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

TerminologyPathogen: organism-causal agents of diseaseParasite: 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 factorsSaprofit, 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 mildPatogenisitas, pathogenisity: capability of parasitic organism as pathogenVirulensi, keganasan, virulence: capability of pathogen to produce the diseaseNekrotrof, necrotroph: parasite by which life and obtain their food from dead tissueBiotrof, 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, tooplastic= changetroph = growth

2. Hypoplastic; hypotrophichypo= low, lack

3. Necrotic and necrotrophic Necrotic= dead or killing tissue

Hyperplastic Symptom: Club root caused by Plasmodiophora brassicae on

cabbage

hiperplastic

Spore of pathogenWilting sysmptom

Root knot nematode damage to tomato in the fields

Galls on tomato roots caused by Root-knot Meloidogyne spp.

Root-knot nematode-affected root system on left, healthy on right.

Roots of a legume. Nitrogen-fixing nodules are attached only to the sides of roots.

Hiperplastic

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)

Hyperplastic

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

Aple mosaic virus

Hypoplastic

Maize chlorotic mottle virus

Strawberry mottle virus

Bean pod mottle virus on soybean

Hypo-Hyperplastic

Oak leaf blister caused by Taphrina caerulescens

Tea leaf blister caused by Exobasidium vexans

Hyperplasic

Symptom of basal rot of garlic cased by F.o. fsp. cepae

Necrotic symptom

Symptom and conidia of Alterneria porrii on

A. Gejala bercak ungu (purple spot) of leek; B. Conidia under stereo microscope; C. Conidia under compound mikrosocpe

Nekrotic

Leaf rot of petsai

caused Rhizoctonia

solani

Necrotic symptom

Necrotic: Anthracnose on avocado caused by Colletotrichum gloeosporioides

Setae of acervulli

Necrotic: leaf spot of cabbage caused by Alternaria brassicae

leaf blight, Phytophthora infestan of tomato is also referred to as buckeye rot because of the characteristic lesions on the fruit.

Nekrotic

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 SYMPTOM1. Kelayuan, wilting2. Etiolasi, etiolation3. Klorosis, chlorosis4. Mosaik, mosaic5. Belang, mottling6. Pemucatan urat daun, Vein clearing7. Penggelapan urat daun, Vein

banding8. Pembusukan, rotting9. Bercak, spot10.Hawar, blight11. Lobang tembak, Shot hole12.Kanker, cancer13.Pemumian, mummification14.Mati pucuk, die-back15.Roset, Rosetting16.Peruntuhan, Abscission17.Keriting, Curling

18.Kudis, Scab19.Bergaris, Streak or stripe20.Kerdil, Stunting21.Rebah semai, damping off22.Fasiasi, fasciation23.Blast24.Karat, rust25.Pustul, Pustule 26.Kalus, Callus27.Salah bentuk, Malformation28.Tilosis, tylosis29. Puru, Gall30.Filodi, phylody31.Sarkodi, Sarcody32.EmbunTepung, powdery mildew33.Embun upas, Donwny mildew34.Antrak, antractnose35.Cacar, blister

Specific symptom caused by some virus

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)

A B C

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

Whitish myselia and Sclerotia looking the seed of brasicae

Disease sign and specific structure Sclerotium rolsii

Disease sign of blood disease of banana

a. Ooze coming out from vascular system of dipped tissues,b. Fogy water after shaking the dipped tissues c. Ooze exuded from cross section of banana peduncled. Ooze exuded by the bract of banana flower

a b-1 b-2 c d

Disease sign- bacterial ooze coming out from the vascular system

A

B

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. Kelayuan, wilting2. Etiolasi, etiolation3. Klorosis, chlorosis4. Mosaik, mosaic5. Belang, mottling6. Pemucatan urat daun, Vein clearing7. Penggelapan urat daun, Vein

banding8. Pembusukan, rotting9. Bercak, spot10.Hawar, blight11. Lobang tembak, Shot hole12.Kanker, cancer13.Pemumian, mummification14.Mati pucuk, die-back15.Roset, Rosetting16.Peruntuhan, Abscission17.Keriting, Curling

18.Kudis, Scab19.Bergaris, Streak or stripe20.Kerdil, Stunting21.Rebah semai, damping off22.Fasiasi, fasciation23.Blast24.Karat, rust25.Pustul, Pustule 26.Kalus, Callus27.Salah bentuk, Malformation28.Tilosis, tylosis29. Puru, Gall30.Filodi, phylody31.Sarkodi, Sarcody32.EmbunTepung, powdery mildew33.Embun upas, Donwny mildew34.Antrak, antractnose35.Cacar, blister