Number range CHAPTER**INFORMATION MEMO FOR THE RECORD**

From: Edward V. Podleckis, Ph.D., Senior Entomologist, APHIS-PPD

Shaharra J. Usnick, Ph.D., Senior Risk Manager, APHIS-PPQ-Plant Health
Programs

Date: September 22, 2005

[Issue]{.underline}:

The government of the Peoples Republic of China requested permission to
export 'Fragrant Pear' (*Pyrus ussuriensis* Maxim.) fresh fruit from the
Korla region in Xinjiang Province into the United States. In 2005, the
Peoples Republic of China verified the scientific name of Fragrant Pear
in a letter to APHIS. They requested that the species name change from
*Pyrus ussuriensis* Maxim to *Pyrus sp.* Nr. *Communis.* Currently, only
Chinese 'Ya Pear' (*Pyrus x bretscheideri* Rehd.) fresh fruits from the
Provinces of Hebei and Shandong are enterable into the United States.
PPQ is proposing to allow Fragrant Pear importations from Xinjiang
Province based on Agency determinations of the pest risk and the
adoption of phytosanitary measures to mitigate the identified risks.
This memo evaluates the scientific basis for the name change and reviews
the pest risks identified in Agency assessments of the proposed
importation and evaluates phytosanitary measures intended, where
necessary, to mitigate those pest risks. This evaluation is based on the
risk assessments completed in 1994 and 1997, a program analysis and trip
report completed in 2001, published literature and additional
information developed during the course of the current Chinese Ya Pear
importation program that has been in place since 1997.

[Background]{.underline}:

The genus *Pyrus* is traditionally divided into two groups, Occidentalis
and Oriental pears, based on their geographical location (Teng et al.,
2002). However, taxonomists disagree about the exact number of species
contained in those two groups. Until relatively recently, the cultivated
species of *Pyrus* originating in China were poorly understood by those
outside of China. As a result, species were often misidentified in
taxonomic literature (Teng et al., 2002). *Pyrus sp.* Nr. *communis*
cultivars are distinct from other Asian pear cultivars (Teng et al.,
2002). This information memo will address Fragrant pears (*Pyrus sp.*
Nr. *communis).*

Fragrant pear (*Pyrus sp.* Nr. *communis)* is also commonly called the
European or common pear. Fragrant pear probably evolved from pear
species that are native to Eastern Europe and Asia Minor near the
Mediterranean, but it is not known when they may have hybridized to
yield *P. communis* (Rieger, 2005).  Approximately 3,000 years ago,
Asian pears were domesticated in China about the same time European
pears were in Europe (Teng and Tanabe, 2004). Chinese writings dating
from 200-1000 BC describe pear propagation and culture (Teng and Tanabe,
2004). Fragrant pears apparently originated in the Korla area
approximately 1600 years ago. Asian pears moved from China to Japan,
Korea, and Taiwan, where they are cultivated commercially today.

Fragrant pears are grown in Korla, a city of approximately 100,000 in
Xinjiang Province. Korla is a 12-hour train ride south of the province's
major city, Urumqi, Xinjiang, population 1,500,000. Urumqi is the
capital city of Xinjiang Province, the most westerly of all provinces in
China. Xinjiang Province is an Autonomous Region is populated mainly by
the Uygurs, a minority ethnic group with strong ties to countries to the
west. The Korla area is west of the Gobi Desert and on the northern edge
of the Takla Makan Desert and is characterized by very hot, dry summers
and exceedingly cold, dry winters. Situated deep in the interior of Asia
and unpenetrated by the air currents from the oceans, Xinjiang has
conspicuous continental climate, with highly changeable temperature,
sharp difference in temperature between day and night, abundant
sunshine, intense evaporation and little precipitation. The mean annual
temperature of northern Xinjiang is 4-8 ºC. and that of southern
Xinjiang 9-12 ºC. The arid south has a mean annual precipitation of
25-100 mm., while the greater part of the north has 100-500 mm
(West-East Gas Project, 2003). The average monthly low for January, the
coldest month, is -19 ºC while the average monthly high for July, the
warmest month is 31 ºC (Xinjiang Province, 2003). Spring and fall are
each approximately 2-3 weeks long. The Korla area is watered by the
Peacock River which comes from snow melt out of the Tain Shan mountains,
a major mountain chain directly to the north. Harvest is approximately 2
weeks long and can occur late August to mid September. Heavy winds can
occur just prior to harvest. There is very little rainfall,
approximately 14 mm annually. Xinjiang Province is significantly
isolated from the rest of China, both in a geographical sense and a
cultural sense. The Fragrant pear growing areas around Korla are also
significantly isolated from the major population center, Urumqi.

Chinese plant quarantine officials negotiating the opening of their
markets in the early 1990\'s indicated a desire to export their
'Fragrant' and 'Ya' pears to the United States. In 1994, PPQ conducted a
pest risk assessment (PRA) for *Pyrus* spp. fruit from China (USDA,
1994). That assessment covered fruit of *P. bretschneideri, P.
ussuriensis* and *P. pyrifolia* (sand pear) and was conducted in PPQ's
"Decision Sheet" format. In 1995, Ya pear imports from the province of
Hebei were approved under a systems approach for pest risk mitigation.
Much of the pest risk of the Ya pears was mitigated by the cultural
practice of bagging the pears during the growing season. In addition,
because the Chinese could not provide trapping data to show the absence
of Oriental Fruit Fly (*Bactrocera dorsalis*) in the production area,
the pears had to be cold treated in-transit. The Fragrant pears, grown
only in Xinjiang Province in western China, are considered to have a
different inherent pest risk because the pest complex and climatic
conditions different from Ya pears in Hebei Province, and bagging was
said to not be possible, as the bags acted as sails in the heavy winds,
causing the fruit to drop.

In 1996 PPQ began work on a Supplemental PRA for Chinese Ya and Fragrant
pears. This revision (USDA, 1997), superseded the 1994 Decision Sheet
and was completed and delivered to Chinese officials in late February,
1997. At that time, PPQ identified 14 pests of concern for the pears of
Xinjiang Province and requested information on them. China's response
mainly stated the 14 pests did not occur in Korla, the Fragrant pear
production area in Xinjiang Province.

