Mexico 2009 DaGraca Final

8/14/2019 Mexico 2009 DaGraca Final

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History and World Situation of

Huanglongbing

John V da GracaTexas A&M University-Kingsville

[email protected]


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Early Reports

Huanglongbing first observed in southernChina late 18th century

Reported in Philippines in 1921 (mottle

leaf)

Greening first reported in South Africa in1928/29


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Chinese origin?

Citriculture 4,000 years old

Chinese farmers observed yellow shootsin 18th century (anecdotal)

Reinkings record (1919) very brief andnot clearly HLB

D. citrifirst positively in 1934; no mentionof HLB symptoms by entomologists

Clear HLB symptoms recorded in 1938


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Citrus dieback India


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Indian origin?

18th century Raghoji Bhonsale (Raja ofNagpur) observed dieback in Central

Provinces

1888 dieback in Assam

1912 - severe problem in Bombay Province

1927 Husain & Nath psyllid damage

resembles HLB (bitter tasting fruit)1963 dieback = Citrus tristeza virus

1969 dieback = greening (HLB)


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Husain & Nath (1927)


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Spread in Southeast Asia

Indonesia 1940s

Taiwan 1950 (D. citriknown in 1908!)

Philippines 1950s (Lee 1921?) Thailand 1960s

Malaysia 1970s


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Records of Citrus Tree Movements

Citrus from India to China via SE Asia?

Citrus introduced into Indonesia fromChina in 1945 (HLB 1948)

Many introductions into Philippines fromIndia, China, Taiwan before 1957 (HLB1957)

Mandarin introduced into Malaysia fromChina 1950s/60s (HLB 1970s)


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HLB a new disease of citrus

Citrus cultivated in China for 4,000 years

Citrus cultivated in India pre-800 BC

No HLB until 1750?

New disease of citrus; fact that no Citrus spp. isresistant/tolerant also suggests it is new


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HLB in Africa

1928/9 farmers report yellow branch(NW Transvaal) & greening (NETransvaal). Clear HLB-like symptoms

Became severe in 1930s in NE, but notelsewhere

1958 Severe in several areas in north

Reported later in other African countries:

Zimbabwe (1967), Kenya (1984),Tanzania (1988), Malawi (1988), etc.


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N. PROVINCE

NATAL

E. CAPE

W. CAPE

NORTH-WEST

GAUTENG

O.F.S.

N. CAPE

SWAZILAND

LESOTHO

NELSPRUIT

DURBAN

PORT ELIZABETHCAPE TOWN

JOHANNESBURG

PRETORIA

PIETERSBURG

= Infected areas= Uninfected areas

Citrus producing areas


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S./E.African citriculture

Arab traders E.Africa from 1000

Portuguese trade between E.Africa/Indiaafter 1500

Wild rough lemon found in Zimbabweintroduced by Portuguese?

1654 citrus planted in Cape Early 20th century rapid expansion to

north of S Africa


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Movement of citrus germplasm in

Africa

CTV endemic in S. Africa

CTV incidence in Anglophone W. Africahigh in 1950s - germplasm from S.Africa

CTV incidence in Francophone W. Africalow in 1950s germplasm fromFrance/N.Africa

S. African budwood probably taken to E.Africa


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Where did HLB come from?

AFRICA

Host range:

Ca. Liberibacter africanus reported in

some wild rutaceae in Africa:


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Vepris lanceolata


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Clausena anisata


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Calodendrum capenseCa. L. africanus ssp capense


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HLB in Asia

Diaphorina citriis an Asian species.

Local hosts include Murrayaspp.

HLB originiated in indigenous Asianrutaceaeous plants?


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Murrayawith HLB


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Clausena lansium(wampee)Asian or African?


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Atalantia (Severinia) buxifolia


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Wood apple - Limonia acidissima


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Beattie et al. hypothesis

HLB originated in Africa

Transported to India 300-500 years ago inC.anisataor citrus from SE African coast

(Mosambi orange ex-Mozambique)

Acquired by D. citri spread by vector and

vegetative propagation Moved to China from India (via SE Asia?)

in 1930s


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Pros/Cons

Pros:

Both psyllid species can transmit HLB

Veprisappears to be asymptomatic to Ca. L. africanus(mild seasonal mottle) (Ca. L. asiaticus?)

Clausenaspp. may be African in origin

Cons:

No L. asiaticus found in Africa (search more? E. Africa)

Coast too hot for Ca. L. africanus No Ca. L. africanus found in Asia

Rapid evolution of Liberibacter spp. ?


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Current HLB status

L. africanus East, Central and SouthAfrica, Yemen

L. asiaticus Asia from Saudi Arabia to

Indonesia & PNG, Americas

L. americanus Brazil and China


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HLB in the Americas

2004 Sao Paulo state, Brazil

2005 Florida, USA

2008 Louisiana, Puerto Rico, Cuba 2009 South Carolina, Georgia, Belize

Note these are HLB confirmation dates.Pathogen must have been present for atleast 2 years


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Possible origins

Ca. L. africanus originated in nativeAfrican rutaceae (Vepris/Clausena) andinfected citrus in S. Africa when land was

cleared for citriculture (early 20th

century) Ca. L. asiaticus probably originated in

India in native Asian rutaceae (Murraya?)and infected citrus in 18th century

Ca. L. americanusmay also have Asianorigins


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Mexico and Texas HLB is gettingcloser

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Mexico 2009 DaGraca Final