Agronomist, Terry Edis (Elders), reports finding false wireworms in a canola crop southeast of West Wyalong, in the South West Slopes district of New South Wales. False wireworms are the larval form of native beetles in the Tenebrionidae family. Larvae were detected after digging around the base of visibly affected canola plants, and it is assumed that they are responsible for the damage. The crop was sown into a long-term pasture paddock, and Terry says more grubs were found in areas of the paddock that were cultivated earlier than the rest of the paddock.
Adult and larval false wireworms normally live in grasslands or pastures and cause little damage in this situation. In crops, they are mostly found in paddocks with high stubble and crop litter contents. They may affect all winter-sown crops. There are a large and varied number of species, including the grey false wireworm, the eastern false wireworm and the southern false wireworm. The species are similar in appearance with larvae generally growing between 10-50 mm in length. Larvae are cylindrical, hard bodied, fast moving and golden brown to black-brown or grey in colour. They have a pair of prominent spines on the last body segment.
False wireworms chew into the seedling stem and roots, weakening the plant or ring-barking the stem. The injury to the seedlings makes them susceptible to dehydration and infection by disease. Feeding damage is often most severe when germination is slowed by continued dry weather. There is evidence suggesting that stubble retention and minimum tillage are contributing to the build-up of false wireworm populations in southeastern Australia.