At bilateral meetings held in 1997 and 1998, China requested APHIS make
progress on the Fragrant pear issue and APHIS requested evidence that
the 14 pests were not present in the growing region. APHIS requested
that a PPQ team visit the growing area to ascertain the situation. In
1999, a PPQ delegation was invited to visit Xinjiang in late August, the
most appropriate time to review the growing, harvesting, processing,
packing, storage, and certification for export.

A Technical Team, consisting of John Thaw, Trade Director for Asia,
Phytosanitary Issues Management Team, PPQ; Mike Guidicipietro, Trade
Specialist, PPQ San Francisco, CA.; and Lu Sidong, APHIS International
Services, Beijing traveled from Beijing to the western province of
Xinjiang, China to assess the pest risk of importing Fragrant pears from
there into the United States.

Based on the information collected in the 1994 and 1997 PRAs and
additional information collected since, APHIS does now have sufficient
information to propose allowing the importation of Fragrant pears from
the Korla region of Xinjiang Province in China. This information is
primarily derived from:

-   the 1994 Decision Sheet (USDA, 1994);

-   the Supplemental PRA for Ya and Fragrant Pears from China (USDA,
    1997);

-   a draft document, entitled "Program Analysis: Pest Risk of the
    Export of Fragrant Pears From the Production Areas of Korla, China
    to the United States" (Thaw, 2001) completed in 2001 as both a trip
    report and an evaluation of the proposed export program.

    [1994 Decision Sheet]{.underline}

    The Decision Sheet document is a one-page analysis with attachments
    that evaluates the pest risk for Chinese pears, specifically Ya,
    Sand and Fragrant pears and provides specific recommendations for
    allowing importation. In the attachments, 64 quarantine pests were
    identified. Thirteen pests were evaluated as pests of concern:

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-   *Carposina niponensis* Walsingham;

-   *Tetranychus viennensis* Zacher;

-   *Tetranychus kanzawai* Kishida;

-   *Conogethes punctiferalis* (Guenée);

-   *Cydia inopinata* (Heinrich);

-   *Cydia funebrana* (Treitschke);

-   *Acrobasis pirivorella* (Matsumura) (Synonym: *Numonia
    pirivorella*);

-   *Bactrocera dorsalis* (Hendel);

-   *Leucoptera malifoliella* Costa;

-   *Alternaria* spp. (especially *A. gaisen* Nagano);

-   *Gymnosporangium* spp. (*G. confusm* is discussed);

-   *Monilinia fructigena* Honey;

-   *Venturia* spp. (*V. nashicola* and *V. pyrina*; anamorph
    *Fusicladium pyrorum*.)

    The entomology findings / recommendations of the analysis were to
    "Permit entry with treatment or the establishment of a fruit fly
    free zone for *Bactrocera dorsalis.* Also we recommend permitting
    entry subject to inspection of clean fruits that have been produced
    under a "Systems Approach". A workplan\....would include such things
    as: phytosanitary measures taken\...to reduce pest load, bagging of
    the fruits\...field inspections, registration of participating
    growers, procedures to prevent co-mingling of fruit not for export
    to the United States, procedures to maintain integrity of the
    shipments, provide safeguards to prevent contamination\...and
    phytosanitary certification."

    The pathology findings /recommendations were similar: "Sand pears
    have been imported into the U.S. from Japan since 1984 and Korea
    since 1991 using a "Systems Approach"\...The program consists of
    timed chemical applications\...cultural methods such as removal of
    diseased tissues, bagging of fruit\...field inspections,
    phytosanitary certification, etc. These programs have been very
    effective in excluding pests\...Although some of the pests\...in
    China differ from those in Japan or Korea, we believe these same
    mitigative measures would be effective."

    [1997 Supplemental Pest Risk Assessment (USDA, 1997)]{.underline}

    The primary components of the supplemental risk assessment are:

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-   A listing of *Pyrus* pests known to occur in China;

-   Selected biological information on those pests;

-   A categorization of those pests to determine which satisfy the
    internationally accepted criteria of quarantine pests (FAO, 2001);

-   Further categorization of those quarantine pests to determine which
    "quarantine pests may reasonably be expected to follow the pathway."
    (USDA, 2000);

-   A qualitative assessment of the consequences of introducing the
    quarantine pests likely to follow the pathway;

-   A qualitative assessment of the likelihood of the establishment of
    quarantine pests likely to follow the pathway;

-   A characterization of the overall pest risk potential; and,

-   Brief recommendations regarding measures to manage plant pest risk.

    The risk assessment identified 280 pests of *Pyrus* in China, 53
    pathogens and 227 arthropods. Of the 280 pests identified, 193 (14
    pathogens and 179 arthropods) satisfied the geographic and
    regulatory requirements of a quarantine pest. Of these 193
    quarantine pests, only ten arthropods and three pathogens were
    expected, based on their biology, to reasonably follow the pathway
    of imported pear fruit for consumption. These ten arthropods and
    three pathogens were then selected for further analysis:

    -   *Bactrocera dorsalis* (Hendel);

    -   *Carposina* *sasakii* Matsumura;

    -   *Conogethes punctiferalis* (Guenée);

    -   *Cydia funebrana* (Treitschke);

    -   *Cydia inopinata* (Heinrich);

    -   *Numonia pirivorella* Matsumura;

    -   *Rhynchites foveipennis* Fairmaire

    -   *Rhynchites heros* Roel

    -   *Tetranychus viennensis* Zacher;

    -   *Tetranychus kanzawai* Kishida;

    -   *Alternaria* *gaisen* Nagano;

    -   *Monilinia fructigena* Honey; and,

    -   Pear rusty skin viroid (syn. *Apple scar skin viroid*)

        The13 pests were rated qualitatively for their "Pest Risk
        Potential" (PRP). The ratings are based on a series of risk
        elements that estimate the likelihood and consequences of a
        pest's introduction (USDA, 2000). The PRP is considered to be a
        biological indicator of the potential destructiveness of the
        pest. All of the pests except *Numonia pirivorella*,
        *Alternaria* *gaisen* and *Pear rusty skin viroid*, were rated
        as high for Consequences of Introduction. These three pests were
        rated as medium. Similarly, all of the pests except *Numonia
        pirivorella* and *Pear rusty skin viroid* were rated high for
        likelihood of introduction. *N. pirivorella* and *Pear rusty
        skin viroid* received ratings of medium for likelihood of
        introduction. The overall "Pest Risk Potential" was determined
        by summing each pest's ratings for consequences of introduction
        and likelihood of introduction. The results are summarized below
        in Table 1.

