disease control 2012 edited

7/24/2019 Disease Control 2012 Edited

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Versi 2013 by: UQ


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Penyakit pada Tumbuhan, biasanya:

starts out at a low level,

becomes of concern to

us only when its

incidence and severityincreases with time.

tidak hanya mengamati kemunculan (incidence) atau keparahan

(severity) sejak titik 0 (nol) yang kemudian meningkat secara

dramatik, tapi juga bisa mengamati pola perkembangan yang

mencolok sejalan dengan waktu.

DiseaseProgress

Phytophthorablight o cucurbit


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Phytophthora blight of pepper seedlings

Perkembangan penyakit (disease progress) cenderung linier(dengan sedikit de!iasi yang kita anggap sebagai random error)

"ontoh disease progress :


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#usarium kernel rot

(busuk bulir) pada

jagung


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Bean rust (karat bii!

$i pihak lain, pada %karat biji& (Uromyces phaseoli) dan bercak abu'

abu pada daun jagung (Cercospora zeae-maydis), terdapat kur!a

meningkat terbatas (deinite upward cur!e): dimana penyakit

meningkat dengan laju yang meningkat pula. ur!anya disebut

exponential.


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"rey leafspot of

#ai$e


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$isease Progress

Penyakit tumbuhan tidak dapat terus meningkat. ila

sudah mencapai level of diseasemendekati *00+,

maka kur!a disease progressmendatar (flatten) secara

bertahap.

"ontoh: pada epidemi dari ineksi !clerotium rolfsii pada

kacang atau ineksi pada tanaman tembakau oleh

"hytophthora parasitica!ar. nicotianae, disease

progress mulai secara linier tetapi melambat ketika

mendekati titik maksimum.


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Sclerotium rolfsiion beans


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Bla%k shank on toba%%o


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$isease Progress

$emikian juga, kur!a disease progress dari "uccinia

graminissubsp. graminicolapada rye grassdan

"yrenophora teres. sp. terespada barley pada

awalnya eponential, tapi ketika tingkat keparahan

mendekati *00+, laju disease progressmelambat

secara bertahap hinga mencapai 0 (-ero) sehingga

membentuk kur!a bentuk sigmoid (bentuk /)


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Bla%k ste# rust on ryegrass


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&et blot%h on barley


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To be sure, not all eamples o

disease progress can be as neatly

categori-ed as these, but in general

plant disease epidemics tend to beeither roughly linear or eponential in

the early stages, and they tend to

le!el o as they approach some limit.


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$ampak penyakit tumbuhan dan kerusakan

yang ditimbulkan merupakan ungsi dari

#disease progress$.

1ntuk menekan dampaknya perlumengeliminasi penyakitnya, dengan cara

mempertahankan perkembangan penyakittersebut di ba'ah le)el* yang diiinkan.

2rtinya, disease progress$dan aktor'aktor

yang mempengaruhinya harus dipahami

sebagai istilah kuantitati (3uantitati!e terms)saja.


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%.what kinds of diseases lead

to linear disease progressandwhat factors affect the slope

of the line &the rate of disease

progress'.

(. what kinds of diseases tend to produce exponential

disease progresscurves and how we can reduce both

the starting level of disease andthe rate of epidemicdevelopment.

). why epidemics sometimes level off and what imposes

limits to their development.


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The "yclical 4ature o Plant

$isease

Plant

disease

epidemi

csare

cyclicalpheno

mena,th

atis,

theycon

sistofrepeate

d

cycleso

fpathog

en

developm

entinre

lationto

thehost.


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The inoculum,

which might

consist of

fungalspore

s,

bacterial

cells,

nematodes,viruses

withinanap

hid

vector,orso

meother

propaguleso

fa

pathogen,

gains entry into and establishment

within the host tissues through the

process of infection.
http://images.google.co.id/imgres?imgurl=http://www.apsnet.org/Education/IllustratedGlossary/PhotosS-V/stoma.jpg&imgrefurl=http://www.apsnet.org/Education/IllustratedGlossary/PhotosS-V/stoma.htm&h=275&w=400&sz=31&hl=id&start=16&tbnid=gxzjSmri90v-_M:&tbnh=85&tbnw=124&prev=/images%3Fq%3Dstomatal%2Bopening%26svnum%3D10%26hl%3Did%26lr%3D


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Patogen berkembang dalam tubuh

inang dan mulai memproduksi

inokulum baru yang pada saatnyaakan5dapat disebarkan ke tempat

lain yang rentan dan memulai ineksi

barunya.


