This section of the FEDERAL REGISTER

contains regulatory documents having general

applicability and legal effect, most of which

are keyed to and codified in the Code of

Federal Regulations, which is published under

50 titles pursuant to 44 U.S.C. 1510.

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the Superintendent of Documents. Prices of

new books are listed in the first FEDERAL

REGISTER issue of each week.

Rules and Regulations Federal Register

8603 

Vol. 76, No. 31 

Tuesday, February 15, 2011 

1To view the interim rule, its supporting and 

related materials, and the comments we received, 

go to http://www.regulations.gov/fdmspublic/ 

component/main?main=DocketDetail&d=APHIS2008-0052. 

DEPARTMENT OF AGRICULTURE 

Animal and Plant Health Inspection 

Service 

7 CFR Part 319 

[Docket No. APHIS–2008–0052] 

RIN 0579–AD07 

Citrus Seed Imports; Citrus Greening 

and Citrus Variegated Chlorosis 

AGENCY: Animal and Plant Health 

Inspection Service, USDA. 

ACTION: Affirmation of interim rule as 

final rule. 

SUMMARY: We are adopting as a final 

rule, without change, an interim rule 

that amended the regulations governing 

the importation of nursery stock to 

prohibit the importation of propagative 

seed of several Rutaceae (citrus family) 

genera from certain countries where 

citrus greening or citrus variegated 

chlorosis (CVC) is present. The interim 

rule also required propagative seed of 

these genera from all other countries to 

be accompanied by a phytosanitary 

certificate with an additional 

declaration that neither citrus greening 

nor CVC are known to occur in the 

country where the seed was produced. 

We took that action because scientific 

evidence indicated that seed of certain 

genera of the family Rutaceae may be a 

pathway for the introduction of those 

diseases. The interim rule was necessary 

in order to prevent the introduction or 

dissemination of citrus greening or CVC 

within the United States. 

DATES: Effective on February 15, 2011, 

we are adopting as a final rule the 

interim rule published at 75 FR 17289– 

17295 on April 6, 2010. 

FOR FURTHER INFORMATION CONTACT: Dr. 

Arnold Tschanz, Senior Plant 

Pathologist, Plant Health Programs, 

PPQ, APHIS, 4700 River Road Unit 133, 

Riverdale, MD 20737–1231; (301) 734– 

0627. 

SUPPLEMENTARY INFORMATION: 

Background 

Citrus greening (known 

internationally as Huanglongbing 

disease of citrus and referred to below 

as HLB) is considered to be one of the 

most serious citrus diseases in the 

world. HLB is a bacterial disease caused 

by strains of the bacterial pathogens 

‘‘Candidatus Liberibacter asiaticus’’, 

‘‘Candidatus Liberibacter africanus’’, 

and ‘‘Candidatus Liberibacter 

americanus’’ that attack the vascular 

system of host plants. The pathogens are 

phloem-limited, inhabiting the foodconducting tissue of the host plant, and 

causes yellow shoots, blotchy mottling 

and chlorosis, reduced foliage, and tip 

dieback of citrus plants. HLB greatly 

reduces production, destroys the 

economic value of the fruit, and can kill 

trees. Once a tree is infected, there is no 

cure for HLB. In areas of the world 

where the disease is endemic, citrus 

trees decline and die within a few years 

and may never produce usable fruit. 

HLB was first detected in the United 

States in Miami-Dade County, FL, in 

2005, and is only known to be present 

in the United States in the States of 

Florida and Georgia, Puerto Rico, two 

parishes in Louisiana, and two counties 

in South Carolina. 

CVC is also a highly injurious disease 

of citrus. Caused by a strain of the 

bacterium Xylella fastidiosa, CVC 

causes severe chlorosis between veins 

on the leaves of affected plants. Leaves 

on affected plants frequently have 

discoloration of the upper leaf coupled 

with brown lesions underneath. CVC 

may reduce plant growth and lead to 

abnormal flowering and fruit 

production. CVC is currently not known 

to occur in the United States. 

The regulations in 7 CFR part 319, 

‘‘Foreign Quarantine Notices,’’ prohibit 

or restrict the importation of certain 

plants and plant products to prevent the 

introduction or dissemination of plant 

pests and noxious weeds into the 

United States. The regulations in 

‘‘Subpart-Nursery Stock, Plants, Roots, 

Bulbs, Seeds, and Other Plant Products,’’ 

§§ 319.37 through 319.37–14 (referred to 

below as the regulations), restrict, 

among other things, the importation of 

seeds for propagation. 

