VG04067 IPM – Lettuce Aphid

During the growing season of 2003/04 a new aphid was found in lettuce crops in Tasmania.

This was the first Australian record of the Currant Lettuce Aphid, Nasonovia ribis-nigri.

This aphid is a pest of lettuce in New Zealand, North America and Europe.

It has been responsible for large yield losses because it lives deep inside the head of maturing lettuces secure from foliar insecticides.

It is not secure from systemic insecticides or predators such as brown lacewing, ladybirds and hoverflies.


Authors

Lionel Hill

Sandra McDougall

Paul Horne

VG04067 Integrating currant lettuce aphid, Nasonovia ribis-nigri, into IPM for lettuce: a commercial trial - 2006
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The Australian vegetable industry is greatly concerned about the impact that this pest may have on lettuce crops. Their strategic plan to help combat the perceived impact of this pest included development of resistant lettuce varieties and high rates of imidacloprid insecticide as a seedling drench.

Many growers have adopted the practice of drenching seedlings just prior to planting with imidacloprid.

Imidacloprid is toxic to a broad range of insects but not caterpillars which are a major pest of lettuce.

If predators are impaired after eating poisoned aphids they are not available to complement the soft insecticides that are increasingly used for caterpillar control or to restrain other pests for which no selective insecticides are available.

This project sought to :

  • Teach Tasmanian lettuce growers how to integrate control of several pests in commercially realistic lettuce crops
  • Demonstrate this (Integrated Pest Management) to a broader audience
  • Demonstrate that seedling insecticidal drenches, although effective against aphids, probably will not integrate with management of caterpillars and perhaps other pests
  • Examine some related issues such as the performance of Nasonovia-resistant lettuce and low drench rates.

Forthside, Tasmania

Summary :

This project has demonstrated to growers and entomologists that there is a viable alternative to high rates of Confidor drenching on seedlings to control lettuce aphid in Australia.

  1. This project was initiated because of the arrival of a new pest, currant lettuce aphid, in Australia. The pest arrived in Tasmania, and not on the mainland, in February 2004.
  2. The only approach officially recognised has been the use of high rates of Confidor on seedlings.
  3. The Confidor treated seedlings have so far controlled lettuce aphid, but have killed predators of aphids and so an IPM approach using native predators is incompatible.
  4. This project assessed for the first time in Australia the potential for a nonpesticide based control method for lettuce aphid.
  5. The aphid reached Victoria by May 2005 and further assessment of the potential for IPM to control lettuce aphid is happening in Tasmania and Victoria.
  6. The assessment at this stage is that there is every expectation that an IPM approach to dealing with this pest will be effective.
  7. The project fast-tracked field testing and adoption of IPM in a novel pestcrop combination with modest expenditure.

Acknowledgements :

Dr Paul Horne and Jessica Page from IPM Technologies P/L provided key professional knowledge and field experience in vegetable IPM to the research team and tuition to participants in field days.

The Department of Primary Industries, Water and Environment, Tasmania provided professional staff in kind, housed technical staff and provided the facilities and staff of the Forthside Vegetable Research and Demonstration Farm at normal research rates.

The NSW Department of Primary Industries provided professional staff – Dr Sandra McDougall, for project design and field events and access to the Lettuce Leaf newsletter.

This project was supported by a loan of planting equipment from Bovill Brothers, access to the Forthside Research and Demonstration Farm belonging to DPIWE, Tasmania, and access to Bovill Brothers’ Farms.

Horticulture Australia Limited provided funds for crop production, technical staff and travel for professional staff for this project.through The National Vegetable R&D Levy.

The Australian Government provides matched funding for all HAL’s R&D activities.


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