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Patogeny

anghanya

punya*siklus

perkembangan(*sikl

usineksi)

disebutseba

gai#ono%y%li%,

sedangkan

yangpuny

alebihdari*

siklusineksidisebutp

oly%y%li%.


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Pada iklim temperatehanya ada * siklustumbuh (crop cycle) per tahun, sehingga istilah

6monocyclic6 dan 6polycyclic6 didasarkan padajumlah siklusnya per tahun.

4amun, pada iklim tropik atau subtropik, dapatada lebih dari * crop cycleper tahun, danpenting diingat bahwa 6monocyclic6 and6polycyclic6 didasarkan pada crop cycletunggal.

7stilah yang sama juga dipakai untuk

mendeskripsi epidemik dan juga patogen./ehinga, kita sering mengucapkan sebagai*monocyclic epidemic*atau *polycyclicepidemic*.


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Epidemic:

Perubahanpadadisease

intensitydalam

sebuah

populasiinang

(host

population)sep

anjangruang

danwaktu.


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Change : oten increase '' a dyna#i% pro%ess

+isease : dealing with diseases+ not just the pathogen (or plant5crop)

ost : 8rganism inected (or potentially

inected) by another organism

"opulation : a population pheno#enon

ime and space : two physi%al di#ensions o interest.


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,pide#iology:

/tudy o epidemics.

!cience of disease in populations.

cology of disease.

!tudy of the spread of diseases, in space andtime,

with the ob/ective to trace factors that areresponsible for, or contribute to, epidemic

occurrence.

he science of populations of pathogens in

populations of host plants, and the diseases resulting therefrom under the influence of

the environment and human interferences.


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All plant diseases result from a three-

way interaction between the host, the

pathogen andthe environment.

An epidemic develops if all three of

these factors are favourable to disease

development.

Therefore, disease can be controlled

by manipulating one or more ofthese factorsso that conditions are

unsuitable for replication, survival or

infection by the pathogen.

*

9


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/ince the beginning o agriculture, generations

o armers ha!e been e!ol!ing practices or

combating the !arious plagues suered by our

crops. #ollowing our disco!ery o the causes oplant diseases in the early nineteenth century,

our growing understanding o the interactions o

pathogen and host has enabled us to de!elop a

wide array o measures or the control o speciic

plant diseases.


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From this accumulated knowledge

base, we can distill some general

principles of plant disease controlthat can help us address the

management of new problems onwhatever crop in any environment.


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;. ;.


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2!oidance>pre!ent disease by selecting a time o the year or

a site where there is no inoculum or where the en!ironment isnot a!orable or inection.

?clusion>pre!ent the introduction o inoculum.

?radication>eliminate, destroy, or inacti!ate the inoculum.

Protection>pre!ent inection by means o a toicant or some

other barrier to inection.

@esistance>utili-e culti!ars that are resistant to or tolerant o

inection.

Therapy>cure plants that are already inected.

Traditional Principles of Plant isease !ontrol


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9. the traditional principles o plant

disease control do not take into

consideration the dynamics o plant

disease, that is, the changes in the

incidence and se!erity o disease in time

and space. (/ee: $isease Progress.)


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. considering that dierent diseases

dier in their dynamics, they do notindicate the relati!e eecti!eness o the

!arious tactics or the controlo a

particular disease. They also ail to show

how the dierent disease control

measures interact in their eects on

disease dynamics.


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A. the traditional principles o plant

disease control tend to emphasi-etactics without itting them into an

ade3uate o!erall strategy.

Th ? id i l i l i $i


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The ?pidemiological asis o $isease

BanagementPlant disease epidemics can be classified into two basic types,

monocyclic and polycyclic, depending on the number ofinfection cycles per crop cycle. "#ee$ The !yclical %ature of

Plant isease.&


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The early stages of a monocyclic epidemic can be

described 'uite well by a linear model, while the early

stages of a polycyclic epidemic can be described with an

e(ponential model. #ince we are concerned with keeping

disease levels well below )**+, there is no need to

adust the models for approaching the upper limit, and

we can use the simple linear and e(ponential models toplan strategies$

1(amining these models we can see that in both there are


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). educe the initial inoculum "in the

monocyclic model and (oin the polycyclic

model&. "Actually (ois the initial incidence of

disease, which is proportional to the initial

inoculum.&

/. educe the rate of infection "in the

monocyclic model and rin the polycyclicmodel&

0. educe the duration of the epidemic "the time,

t, at the end of the epidemic&

1(amining these models, we can see that in both there are

three ways in which we can reduce (at any point in the

epidemic$


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These can be used as three maor

strategiesfor managing plant diseaseepidemics, and we can organi2e our

plant disease control tacticsunder one

or more of these overall strategies.