In an interim rule 1 effective and 

published in the Federal Register on 

April 6, 2010 (75 FR 17289–17295, 

Docket No. APHIS–2008–0052), we 

amended the regulations to prohibit the 

importation of propagative seed of 

several Rutaceae (citrus family) genera 

from certain countries where HLB or 

CVC is present, and to require 

propagative seed of these genera from 

all other countries to be accompanied by 

a phytosanitary certificate with an 

additional declaration that neither HLB 

nor CVC is known to occur in the 

country where the seed was produced. 

Comments on the interim rule were 

required to be received on or before June 

7, 2010. We received three comments by 

that date, from a citrus nursery, a 

company engaged in the commercial 

production, packing, and shipping of 

citrus products, and a State department 

of agriculture. The comments are 

addressed below, by topic. 

General Comments on the Interim Rule 

One commenter stated that countries 

in which HLB or CVC is present would 

respond to the prohibitions of the 

interim rule by in turn prohibiting the 

importation of citrus articles from the 

United States. Because the loss of 

foreign markets would adversely impact 

the U.S. citrus industry, the commenter 

stated that the rule should be 

withdrawn. 

On September 19, 2005, the Animal 

and Plant Health Inspection Service 

(APHIS) of the United States 

Department of Agriculture (USDA) 

reported the first two confirmed 

detections of HLB within the United 

States to the International Plant 

Protection Convention. Since that time, 

it has been at the discretion of foreign 

countries to promulgate regulations 

prohibiting or restricting the 

importation of host articles of HLB from 

the United States, based on an 

assessment of the potential risk to 

plants, plant parts, and plant products 

within those countries that could be 

associated with the introduction or 

dissemination of the disease. We note, 

however, that countries that are 

members of the World Trade 

Organization have committed 


jdjones on DSK8KYBLC1PROD with RULES
8604 Federal Register / Vol. 76, No. 31 / Tuesday, February 15, 2011 / Rules and Regulations 

2Halbert, Susan and Keremane L. Manjunath. 

Asian Citrus Psyllids (Sternorrhyncha: Psyllidae) 

and Greening Disease of Citrus: A Literature Review 

and Assessment of Risk in Florida. Found at 

http://www.bioone.org/doi/pdf/10.1653/0015- 

4040(2004)087[0330:ACPSPA]2.0.CO;2. 

3Benyon, L.S., et al. Transmission of ‘Candidatus 

Liberibacter asiaticus’ from seeds to seedlings in 

citrus along with a low bacterial tier and atypical 

HLB symptoms. Available by contacting the 

individual listed under FOR FURTHER INFORMATION

CONTACT. 

4Albrect, Ute and Kim D. Bowman. 2009. 

Canidatus Liberibacter asiaticus and 

Huanglongbing Effects on Citrus Seeds and 

Seedlings. HortScience 44: 1967–1973. Available at 

http://ddr.nal.usda.gov/bitstream/10113/38868/1/ 

IND44303043.pdf. 

5Shokrollah, Hajivand, et al. Determination of the 

Presence of Huanglongbing in Seeds and Movement 

of the Pathogen in Citrus reticulata. American 

Journal of Applied Sciences 6: 60: 1180–1185. 

Available at http://www.allbusiness.com/medicinehealth/disease-agents-vectors/13080162-1.html. 

6Li, W.B., W.D. Pria, Jr., P.M. Lacava, et al. 

Presence of Xylella fastidiosa in Sweet Orange Fruit 

and Seeds and Its Transmission to Seedlings. 

Phytopathology (Vol. 93, No. 8) 2003, 953–958. 

themselves to basing prohibitions or 

restrictions on the importation of 

articles (such as, in this case, citrus from 

the United States) on scientific evidence 

and risk assessment. 