  ----------------------------------- -----------------------------------
  **Table 1: Pest Risk Potential**    

  **Pest**                            **Pest Risk Potential**

  *Bactrocera dorsalis*               High

  *Carposina sasakii*                 High

  *Conogethes punctiferalis*          High

  *Cydia funebrana*                   High

  *Cydia inopinata*                   High

  *Numonia pirivorella*               Medium

  *Rhynchites foveipennis*            High

  *Rhynchites heros*                  High

  *Tetranychus kanzawai*              High

  *Tetranychus viennensis*            High

  *Alternaria gaisen*                 High

  *Monilinia fructigena*              High

  Pear rusty skin viroid              Medium
  ----------------------------------- -----------------------------------

Unlike the 1994 Decision Sheet (USDA, 1994; **Attachment 1**), the 1997
PRA, while not recommending specific mitigation measures, states, "Pests
rated with Low PRPs may require only Port of Entry inspection to
maintain phytosanitary security. However, pests with Medium to High PRPs
may require phytosanitary measures more stringent than those provided,
solely, by Port of Entry inspections."

[Program Analysis: Pest Risk of the Export of fragrant Pears from the
Production Areas of Korla, China to the United States (Thaw,
2001)]{.underline}

This document reviews the risk associated with 14 pests identified in
the earlier PRAs as attacking *Pyrus* spp. in China. The pests are
evaluated using evidence from published literature, a 2000 site visit,
firsthand observations of APHIS IS officials and from the government of
China. A short data sheet was developed for each of the 14 pests of
concern listed in the document. The 14 pest include the 13 listed in the
1997 PRA plus one additional fungal pest:

-   *Bactrocera dorsalis* (Hendel);

-   *Carposina* *sasakii* Matsumura;

-   *Conogethes punctiferalis* (Guenée);

-   *Cydia funebrana* (Treitschke);

-   *Cydia inopinata* (Heinrich);

-   *Numonia pirivorella* Matsumura;

-   *Rhynchites foveipennis* Fairmaire;

-   *Rhynchites heros* Roel;

-   *Tetranychus viennensis* Zacher;

-   *Tetranychus kanzawai* Kishida;

-   *Alternaria* *gaisen* Nagano;

-   *Monilinia fructigena* Honey;

-   *Mycosphaerella pomacearum* (Cord.) Sacc. and,

-   Pear rusty skin viroid (syn. *Apple scar skin viroid*)

    Based on its distribution, host range, biology, symptoms / economic
    impact and survey data, each pest was evaluated qualitatively as to
    the pest risk it presents in commercial shipments of Fragrant pear
    fruit from the Korla region. For 13 of the 14 pests, the analysis
    characterized the risk as low, based for most on their absence from
    the production area. Only *T. viennensis*, a tetranychid mite, was
    considered slightly more risky, low to moderate, based on its
    presence in Xinjiang Province, though not in the Korla production
    area.

    The Program Analysis concluded, "We were unable to find any pest
    condition that would indicate there is unacceptable risk to American
    agriculture due to the importation of Fragrant pears from Xinjiang
    Province" and recommended "\...that Fragrant pears be allowed
    entry."

    In 2005, at the request of China, we changed the Latin name of
    Chinese Fragrant pear from *Pyrus ussuriensis* to *Pyrus sp.*Nr.
    *Communis*. At that time, the information memo was re-evaluated for
    accuracy. A literature search for additional pests of concern was
    also done. No pests that were not previously addressed in the PRA
    and informational memo were found to be on Fragrant pears in the
    Korla region of China.

    [Evaluation of the Various Pests of Concern]{.underline}

    A total of 17 different pests of concern were identified by the
    three different analyses described above. The following section
    briefly describes the evidence used by APHIS to determine that none
    of these pests poses an inherently unacceptable risk or a risk that
    cannot be adequately mitigated. The evidence cited was gathered from
    the above documents, published literature and existing APHIS import
    programs.

1.  *Bactrocera dorsalis* (Hendel)

    Two major factors contribute to the conclusion that this fruit fly
    is unlikely to pose a risk in Fragrant pear fruit exports from
    Korla: pest distribution (or lack of distribution in Xinjiang) and
    an unfavorable climate in the production area. According to CABI
    (CPC, 2002), *B. dorsalis* is found in Southeast Asia, including the
    following provinces in China: Sichuan, Yunnan, Guizhou, Hunan,
    Guangxi, Guangdong, Fujian, and Taiwan (**Figure 1**). In addition,
    *Bactrocera dorsalis* is found in Bangladesh, Bhutan, Brunei
    Darussalam, Cambodia, India, Laos, Macau, Malaysia, Myanmar, Nepal,
    Pakistan, Thailand, Vietnam, Hawaii, and Guam. The closest natural
    occurrence of *B. dorsalis* is in Sichuan Province, approximately
    1000 miles away. There is little direct commerce between Sichuan
    Province and Xinjiang (Thaw, 2001).