Furthermore, by means of the model we

can assess the 'uantitative impact of

each strategy, not only by itself, but in

its interaction with others.


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3t is clear from the above model of a monocyclic

epidemic that , , and t have e'ual weight intheir effect on (. A reduction in the initial

inoculum or the rate of infection will result in a

reduction in the level of disease by the sameproportion at any time, t, throughout the epidemic.

3f tcan be reduced "for e(ample, by shortening the

season&, disease will be reduced proportionately.

The monocyclic

model

The polycyclic


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The polycyclic

model 7 ris !ery high, the apparent

eect o reducing ois to delaythe epidemic.

7 ris !ery high, omust be reduced to !ery low

le!els to ha!e a signiicant eect on theepidemic.

@educing rhas a relati!ely greater eect on

the epidemic than reducing o.

@educing omakes good strategic sense onlyi ris low or i ris also being reduced.


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The Traditional Principles @e!isited

To make the conceptual leap rom disease

control to disease management, the

traditional principles can be modiied by

itting them as tacticswithin each o the three

major disease management strategies and

by slightly changing the wording to relect the3uantitati!e impact o the action rather than

an absolute eect:


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Versi 2012 by: UQ


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P@74/7P P?4C?D8D224 P?4E27T

T1B1;24

Pada prinsipnya, untuk mengelola penyakit tumbuhan

ada strategidan ada taktikyang dapat digunakan. Taktik dipakai untuk mencapai tujuan berdasar strategi

yang dicanangkan.

/ecara umum, ada tiga strategi yang dapat dilakukanuntuk pengendalian penyakit tumbuhan yaitu :

F (*) strategi untuk mengurangi inokulum awal,

F (9) strategi untuk mengurangi laju ineksi, dan

F () strategi untuk mengurangi lamanya epidemi. /edangkan taktik pada prinsipnya ada enam, yaitu

a!oidan, ekslusi, eradikasi, proteksi, resistensi, danterapi.


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Tactics or the @eduction o 7nitial 7noculum

-)oidan%e>reduce the le!el o disease by selecting aseason or a site wherethe amount o inoculum is loworwherethe en!ironment is una!orable or inection

,.%lusion>reduce the amount o initial inoculumintroduced rom outside sources

,radi%ation>reduce the production o initial inoculum bydestroying or inacti!ating the sources o initial inoculum(sanitation, remo!al o reser!oirs o inoculum, remo!al oalternate hosts, etc.)

Prote%tion>reduce the le!el o initial inection by means oa toicant or other barrier to inection

/esistan%e>use culti!ars that are resistant to inection,particularly the initial inection

Therapy>use thermotherapy, chemotherapy and5ormeristem culture to produce certiied seed or !egetati!eplanting stock


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a%ti%s for the /edu%tion of

the nfe%tion /ate

2!oidance>reduce the rate o production o inoculum, therate o inection, or the rate o de!elopment o the pathogenby selecting a season or a site where the en!ironment is nota!orable

?clusion>reduce the introduction o inoculum rom eternal

sources during the course o the epidemic ?radication>reduce the rate o inoculum production during

the course o the epidemic by destroying or inacti!ating thesources o inoculum (roguing)

Protection>reduce the rate o inection by means o a

toicant or some other barrier to inection @esistance>plant culti!ars that can reduce the rate oinoculum production, the rate o inection, or the rate opathogen de!elopment

Therapy>cure the plants that are already inected or reducetheir production o inoculum


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a%ti%s for the /edu%tion of the uration

of the ,pide#i%

-)oidan%e>plant early maturing culti!ars or plant at

a time that a!ors rapid maturation o the crop

,.%lusion>delay the introduction o inoculum rom

eternal sources by means o plant 3uarantine

PENGENDALIAN PENYAKIT TUMBUHAN

PENGENDALIAN PENYAKIT TUMBUHAN


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MENGURANGI LAJU INFEKSIMENGURANGI LAJU INFEKSI

MENGURANGI LAMANYA EPIDEMIMENGURANGI LAMANYA EPIDEMI

MENGURANGI INOKULUM AWALMENGURANGI INOKULUM AWAL

EKSLUSIEKSLUSI

AVOIDANAVOIDAN

STRATEGISTRATEGI

Waktu tanam, lahan, lingkungan yg tak cocok untukpatogen

Mengurangi jumlah inokulum awal yang berasal dariluar lahan

Sanitasi, buang sumber inokulum, musnahkan inangantara, dsb.

