Wireworms are named for the supposed wire-like appearance of their larvae. True wireworm adults are elongated beetles that jump and click when disturbed.
|Scientific name||Agrypnus spp.|
|Description||Eggs are ovoid, 0.6 × 0.5 mm. Larvae grow to 35 mm long, are shiny and cream, yellow or tan, with three pairs of legs behind the head. Unlike false wireworms, they are soft-bodied, and flatter in cross-section with a flattened head. Adult beetles are 25 mm long, grey to brown and are known as click beetles.|
|Similar species||Larvae are similar to false wireworm larvae .|
|Crops attacked||All field crops. Sugarcane wireworms are omnivorous. They originally inhabited native grasslands but have adapted to feeding on cultivated crops including field crops and pastures. They are also predatory, feeding on soil invertebrates.|
|Life cycle on maize||Most individuals complete a single generation in a year but a small number complete two generations in a year. In Queensland, adults emerge between late October and early February, with most emerging between November and early December. Adults shelter in refuges for several weeks, then move into the soil, where they may be found to a depth of 7 cm. Three to four weeks after emergence, females lay eggs either singly on the soil surface or in batches of 10-15 eggs in crevices to 5 cm deep in the soil. There are eight larval instars with a total average larval duration of 315 days; the last instar, the most damaging, occupies 48% of this time. Larvae pupate in cells in the soil during October to January. Adults emerge after 14 days. Adult females live for a maximum of seven weeks in the field. In contrast to a number of species of click beetles, sugarcane wireworm adults do not fly to lights. Adults and larvae feed in the soil on vegetation, including roots. Larvae may also feed on soil and invertebrates.|
|Risk period||Immediately after sowing and early seedling growth, especially if germination is delayed by cold, wet weather.|
|Damage||Larvae bore into germinating seed and chew on seedling roots and shoots resulting in reduced vigour or seedling death.|
|Monitoring and action level||
Use germinating seed baits (GSB) or soil sampling to detect larvae prior to sowing. Monitor crops after sowing until establishment.
Treatment is required if more than 25 wireworm larvae are found in 20 GSB.
|Chemical control||Seed dressings, in-furrow sprays and granular insecticides offer some control. For current chemical control options see Pest Genie or APVMA.|
Common brown earwig.
- Crop Insects: The Ute Guide Northern Grain Belt
- Pests of Field Crops and Pastures: Identification and Control. Editor: P.T. Bailey