Disease, Symptom, and causal
agent of plant diseases
Dr. Hadiwiyono
Schematic
representation
of the basic
function in a
plant (left) and
the interference
with this
function (right)
caused by
general type of
disease
PLANT DISEAE CONCEPT
Disease
• “Any malfunctioning of host cells and tissues that results
from continues irritation by a pathogen or environmental
factor and leads to development to symptom (Agrios,
2005)”
• Adanya sel dan jaringan inang yang malfungsi sebagai
akibat dari iritasi yang terus-menerus oleh suatu agens
patogen atau faktor lingkungan dan mengarah pada
berkembangnya gejala
• What is the healthy plant?
Disease based on the causal agents
• Infectious disease
= pathogenic disease
= parasitic disease
= parasite disease
= biotic disease
• non-infectious disease
= non pathogenic disease
= non parasitic disease
= non parasite disease
= physiologic disease
= abiotic disease
Terminology
Pathogen: organism-causal agents of disease
Parasite: organism life in/on other organism.
Facultative Parasite: saprophyte being bale to life as
parasite. Obligative parasite: just life as parasite or
true parasite
Fisiopat, physiopath: causer from abiotic factors
Saprofit, saprophyte: organism life in/on organism
residue or debries. Obligative saprophyte: true
saprophyte or jast life as saphrophyte
Inang, Host: organism where the parasite or pathogen
life.
Perentan, Suscept: host of pathogen and condicuve to
establish a disease. Rentan, susceptible: host
character by which the disease to be conduce for
disease occur><tahan, resistant.
Terminology( continued )
Toleran, tolerant: suitable as host but the disease
is very mild
Patogenisitas, pathogenisity: capability of
parasitic organism as pathogen
Virulensi, keganasan, virulence: capability of
pathogen to produce the disease
Nekrotrof, necrotroph: parasite by which life and
obtain their food from dead tissue
Biotrof, biotroph: parasite by which life and obtain
their food from life tissue
DISEASE SYMPTOM
Symptoms:
“are the expressions by suscept or host of a
pathogenic condition by which a particular plant
disease may be distinguished from other
diseases” (Ilag, 1987).
• Adalah kenampakan perentan atau inang dari
suatu keadaan patogenik sehingga suatu
penyakit tertentu dapat dibedakan dari penyakit
lain
Based on the type of symptom:
1. Hyperplasic; hypertrophic
hyper=high, too
plastic= change
troph = growth
2. Hypoplastic; hypotrophic
hypo= low, lack
3. Necrotic and necrotrophic
Necrotic= dead or killing tissue
Hyperplastic Symptom: Club root caused
by Plasmodiophora brassicae on
cabbage
hiperplastic
Wilting sysmptom
Spore of pathogen
Hiperplastic
Root knot nematode damage to
tomato in the fields
Root-knot nematode-affected root
system on left, healthy on right.
Galls on tomato roots caused by Rootknot Meloidogyne spp.
Roots of a legume. Nitrogenfixing nodules are attached
only to the sides of roots.
Hyperplastic
Crown gall of Mark apple rootstock
(Courtesy A.L. Jones).
Crown gall tumour on an elm tree.
Crown gall symptoms on
organically grown tomato (cv.
Dometica)
Hipoplastic, Banana bunchy to virus
Hypoplastic: RICE GRASSY STUNT VIRUS
Hipoplastik: Tomato Stunted Curly Top Virus
Mosaic Virus symptoms on Rose
Pea enation mosaic virus
Hypoplastic
Aple mosaic virus
Strawberry mottle virus
Maize chlorotic mottle virus
Bean pod mottle virus on soybean
Hypo-Hyperplastic
Oak leaf blister caused by
Taphrina caerulescens
Hyperplasic
Tea leaf blister caused by Exobasidium
vexans
Symptom of basal rot of garlic
cased by F.o. fsp. cepae
Necrotic symptom
Symptom and conidia of Alterneria
porrii on
Nekrotic
A. Gejala bercak ungu (purple spot) of leek; B. Conidia under stereo microscope; C.
Conidia under compound mikrosocpe
Necrotic symptom
Leaf rot of
petsai
caused
Rhizoctonia
solani
Setae of acervulli
Necrotic: Anthracnose on avocado caused by Colletotrichum
gloeosporioides
Necrotic: leaf spot of cabbage caused by
Alternaria brassicae
Nekrotic
leaf blight, Phytophthora infestan of tomato is also referred to as
buckeye rot because of the characteristic lesions on the fruit.