    ![](media/image1.wmf){width="6.521527777777778in"
    height="4.596527777777778in"}

    **Figure 1. Distribution of *Bactrocera dorsalis* in Asia (CPC,
    2002)**

    This is a tropical fruit fly, which would not survive the winters of
    Korla. The adults are best able to survive low temperatures with a
    normal torpor threshold of 7 ºC, dropping as low as 2 ºC in winter
    (EPPO, 1997). Immatures did not develop at temperatures lower than
    12 ºC (PNKTO, 1982). As noted above, the mean annual temperature of
    northern Xinjiang is 4-8 ºC. and that of southern Xinjiang 9-12 ºC,
    but the average monthly low for January, the coldest month, is -19
    ºC (West-East Gas Project, 2003; Xinjiang Province, 2003) well below
    the temperature limits of *B. dorsalis*. The Korla production region
    falls in the equivalent of Zone 6 on the USDA Plant Hardiness Zones
    Map (USDA, 1990). This would correspond to areas in the United
    States ranging between Boston, Philadelphia and New York- areas well
    outside the range where tropical fruit flies could reasonably be
    expected to survive.

    In addition, China conducted trapping for *B. dorsalis* for three
    years in the orchards at 1 trap per hectare using Jackson traps with
    methyl eugenol lure as requested by APHIS (Thaw, 2001). All results
    have been negative. Approximately 10,000 metric tons of pears are
    exported from Xinjiang annually (Thaw, 2001). There has never been a
    report from trading partners of an interception of a fruit fly
    larvae in pears from Xinjiang Province (Thaw, 2001; Canada, 1995).
    During processing, the pears are closely inspected for insects and
    insect damage and packers have never reported an interception of a
    fruit fly larvae (Thaw, 2001). To satisfy the Japanese, who import
    Fragrant pears, fruit fly traps are maintained in the 28th Regiment
    during the growing season. No *B. dorsalis* have ever been found
    (Thaw, 2001).

2.  *Carposina* *sasakii* Matsumura (syn.: *Carposina niponensis*
    Walsingham)

    The conclusion that this moth is unlikely to pose a risk in Fragrant
    pear fruit exports from Korla is based on its absence from the
    production area and the Province of Xinjiang. CABI (CPC, 2002) lists
    the distribution of this pest in China as Fujian, Guangdong, Hebei,
    Heilongjiang, Henan, Jiangsu, Jilin, Liaoning, Shaanxi, Ningxia,
    Shandong and Zhejiang Provinces- all in eastern China (**Figure
    2**).

    Specific surveys have not been conducted for *C. sasakii* in the
    production area or the Province, but according to Thaw (2001)
    general survey teams work in the area and APHIS has reports of the
    surveys in the Korla region:

-   Between 1971 and 1975, part of Bazhou was surveyed using sweep nets
    and black light traps in the orchards. Unfortunately, *C. sasakii*
    does not come to black light traps. None found.

-   Between 1985 and 1989 Li Jianglin of the Bazhou Plant Protection
    Station Production Farm of Xinjiang Shihezi Agriculture University
    conducted a general inspection. Again, no *C. sasakii* found.

-   Between 1991 and 1996, Urumqi Animal and Plant Protection Station,
    Bazhou Plant Protection Station, Forest Bureau of No.2 Farm, Urumqi
    Plant Protection Station continued their general surveys and
    conducted limited research on selected pests of Fragrant pears. No
    *C. sasakii* found.

    **Figure 2. Distribution of *Carposina sasakii* in Asia (CPC,
    2002)**

    ![](media/image3.wmf){width="6.404861111111111in"
    height="4.6194444444444445in"}

3.  *Conogethes punctiferalis* (Guenée)

    The conclusion that this moth is unlikely to pose a risk in Fragrant
    pear fruit exports from Korla is based on its absence from the
    production area and the Province of Xinjiang. CABI (CPC, 2002) lists
    the distribution of this pest in China as the following provinces in
    eastern and southern China: Liaoning, Tianjin, Hebei, Shandong,
    Shanxi, Shaanxi, Henan, Jiangsu, Anhui, Hubei, Sichuan, Zhejiang,
    Jiangxi, Hunan, Fujian, Guangdong, Guangxi, Xizhang and Yunnan
    (**Figure 3**). *C. punctiferalis* is also present in Australia,
    India, Indonesia, Japan, Korea, Laos, Malaysia, Myanmar,
    Philippines, Sri Lanka, Taiwan, Thailand, and Vietnam.

    ![](media/image5.wmf){width="6.404861111111111in"
    height="4.608333333333333in"}

    ![](media/image6.wmf)

    **Figure 3: Distribution of *Conogethes punctiferalis* in Asia (CPC,
    2002).**

    According to Thaw (2001), between 1971 and 1975; part of the
    production area was surveyed using general inspection and black
    light traps in the orchards at a density of 1 trap per 25 km^2^ per
    acre. *C. punctiferalis* is attracted to black lights and would have
    been detected if it had been present. Black lights were also used in
    the annual surveys of 1985-1989, and 1991-1996. Again, no *C.
    punctiferalis* were found. *C. punctiferalis* has never been
    intercepted in any of the fruit exported from the Korla region
    (Thaw, 2001).

    *C. punctiferalis* is one of the most important insect pests on
    peaches in southern China and an important pest on apples in
    northern China, and infestations result in the stunting, scorching
    and falling of fruit (Thaw, 2001). *C. punctiferalis* excretions,
    which cover the fruit surface and have high sugar content, attract
    other insect pests and diseases, which damage fruit. Peaches
    attacked by *C. punctiferalis* appear discolored, scorched, and are
    covered with brown excretion mass around holes. The fruits fall or
    rot with an unpleasant smell (CPC, 2002). The damage it causes to a
    variety of crops should also make it fairly obvious were it present.
    Given the careful scrutiny each fruit receives as part of the
    standard pack house procedures and phytosanitary inspections by
    Chinese officials at origin, APHIS believes inspection of a sample
    of the fruit on arrival should be a sufficient mitigative procedure
    for this insect.

    4\. and 5. *Cydia funebrana* (Treitschke) and *Cydia inopinata*
    (Heinrich) (syn. *Grapholita inopinata)*

    The conclusion that these moths are unlikely to pose a risk in
    Fragrant pear fruit exports from Korla is based on their absence
    from the Korla production area and the Province of Xinjiang. CABI
    (CPC, 2002) lists the distribution of *C. inopinata* in China as the
    following provinces: Guangdong, Heilongjiang, Henan, Jilin and
    Liaoning (**Figure 4**). *C. funebrana* present in Hebei, Jilin, and
    Liaoning Provinces (CIE, 1978) is somewhat more restricted in its
    distribution.

