2011 Mexico Xia mundial

8/4/2019 2011 Mexico Xia mundial

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Experience in the Use of Nutrition forthe Management of HLB in China, with

a Reference to the Practice in Florida

Yulu Xia North Carolina State University

Ron Sequeira USDA APHIS PPQ CPHST

Santiago, Manzanillo, Mexico

August 18, 2011


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Content

The Big picture Why the topic?

A Brief on Citrus production, HLB, and ACP in China

Nutritional approach for HLB management inChina

Overall situation

Selected studies since 1937

Field practice and lessons learned Conclusions

Other considerations


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Why the topic?

Using nutritional approach

gathers momentum in Florida. Nutrition makes grove look

good (slides on right: top:GD/China, bottom: Florida)

The long time before thesymptom shows up after theinitial infection

The infected trees never die,just fade away

Data from field research is in earlystage or incomplete


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Why the topic?

Scientific community andgrowers

We must provide theanswers

Experience in China mayshortcut our experience

China experienced thesame frustration

Save our $, moreimportantly, time


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Citrus Growing Area in China

China has a much larger citrus production area.


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The Big Pictures ACP Occu.ACP Reported in at least 11 prov


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The Big Pictures HLB Occur.

HLB mainly occurs in the southern costalprovinces: Guangdong, Guangxi, andFujiang

Major HLB OccurrenceThe HLB Belt


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The first observations of diseased

citrus corresponding to what is nowrecognized as HLB werein southernChina in the late 19th century. In themid-20th century, the Chinese

researcher K.H. Lin provided ascientific description of HLB anddemonstrated its infectious nature.

--- National Research Council,Strategic Planning for the Florida CitrusIndustry: Addressing Citrus GreeningDisease (Huanglongbing), May 2010


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K. H. Lin promoted in China, in the middleof the 20th century, a three-prongedapproach to combating HLB after its

appearance in a region

(i)elimination of liberibacter inoculum byremoval of symptomatic trees,

(ii) insecticide treatments to keep psyllidvector populations as low as possible,and

(iii) production of healthy citrus trees

in closed, insect-proof nurseries for neworchards as well as for replacements ofremoved symptomatic trees


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Picture taken in 1930s showing HLBin Chaoshan, Guangdong


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Long and diverse citrus productionsystem


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Nutritional approach for HLB managementin China

A Brief of our current projects inChina

Overall situation Selected studies since 1937

Field practice and lessons learned

Conclusions & Questions


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Our current projects in China

Two grant projects by USDA APHIS

APHISs emphasis on methoddevelopment

ACP/HLB Field Method Development and

Outreach

Chinese HLB/ACP Literature Inventory


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Nutritional approach for HLB management inChina

A Brief of our current projectsin China

Overall situation Selected studies since 1937

Field Practice and Lessonslearned

Conclusions and Questions


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A Review of research on nutritionfor HLB management since 1937

- Overview

Using nutritional approach for HLBmanagement had been proposed since1930s

There were fierce debates on the issuesince 1950s all the way to 1980s

Numerous field studies, area-wide

programs, and surveys have beenconducted, no indication of effectiveness

Difference in response to nutrition amongcitrus species/cultivars


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Selected studies

First study was conducted during the

period of 1937 1941 by professor

CHEN Che Poh, in the middle of theworld II (Japan occupied China)

CHEN QB: 1943. A report of a study ofHuanglongbing in Chaoshan.Quarterly Bulletin of New Agriculture.

142 175


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Nutritions

zinc sulphate (ZnSo4), copper sulphate(CuSo4), boron(H3BO3), calcium sulphate(CaSo4), ferric sulphate(FeSo4), potassiumhydrophosphate (KH2PO4), magnesiumsulphate(MgSo4), soy bean residue, etc.

Application methods

foliar application

trunk injection

soil application

CHEN QB: 1943. A report of a study of Huanglongbing in Chaoshan. Quarterly Bulletin ofNew Agriculture. 142 175


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Conclusions

Application of various nutritions by threemethods did result any meaning differencesymptoms and growth, compared to theuntreated.

Problems with the experiment

Apparently no psyllid control

Relatively small experimental size and

duration

Fairly sick trees.

CHEN QB: 1943. A report of a study of Huanglongbing in Chaoshan. Quarterly Bulletin ofNew Agriculture. 142 175

A l b f fi ld t di


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A large number of field studies wereconducted using nutrition/fertilization andother cultural practices for managing HLB

from early 1940s to 1980s in China, nolong-term success or benefit had beendemonstrated.

LIN KH 1977. The Key Issues in Management of HLB.Bulletin of Citrus Technology and Technology 3-4: 28 37

ZHAO XY & YH JIANG. 1986. Effective HLBmanagement is a key step in Liuzhous citrus production

Chinese Southern Fruit. 2: 21 - 22

Again, they didnt pay much attention to 1)psyllid management, 2) differentiation of citruscultivars, 3) HLB infection rate, 4) age of the

plants, 5) citrus cultivation


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A Brief of our current projects inChina

Selected studies since1937

Field practice and lessonslearned

Conclusions and Questions


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Field Practice and Lessons Learned

The three-pronged approach, e.g. 1)using pathogen free seedlings, 2)removal of the infested plants, and3) control of vector insects, was

proposed by Dr. Lin and otherresearchers in 1950s.

