PLANT DISEASE DIAGNOSIS

Question 1

Identification of diseases based on symptoms and signs

Answer 1

Plant Disease Diagnosis

Question 2

Manifestation or expression of a plant as a result of disease

Answer 2

Symptom

Question 3

A pathogen or parts of a pathogen found on the host plant

Answer 3

Sign

Question 4

Expressed as physiological or structural changes in a limited area of the tissues of the host

Answer 4

Local symptoms

Question 5

Examples of Local symptoms

Answer 5

galls, spots, cankers

Question 6

Examples of Systemic symptoms

Answer 6

dwarfing, wilting, yellowing, mosaic

Question 7

Primary symptoms

Answer 7

Direct result of pathogen activity on the invaded tissues

Question 8

Secondary symptoms

Answer 8

Physiological effects on distant and uninvaded organs

Question 9

Macroscopic symptoms

Answer 9

Expressions of the disease in the plant or in its parts that can be studied with the unaided eye

Question 10

Microscopic symptoms

Answer 10

Expressions of disease in cell structure or arrangement that can be studied only under the microscope

Question 11

Hyperplasia

Answer 11

Plant overgrowth due to increased cell division

Question 12

Hypertrophy

Answer 12

Plant overgrowth due to abnormal cell enlargement

Question 13

Rosette

Answer 13

short, bunchy habit of plant growth

Question 14

Stem-pitting

Answer 14

Characterized by depressions on the stem of the plant

Question 15

Bunchy

Answer 15

leaves progressively becomes dwarfed, upright and bunched at the top of the plant

Question 16

Stunt

Answer 16

reduction in size and vigour

Question 17

Yellowing / Chlorosis

Answer 17

discoloration of normally green tissue due to chlorophyll destruction or failure of chlorophyll formation

Question 18

Witches’ broom

Answer 18

broomlike growth or massed proliferation caused by the dense clustering of branches of woody plants

Question 19

Enation

Answer 19

tissue malformation or overgrowth induced by certain virus infections

Question 20

Scab

Answer 20

roughened, crust-like diseased area on the surface of a plant organ; a disease in which such areas form

Question 21

Tumor

Answer 21

uncontrolled overgrowth of tissue or tissues

Question 22

Gall

Answer 22

swelling or overgrowth produced on a plant as a result of infection by certain pathogens

Question 23

Smut

Answer 23

characterized by masses of dark, powdery and sometimes odorous spores

Question 24

Wilt

Answer 24

loss of rigidity and drooping of plant parts generally caused by insufficient water in the plant

Question 25

Damping-off

Answer 25

destruction of seedlings near the soil line, resulting in the seedlings failing over on the ground

Question 26

Dieback

Answer 26

progressive death of shoots, branches, and roots generally starting at the tip

Question 27

Anthracnose

Answer 27

black and sunken leaf, stem or fruit lesions caused by a fungus

Question 28

Blight

Answer 28

general and rapid killing of leaves, flowers, and stems

Question 29

Shot-hole

Answer 29

small, diseased fragments of leaves fall off and leave holes in their space

Question 30

Blotch

Answer 30

large, and irregular in shape, spots, or blots on leaves, flowers and stems

Question 31

Canker

Answer 31

necrotic, often sunken lesion on a leaf, fruit stem, branch, or twig of a plant

Question 32

Spot

Answer 32

self-limiting lesion on leaves or other parts of the plant

Question 33

Mummification

Answer 33

drying and shrivelling of fruit

Question 34

Rot

Answer 34

softening, discoloration and often disintegration of succulent plant tissue as a result of fungal or bacterial infection

Question 35

Soft rot

Answer 35

rot of fleshy fruit, vegetable or ornamental in which the tissue becomes macerated by tbe enzymes of the pathogen

Question 36

Ringspot

Answer 36

circular area of chlorosis with a green center; a symptom of many virus diseases

Question 37

Mottle

Answer 37

irregular pattern of indistinct light and dark areas

Question 38

Mosaic

Answer 38

intermingled patches of normal and light green or yellowish color

Question 39

Signs of Fungi

Answer 39

spores, pustules, sclerotial bodies, mycelia, mildew (powdery / downy)

Question 40

Mildew

Answer 40

mycelium and spores of the fungus are seen as whitish growth on the surface of leaves, stems, and fruits

Question 41

Powdery mildew

Answer 41

Whitish growth on the upper side of the leaf surface

Question 42

Downy mildew

Answer 42

Whitish growth on the underside of the leaf surface

Question 43

Signs of Bacteria

Answer 43

bacterial ooze

Question 44

Signs of Nematodes

Answer 44

egg mass, cysts/pearls (cyst nematodes), juvenile and adult nematodes