Explain the mode of penetration in case of fungi and bacteria

April/Mei 2009

BGT 213 / 3 - Plant Pathology [Patologi Tumbuhan ]

Duration: 3 hours [Masa : 3 jam]

Please ensure that this examination paper contains SEVEN printed pages before you begin the examination.

[Sila pastikan bahawa kertas peperiksaan ⁱⁿⁱ mengandungi TUJUH muka surat yang bercetak sebelum anda memulakan peperiksaan ini.]

Instructions: Answer FIVE (5) out of SIX (6) questions^, in English or Bahasa Malaysia. Eachquestion carries^{20 marks}

.

fArahan: Jawab LIMA ⁽5) daripada ENAM ⁽⁶⁾ soalan yang ^diberikan dalam Bahasa Inggeris atau Bahasa Malaysia^{. Tiap-}tiap soalan bernilai 20 markah.]

21

-

mm m

6 6

[BGT 213/3]

-

²

-

One day a farmer came ^toask you about a disorder in ^his cultivatedplants

.

In order to diagnose this disorder precisely, how do you prepare the protocol? Write a series of procedures to diagnose ^thedisorder

.

1.

(20 marks)

Viruses, viroids, mollicutes, fastidious bacteria ^and protozoa can not penetrate the host plant but are transmitted through wounds created by vectors or tools. Explain the mode of penetration in case of ^fungi and bacteria

.

2.

(20 marks)

3

.

[a] Explain thefollowing technical terms

.

W

Heteroecism.

(2 marks) [ii] T toxin.

(2 marks) [iii] Formationof cork layer.

(2 marks) [iv] Tyloses

.

(2 marks) [v] Phytoalexin.

(2 marks)

31

-

m mm

6 4

[b]

Based

on these figures below, explain the behavior of the pathogen

and

its infection relatedto the environmental condition.

(10marks)

Foliagedensity 100-ⁱ

•

^Dense

O'

-

¹

-

^{o Sparse}

80-

o^; u C

QJ

°

^U_C ^60-

IQ

X ^40-

o 20^-

0 7 May

100_n

80^-

a1

uc a^;

°

^60-

uc

Ol V)

IQ

X ^{40 -}

D

p O^'

20-

0 6

December November

%

F I G U R E 8-^{1 0} Effect ^{of foliage density on} development of Phy- tophthora infestans during a period ^{of partly} favorable weather

(May-

June

^{) and of very} favorable weather ⁽November-^December).

[From Rotem and Ben-Joseph⁽1970⁾. Plant Dis. Rep.54, ^/68-7^/1

.

]

4/-

•^••

65

[BGT213/3]

-

⁴

-

The following are FIVE (5) disease symptoms ^that

cause

growth and distortion of plant parts^. Write a brief description ^of each symptom and provideillustration where ever possible.

4

.

^[a]

Gall

.

[>]

Warts.

[ii]

Club root

.

[iii]

Witchesbroom. [iv]

Leaf curls

.

[v]

(10 marks)

Write short notes on methods to control vascular wilt of banana (Panana disease)

.

[b]

(10 marks)

Write an essay on soft rot disease causedby Rhizopussp. 5

.

(20 ^marks)

Describe briefly the penetration and intercellular development of bacterialinfectionon host plant

.

6

.

^[a]

(10 marks⁾

[b] Insect vectors consist of persistent and non-persistent types

.

^Write

short noteson how the persistent type transmit virus into the host

.

(10marks⁾

5/-

•

6 t >

Pada suatu han

seorang

petani

datang

berlanya mengenai suatudisorder atau

gangguan terhadap tanamannya

.

Dalam

usaha untuk

mendings

disorder tersebut ,

bagaimanakah anda menyediakan protokolnya Tul

s

satu^sirikaedah untuk mendiagnosis

disorder

tersebut^{. Y}

1.

(20 markah)

Virus

,

^viroid, molikutes, bakteria fastidius dan protozoa tidak mampu

menembusi

^{tumbuhan perumahnya tetapi ditularkan} melalui luka yang dibuat oleh vektor atau alat pertanian

.

Terangkan mod ^(atau cara⁾

kemasukan

kulat dan bakteria

.

2.

(20markah)

3

.

Huraikan istilah ^teknikal yang^berikut: Heteroesisme

.

[i]

(2markah) ToxinT

.

[i

>

^]

(2 markah) Pembentukan lapisan gabus

.

[iii]

(2 markah) [iv] Tilosa

.

(2 markah) Fitoaleksin^.

[v]

(2 markah)

61

-

•^{m m}

G 7

[BGT 213/3]

-6

-

Berdasarkan kepada rajah-rajah yang berikut^,huraikan ^tingkah-laku patogen dan jangkitannya yang berkaitan ^dengan

keadaan

persekitaran.

[b]

(10 markah)

Foliage density 100-n

*

^Dense

O Sparse O

80^- o^/ u CQJ 73_U 60^-

C

<u

2 ^40-

D

£

20^-

0 O

7 15 22 30 5 12

May June

100_n

80^-

OJv ca^; 73U 60 -

c

«3

X ⁴⁰-

op o^'

20^-

0

*

_{6 12 16 21} ^/"H / /

—

^I

16 30 9

December

19

November

G U R E 8 1 0 _{Effect of} foliage density on development of Phy_-

rr

^May

June

^{* )} _{and of}

”

⁵_very^durmg_favorable^{a period}_weather^of

Partl

_(November^{7 favorable}_- ^weather

December) U^-rom Rotem _{and Ben}-Joseph (1970). Plant Dts. Rep. 54 768-771 ]

71

-

••

G 8

Benkut adalah LIMA (5) gejala penyakit yang menyebabkan pertumbuhan dan

kecacatan

pada

bahagian

_{tumbuhan. Tuliskan} huraian ringkas

tentang

setiap simptom tersebut dan

ilustrasi di mana mungkin. 4

.

^[a]

berikan Gall.

[i]

Ketuat.

[ii]

[ill] Akar belantan

.

[iv] Penyapu

.

[v] Ikal daun

.

(10 markah)

Tuliskan nota pendek tentang kaedah pengawalan penyakit layu vaskularpada pisang (penyakit Panama)

.

[b]

(10 markah)

Tuliskan esei mengenai penyakit reput lembut yang disebabkan oleh Rhizopus sp

.

5

.

(20 markah)

Huraikan secara ringkas ^tentang

penembusan

^dan perkembangan interselular oleh bakteria ^terhadap tumbuhan perumah

.

6

.

[a]

(10 markah⁾

terdiri

dari jenis persisten ⁽tekal) dan tidak Tuliskan nota

pendek

bagaimana serangga ^jenis [b] Vektor serangga

persisten.

persisten menularkan virus^ke dalam

perumah

^.

(10 markah)

-oooOooo -

69