    ![](media/image7.wmf)

    ![](media/image8.wmf)**Figure 4. Distribution of *Grapholita
    inopinata* in Asia (CPC, 2002)**

    A synthetic pheromone blend is used for *Grapholita* *molesta*
    detection that is quite similar to that used for *C. funebrana* in
    other countries and the same as that used for *C. inopinata* (Thaw,
    2001)*.* In the Korla region, Chinese officials routinely use
    detection traps for *G. molesta* (Thaw, 2001); these traps would
    also detect *C. inopinata* were it in Xinjiang. CIQ indicates they
    do not know whether the moth comes to black lights or not. *C.
    inopinata* has never shown up in any of the general surveys, dating
    back to 1971. It is not widely found in eastern China. It has never
    been found in any domestic or export marketed Fragrant pears (Thaw,
    2001).

    *C. funebrana* larvae bore into the fruit leaving a conspicuous
    entrance hole surrounded by frass. The larvae tunnel into the pulp,
    leaving behind decaying tissues mixed with excrement (Bradley, *et
    al.*, 1979. Infested fruits tend to ripen prematurely (Alford,
    1981). These symptoms make infested fruit easy to detect,
    particularly late in the season when fruit ripens prematurely (Thaw,
    2001). Thaw (2001) states that, according to the Chinese, when *C.
    inopinata* larvae bore into pear fruit, they leave a hole. The area
    around the hole turns blackish brown and the hole fills with
    excrement. The larvae are visible to the naked eye (CPC, 2002).

    6\. *Leucoptera malifoliella* Costa

    This pest was initially included as a pest of concern in the 1994
    Decision Sheet (USDA, 1994). In subsequent assessments (USDA, 1997),
    the analysts concluded that the pest was not likely to follow the
    pathway because this pest is primarily a leafminer. Larvae do not
    feed on fruit, but have been intercepted on fruit as pupae usually
    in the stem or calyx end cavities (PNKTO, 1985). Larvae prefer to
    pupate on leaves. In climates with long growing seasons, late season
    generations of high population densities may seek less desirable
    pupation sites such as fruit (PNKTO, 1985). However, such long
    growing seasons are uncharacteristic for Korla. Fruit interceptions
    have occurred on European apples and pears (PIN309, 2003).
    Interceptions have not been made on Chinese fruit. Distribution in
    China is not definitively known- the single Japanese report cited in
    USDA, 1994 and PNKTO, 1985 describes the distribution as "Northern
    China). No reports of this pest in Xinjiang are known to exist. The
    obvious leaf mines and premature leaf drop this pest causes
    (PNKTO, 1985) would have been detected in the general surveys
    carried in the production area if this pest was present. Both
    PNKTO (1985) and the Decision Sheet (USDA, 1994) indicate that this
    pest may be inspected for, if it were present.

    7\. *Numonia pyrivorella* (Matsumura) (syn.: *Acrobasis
    pirivorella)*

    The conclusion that this moth is unlikely to pose a risk in Fragrant
    pear fruit exports from Korla is based on its absence from the Korla
    production area and the Province of Xinjiang. CABI (CPC, 2002) lists
    the distribution of *N. pyrivorella* in China as the following
    provinces: Heilongjiang, Liaoning, Shaanxi, Jilin and Nei Menggu
    (**Figure 5**).

    *N. pyrivorella* is attracted to black lights. Black light traps
    were used in the surveys conducted in 1971-1975, 1985-1989 and
    1991-1996 (Thaw, 2001). Furthermore, in spring, the larvae emerge
    and move to fresh buds, feeding on the developing buds, flowers and
    fruitlets, eating out the core of the latter. Larvae may move from
    fruit to fruit. The older larvae penetrate into the developing fruit
    to pupate. Before doing so, they wander over the surface of the
    fruit spinning a web particularly around the stalk. The larvae
    generally enter the fruit near the calyx end or on the side of the
    fruit, making a prominent hole with an overhanging lip of silk and
    excreta. Fruits that have been infested by larvae remain black and
    shriveled on the tree (CPC, 2002) and would be readily detected
    during general surveys. No *N. pyrivorella* have ever been detected
    in Xinjiang Province.

    The main means of spread would be international trade of planting
    material with infested buds. Infested fruits may also carry the
    pest, but its presence is conspicuous (CPC, 2002).

    ![](media/image9.wmf){width="6.439583333333333in"
    height="4.584722222222222in"}

    ![](media/image10.wmf)

    **Figure 5. Distribution of *Numonia pyrivorella* in Asia (CPC,
    2002)**

    8\. and 9. *Rhynchites foveipennis* Fairm. and *Rhynchites heros*
    Roel

    The conclusion that these weevils are unlikely to pose a risk in
    Fragrant pear fruit exports from Korla is based on their absence
    from the Korla production area and the Province of Xinjiang and
    aspects of their biology that make them unlikely to be present in
    export quality fruit and readily detectable if they were.

    There is some confusion about the existence of *Rhynchites heros* in
    China. A 1966 reclassification of the species of *Rhynchites* in
    China (Chao and Lee, 1966) seems to indicate *R. heros* exists only
    in Japan. It is probable that the literature references indicating
    R*. heros* in eastern China are actually *R. foveipennis.* Because
    of this confusion and the similarity in their biology, these two
    weevils are treated together in this discussion. *R. foveipennis*
    (including *R. heros)* occurs in the following provinces in China:
    Hebei, Hubei, Shandong, Shanxi, Liaoning, Jilin, Helongjiang, Inner
    Mongolia, Zhejiang, Fujiang, Shannan, Sichuan, and Yunnan Provinces
    (Chao and Lee, 1966).

