agric

ultu

re,

fore

stry

& fi

sher

ies

Dep

artm

ent:

Agr

icul

ture

, For

estry

and

Fis

herie

sR

EPU

BLI

C O

F SO

UTH

AFR

ICA

Econ

omic

impl

icat

ions

C

itru

s g

ree

nin

g r

ed

uce

s th

e q

ua

ntit

y a

nd

qu

alit

y o

f ci

trus

fru

it an

d ev

entu

ally

the

infe

cted

tre

es b

ecom

e un

prod

uctiv

e. A

n in

fect

ed t

ree

prod

uces

fru

it th

at is

un

suita

ble

for

sale

as

fres

h fr

uit o

r fo

r ju

ice

mak

ing.

It is

a q

uara

ntin

e pe

st in

the

coun

trie

s w

here

it is

not

ye

t pre

sent

. The

spr

ead

of th

is d

isea

se w

ithin

a p

revi

-ou

sly

pest

-fre

e co

untr

y ca

n ha

mpe

r th

e op

port

unity

of

that

cou

ntry

to a

cces

s po

tent

ial c

itrus

mar

kets

whi

ch

may

impo

rt o

nly

from

citr

us g

reen

ing

pest

-fre

e ar

eas.

C

itrus

gre

enin

g, t

here

fore

, ne

gativ

ely

affe

cts

acce

ss

to m

ajo

r in

tern

ati

on

al

citr

us

ma

rke

ts,

such

as

the

Uni

ted

Sta

tes

of A

mer

ica

and

the

Eur

opea

n U

nion

.

Legi

slat

ive

impl

icat

ions

In

ter

ms

of t

he A

gric

ultu

ral P

ests

Act

, 19

83 (

Act

No.

36

of

1983

), C

ontr

ol M

easu

res

R.1

10 o

f 27

Jan

uary

19

84 (

as a

men

ded)

, mov

emen

t of c

itrus

pro

paga

tion

mat

eria

l fro

m o

ne a

rea

to a

noth

er w

ithin

the

Rep

ublic

of

Sou

th A

fric

a is

pro

hibi

ted

unle

ss t

he m

ovem

ent

is

au

tho

rise

d b

y m

ea

ns

of

a p

erm

it o

r th

e m

ate

ria

l is

cert

ified

as

pest

free

. The

Dep

artm

ent o

f Agr

icul

ture

, F

ore

stry

an

d F

ish

eri

es

ren

de

rs in

spe

ctio

n s

erv

ice

s an

d is

sues

per

mits

to e

nsur

e co

mpl

ianc

e w

ith th

e ap

-pl

icab

le c

ontr

ol m

easu

res.

The

abo

vem

entio

ned

inte

rven

tions

will

ass

ist

in p

re-

vent

ing

the

furt

her

spre

ad o

f citr

us g

reen

ing.

Sour

ces

of in

form

atio

n

A

PH

IS F

acts

heet

, 200

7, C

itrus

Gre

enin

g: Q

uest

ions

and

Ans

wer

s,

Uni

ted

Sta

tes

Dep

artm

ent o

f Agr

icul

ture

.

J.V

. DA G

RA

CA 1

991,

Citr

us g

reen

ing

dise

ase,

Phy

topa

thol

ogy,

29:

10

9–13

6.

UN

IVE

RS

ITY O

F F

LO

RID

A,

20

05

, C

itru

s g

ree

nin

g—

An

oth

er

Th

rea

t to

A

gric

ultu

re, U

F-I

FA

S, U

SA

.

PIE

TE

RS

EN,

G.,

AR

RE

BO

LA,

E.,

BR

EY

TE

NB

AC

H,

J.H

.J.,

KO

RS

TE

N L

., L

E

RO

UX, H

.F.,

LA G

RA

NG

E H

., LO

PE

S, S

.A.,

ME

YE

R J

.B.,

PR

ET

OR

IUS M

.C.,

SC

HW

ER

DT

FE

GE

R, M

., V

AN V

UU

RE

N S

.P. &

YA

MA

MO

TO, P

. 201

0. A

sur

vey

for

“Can

dida

tus

Libe

ribac

ter”

spe

cies

in S

outh

Afr

ica

conf

irms

the

pre

sen

ce o

f o

nly

“C

a.

L.

afr

ica

nu

s” in

co

mm

erc

ial C

itru

s. P

lan

t D

isea

se,

94: 2

44–2

4.

Des

crip

tion

C

itrus

gre

enin

g, a

lso

know

n as

yel

low

dra

gon

dise

ase

or H

uang

long

bing

, is

one

of th

e m

ost s

erio

us b

acte

rial

dis

ea

ses

of

citr

us.

Th

ere

are

th

ree

kn

ow

n f

orm

s o

f ci

trus

gre

enin

g ca

usin

g ba

cter

ia,

nam

ely

the

Afr

i can

fo

rm (

‘Can

dida

tus

Libe

riba

cter

afr

ican

us’)

, th

e A

sian

fo

rm (

‘Ca

nd

ida

tus

Lib

eri

ba

cte

r a

sia

ticu

s’)

an

d t

he

Am

e ric

an fo

rm (

‘Can

dida

tus

Libe

ribac

ter a

mer

ican

us’).

