Wireworms - sustainable long-term management of wireworms on potato

The incidence of wireworm damage on potato is on an upward trend both in traditional risk situations following grass and in fields in all-arable rotations ('arable wireworm'). Even low wireworm populations can cause a severe loss of tuber quality. Wireworm risk assessment has advanced via the development of pheromone trap systems, but management of the pest is limited as no new suitable chemistry has been forthcoming and knowledge of the effect of factors such as rotation on wireworms is limited.

Collaboration

ADAS, University of Plymouth, Babraham Farms, Bayer CropScience, Becker Underwood, DEFRA, Farmcare, Greenvale AP, J Sainsbury, Solanum, Syngenta

Approach

This project was sponsored by Defra and the AHDB Potatoes through the Sustainable Arable LINK programme. The project also provided more information on the ecology of the pest, using molecular techniques to distinguish between the different species present and field experiments to determine the effect of rotational factors on wireworm populations. The response of adults (click beetles) to pheromone traps was also studied to aid the interpretation of pheromone trap catches.

Key Findings

Wireworm populations were low throughout the experimental period and at the limits of sensitivity for soil testing. In contrast, pheromone trapping was effective throughout the experiment period, catching large numbers of click beetles. A. sputator was the dominant species by number caught in pheromone traps.

Field work on biofumigants has not demonstrated a measurable effect on wireworm populations. However, the biofumigants did have a very noticeable impact on weed germination and re-growth in the plots where mustard was grown in 2007 and 2008. Mustard may be a useful addition to the rotation, although not significantly affecting wireworm population size or damage to tubers. There was no evidence from pot trials that defatted mustard meal (BioFence) or entomopathogenic nematodes or fungi may provide useful biological control.

The reports from previous projects (2001-2003) to evaluate the use of click beetle (Agriotes spp.) sex pheromone traps as an aid to risk assessment for wireworms are also provided below