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Management of Citrus OrchardsChina: The Past 50 YearsYulu Xia

North Carolina State University

Ron Sequeira

Veracruz, Mexico ugus ,

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Content

Introduction of citrus production, HLB and

A Brief on our method development andsurvey programs in China

,management of the newly planted groves

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Introduction of citrus production, HLB

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, ,

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Citrus Production in China: diverse environment and practices

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Citrus Production in China: good

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Citrus Production in China: bad with HLB infestation

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China HLB Belt

?

reported 1919

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Guangdong Province in 1919. But itwas poss y n ere s nce a e1800s

The disease is still #1 factor limiting

c rus pro uc on n uang ong,Guan xi and Fu ian

In spite of the long present, HLB hasnot spread to all areas where the

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A Brief on Our Method Developmentan urvey rograms n na

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Collaborators: South China Agri. Univ. (SCAU) Fujian Academy of Agri. Sci (FAAS) uangx rus esearc ns . Guangdong Entomological Insti. (GEI) , .

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Survey SCAU, FAAS, GCRI The epidemiological significance of Murraya paniculata and

Murraya spp. - FAAS

Microbials and Plant Immune Activation - FAAS Dynamics of Reset Plants Migration patterns of ACP - SCAU

Oils and Soaps for Field Management - GEI Best Practices for ACP/HLB Management GEI & Additional Insect Vectors and Host plants - SCAU

Chinese literature review and inventory GEI ACP insecticide resistance and resistance management

(GCRI)

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anagemen n na, nc u ngmana ement of the newl lantedgroves

e w start w t t e pr nc p es, messages,lessons learned, etc Then some examples

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Chinese have been dealin with thedisease for over 80 years.

are o success an a ure

HLB infested plants taken in 1930 in chaoshan

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1. HLB is a ver tou h disease due to thenatures such as:.

b. No effective agent against the diseasec. Infection by the vector and other means,

,2. HLB is cancer only to individual plant. To a

grove/region, HLB is a manageable

disease assumin ou follow the booknot mess around

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a. Removing the infested plants ASAPb. Control of ACP

-.

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What is the mess around?

b. Not effective control of ACP

c. Dont use pathogen-free seedlings

Chinese experience showed that addingnutr t on as no ong term ene t. t s adangerous practice by leaving inoculum

source

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plants under peak production

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plantations in China was destroyed, dueto slow in removing the infested plants

see the color

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This view became widespread by the late,

sponsored Mass Area-wide of HLB,

increasing fertilization, cutting the heavily,

decayed roots, across the huge HLB,

especially in Fujian and Guangdong, . ,

the program failed. HLB became even.

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A four-year old groves with 100% infested HLBl n . B i l k in h rin wi h

fertilization and irrigation

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You cant follow the book in one year,

disease/ACP in the area Skip even just one season can cost youa lot.

This is particularly true for the small

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anagemen n na, nc u ng

mana ement of the newl lantedgroves

e w start w t t e pr nc p es, messages,lessons learned, etc Then some examples

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Guangdong Province

Where HLB was first reportedStill the most severe region

aos an, rs

reported HLB

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Guangdong Province

Yangcun Citrus Plantation (YCP),

research institute (figure below), hospital,, ,

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OccurrenceHistory of HLB in YCP 1953 - 2010

HLB Rate80%

1st Generation Citrus 2nd Gen. 3rd Gen.

1953 - 1973 19821975

1995 2010

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YCP 1 st Generation PlantsHLB Rate

80%

The year of reduced insecti. use and OCs ban

ACP o .Urate was below 0.01%

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2nd Generation PlantsHLB Rate

80%

ar ng am y- ase c rusproduction system

1986 and 1987 were the

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3 rd Generation Plants

HLB Rate80%

1995

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G i i

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Guangxi Province

Among the top three HLB devastatingareas

But HLB is under control b followin thebook

Guangxi

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Massive grass-root efforts in control of HLB (Credit: Bai XJ)

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5.98

7

5

6

3.94

1.82.16

2

0

1

2005 2006 2007 2008 2009

Province-wide HLB incidence rate in Guan xi

2005-2009

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HLB Rate (%)

23,45%

15%

8%10%

1% 1%0 44%

5%

, , ,0%

1 2 3 4 5 6 7 8 9

HLB Occurrence in Li Xing Citrus Plantation, Guangxi Prov. credit: Bai XJ

ear: =

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Key Points

manageable disease. The three-pronged approach has to be

followed.

Management of HLB is more of an issue of, .

No resistance scion and/or rootstock wasobserved.

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Mineral/agri//horticultural oils are effective

aga ns y o nsec c e ac v y,

possibly repellency. Insecticide resistance has been observed

immidacloprid. ACP shows migration long distance

followin the wind. Flushing control shows good outcome, but

inappropriately.

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ACP can come and go pretty quickly

Come: reproduction can be fast if the

environment is suitable Go: natural factors can cause over 90%

mortality. In the new area, natural enemy

plays less role at the beginning, but will catchup

Monitoring population is a key when ACP

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rac as

43- ear mandarin tree(Lu mandarin, C. reticulata)

A more than 200 year-old of Citrus sunki grows well in Guangxi, in spiteHLB area of Fujian prov.of the fact that the province is one of the most serious HLB occurrence area in the world

(credit: BAI XJ)