The

Afr

ican

form

is h

eat s

ensi

tive

and

sym

ptom

s ar

e pr

oduc

ed u

nder

rel

ativ

ely

cool

con

ditio

ns (

20–2

4 °C

) w

hile

th

e A

sia

n f

orm

de

velo

ps

un

de

r b

oth

co

ol a

nd

war

m te

mpe

ratu

res

(up

to 3

2 °C

). L

ittle

is k

now

n ab

out

tem

pera

ture

req

uire

men

ts o

f the

Am

eric

an fo

rm.

Orig

in a

nd g

loba

l dis

trib

utio

nC

itru

s g

ree

nin

g p

rob

ab

ly o

rig

ina

ted

in C

hin

a in

th

e 19

00s.

20

13

Pub

lishe

d by

D

epar

tmen

t of A

gric

ultu

re, F

ores

try a

nd F

ishe

ries

P

rivat

e B

ag X

144

P

RE

TOR

IA

0001

Citr

us

gree

ning

– to

rep

ort o

ccur

renc

e or

sus

pect

ed o

ccur

renc

e of

the

dise

ase

–

Dire

ctor

ate:

Pla

nt H

ealth

Div

isio

n:

Ear

ly W

arni

ng S

yste

ms

Tel

:

01

2 31

9 63

84

Em

ail:

JanH

endr

ikV

@da

ff.go

v.za

– fo

r aw

aren

ess

and

prom

otio

n en

quiri

es –

Dire

ctor

ate:

Foo

d Im

port

and

Exp

ort S

tand

ards

Div

isio

n:

Pla

nt H

ealth

Pro

mot

ion

Tel

: 01

2 31

9 62

95

Em

ail:

Info

.sps

@da

ff.go

v.za

Nee

d m

ore

info

rmat

ion

?

‘Can

did

atu

s L

iber

ibac

ter

afri

can

us’

‘Can

did

atu

s L

iber

ibac

ter

asia

ticu

s’

‘Can

did

atu

s L

iber

ibac

ter

amer

ican

us’

teris

tic o

f gre

enin

g. O

ther

sym

ptom

s in

clud

e tw

ig d

ie-

back

, poo

r flo

wer

ing

and

stun

ted

grow

th.

Fru

it fr

om d

isea

sed

tree

s is

sm

all,

ofte

n ab

norm

al a

nd

typi

cally

som

e gr

een

colo

ur re

mai

ns e

ven

on ri

pe fr

uit.

Gre

en

ing

-aff

ect

ed

fru

it t

ast

e b

itte

r, m

ed

icin

al

an

d so

ur. S

eeds

usu

ally

abo

rt, a

nd fr

uit f

orm

atio

n is

poo

r.

Sym

p to

ms

vary

acc

ord

ing

to

th

e t

ime

of

infe

ctio

n,

stag

e of

dis

ease

, tre

e sp

ecie

s an

d tr

ee m

atur

ity.

Tran

smis

sion

T

his

dis

ea

se is

pri

ma

rily

sp

rea

d b

y tw

o s

pe

cie

s o

f ps

yllid

inse

ct, n

amel

y th

e A

sian

citr

us p

sylli

d (D

ia ph

o r-

ina

citr

i) an

d th

e A

fric

an c

itrus

psy

llid

(Trio

za e

rytr

eae)

. B

oth

sp

eci

es

tra

nsm

it th

e c

itru

s g

ree

nin

g p

ath

og

en

from

infe

cted

tre

es t

o he

alth

y tr

ees

as t

hey

feed

on

the

plan

ts. C

itrus

gre

enin

g ca

n al

so b

e tr

ansm

itted

by

graf

ting

infe

cted

bud

woo

d, b

y do

dder

, and

, pos

sibl

y,

by in

fect

ed s

eed.

Hos

t ran

geC

itrus

gre

enin

g in

Sou

th A

fric

a is

larg

ely

a di

seas

e of

sw

eet o

rang

e (C

itrus

sin

ensi

s), w

ith v

alen

cias

sho

w-

ing

mor

e di

stin

ct le

af s

ympt

oms

than

nav

els.

It is

als

o pa

rtic

ular

ly s

ever

e on

man

dari

ns (

C.

reti c

ulat

a) a

nd

tan

ge

los

(C.

sin

en

sis

x C

. re

ticu

lata

), b

ut

less

on

lem

on

(C

. lim

on

), g

rap

efr

uit

(C.

pa

rad

isi)

an

d s

ou

r or

ange

(C

. aur

antiu

m).

How

ever

, cul

tivar

s su

ch a

s lim

e (C

. aur

antif

olia

), p

om-

elo

(C. g

rand

is),

and

trifo

liate

ora

nge

(Pon

iciru

s tr

ifoli-

ate)

are

tole

rant

to th

e di

seas

e. In

gen

eral

, mos

t citr

us

spec

ies

and

thei

r re

lativ

es a

re s

usce

ptib

le.

