Activity 21

Managing wireworms in vegetable crops  

Wireworms in Potato (Photo by Andrew Hammermeister)

Project Introduction

Wireworms are subterranean and seriously pestilent larvae of agricultural crops. In the absence of pest control products, organic crops are particularly vulnerable. Economic losses due to wireworm on organic farms are significant. For perspective, crop loss in conventionally-grown potato (where pest control products are used) in Prince Edward Island is estimated at $6M/year. Small-scale vegetable producers in BC report large crop losses or the inability to grow marketable produce. Control products and agricultural practices will be developed to address wireworm management in small-scale organic vegetable crops, to enable management of this pest and growth of the organic sector.

The nascent development of new control products offers hope for organic growers: i) biological and bioproduct controls, and innovation in specific application patterns have been used with success in Europe and experimentally in Canada; and ii) new formulations and uses of semiochemicals are promising for mating disruption and mass trapping of adult click beetles. Drawing on existing- and newly-developed technology, the aim is to fully develop these products and recommendations for their use, so that organic farmers can have access to a pest control product tools to combat wireworm infestations.

Drawing on decades of wireworm research experience and historical literature, it is understood that cropping and other farming practices affect wireworm populations through their action on several life stages: larvae (neonate and subsequent instars), pupae, eggs, and adults. Organic farmers are particularly adaptive to new cultivation techniques, and from findings arising from this research, there is opportunity to offer growers new cultivation practices to manage wireworms directly while conserving their natural enemies.

A multifaceted approach will address wireworm infestations, developing a range of products and practices targeting all stages of the wireworm life cycle. Biological control uses Metarhizium brunneum strain LRC112 and toxic frass of the black soldier fly to target wireworms and protect transplanted crops from their feeding. Both bio-based materials take advantage of an important wireworm trait: their attraction to carbon dioxide (CO2). Applied together with CO2-generating materials, wireworms will be lured to the control substances for improved targeting. Mass trapping takes advantage of pheromones for wireworm adults, or click beetles. Pheromones attract enormous numbers of male click beetles. Without males to mate with females, egg-laying and the input of new wireworm larvae ceases. In a similar way mating disruption takes advantage of pheromones in a granular form. Broadcast pheromone granules cause male beetles to become disoriented and unable to find female mates, with a similar outcome.

The development of cropping practices will complement the use of bioproducts. Trap crops are single rows of sacrificial crops, such as wheat, planted between the food crop to attract and concentrate wireworms, thereby protecting the food crop. Folk knowledge often refers to crop cultivation techniques such as timing of tillage to kill click beetle eggs and young larvae to reduce wireworm populations. Research aimed at testing these techniques will help answer why and how they work, laying the groundwork for their refinement into predictable and reliable pest control outcomes. The study of these practices will consider the effect on wireworm natural enemies such as beneficial ground beetles, adding conservation pest management to the range of management methods. Planting and harvest periods will be identified so that periods of intense wireworm feeding and crop damage are avoided.

While mechanically preventing wireworms from feeding on high value crops such as melons, tomatoes and cucurbits may seem obvious and simplistic, practical methods for farmers need identification and development. Plastic mulches and other mechanical methods of protecting crops will be identified along with recommendations for their use in a practical farm setting.

An emphasis on grower engagement, student and staff training, and knowledge transfer will serve to advance these sustainable pest management practices that are aimed at effective wireworm control while sustaining optimum environmental and human health.

Final Report Summary

Wireworms are a subterranean and seriously pestilent larvae of agricultural crops. As there are no pest control products available to organic farmers, they lack effective controls for wireworms. Small-scale vegetable producers in BC report large crop losses or the inability to grow marketable produce due to wireworm damage, resulting in economic losses. Because of the damage wireworms do to crops, there is reduced availability of organic produce. Wireworm infested land means farmers are wary of opening up new land for production, thereby constraining the expansion of the organic industry. 

Through field research, we sought to develop new methods for managing wireworms at levels that enable an abundance of organic food production...

Keep Reading [PDF 2.28 MB]

Publications and Other Resources

Organic Science Canada- Spring 2023 (Page 23)

ES CropConsult supports the integrated pest management and wireworm control ( )

Podcast: Organic Scinece Conversations- The Ecological Challenge of Controlling the Pestilent Wireworm

Early application of Metarhiziumbrunneumfor managementof wireworm in popcorn, Zea mays var. everta.

Biogeography and genotypic diversity of Metarhizium brunneum and Metarhizium robertsii in northwestern North American soils

Local Depletion of Click Beetle Populations by Pheromone Traps Is Weather and Species Dependent

Evaluation of Pheromone Traps and Lures for Trapping Male Agriotes sputator (Coleoptera: Elateridae) Beetles in Eastern Canada

Wireworm (Coleoptera: Elateridae) genomic analysis reveals putative cryptic species, population structure, and adaptation to pest control

Limoniic Acid - Major Component of the Sex Pheromones of the Click Beetles Limonius canus and L. californicus

Genetic structure and population demographics of Hypnoidus bicolor (Coleoptera: Elateridae) in the Canadian Prairies

Biological Control of Wireworms

Modification of reproductive schedule in response to pathogen exposure in a wild insect: Support for the terminal investment hypothesis

Effect of Collection Month, Visible Light, and Air Movement on the Attraction of Male Agriotes obscurus L. (Coleoptera: Elateridae) Click Beetles to Female Sex Pheromone

The effect of synthetic female sex pheromone on the transmission of the fungus Metarhizium brunneum by male Agriotes obscurus click beetles

Limoniic Acid and Its Analog as Trap Lures for Pest Limonius Species (Coleoptera: Elateridae) in North America

(Z,E)-α-Farnesene – sex pheromone component of female click beetle Selatosomus aeripennis destructor with intra- and inter-sexual communication function

Distribution of two European elaterids, Agriotes obscurus and A. lineatus in British Columbia: New records, and potential implications of their dispersal

Distribution of Pest Wireworm (Coleoptera: Elateridae) Species in Alberta, Saskatchewan, and Manitoba (Canada).

Three years of surveillance associates agro-environmental factors with wireworm infestations in Manitoba, Canada

Comparative Evaluation of Pitfall Traps for Click Beetles (Coleoptera: Elateridae)

Field Evaluation of Selected Plant Volatiles and Conspecific Pheromones as Attractants for Agriotes obscurus and A. lineatus (Coleoptera: Elateridae)

Evaluation of Standardized Bait Trapping Approaches and Climatic Factors That Influence Wireworm Catch in the Canadian Prairies

Identification of the Major Sex Pheromone Component of the Click Beetle Agriotes ferrugineipennis

Seasonal and Diel Communication Periods of Sympatric Pest Limonius Click Beetle Species (Coleoptera: Elateridae) in Western Canada

Lack of avoidance of the fungal entomopathogen, Metarhizium brunneum, by male Agriotes obscurus beetles

Are Metarhizium brunneum conidia transferred between male and female Agriotes obscurus adults?

Scientific Note: Agriotes oregonensis (Coleoptera: Elateridae) in Canada (PDF)


Activity Researchers

Name   Organization/Location
Todd Kabaluk (Activity Leader) AAFC- Agassiz
Mike Bomford Kwantlen Polytechnic University
Stefan Vidal Georg-August University (Göttingen, Germany)
Anant Patel University of Applied Sciences (Bielefeld, Germany)
Jenny Cory Simon Fraser University
Wim van Herk AAFC- Agassiz
Paul Abram AAFC- Agassiz
Beth McCannel AAFC- Agassiz
Peggy Clarke AAFC- Agassiz