    Between 1971 and 1975, part of Korla was surveyed using sweep nets
    and black light traps located in orchards. No *Rhynchites heros* or
    *R. foveipennis* found. Between 1985 and 1989 a general inspection
    by Li Jianglin of the Bazhou Plant Protection Station Production
    Farm of Xinjiang Shihezi Agriculture University found no *R. heros*
    or *R. foveipennis* (Thaw, 2001). And between 1991 and 1996, Urumqi
    Animal and Plant Protection Station, Bazhou Plant Protection
    Station, Forest Bureau of No.2 Farm, continued their general surveys
    and conducted limited research on selected pests of Fragrant pears.
    No *R. heros* or *R. foveipennis* found (Thaw, 2001).

    *R. heros* infests apple, peach, pear, cherry, plum, apricot,
    quince, and fig (INKTO, 1958). Adult females feed on buds, flowers,
    and immature fruit. According to Hanson (1963), "This weevil eats
    pears day and night with its sharp mouth, causing great damage."
    This damage would be readily evident to surveyors and fruit packers.
    "Moreover, the adult after having laid an egg in the fruit cuts the
    stalk\..." (Hanson, 1963). The fruit may drop to the ground after
    the female lays an egg in the fruit and cuts the stem (Roberts,
    1950; AQIS, 1998), or it may remain on the tree (INKTO 45, 1958).
    *Rhynchites* sp. was intercepted once on Chinese pear; presumably,
    these were larvae (PIN309, 2003).

    10\. *Tetranychus kanzawai* Kishida

    The spider mite, *Tetranychus kanzawai* Kishida, was synonymized
    with *Tetranychus hydrangeae* Pritchard & Baker (Navajas *et al*.,
    2001). *Tetranychus hydrangeae* is present in the United States and
    is not considered a quarantine pest at this time.

    11\. *Tetranychus viennensis* Zacher

    APHIS' estimate of the risk posed by *T. viennensis* in Fragrant
    pear fruit exports from Korla as low to moderate is based on its
    absence from the Korla production area, though it is present in the
    Province of Xinjiang. CABI (CPC, 2002) lists the distribution of *T.
    viennensis* in China as the following provinces: Anhui, Gansu,
    Henan, Jiangsu, Liaoning, Ningxia, Shandong and Xinjiang. Within
    Xinjiang Province, *T. viennensis* occurs in Heshuo, a small farming
    community approximately 50 miles north of Korla, in the mountains,
    where they raise vegetables, livestock, corn, wheat, and apples.
    Pear trees are used in places as windbreaks. There is no commercial
    production of pears or any other commodity. China indicates it is
    unlikely *T. viennensis* will move from Heshuo as there is very
    little reason someone would take agricultural commodities to Korla.
    Heshuo residents go to Korla to buy the food and any produce they
    lack (Thaw, 2001). This mite is, however, windborne and may be
    carried accidentally by large insects, birds and even humans on
    their clothing (CPC, 2002).

    Plant quarantine officials in Xinjiang are very aware of U.S. and
    Canadian concerns about the population of *T. viennensis* in the
    little community of Heshuo. These concerns arise from rejections of
    Fragrant pear shipments to Canada due to the presence of mites
    (Canada, 1995). China understands that the presence of *T.
    viennensis* in the Korla production area would impact their ability
    to export pears (Thaw, 2001). General survey teams work in the
    region and APHIS has their survey reports. Between 1971 and 1975,
    part of the region was surveyed using sweep nets and black light
    traps located in orchards. During this period, a mite, *Tetranychus
    turkestani,* was found, but no *T. viennensis*. Between 1985 and
    1989 Li Jianglin of the Bazhou Plant Protection Station Production
    Farm of Xinjiang Shihezi Agriculture University conducted a general
    inspection. Again, no *T. viennensis* were found, nor was any new
    species of mite. Between 1991 and 1996, Urumqi Animal and Plant
    Protection Station, Bazhou Plant Protection Station, Forest Bureau
    of No.2 Farm, continued their general surveys and conducted limited
    research on selected pests of Fragrant pears. No *T. viennensis*
    found. In 1996 - 1997, because of the problems caused by rejections
    of shipments of pears by Canada due to mite interceptions, Chinese
    officials organized a workshop to give advanced identification
    training to their extension agents in Korla. They conducted several
    intensive surveys and identified all mites that were collected.
    These surveys indicated that *Tetranychus turkestani, T.
    cinnabarinus, T. truneatus, and Eotetranychus pruni* are present in
    the area (Thaw, 2001). None of these species of mites are considered
    of quarantine significance by the United States.

    *T. viennensis* is found mainly on the leaves and stems of host
    plants, especially during the flowering, seedling, and vegetative
    growing stages (CPC, 2002). The female overwinters mainly in cracks
    in the bark of host trees, rarely in the calyx of host fruit.
    CPC (2002) specifically lists fruit as a plant part *not* known to
    carry the pest, however this pest has been intercepted on fruit
    (PIN309, 2003).

    Some Ya pear fruit packers in eastern China to eliminate mites use
    forced air cleaning of the stem and calyx ends of fruit, but this
    may not be feasible on Korla. APHIS has used inspection to mitigate
    for *T. viennensis* on European apples, but has no experience with
    this pest on pears.

    12\. *Alternaria* spp.

    The conclusion that these fungi are unlikely to pose a risk in
    Fragrant pear fruit exports from Korla is based on their absence
    from the Korla production area and the Province of Xinjiang. CABI
    (CPC, 2002) lists the distribution of *A. gaisen* in China as the
    following provinces: Guangdong, Guangxi, Hebei, Henan, Jiangsu,
    Jilin, Liaoning, Qinghai and Zhejiang (**Figure 6**). In 2002, PPQ
    intercepted one, possibly two previously undescribed Alternaria
    species on Ya pear fruit from Hebei Province in China (Roberts,
    2002). Chinese officials identified these previously undescribed
    species as *A. alternata* (a nonquarantine species). Other than
    Hebei Province, where the rejected pear shipments originated, the
    distribution of this previously undescribed *Alternaria* is unknown.

