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Wireworms (Family Elateridae)

wireworm larvae

Wireworms biology & life cycle

Wireworms are the larvae of click beetles and a common pest found in field and vegetable crops. Adult click beetles overwinter in the soil and emerge in the early spring, around late April to early May. Each female lays 200 to 400 eggs between late May and early June, depositing them on the soil surface down to a depth of 15 cm (nearly 6 inches).

The larvae hatch within three to seven weeks and spend the next three to five years feeding on roots and germinating seeds and moving up and down in the soil profile. When they’re ready, larvae go through a short pupation, about a month long, and emerge as adult click beetles in the soil. They overwinter there and emerge the following spring to lay eggs and begin the cycle again.

There are many different species of wireworms within the Family Elateridae, but the three most predominant species of economic concern to Canadian prairie crops are Selatosomus aeripennis destructor, Hypnoidus bicolor and Limonius californicus. All of these species can be found together in the same field. Check the wireworm map (below) for the location nearest you to see what species were identified in our wireworm surveys.

Different wireworm species are able to do different levels of damage. H. bicolor is the most common species but is smaller and therefore able to do less damage at moderate populations. S. destructor larvae are the largest of the three significant species, and the most destructive even at moderate populations. Heavy infestations of S. destructor can lead to a cereal crop failure.

Because of their long and somewhat variable life cycle, it’s important to note that a field infested with wireworms is likely to contain populations at all growth stages, at the same time.

wireworm lifecycle

Identifying Wireworms

wireworm

Wireworms: Larvae

Wireworms are tan or copper-coloured, cylindrical and hard-bodied. They vary in size from 1 to 3 cm in length (½ to 1½ inches) and have three pairs of legs near the head end.

Wireworms: Pupae

Pupae are white and contained within earthen cells in the soil.

Adult

Wireworms: Adult

Adult wireworms, or click beetles, are hard-shelled, black-brown in colour and cause no crop damage at this stage in their life cycle. When placed on its back the adult will flip over by flexing the middle part of its body. This creates a distinctive ‘click’ sound which is why the adult pest if often referred to as a ‘click beetle’.

Wireworms: Management

Plants damaged by wireworms suffer from slow development and can be killed by extensive feeding or secondary infection. Because of their life cycle, wireworms are a significant threat to young plants which are most susceptible so early control is critical.

Syngenta conducted surveys in 2010, 2016 and 2017 to detect the presence of click beetles and wireworms (the larval form of click beetles) across the Prairies, and to identify the species. The map below indicates where wireworms were found in 2010 (orange pins), and where click beetles were found in 2016* (blue pins) and 2017* (green pins). Pins indicate sampled areas where wireworms or click beetles were found; the absence of a pin does not necessarily indicate wireworms or click beetles were not present in the area.

*In some 2016 and 2017 locations, we also looked for wireworms.

Legend



There are a number of cultural and chemical wireworm control options available to growers, and all should be included as part of an integrated crop management plan.

Recommended management practices include:
  • Effective Scouting. Walk fields to identify wilted plants or gaps where or areas of dead plants. Dig around the plant to look for feeding damage and insect larvae, to confirm the cause of the damage.
  • Wireworms can be monitored in the fall (or in the early spring for later-planted crops) using bait stations. A count of 0.5 to 1 wireworm per bait station indicates a potential problem. Make your planting and seed treatment decisions accordingly.
  • Check out the wireworm video blog for tips on how to bait balls can be used assess wireworm field populations


Sources:
OMAFRA

Resources

Recommended solution

Cruiser Vibrance Quattro logo

Cruiser® Vibrance® Quattro is a cereal seed treatment that combines four fungicides and an insecticide for control of seed- and soil-borne diseases and wireworms.

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