United States Department of Agriculture Animal and Plant Health Inspection Service Plant Protection and Quarantine



# Importation of Perennial Wall Rocket Leaves, (

Diplotaxis tenuifolia , (L.) from the United Kingdom into the continental

United States

Risk Management Document

January 20, 2010

Plant Health Programs (PHP) Regulations, Permits and Manuals (RPM) Contact Person: Claudia FergusonRisk Management Document: Wall Ro cket Leaves from United Kingdom.

January 20, 2010 2 

## 1. Introduction

This document describes the risk manageme nt measures for the importation of wall rocket leaves, Diplotaxis tenuifolia (L.), from the United Kingdom (UK) into the

continental United States. The volume of wa ll rocket to be shipped from the United Kingdom to the United States is estimated at less than ten 40 foot long maritime containers per year. (USDA, 2008)

United States Code of Federal Regulations (7 CFR 319.56) authorize importation of fruits and vegetables from foreign countries into the United States. Curre ntly, fresh perennial wall rocket from the UK is pr ohibited by these regulations.

The United States Department of Agricultu re, Animal and Plant Health Inspection Service (USDA, APHIS) conducted a pest risk assessment (PRA) in response to a request to allow imports of fresh perennial wall rock et leaves from the UK into the continental United States (USDA, 2008). Two pests of quarantine significance were identified, which would be likely to be introduced into the continental United States via leaves of perennial wall rocket. This document evalua tes the appropriate pest risk management measures for these quarantine pests.



## 2. Quarantine Pests of Conc ern for Wall Rocket Leaves from the United Kingdom

The list of quarantine pests of wall rocket l eaves from the United Kingdom was prepared

based on:

(1) United States Department of Agricult ure (USDA), Animal and Plant Health Inspection Service (APHIS) records of intercepted pests (USDA, 2007), and

(2) Scientific literature.

The pest risk assessment, ‘Importation of Perennial Wall Rocket Leaves ( Diplotaxis tenuifolia (L.)) from the United Kingdom into the Continental United States’, A Pathway-Initiated Assessment, represents a ba seline risk associated with the unmitigated importation of fresh leaves of wall rocket from the United Kingdom (USDA, 2008).

The PRA identified the following two pests, both having a medi um risk potential to follow the pathway:

Chromatomyia horticola (Goureau) (Diptera: Agromyzidae) Liriomyza strigata (Meigen) (Diptera: Agromyzidae)Risk Management Document: Wall Ro cket Leaves from United Kingdom.

January 20, 2010 3 There were no pests identified as having a high risk potential to follow the pathway.



## 3. Risk Management Measures

APHIS proposes that fresh leaves of perenni al wall rocket grown in the United Kingdom may be imported into the continental United States only under the following conditions:

A) Wall rocket leaves must be imported as commercial consignments only.

B) Each consignment of wall rocket leaves must be accompanied by a Phytosanitary Certificate (PC) with an Additional Declar ation (AD) issued by the Department of Environment Food and Rural Affairs (DEF RA) bearing the following: “Wall rocket leaves in this consignment we re inspected and found free from Chromatomyia

horticola and Liriomyza strigata .”



## 4. Rationale for Risk Management Measures

According to USDA, guidelines for pathway initiated pest risk assessments (USDA, 2000), pests with ‘Medium’ pe st risk potential may re quire specific phytosanitary

measures.

The PRA identified two quarantine pests that could be introduced into the United States via the importation of perennial wa ll rocket from the United Kingdom: Chromatomyia

horticola and Liriomyza strigata (USDA, 2008)

. Both are Dipteran leaf miners in the family Agromyzidae and both have ‘Medium’ pest risk potentials. In ge neral, leaf miners have minimal natural dispersal potential. Larvae remain inside the leaf where the egg they hatched from was laid, until they pupate . Adults do not disper se long distances on their own. They can be transported through wind currents, but since a successful dispersal requires that suitable plant hosts be available at the destination duri ng the relatively short lifespan of the miner, this is therefore not a common method of dispersal (CABI, 2007). Both the leaf miners produce visible and obvi ous signs of infestation as small punctures in the leaf epidermis and whitish, irregularly linear mines. Pupae or exuviae may be present at the end of mines; frass occurs at short intervals along the mines in irregular, well-separated grains (CABI, 2006).

As the damage caused by leaf miners is usua lly visible, post-harvest treatments including washing and culling will reduce or eliminate in fested leaves. Port inspectors are capable of finding both pests. Requi ring an additional declarat ion with the phytosanitary

certificate ensures that the wa ll rocket leaves we re grown in UK and are a product of the United Kingdom.Risk Management Document: Wall Ro cket Leaves from United Kingdom.

January 20, 2010 4 

## 5. Summary

The requirements of a phytosanitary certificat e with additional decl aration from DEFRA will document that the importation is a pr oduct of United Kingdom. A Phytosanitary Certificate also provides phytosanitary security by requiring DEFRA to conduct inspections for pests.

Importations of wall rocket leaves from th e United Kingdom will also be subject to inspection at the first port of entry into the continental United States. These inspections doubles the number of inspections that each consignment of wall rocket

leaves receives.



## Author

Devaiah A. Muruvanda, Ph.D., Senior Risk Manager, USDA, APHIS, PPQ, Regulations,

Permits & Manuals



## Reviewer:

Claudia Ferguson, Regulatory Policy Special ist, USDA, APHIS, PPQ, Regulations,

Permits & Manuals



## 6. References

CABI. 2006. Crop Protection Compendium, 2006 Edition. CAB International, Wallingford, UK. CABI. 2007. Crop Protection Compendium. CD-ROM. CAB International (CABI), Wallingford, UK. USDA. 2000. Guidelines for Pathway-Initiated Pest Risk Assessments, Version 5.02. 30 pp. USDA. 2008. Importation of Perennial Wall Rocket Leaves ( Diplotaxis tenuifolia (L.)) from the United Kingdom into the continental United States. – A PathwayInitiated Risk Assessment. July 2008. Unite d States Department of Agriculture, Animal and Plant Health Inspection Service, Plant Protection and Quarantine, Center for Plant Health Inspection Servi ce, Plant Epidemiology and Risk Analysis Laboratory. Raleigh, NC. 24 pp.

USDA. 2007 Pest ID Database: United States Department of Agriculture, Animal and Plant Health Inspection Service, Plant Pr otection and Quarantine, Riverdale, MD.