Algal leaf spot (red rust) on mango and many other tropical fruit crops is
caused by the green alga, Cephaleuros virescens. The algal thallus is
orange to rust colored and develops below the host cuticle under wet
conditions.
SPICIFIC SYMPTOM
1.
2.
3.
4.
5.
6.
7.
Kelayuan, wilting
Etiolasi, etiolation
Klorosis, chlorosis
Mosaik, mosaic
Belang, mottling
Pemucatan urat daun, Vein clearing
Penggelapan urat daun, Vein
banding
8. Pembusukan, rotting
9. Bercak, spot
10. Hawar, blight
11. Lobang tembak, Shot hole
12. Kanker, cancer
13. Pemumian, mummification
14. Mati pucuk, die-back
15. Roset, Rosetting
16. Peruntuhan, Abscission
17. Keriting, Curling
18.Kudis, Scab
19.Bergaris, Streak or stripe
20.Kerdil, Stunting
21.Rebah semai, damping off
22.Fasiasi, fasciation
23.Blast
24.Karat, rust
25.Pustul, Pustule
26.Kalus, Callus
27.Salah bentuk, Malformation
28.Tilosis, tylosis
29. Puru, Gall
30.Filodi, phylody
31.Sarkodi, Sarcody
32.EmbunTepung, powdery mildew
33.Embun upas, Donwny mildew
34.Antrak, antractnose
35.Cacar, blister
Specific symptom caused by
some virus
A
B
C
A. cucumber mozaic virus on lettuce, B. Beet yellow stunt virus on crisphead lettuce
(Davis et al. 2002), C. Zucchini yellow mozaic virus pada Summer squash (Zitter et
al.,1998)
Examples of symptom caused by toxic
herbicide being like symptom caused
by virus
A. Leaf of squash is damaged by 2,4-D, B. Glyphosate
Examples of symptom caused by mites
being like symptom caused by virus
A. Symptom of cucumber leaf attacked by spider mites, B. Spider mites,
Tetranychus sp.
DISEASE SIGN
Pathogen structure associating cell, tissue,
organ of infected plant
As indicator of the disease where the
infection occur on/in the cell, tissue, organ
of infected plant
Some disease signs need microscopic
observation
Disease sign and specific
structure Sclerotium rolsii
Whitish myselia and Sclerotia
looking the seed of brasicae
Disease sign of blood disease of
banana
a
a.
b.
c.
d.
b-1
b-2
c
d
Ooze coming out from vascular system of dipped tissues,
Fogy water after shaking the dipped tissues
Ooze exuded from cross section of banana peduncle
Ooze exuded by the bract of banana flower
Disease sign- bacterial ooze coming out from
the vascular system
B
A
A. Sticky strand test on cut stem with bacterial streaming
(oozing) from xylem vessels of melon infected Ervinia
tracheiphila, causing bacterial wilt
B. Oozing test , showing bacterial mass coming out from
vascular tissue
Disease sign: specific structure of virus in
infected tissue
• Potyviridae producing
‘pinwheel’ inclusions
Powdery mildew on Oak leaf
Powdery mildew on melon caused by
Erysiphe cichoracearum
Assignment I: explain what type of the symptoms and
give a sample of each. Do with hand writing!
1.
2.
3.
4.
5.
6.
7.
Kelayuan, wilting
Etiolasi, etiolation
Klorosis, chlorosis
Mosaik, mosaic
Belang, mottling
Pemucatan urat daun, Vein clearing
Penggelapan urat daun, Vein
banding
8. Pembusukan, rotting
9. Bercak, spot
10. Hawar, blight
11. Lobang tembak, Shot hole
12. Kanker, cancer
13. Pemumian, mummification
14. Mati pucuk, die-back
15. Roset, Rosetting
16. Peruntuhan, Abscission
17. Keriting, Curling
18.Kudis, Scab
19.Bergaris, Streak or stripe
20.Kerdil, Stunting
21.Rebah semai, damping off
22.Fasiasi, fasciation
23.Blast
24.Karat, rust
25.Pustul, Pustule
26.Kalus, Callus
27.Salah bentuk, Malformation
28.Tilosis, tylosis
29. Puru, Gall
30.Filodi, phylody
31.Sarkodi, Sarcody
32.EmbunTepung, powdery mildew
33.Embun upas, Donwny mildew
34.Antrak, antractnose
35.Cacar, blister