Comments Regarding Transmission of 

HLB Through Propagative Seed 

In the interim rule, our stated 

rationale for imposing prohibitions on 

the importation of seed of genera that 

are hosts of HLB was that emerging 

evidence suggested that such seed could 

transmit the disease. To that end, we 

cited a peer-reviewed article by Susan 

Halbert and Keremane Manjunath that 

detailed that, when seedlings are 

generated from seed that is infected 

with HLB, a small percentage of those 

seedlings have been found to be infected 

with HLB.2

All three commenters stated that the 

Halbert and Manjunath article did not 

provide an adequate scientific basis for 

considering seed to be a pathway for the 

transmission of HLB. Two of the 

commenters pointed out that Halbert 

and Manjunath did not conduct original 

research regarding seed transmission, 

but instead referenced a 1981 study. The 

same commenters also pointed out that 

researchers in the 1981 study collected 

only a small number of seeds, and did 

not test the seedlings derived from this 

seed for the disease, but rather 

determined them to have the same 

stunted, chlorotic appearance as 

infected plants. Both commenters 

concluded by citing Halbert and 

Manjunath’s assessment that the 1981 

experiment ‘‘bears repeating’’ as 

evidence that Halbert and Manjunath 

themselves had concerns about the 

study’s findings. Finally, one 

commenter cited two more recent 

studies, published in 2009, that the 

commenter asserted conclude that HLB 

is not seed-borne. All three commenters 

stated that we should amend the interim 

rule to allow the importation of 

propagative seed from countries where 

only HLB is present. 

We disagree with the commenters’ 

interpretation of Halbert and 

Manjunath’s assessment of the 1981 

experiment; stating that an experiment 

bears repeating is not tantamount to 

stating that one has concerns with its 

findings, and is, in fact, consistent with 

the basic elements of the scientific 

method. 

Moreover, the Halbert and Manjunath 

article was not our sole basis for taking 

regulatory action; we referenced it in 

order to illustrate some of the 

information that factored into our 

determination. We considered other 

evidence. For example, as we 

mentioned in an interim rule that 

established domestic quarantine 

regulations for HLB and that was 

published in the Federal Register and 

effective on June 17, 2010 (75 FR 

34322–34336, Docket No. APHIS–2008– 

0015), researchers at USDA’s 

Agricultural Research Service (ARS) and 

APHIS’ Center for Plant Health Science 

and Technology (CPHST) have recently 

undertaken extensive studies to 

determine the likelihood of seed 

transmission of HLB. Both the ARS and 

CPHST studies found that a percentage 

of seedlings from infected seed tested 

positive for HLB via polymerase chain 

reaction (PCR) analysis; in the ARS 

study, the infection rate varied, but was 

as great as 78.5 percent in certain 

instances.3 ARS researchers did note, 

however, that the bacterium causing 

HLB remained at a very low titer in 

affected plants, and that most infected 

seedlings remained largely or entirely 

asymptomatic several years after testing 

positive for the disease. 

One of the 2009 articles 4 referenced 

by the commenter does not contradict, 

and in fact is generally consistent with, 

the findings of the ARS study. The 

article details a 2007 study, conducted 

by Ute Albrecht and Kim Bowman, in 

which more than 15,000 seeds were 

obtained from symptomatic trees of the 

following species: Citrus macrophylla 

Webster, Citrus vangasay bojer, 

X Poncirus trifoliata, Citrus reticulata 

Blanco, Citrus aurantium L., and Citrus 

sinensis. Of the seedlings grown from 

these seeds, 769 were tested for HLB via 

PCR analysis at time periods ranging 

from 7 weeks to 9 months after sowing. 

Five of these 769 seedlings tested 

positive for the disease. However, titer 

levels of the bacterium were low, and 

the plants remained asymptomatic. In 

addition, repeated retesting of the 

positive plants several months after the 

initial test yielded negative PCR results. 

The other article 5 referenced by the 

commenter details an experiment that 

Hajivand Shokrollah conducted in order 

to determine the transmissibility of HLB 

through seed obtained from infected 

Citrus reticulata plants. As part of the 

experiment, Shokrollah tested 20 

seedlings grown from such seed by 

using PCR analysis. While each seedling 

tested negative for HLB, we do not 

consider 20 plants, all of the same 

species, to be a large enough or varied 

enough sample size to yield conclusive 

results regarding disease transmission. 

We acknowledge that all the studies 

referenced above suggest that the 

transmission of HLB via propagative 

seed is fundamentally different than its 

transmission via other vectors, such as 

budwood or Asian citrus psyllid: The 

bacterium is present in infected 

seedlings at low concentration levels, 

plants remain largely asymptomatic, 

and plants may test negative for the 

disease after initially testing positive. 