Aplikasi fungisida, atau buat penghalang infeksi pdtanaman

Kultivar yang tahan terhadap infeksi inokulum awal

erapi panas, kimia, benih ! bag. tan. vegetativ bebaspenyakit

EKSLUSIEKSLUSI

TERAPITERAPI

ERADIKASIERADIKASI

RESISTENRESISTEN

PROTEKSIPROTEKSI

TAKTIKTAKTIK

AVOIDANAVOIDAN

"aju dikurangi dg waktu tanam, lahan, lingkungan ygtak cocok

Kurangi masuknya inokulum selama terjadinyaepidemi

ebang, pangkas, musnahkan inokulum saatterjadinya epidemi

Kurangi laju infeksi dengan fungisida atau

penghalang lainKultivar yang mengurangi laju in#feksi!perkemb.patogen!inokulum

Sembuhkan tanaman yang telah terinfeksi

EKSLUSIEKSLUSI

TERAPITERAPI

ERADIKASIERADIKASI

RESISTENRESISTEN

PROTEKSIPROTEKSI

AVOIDANAVOIDAN

anaman cepat dewasa agar terhindar dari infeksi

$ambat introduksi inokulum dari luar dengankarantina


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Peranan pengendalian

terhadap penyakit tumbuhan

$itujukan untuk mencegah atau mengurangi

terjadinya penyakit sehingga tanaman dapat

memberikan hasil yang menguntungkan.

1saha ini biasanya ditujukan terhadap tanaman

sebagai populasi dan tidak terhadap tanaman

sebagai indi!idu.

ebanyakan dari usaha pengendalian penyakitmemerlukan perpaduan dari berbagai cara.


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"ara pendekatan pendekatan terhadap tanaman

pendekatan yang ditujukan terhadappenyebab penyakit tertentu

Terintegrasi ke dalamB?T8$2 P?4C?4$2D724


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Penghindaran patogen

Pemilihan daerah pertanian.

Pemilihan waktu tanam.

Penggunaan benih yang bebas penyakit.


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Eksklusi patogen

Perawatan bahan tanaman.

arantina tumbuhan.

Pembasmian serangga !ektor.


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Eradikasi patogen

Pergiliran tanam.

Bembuang atau menghancurkan tanaman

atau bagian tanaman yang terserang.

Perlakuan tanah.


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Perlindungan tanaman

Pengendalian serangga pembawa

patogen.

Bengubah keadaan lingkungan.

Bengubah keadaan -at hara.

M b k t


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Mengembangkan tanaman yang

resisten

@esistensi isiologis

@esistensi mekanis

@esistensi ungsional

@esistensi oleh hemoterapi


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a. @esistensi isiologis yang biasanya didasarkan

kepada adanya -at di dalam protoplasma yang

menghambat ineksi patogen dan

perkembangannya lebih lanjut di dalam tanaman.

b. @esistensi mekanis yang berhubungan denganstruktur atau morologi dari bagian'bagian

tanaman tertentu meliputi siat karakteristik yang

dipunyai oleh tanaman yang menyulitkan patogen

mengadakan kontak secara langsung dengan

bagian yang akan diineksinya seperti adanyalapisan kutikula atau lapisan gabus yang tebal.


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c. @esistensi ungsionalyang berhubungan dengan

waktu penutupan stomata.

d. @esistensi oleh hemoterapidimana terdapat

kemungkinan mengubah ketahanan terhadap

patogen yang terdapat dalam protoplasma dengan

pemberian senyawa kimiapada tanaman. Pada

umumnya cara tersebut memperlambat atau

mengurangi timbulnya penyakit.