    *Alternaria* species produce obvious and recognizable symptoms on
    pear leaves, shoots, flowers and fruits (CPC, 2002; Jones and
    Aldwinckle, 1990), yet no *Alternaria gaisen* was detected in the
    surveys conducted in 1971- 1975, 1985-1989 and 1991-1996 (Thaw,
    2001).

    ![](media/image11.wmf){width="6.4631944444444445in"
    height="4.596527777777778in"}**Figure 6. Distribution of *Alternaria
    gaisen* in Asia (CPC, 2002).**

    13\. *Gymnosporangium* spp.

    The 1994 Decision Sheet cites two species *G. asiaticum* and *G.
    confusm*. Both species are also reported to occur in the United
    States and would not be considered quarantine pests. The 1997 PRA
    (USDA, 1997) also mentions two species, *G. asiaticum* and *G.
    fuscum*. A single report of *G. fuscum* in Shaanxi Province in
    Central China exists (CPC, 2002). There are no reports indicating
    that these fungi are present in the Korla production area or the
    Province of Xinjiang. *G. fuscum* has also been reported to occur in
    the United States (Alabama and California) (CPC, 2002) though it has
    not been seen in California in about 20 years (Palm, 2002).

    Laundon (1977) stated that *G. confusm* only causes occasional weak
    infections on pear fruit. CPC (2002) states, "While fruits can be
    infected \[by *G. fuscum*\], it is very unlikely that infected
    fruits would be harvested or meet quality standards for export." The
    CPC (2002) also states "*G. fuscum* has been deregulated in the USA
    \[on nursery stock\], essentially since it was found that the
    commonly used fungicides were cheaper than regulation. The
    possibility of deregulation has also been under discussion in
    Canada." *G. fuscum* was recently listed as a reportable pest in the
    USDA Catalogue of Reportable pests (Palm, 2002) meaning that
    quarantine action would be taken on a commodity if this pest were
    detected.

    14\. *Monilinia fructigena* Honey

    The conclusion that this fungus is unlikely to pose an unacceptable
    risk in Fragrant pear fruit exports from Korla is based on its
    absence from the Korla production area and the Province of Xinjiang
    and the fact that it is readily detected by visual inspection of the
    fruit. According to CPC (2002), *M. fructigena* occurs in the
    following provinces in China: Gansu, Hebei, Heilongjiang, Henan,
    Jiangsu, Liaoning, Ningxia, Shaanxi, Shandong, Shanxi, Sichuan,
    Taiwan, Yunnan, and Zhejiang (**Figure 7**).

    ![](media/image13.wmf)**Figure 7. Distribution of *Monilinia
    fructigena* in Asia (CPC, 2002)**

    ![](media/image14.wmf){width="6.38125in"
    height="4.502777777777778in"}

    Brown rot on ripening or mature fruit typically develops as a
    rapidly spreading, firm, brown decay. Infection of fruits can take
    place at any stage during fruit development but only in those fruits
    approaching the ripening stage is the disease more severe (**Figure
    8**). The first symptoms on ripe fruits are small, superficial,
    circular brown spots that quickly turn to rotting. Eventually the
    whole fruit becomes discolored and water is lost so that a mummified
    fruit is formed. Diseased fruits tend to remain attached to the
    tree. Mummified fruit hang on branches of trees until spring or,
    alternatively fall to the ground where they remain throughout the
    winter months, partly or completely buried beneath the soil or leaf
    litter. Disease symptoms are clearly visible in the field (CPC,
    2002).

    **Figure 8. Symptoms of *Monilinia fructigena* pear (CPC, 2002)**

    ![](media/image15.wmf){width="6.375in"
    height="4.291666666666667in"}Between 1971 and 1975, part of the
    region was surveyed for agricultural pests (Thaw, 2001). *M.
    fructigena* symptoms can clearly be seen in the field. Any
    reasonable survey would have found the disease. No *M. fructigena*
    were detected in the similar surveys conducted in 1985-1989 ( and
    1991-1996 (Thaw, 2001). The United States already imports a number
    of host plant commodities from other countries where *M. fructigena*
    occurs (7CFR § 319.56-2r) without requiring measures beyond normal
    port of entry inspection.

    15\. *Mycosphaerella pomacearum* (Cord.) Sacc.

    The conclusion that this fungus is unlikely to pose an unacceptable
    risk in Fragrant pear fruit exports from Korla is based on its
    absence from the Korla production area and the Province of Xinjiang.
    Biological information also indicates that this fungus does not
    attack the fruit. *M. pomacearum* occurs only in the following
    provinces in eastern China: Jilin, Hebei, and Shandong (Tai, 1979).

    According to information provided by China, *M. pomacearum* is only
    found on the leaves (Thaw, 2001). This is consistent with other
    species of *Mycosphaerella* known to attack pears in the United
    States and elsewhere (Jones and Aldwinckle, 1990).

    This pathogen was not listed in the original 1994 Decision Sheet
    (USDA, 1994). In the 1997 PRA (USDA, 1997), it was listed as a
    quarantine pest, but was *not* included on the list of quarantine
    pests likely to follow the pathway. It is unclear why, as indicated
    in Thaw (2001) it was later included as a pest of concern. The
    Thaw (2001) report and this analysis have been unable to uncover
    evidence to support the assumption that *M. pomacearum* is likely to
    follow the pathway of imported fresh Fragrant pear fruit from Korla.

    16\. *Venturia nashicola*

    This fungus was listed in the 1994 Decision Sheet (USDA, 1994),
    however the discussion centered on Japan and Korea. This is probably
    because the distribution of *V. nashicola* is restricted to those
    two countries (CPC, 2002; CABI /EPPO, 1998). No reports of
    distribution in China were listed in previous assessments, nor were
    any uncovered during this analysis. Furthermore, Jones and
    Aldwinckle (1990) listed *V. nashicola* as a synonym of *V. pirina*,
    the causal agent of pear scab disease, which occurs in the United
    States. For these reasons, *V. nashicola* was not listed as
    attacking Fragrant and Ya pears in China in the 1997 PRA
    (USDA, 1997) nor was it addressed by Thaw (2001).

