Updated 01/16/09

Eric H. LaGasa¹ John Agnesani², Sahabra Tipton², and Denise Bowden²

Figure 1. Leek Moth Survey in U.S., 2003 (USDA)

Background

Native to Asia, the Leek Moth (LM) was first found in North America in 1993, in Ottawa, Canada, where the pest is now established (CFIA, 2001). To date, the pest has not been detected in the United States (Figure 1 - APHIS NAPIS, 2003).

In Europe, the pest causes heavy damage to leeks, onions, garlic, and related crops by mining and feeding within the foliage and bulbs (see Figure 2), and infested bulbs are subject to extensive rotting in storage. Larval damage to stalks can also reduce seed production (USDA-ARS, 1960). Pest status is characterized as a 'minor pest of onions' in some references (Hill, 1983 and 1987), a 'serious pest in continental Europe' (Carter, 1984), and a potential pest of native (North American) and ornamental plants in the genus Allium (APHIS NPAG, 2000).

2002 Project Objective

Conduct pheromone-trap detection survey throughout populous western Washington.

• Place and monitor pheromone-traps in areas of commercial and home garden Allium culture.
  

Screen and identify captured specimens, including non-target material when possible.

Figure 2. Leek Moth Life Stages and Damage

Project Methods and Materials

Three hundred and ninety-six pheromone-lure baited traps were placed in counties along the Interstate-5 corridor in western Washington, from the Canadian border south to Clark County on the Columbia River / Oregon border. Trap placement, by county, is presented in Table 1. Traps were hung in roadside or residential yard trees, primarily in areas where home gardens could provide Allium spp. hosts (ornamental and table crop).

Trap placement began in June to allow for completion of all initial trap sets by the beginning of expected adult moth flight in late-June or early-July, and most traps were removed by the end of August.

Pherocon 2® type traps (a.k.a. "diamond" traps) were used in this survey, based on trap performance in prior WSDA CAPS surveys, ease of use, and the avoidance of small-bird capture/mortality (which is a problem with other trap designs, particularly “wing-traps”). Traps were baited with pheromone-lures provided by the USDA APHIS Otis Methods Development Center. The leek moth pheromone-lures consisted of gray rubber septa (West Co., Lionville, PA. cat. no. 1060-0275), each loaded with 0.1 ml (1 mg) of (Z)-11- Hexadecanol.

Pheromone lures were changed every two weeks as much as possible during the expected (probable) period of adult flight. Traps with specimens were processed at the Olympia Entomology Lab, where captured specimens were identified and counted. Selected specimens were removed from the traps with Hemo-D citrus based solvent and had genitalia extracted and cleared (in KOH) for identification.

Project Results

No leek moth specimens were collected in this survey.

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This project was a cooperative effort of the Washington State Department of Agriculture and the USDA Animal and Plant Health Inspection Service (APHIS). Funding for field and lab support staff was provided in part by a Cooperative Agricultural Pest Survey (CAPS) grant from the USDA APHIS Western Region (#00-8553-0249-CA). 1Eric LaGasa, Chief Entomologist, Pest Program / Plant Protection Division, Washington State Department of Agriculture,  P.O. Box 42560, Olympia, Washington  98504-2560,  (360) 902-2063  PestProgram@agr.wa.gov 2WSDA Entomology Aide (Project Field Staff) Inquiries regarding availability of this publication in alternative formats should be directed to the WSDA Receptionist at (360) 902-1976.