However, it is well-documented that the 

bacterium associated with HLB may be 

unevenly distributed throughout an 

infected plant, that the latency period 

for expression of symptoms may be 

pronounced, and that the manner in 

which those symptoms are expressed is 

influenced by a multitude of factors. 

Accordingly, because of the severity of 

HLB, in order for us to deregulate 

propagative seed as a host of the 

disease, we would need clear evidence 

that the disease cannot be transmitted 

via propagative seed or that infected 

seedlings cannot serve as vectors of the 

disease. Such evidence does not 

currently exist. Hence we are making no 

change to the interim rule in response 

to these comments. 

One commenter stated that hot water 

dips are effective in treating seed for 

HLB. However, the commenter failed to 

provide any evidence in support of this 

assertion. 

Comments Regarding CVC Transmission 

Through Propagative Seed 

In the preamble of the interim rule, 

our stated rationale for imposing 

prohibitions on the importation of seed 

of genera that are hosts of CVC was that 

there was also emerging evidence that 

propagative seed could transmit this 

disease. To that end, we cited a 2003 

study 6 by W.B. Li et al. (referred to 

below as Li et al.). 

One commenter pointed out that Li 

et al. was conducted only on three 


jdjones on DSK8KYBLC1PROD with RULES
Federal Register / Vol. 76, No. 31 / Tuesday, February 15, 2011 / Rules and Regulations 8605 

subspecies of sweet oranges, did not 

evaluate disease transmission from 

seeds taken from asymptomatic fruit, 

and was aborted before conclusive 

findings could be drawn. The 

commenter therefore asserted that seed 

should not be regulated as a host of CVC 

until further research is conducted. 

The commenter is right in pointing 

out that Li et al. was aborted abruptly, 

because of a hurricane, and that only a 

study on three subspecies of sweet 

oranges was concluded by that time. 

However, CVC seed infection rates were 

greater than 22 percent for one 

subspecies evaluated in that study, and 

the transmission from seeds to seedlings 

was determined to be ‘‘efficient.’’ 

Moreover, research had begun on 

several other species, and was tending 

towards the results of the sweet orange 

study. Finally, we note that no studies 

have been conducted since 2003 that 

call into question the findings of Li 

et al. For these reasons, we have 

determined that Li et al.’s conclusion, 

that the study ‘‘demonstrated that [CVC] 

can be transmitted through seed to 

seedlings,’’ is correct, and constitutes a 

sufficient basis for the prohibitions in 

the interim rule. 

Therefore, for the reasons given in the 

interim rule and in this document, we 

are adopting the interim rule as a final 

rule, without change. 

This action also affirms the 

information contained in the interim 

rule concerning Executive Order 12988 

and the Paperwork Reduction Act. 

Further, this action has been 

determined to be not significant for the 

purposes of Executive Order 12866 and, 

therefore, has not been reviewed by the 

Office of Management and Budget. 

Regulatory Flexibility Act 

This rule affirms an interim rule that 

amended the regulations governing the 

importation of nursery stock to prohibit 

the importation of propagative seed of 

several Rutaceae (citrus family) genera 

from certain countries where citrus 

greening or citrus variegated chlorosis 

(CVC) is present. The interim rule also 

required propagative seed of these 

genera from all other countries to be 

accompanied by a phytosanitary 

certificate with an additional 

declaration that neither citrus greening 

nor CVC are known to occur in the 

country where the seed was produced. 

The action was necessary in order to 

prevent the introduction or 

dissemination of citrus greening or CVC 

within the United States. 

We have prepared a final regulatory 

flexibility analysis addressing the 

economic effects of the interim rule on 

small entities, as required by the 

Regulatory Flexibility Act. The analysis 

identifies importers of citrus seed as 

entities potentially affected by the 

interim rule. The full analysis may be 

viewed on the Regulations.gov Web site 

(see ADDRESSES above for instructions 

for accessing Regulations.gov) or 

obtained from the person listed under 

FOR FURTHER INFORMATION CONTACT. 

List of Subjects in 7 CFR Part 319 

Coffee, Cotton, Fruits, Imports, Logs, 

Nursery stock, Plant diseases and pests, 

Quarantine, Reporting and 

recordkeeping requirements, Rice, 

Vegetables. 

