Wireworm-true and false
Wireworm-true and false
True wireworm (adult and larva).
False wireworm (adult and larva).
Old wireworm damage (left) and fresh damage (right) on sweetpotato storage roots.
General information
True and false wireworms are the larval stages of two types of beetles. The adults of true wireworms are commonly called click beetles while the adults of false wireworms are known as darkling beetles.
There are 667 different species of true wireworms found in Australia. BSES entomologists identified 26 species of true wireworm in established cane fields in north, central and southern Queensland and in New South Wales.
Scientific name
True wireworms of recorded agronomic importance in Australia include potato wireworm (Hapatesus hirtus) and sugarcane wireworm (Agrypnus variabilis). False wireworms are major soil insect pests of establishing summer and winter crops in Queensland and New South Wales. False wireworms of agronomic importance in Australia include northern false wireworm (Gonocephalum carpentariae),           southern false wireworm (Gonocephalum macleayi), small false wireworm (Gonocephalum misellum), eastern false wireworm (Pterohelaeus darlingensis) and striate false wireworm (Pterohelaeus alternatus).
Life history
The lifecycle of true wireworms varies greatly between species. For example, sugarcane wireworm takes one year with four larval instars to complete its cycle whilst the potato wireworm takes approximately four years with 10 larval instars.
Summary of the lifecycle of the sugarcane wireworm (a true wireworm): Beetles emerge in October-November and migrate if habitat is not suitable. Female beetles require food (green leaf material) before they begin egg laying. Females lay eggs in November-February in batches of approximately 10 to 15 eggs. Eggs are laid on soil surface or           in small crevices.
Once larvae have emerged they generally remain in the top 50 mm of the soil profile during the first instar stage. Later larval instars will move deeper in the soil profile in response to moisture and temperature. Sugarcane wireworm take ten months and four instars for larvae to fully develop in SE           Queensland. Once larvae mature (in September-October) they hollow out small soil cells to pupate within. This stage generally takes about two weeks.
The lifecycles of the major false wireworm pest species are all similar: In central Queensland beetles emerge in October-January and migrate if the habitat is not suitable. Female beetles require food (green leaf material) before they begin egg laying. One month after emergence the females begin laying eggs on           the soil surface or just below. Egg laying may continue for up to 20 weeks but is terminated by cool weather. Females are capable of laying 1000 eggs or more.
Once larvae have emerged they generally remain in the top 50 mm of the soil profile and are relatively immobile. Larvae develop through autumn, winter and spring. It is not possible to distinguish between larvae instars. They are believed to have up to 11 instars.
Pupation occurs in September-October and is triggered by rainfall. This stage generally takes about two weeks.
Distribution