Biological control of the leek moth Acrolepiopsis Assectella a pest of Allium spp

Project code: PRR03-360

Project Lead

Peter Mason - Agriculture and Agri-Food Canada

Objective

To develop and implement a classical biological control system for management of leek moth, an invasive pest on onions, leeks and garlic

Summary of Results

The leek moth, Acrolepiopsis assectella (Lepidoptera: Acrolepiidae) is an invasive alien species which has recently become established in the Ottawa valley region, and continues to expand its range. Local garlic and onion growers have noted significant damage to their crops and surveys recorded up to nine mature larvae per plant in some fields. In Europe, where the leek moth originated, damage of upwards of 70% of leeks and 40-50% of onions has been experienced in some regions. Damage is caused when young larvae mine the green leaves and mature larvae penetrate the young leaves, flower stalk or inflorescence of the host plant. Apart from loss of produce value due to visible damage, the larval feeding also causes reductions in plant growth, and thus affects yield.

Research was implemented to discover and assess suitable biological control agent(s) for use in Canada. Development of classical biological control as part of an integrated control strategy before leek moth becomes widespread in Canada will foster adoption of alternative management practices that reduce risk to the environment.

Studies conducted in Europe from 2004-2006 determined that the egg and pupal stages of leek moth consistently suffered the greatest mortality. Among the natural enemies found, Diadromus pulchellus, an ichneumonid parasitoid of the pupal stage, caused the highest mortality to leek moth. Literature records indicated that this parasitoid was specific to leek moth, thus further study was warranted. Investigations on the host range of D. pulchellus were carried out in 2006-2007 in Europe and in containment in Canada, and a dossier detailing this and other information pertinent to the release of a non-native species in Canada was compiled into a petition for release. This petition for release of the agent was submitted to the Canadian Food Inspection Agency (CFIA) for regulatory approval in spring 2009, and approval was granted in the fall of 2009. Releases of D. pulchellus are anticipated to begin in 2010.

These research results combined with information generated in project MU03-ENT2 are being compiled to provide growers with an integrated pest management strategy for control of leek moth in their allium crops. Growers will be advised to use pheromone trap data and ambient temperatures records to determine appropriate times for using row covers and applying reduced risk insecticides to protect their crops. The biological control component developed in this project provides another reduced risk pest management tool for integration with other control strategies such as those that target oviposition (row covers) and larvae (reduced risk pesticides such as Spinosad).

Factsheet on An Integrated Approach to Management of Leek Moth

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