Iden

tifi c

atio

n m

etho

ds

The

onl

y de

finiti

ve m

etho

d of

dia

gnos

is o

n tr

ees

sus-

pect

ed to

be

infe

cted

by

the

citr

us g

reen

ing

path

ogen

(H

uang

long

bing

) is

pol

ymer

ase

chai

n re

actio

n (P

CR

) in

an

auth

or is

ed p

lant

dia

gnos

tic la

bora

tory

. In

Sou

th

Afr

ica,

this

can

be

done

by

the

Dep

artm

ent o

f Agr

i cul

-tu

re, F

ores

try

and

Fis

herie

s’ d

iagn

ostic

labo

rato

ries

in

Ste

llenb

osch

.

Con

trol

met

hods

Con

trol

of c

itrus

gre

enin

g ca

n be

ach

ieve

d th

roug

h an

in

teg

rate

d a

pp

roa

ch w

hic

h in

clu

de

s e

rad

ica

ting

in-

fect

ed p

lant

mat

eria

l, in

trod

ucin

g cl

ean

nurs

ery

seed

-lin

gs, a

dher

ing

to r

egul

ator

y m

easu

res

and

elim

inat

ing

inse

ct v

ecto

rs b

y m

eans

of s

yste

mic

inse

ctic

ides

(as

th

ey a

re s

ap fe

eder

s).

Tre

atin

g a

ffe

cte

d t

ree

s w

ith in

ject

ion

s o

f a

ntib

iotic

s a

llevi

ate

s th

e s

ymp

tom

s, b

ut

do

es

no

t cu

re t

he

dis

-ea

sed

plan

ts. P

rom

pt e

limin

atio

n of

dis

ease

d tr

ees

is

stro

ngly

adv

ised

.

The

Asi

an fo

rm (‘

Can

dida

tus

Libe

ri bac

ter a

siat

icus

’) is

th

e m

ost

se

vere

an

d g

eo

gra

ph

ica

lly w

ide

spre

ad

. It

oc

curs

thro

ugho

ut A

sia,

the

Indi

an s

ubco

ntin

ent a

nd

ne

igh

bo

uri

ng

isla

nd

s, t

he

Sa

ud

i Ara

bia

n p

en

insu

la,

Bra

zil,

sout

hern

Flo

rida

, C

alifo

rnia

, C

uba,

Mau

ritiu

s,

Reu

nion

and

Eth

iopi

a.

The

Afr

ican

form

(‘C

andi

datu

s Li

beri b

ac te

r af

rican

us’)

is le

ss s

ever

e an

d is

mor

e re

stric

ted

geog

raph

ical

ly. I

t is

foun

d in

Afr

ica,

sou

th o

f the

Sah

ara.

The

Am

eric

an f

orm

(‘C

andi

datu

s Li

beri

bact

er a

mer

i-ca

nus’

) is

so

far

know

n to

occ

ur in

Bra

zil,

Cub

a, F

lor i-

da, B

eliz

e, M

exic

o an

d D

omin

ican

Rep

ublic

.

Sym

ptom

sC

itrus

pla

nts

affe

cted

by

citr

us g

reen

ing

bact

eria

may

n

ot

sho

w s

ymp

tom

s fo

r ye

ars

fo

llow

ing

in

fect

ion

. In

itial

sym

ptom

s on

a tr

ee in

clud

e th

e ap

pear

ance

of

yello

w s

hoot

s. A

s th

e ba

cter

ia m

ove

with

in a

tree

, the

en

tire

cano

py p

rogr

essi

vely

dev

elop

s a

yello

w c

olou

r.

Th

e t

hre

e f

orm

s o

f b

act

eri

a p

rod

uce

sim

ilar

sym

p-

tom

s.

Th

e m

ost

ch

ara

cte

rist

ic f

olia

r sy

mp

tom

s o

f ci

tru

s gr

eeni

ng a

re b

lotc

hy m

ottli

ng o

f the

leav

es a

nd y

ello

w-

ing

of le

af v

eins

and

sho

ots.

You

ng le

aves

may

dis

play

sy

mpt

oms

that

can

be

mis

diag

nose

d as

sig

ns o

f zin

c de

ficie

ncy.

Old

er le

aves

take

on

the

mot

tling

cha

rac-

Nym

ph o

f th

e A

sian

ci

trus

psy

llid

Nym

ph o

f Afr

ican

citr

us p

sylid

Adu

lt of

the

Afr

ican

citr

us

psyl

lid

Adu

lt A

sian

citr

us

psyl

lidA

dlt

Ai

itT

ypic

al b

lotc

hy m

ottli

ng

sym

ptom

s of

citr

us

gree

ning

on

citr

us s

pp

Fee

ding

dam

age

to c

itrus

le

aves

cau

sed

only

by

the

Afr

ican

citr

us p

sylli

d,

Trio

za e

rytr

eae

Infe

cted

ora

nge