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Betode pengendalian

%. 0egulatory

(. Cultural

). 1iological

2. "hysical

3. Chemical


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@egulatory control

Benangkal suatu patogen dari

suatu inang atau dari suatu areageograis tertentu


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@egulatory "ontrol


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"ultural control

Bengusahakan tanaman terhindar dari

kontak dengan patogen, mengusahakan

kondisi lingkungan tidak menguntungkan

bagi patogen dan melenyapkan atau

mengurangi jumlah patogen pada suatu

tanaman, lahan atau wilayah


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iological control

Beningkatkan resistensi inang atau

menciptakan kondisi yang menguntungkan

bagi mikroorganisma antagonistik bagi

patogen


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Physical and chemical control

Belindungi tanaman dari inokulum patogen

yang sudah ada atau akan ada, atau

mengobati suatu ineksi yang sudah5sedang

berlangsung


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MENGURANGI LAJU

INFEKSI

MENGURANGI LAJU

INFEKSI

MENGURANGI LAMANYA

EPIDEMI

MENGURANGI LAMANYA

EPIDEMI

MENGURANGI

INOKULUM AWAL

MENGURANGI

INOKULUM AWAL

PENGENDALIAN PENYAKIT TUMBUHANPENGENDALIAN PENYAKIT TUMBUHAN

EKSLUSIEKSLUSI

AVOIDANAVOIDAN

STRATEGISTRATEGI

EKSLUSIEKSLUSI

TERAPITERAPI

ERADIKASIERADIKASI

RESISTENRESISTEN

PROTEKSIPROTEKSI

TAKTIKTAKTIK

AVOIDANAVOIDAN

EKSLUSIEKSLUSI

TERAPITERAPI

ERADIKASIERADIKASI

RESISTENRESISTEN

PROTEKSIPROTEKSI

AVOIDANAVOIDAN

Regulat

ory

con

trol

Cultur

al

control

Biological

control


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P1%41%A53A% P1%6A73T

T89:8;A% #1!AA 7393A


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P?@2T1@24 P?B?@74T2; 48. G

T2;14 *=G

1ntuk melindungi keselamatan manusia

dan sumber'sumber kekayaan alam

khususnya kekayaan alam hayati, dansupaya pestisida dapat digunakan eekti,

maka peredaran, penyimpanan dan

penggunaan pestisida diatur dengan

Peraturan Pemerintah 4o. G Tahun *=G.

$alam peraturan tersebut antara lain

ditentukan bahwa:

tiap pestisida harus didatarkan kepada Benteri


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tiap pestisida harus didatarkan kepada BenteriPertanian melalui omisi Pestisida untuk dimintakani-in penggunaannya

hanya pestisida yang penggunaannya terdatar danatau dii-inkan oleh Benteri Pertanian boleh disimpan,diedarkan dan digunakan

pestisida yang penggunaannya terdatar dan ataudii-inkan oleh Benteri Pertanian hanya boleh

disimpan, diedarkan dan digunakan menurutketentuan'ketentuan yang ditetapkan dalam i-inpestisida itu

tiap pestisida harus diberi label dalam bahasa7ndonesia yang berisi keterangan'keterangan yang

dimaksud dalam surat eputusan Benteri Pertanian4o. A9=5 pts5Bm5*5*=G dan sesuai denganketentuan'ketentuan yang ditetapkan dalampendataran dan i-in masing'masing pestisida.


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ulti4siteulti4site 5ite4spe%ifi%5ite4spe%ifi%

/ystemicity


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/ystemicity

$o not penetrate into plant

@edistribute on plant suraces

Bulti'site inhibitors ills spores5inhibits

germination

Protectant only

road spectrum

Penetrate into plant

@edistribute on I within plants

/ingle'site inhibitors 7nhibits spore germination and

or mycelial growth

Protectant and curati!e

/electi!e

4on'systemic /ystemic

4on systemics


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4on'systemics

Bimimal redistribution romthe point o deposition


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/ystemics

Docal /ystemic

F Docal redistribution

rom the point o

depositionF 8n the cuticle

F Through the lea

(translaminar)F ?tent is !ariable


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/ystemics

Dimited systemic

(acropetal penetrant)

F Cood mo!ement rom

the point o applicationF Through tissues

F 7nside the !asculature

F ulk mo!ementF $B7s, Phenylamides


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/ystemics

True /ystemics(asipetal penetrant)

F 8nly one ungcide

F #osetyl'2lF Bo!es through plant

F $own into roots

F Cood against soil'borne oomycetes

/ingle /ite ! Bulti'site


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/ingle /ite !. Bulti site

/ystemic !. non'/ystemic

Protectant only

"an wash o

/horter application inter!als

road spectrum

6o' /isk of /esistan%e

Protectant and curati!e

Dess prone to washing o

Donger application inter!als

/electi!e

7igh /isk of /esistan%e

4on'systemic5Bulti'/ite /ystemic5/ingle /ite

Pola Daku imiawi pada


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Biologi%al #ode of a%tion

-ksi 8ungisida dapat diekspresikan #elalui

salah satu dari dua %ara ekspresi fisik

Penghambatan perkecambahan

spora.

