stunting Iron is immobile (younger parts of plant) Looks like: root rot, sulfur deficiency, early stages of wilt
56
Calcium Deficiency
Utilization: structural component of cell wall, chemical gradients, enzyme cofactor Symptoms: leaf cuppings, margin burn, distorted growth, aborted flowers and fruit Ca is mobile (older parts of plant) Looks like: viruses, soft rot, root rots, bacterial leaf spot

Weed & Disease (3 decks)

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