PART 319—FOREIGN QUARANTINE 

NOTICES 

Accordingly, we are adopting as a 

final rule, without change, the interim 

rule that amended 7 CFR part 319 and 

that was published at 75 FR 17289– 

17295 on April 6, 2010. 

Done in Washington, DC, this 9th day of 

February 2011. 

Kevin Shea, 

Acting Administrator, Animal and Plant 

Health Inspection Service. 

[FR Doc. 2011–3367 Filed 2–14–11; 8:45 am] 

BILLING CODE 3410–34–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2010–1113; Directorate 

Identifier 2010–NM–121–AD; Amendment 

39–16603; AD 2011–04–03] 

RIN 2120–AA64 

Airworthiness Directives; Bombardier, 

Inc. Model CL–600–2B19 (Regional Jet 

Series 100 and 440) Airplanes 

AGENCY: Federal Aviation 

Administration (FAA), Department of 

Transportation (DOT). 

ACTION: Final rule. 

SUMMARY: We are adopting a new 

airworthiness directive (AD) for the 

products listed above. This AD results 

from mandatory continuing 

airworthiness information (MCAI) 

originated by an aviation authority of 

another country to identify and correct 

an unsafe condition on an aviation 

product. The MCAI describes the unsafe 

condition as: 

During flight-testing of a wing anti-ice 

piccolo tube containing a deliberate small 

breach, it was determined that the wing 

leading edge thermal switches Part Number 

(P/N) 601R59320–1 were not detecting the 

consequent bleed leak at the design 

threshold. As a result, Airworthiness 

Limitation (AWL) tasks, consisting of a 

functional check of the wing leading edge 

thermal switches (P/N 601R59320–1) and an 

inspection of the wing anti-ice duct piccolo 

tubes on aeroplanes with these switches 

installed, have been introduced. These tasks 

will limit exposure to dormant failure of the 

wing leading edge thermal switches in the 

event of piccolo tube failure, which could 

potentially compromise the structural 

integrity of the wing leading edge and the 

effectiveness of the wing anti-ice system. 

* * * * * 

The unsafe condition is loss of control 

of the airplane. We are issuing this AD 

to require actions to correct the unsafe 

condition on these products. 

DATES: This AD becomes effective 

March 22, 2011. 

The Director of the Federal Register 

approved the incorporation by reference 

of certain publications listed in this AD 

as of March 22, 2011. 

ADDRESSES: You may examine the AD 

docket on the Internet at http:// 

www.regulations.gov or in person at the 

U.S. Department of Transportation, 

Docket Operations, M–30, West 

Building Ground Floor, Room W12–140, 

1200 New Jersey Avenue, SE., 

Washington, DC. 

FOR FURTHER INFORMATION CONTACT: 

Cesar Gomez, Aerospace Engineer, 

Airframe and Mechanical Systems 

Branch, ANE–171, FAA, New York 

Aircraft Certification Office (ACO), 1600 

Stewart Avenue, Suite 410, Westbury, 

New York 11590; telephone (516) 228– 

7318; fax (516) 794–5531. 

SUPPLEMENTARY INFORMATION: 

Discussion 

We issued a notice of proposed 

rulemaking (NPRM) to amend 14 CFR 

part 39 to include an AD that would 

apply to the specified products. That 

NPRM was published in the Federal 

Register on November 15, 2010 (75 FR 

69609). That NPRM proposed to correct 

an unsafe condition for the specified 

products. The MCAI states: 

During flight-testing of a wing anti-ice 

piccolo tube containing a deliberate small 

breach, it was determined that the wing 

leading edge thermal switches Part Number 

(P/N) 601R59320–1 were not detecting the 

consequent bleed leak at the design 

threshold. As a result, Airworthiness 

Limitation (AWL) tasks, consisting of a 

functional check of the wing leading edge 

thermal switches (P/N 601R59320–1) and an 

inspection of the wing anti-ice duct piccolo 

tubes on aeroplanes with these switches 

installed, have been introduced. These tasks 

will limit exposure to dormant failure of the 

wing leading edge thermal switches in the 

event of piccolo tube failure, which could 

potentially compromise the structural 

integrity of the wing leading edge and the 

effectiveness of the wing anti-ice system. 


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