Wireworm

Wireworm is the common name for the larvae of click beetles (family Elateridae), and the term is also used loosely in Australia for similar-looking false wireworms (family Tenebrionidae), which cause comparable damage. True wireworm larvae are slender, cylindrical, tough-skinned grubs from about 10 to 30mm long, ranging from pale yellow to reddish-brown or dark brown, with a shiny, almost wire-like appearance and three pairs of small legs just behind the head. The adult click beetles are dull brown to black, 8 to 15mm long, elongated and narrow, and get their name from the clicking sound they make when flipped onto their back to right themselves. Adults are rarely noticed as a problem; it is the underground larval stage that causes damage, living in soil and moving up and down through the profile depending on temperature and moisture.

Wireworms are found across most of Australia's cropping and horticultural regions, including home gardens and turf areas, particularly where soil has recently been under pasture, turf or lying fallow before being turned over to vegetables or new lawn. The larval stage can persist in soil for one to several years before pupating, so populations can be present long after the paddock or bed's previous use.

Damage is most often seen in newly established vegetable beds, seed beds and lawns, especially in cooler months and early spring when larvae are active near the soil surface feeding on germinating seed and young roots. In established gardens, numbers tend to decline over time as soil is regularly cultivated and organic matter breaks down, since wireworms favour undisturbed, grassy or trashy soil.

Management relies on cultural practice rather than routine chemical control in home gardens. Turning over soil ahead of planting exposes larvae to birds and desiccation, and removing grassy weeds and old turf residue before sowing reduces food source and habitat. In vegetable beds, delaying sowing of susceptible crops like potatoes, carrots and corn in paddocks recently under pasture, and monitoring with baited traps (buried pieces of potato or carrot), helps gauge whether numbers are high enough to warrant treatment.