Penghambatan pertmbuhan jamur.

Pola Daku imiawi pada

Pengendalian Penyakit Tanaman


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Physiologi%al #ode of a%tion

-pa yang teradi pada tingkatan

seluler shg dapat #enyebabkan

pengaruh )isibel pada

perke%a#bahan spora danpertu#buhan a#ur9


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Mengapa perlu mengenali pola laku

fungisida secara fisiologis?

= For resistance management= and preservation of fungicide

effectiveness.

1ntreated

Treated


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he physiologi%al #ode of

a%tion #ungicides are metabolic inhibitors andtheir modes o action can be classiied into

our broad groups.

F 7nhibitors o electron transport chain.F 7nhibitors o en-ymes.

F 7nhibitors o nucleic acid metabolism and

protein synthesis.

F 7nhibitors o sterol synthesis.

A typical cell and cell components


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A typical cell and cell components

>1lectron transport chain

>1n2ymes

>%ucleic acid metabolism

and protein synthesis>#terol synthesis


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nhibition of ele%tron transport %hain

(/espiration in #ito%hondria! /ulur

F $isrupts electron transport along the

cytochromes

/trobilurins (a-oystrobin, kresoim'methyl,pyraclostrobin, triloystrobin)

F 7nhibit mitochondrial respiration, blocking the

cytochrome bc* comple.

$isco!ery and /ynthesis rom


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$isco!ery and /ynthesis rom

4atural Products

!trobilurus tenacellus

4udemansiella mucida

5yxococcus fulvus

/ynthesis rom 4atural Products


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8udemansin 2

8

88

8

/trobilurin 2

88

8

?nol ether stilbene

88

8

?nol ?ther Croup

"4

8 8

4 4

88

8

8ime ?ther Croup

8

884

8

/ynthesis rom 4atural Products

Inhibition of enzymes


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Inhibition of enzymes= !opper

>%onspecific denaturation of proteins anden2ymes.

= ithiocarbamates"maneb, man2ate, dithane, etc&

>3nactivate >#; groups in amino acids, proteins

and en2ymes.

= #ubstituted aromatics"chlorothalonil, P!%:&

>3nactivate amino acids, proteins and en2ymes

by combining with amino and thiol groups.

= ?rganophosphonate"fosetyl-Al&

>isrupts amino acid metabolism.

I hibiti f l i id t b li


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Inhibition of nucleic acid metabolism

and protein synthesis

= :en2imida2oles"thiophanate-methyl&

>3nhibit %A synthesis "nuclear division&.

= Phenylamides"mefeno(am&>3nhibits %A synthesis.

= icarbo(imides"iprodione, vinclo2olin&

>3nhibits %A and %A synthesis, cell divisionand cellular metabolism.


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Inhibition of sterol synthesis

Inhibit demethylation of ergosterol!

= 1rgosterol is the maor sterol in most fungi.

= 3t is essential for membrane structure and function.


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"terol inhibiting fungicides

= 3mida2oles"ima2alil&

= Tria2oles"propicona2ole, myclobutanil,

tebucona2ole, trifluma2ole&= 9orpholines"dimethomorph&

>3nhibits sterol production at different site than

imida2oles and tria2oles. Affects cell wall

production.