    However, in March of 2002, PPQ intercepted Chinese Ya pears from
    Hebei Province with what was identified as the *Fusicladium*
    anamorph (asexual) state of *V. nashicola* (Feinstein, 2002).
    Quarantine action was taken on the shipment and Chinese officials
    were made aware of the need to control scab in export orchards. The
    scab fungi, like *Alternaria* species, produce obvious and
    recognizable symptoms on pear leaves and fruits (**Figure 9**). The
    two diseases pose similarly low risks since neither is known to
    occur in the Korla production region and would be mitigated in much
    the same way.

    **Figure 9. Pear scab symptoms**

    ![](media/image16.wmf){width="2.88125in"
    height="3.126388888888889in"}

    17\. Pear rusty skin viroid (syn. *Apple scar skin viroid*)

    Pear rusty skin viroid is a synonym for *Apple scar skin viroid*
    (ASSVd) the type member of the Apscaviroid genus in the
    Pospiviroidae family (ICTV, 2000). Technically it is correct, in one
    sense, to say that ASSVd follows the pathway: infected pear trees
    will produce at least some fruit with pulp containing the viroid.
    Such fruit is of no consequence, however, in the spread of the
    disease. There are no known vectors for ASSVd and at least two
    separate studies (Hurtt and Podleckis, 1995; Howell, *et al.*, 1998)
    have demonstrated that ASSVd is not seed transmitted in pears.
    Consequently, fruit poses no risk for the movement of this viroid
    and it should be removed from the list of pests of concern.

    [Conclusion]{.underline}

    We have reviewed the 1994 Decision Sheet (USDA, 1994), the 1997 risk
    assessment (USDA, 1997),the draft document, entitled "Program
    Analysis: Pest Risk of the Export of fragrant Pears from the
    Production Areas of Korla, China to the United States (Thaw, 2001),
    published literature and other relevant information. We find that
    the evidence, assumptions and conclusions support the proposal to
    allow the importation of fresh, commercial Fragrant pear fruit from
    the Korla production region of Xinjiang Province, China provided
    certain safeguards are incorporated into the operational workplan
    for the proposed importation. Those safeguards include, but are not
    necessarily limited to the following:

    **A. Grown in Korla Regain, Province of Xinjiang, China**:

    *Bactrocera dorsalis*; Oriental Fruit Fly - As discussed above this
    is a tropical fruit fly that could not become established in the
    climate that exists in Korla. Requiring that the pears originate
    from this region is sufficient mitigation along with normal general
    surveys and inspections conducted as part of normal production
    procedures.

    **B. Pest free production site and shipment freedom required for
    these pests:**

    *Carposina sasaki* Peach Fruit Borer- APHIS requires bagging for
    this pest from on pears from other areas (*e.g.*, 7CFR§ 319.56-2ee).
    *Pyrus* spp. is a primary host, the pest survives in stored fruit
    and several larvae can infest a single fruit ( CPC, 2002 ). APHIS
    intercepts this pest regularly in fruit (PIN309, 2003).

    *Conogethes punctiferalis* Yellow Peach Moth - APHIS requires
    bagging for this pest from other areas (*e.g.*, 7CFR§ 319.56-2ee).
    *Pyrus* spp. is not a primary host but the pest survives in stored
    fruit ( CPC, 2002 ). APHIS intercepts this pest regularly in fruit
    (PIN309, 2003).

    *Cydia inopinata* Apple Fruit Moth - *Pyrus* spp. is not a primary
    host but the pest survives in stored fruit. This is a serious pest.
    ( CPC, 2002 ). APHIS has little experience with this pest and with
    fragrant pears because of their limited distribution.

    *Tetranychus viennensis* Hawthorn Spider Mite - Although, APHIS has
    used inspection as the main mitigation for this pest on apples from
    Europe because it is not associated with commercial shipments, we
    have little experience with this pest on pears especially with
    fragrant pears.

    *Cydia funebrana* Red Plum Maggot - Although, APHIS has uses
    inspection as the main mitigation on apples for this pest from
    Europe (7CFR§ 319.56-2r) because it is not normally associated with
    commercial shipments, we have little experience with this pest on
    pears especially with fragrant pears.

    *Monilinia fructigena* Brown Rot - Although, APHIS has used
    inspection as the main mitigation on apples for this pest from
    Europe (7CFR§ 319.56-2r) because it is not normally associated with
    commercial shipments, we have little experience with this pest on
    pears especially with fragrant pears.

    *Alternaria* spp., *Venturia nashicola* (*Fusicladium* anamorph),
    *Gymnosporangium fuscum*- Like *M. fructigena* these fungi produce
    recognizable symptoms and are not known to occur in the Korla region
    but they are potentially serious pests so an added declaration of
    production site and shipment should be required.

    **C. Shipment freedom required for these pest:**

    *Numonia pirivorella* Large Pear Borer - *Pyrus* spp. is a primary
    host but the infested fruits are much damaged and are unlikely to be
    shipped . If infested fruit was shipped inspection would be adequate

    *Rhynchites foveipennis* Pear Curculio - *Pyrus* spp. is a primary
    host but the fruit infested by *Rhynchites* spp. are much damaged
    and are unlikely to be shipped ( INKTO 45, 1958 ). If the shipment
    was infested inspection would provide adequate mitigation.

    *Rhynchites heros* Japanese Apple Curculio - *Pyrus* spp. is a
    primary host but the fruit infested by *Rhynchites* spp. are much
    damaged and are unlikely to be shipped ( Hanson, 1963 ). If the
    shipment was infested inspection would provide adequate mitigation.

    This memo has been reviewed by Edwin Imai and Gary Cave of the
    Center for Plant Health Science and Technology, Wayne Burnett and
    Paul Gadh of the Plant Protection and Quarantine, Phytosanitary
    Issues Management Team and Richard Fite and Charles Miller of the
    Policy and Program Development Risk Analysis Staff and they are in
    agreement with the conclusions herein.

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