However, this approach was notwidely adopted in China, even at

minority sometimes, using nutritionand other culture practice wasrepeatedly advocated by growersand event scientists.

LIN KH 1956, 1957, and 1962


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A test of removal infested tree, conducted byDr. Lin KH.

08-1956 to 03-1961

LIN KH 1962. Ten Year Debate on HLB and the Future. TheSouth Daily. March 29, March 30, March 31, 1962.

# of Citrus Tree Removal Area Control

Total plants at start 229 197

Total infested plants at start 11 (4.8%) 13 (6.6%)

Newly Infested - 1958 8 (3.5%) 19 (9.6%)

Newly infested - 1961 67 (29.2%) 112 (56.8%)


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Removal of the infected citrus

plants is no doubt the fundamentalin an effective HLB managementprogram.

In my view, current argumentis not about whether, butabout WHEN


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LIN KH 1956. Observation on yellow

shoot of citrus: aebiological studies ofyellow shoot of citrus. ActaPhytopathologica Sinica 2: 1 42.

LIN KH 1962. Ten Year Debate on HLBand the Future. The South Daily. March29, March 30, March 31, 1962.


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This view became widespread by the late

of 1950s, lead to local governmentsponsored Mass Area-wide of HLBManagement Program, mainly by

increasing fertilization, cutting the heavily

infested branches, and removingdecayed roots, across the huge HLBoccurrence area in southern China,

especially in Fujian and GuangdongProvinces, started in 1958. As expected,the program failed. HLB became evenmore serious.


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1960s and later Nutrition and other cultural practice have

been practiced among the small-scale,family-own groves. The three-prongedapproach is not widely used by thesegrowers.

Few scientists, especially those whodidnt conduct field study on the issue,

advocated the approach.

E.g. HOU XY 1985, distinguished botanist

and An Academician of CAS. This is the main reason that HLB is still a

problem there.


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Credit: Bai XJ


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The three-pronged approach adopted bythe bigger, professional growers, andworks well across China.

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8%

5%

1% 1% 0.44% 0.23% 0.13% 0.05%

0

0.05

0.1

0.15

0.2

0.25

1 2 3 4 5 6 7 8 9

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

HLB Rate

Year: 1 = 2001


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WU DY 2010HLB and Integrated

Management.

Pp. 177. Guangdong

Scientific Press.

LIN KH 1962. Ten Year Debate on HLB andthe Future. The South Daily. March 29,March 30, March 31, 1962.


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A Brief of our current projectsin China

Selected studies since1937

Field practice and lessonslearned

Conclusions

HLB i bl di if f ll


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HLB is a manageable disease if you follow

the principle

Nutrition/fertilization is not effective

generally. However, we find a number ofanecdotal evidences that the approachmay have value in following case

1. Mature plants, still look healthy,2. Vigorous psyllid management

3. And sound citrus management

4. Pomelo > sweet orange > mandarin >Limon

5. Then, you have to consider all otherfactors such as infection rate, age of

grove, etc.


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1. Ponkan and Jiaogan mandarins (Citrusreticulata), regarded as the most succeptibleto HLB , planted in 1967, in Fujian, China

2. Infection occurred in 2010 -2011.

3. By using foliar nutritional appli., keep psyllidvery low, lots of the infected trees still w/

decent production


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1. If you have to nutritionalapproach, it almost certain youCANT reduce the bacterium titer

in the plants, so??


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City/Country High temp Temp mean Hottest Record


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mean value

(C)value (C) month highest

temp (C)Guangzhou/China 32.7 28.5 July 39.1

Miami/US 31.7 28.2 August 37.8So Paulo/Brazil 28.0 22.4 February 37.0Bangalore/India 34.2 28.0 April 38.9Taipei/Taiwan 32.0 28.4 July 38.8Bali/Indonesia N/A N/A N/A 35.2Manzanillo/Comila/

MexicoN/A N/A July 33.0

Okinawa/Japan 30.7 28.1 August 35.6Ho Chi Min City/Vietnam N/A N/A N/A 39.4

New York City /USA 28.2 24.2 July 41.7Bakersfield(CA)/USA 36.9 28.9 July 47.2McAllen(TX)/USA 36.0 N/A July 43.0Jeddah/Saudi Arabia 37.6 32.4 July 52.0


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Since vector control is critical innutritional approach. Other citrusfeeding psyllids?

the pomello psyllids, Cacopsylla (Psylla) citrisuga, we find in

China, is likely another vector of HLB, pending furthertransmission study

Th k !


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Thank you!

Documents

2011 Mexico Xia mundial