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iological control o plant

pathogens"hristine @oath

8 i


88/109

8!er!iew


89/109


90/109


91/109


92/109

g p

pathogens

-ntibiosisF inhibition o one organism byanother as a result o diusion o an

antibiotic

F2ntibiotic production common in soil'dwellingbacteria and ungi

F ?ample: -wittermicin 2 production by 1.

cereusagainst "hytophthoraroot rot in alala

Bechanisms o biological control o


93/109

g

plant pathogens

&utrient %o#petitionF competitionbetween microorganisms or carbon,

nitrogen, 89, iron, and other nutrients

F Bost common way organisms limit growth oothers

F ?ample

". fluorescens, J7T"1/, pre!ents bacterial blotchby competing with ". tolaasii

Bechanisms o biological control o


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g

plant pathogens

estru%ti)e #y%oparasitis#F theparasitism o one ungus by another

F $irect contact

F "ell wall degrading en-ymes

F /ome produce antibiotics

F ?ample

richoderma harzianum, ioTrek, used as seedtreatment against pathogenic ungus

@e3uirements o successul


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3

biocontrol

*. ;ighly eecti!e biocontrol strain must beobtained or produced

a. e able to compete and persist

b. e able to coloni-e and prolierate

c. e non'pathogenic to host plant and

en!ironment



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3

biocontrol

9. 7nepensi!e production and ormulationo agent must be de!eloped

a. Production must result in biomass with

ecellent shel li!eb. To be successul as agricultural agent must

be

i. 7nepensi!e

ii. 2ble to produce in large 3uantities

iii. Baintain !iability



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3

biocontrol

. $eli!ery and application must permit ullepression o the agent

a. Bust ensure agents will grow and achie!e

their purpose

Coiling ofTrichodermaaround a pathogen.

(Plant Biocontrol byTrichoderma spp.IlanChet, Ada Viterbo and Yariv Brotman)

Plant pathogen control by richoderma


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p g y

spp.

richoderma spp. are present in nearly allagricultural soils

2ntiungal abilities ha!e been known since

*=0s Bycoparasitism

4utrient competition

2griculturally used as biocontrol agent andas a plant growth promoter

http://www.ars.usda.gov/is/pr/2002/021231.trichoderma.jpg

Plant pathogen control by


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p g y

richoderma spp.

;ow is it appliedH

#a!ored by presence o high le!els o plant roots

/ome are highly rhi-osphere competent

F "apable o coloni-ing the epanding root suraceF "an be used as soil or seed treatment

http://www.nysaes.cornell.edu/ent/biocontrol/pathogens/images/trichoderma3.jpg



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p g y

richoderma spp.

2ction against pathogenic ungi

*. 2ttachment to the host

hyphae by coiling

a. Dectin'carbohydrate

interaction

(Hubbard et al., 1983. Phytopathology 73:655-659).



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richoderma spp.

2ction against pathogenic ungi

9. Penetrate the host cell walls by

secreting lytic en-ymes

a. "hitinases

b. Proteases

c. Clucanases

(Ilan Chet, Hebrew University of Jerusalem).



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richoderma spp.

/ome strains coloni-e the root withmycoparasitic properties

F Penetrate the root tissue

F 7nduce metabolic changes which induceresistance

2ccumulation o antimicrobial compounds



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richoderma spp.

"ommercial a!ailability

T'99 /eed coating, seed pieces, transplant starter

Protects roots rom diseases caused by "ythium,0hizoctoniaand 6usarium

7nteracts with the @hi-osphere, near the root hairs

and increases the a!ailable orm o nutrients

needed by plants.



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richoderma spp.

#uture de!elopments Transgenes

iocontrol microbes contain a large number o

genes which allow biocontrol to occur "loned se!eral genes rom richodermaas

transgenes

F Produce crops which are resistant to plant diseases

"urrently not commercially a!ailable


105/109

5U5-&-B6, -&-",,& 8

564B/&, P6-& 5,-5,5

a reduction of


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a reduction of

biodiversity of

soil organisms

Soil-borne

diseases

Restoring beneficial

organisms that attack,

repel, or otherwise

antagonize disease-causing pathogens will

render a soil disease-

suppressive

Plants growing in

disease-suppressive soil

resist diseases much

better than in soils low inbiological diversity

!eneficial organisms can be

added directly, or the soilenvironment can be made more

favorable for them through use

of compost and other organic

amendments

"ompost #ualitydetermines its

effectiveness at

suppressing

soil-borne plant

diseases


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yPlant diseases result when a susceptible host

and a disease'causing pathogen meet in a

a!orable en!ironment

7 any one o these threeconditions were not met,

there would be no

disease.


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Bany inter!ention practices (ungicides,methyl bromide umigants, etc.) ocus on

taking out the pathogen ater its eects

become apparent.

;ow to emphasi-es on making the

en!ironment less disease'a!orable and thehost plant less susceptible.


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disease control 2012 edited

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