False wireworm

  • Eastern False Wireworm, Striate False Wireworm, Pterohelaeus sp., adult, larva, insect, pest
    Eastern False Wireworm, Striate False Wireworm, Pterohelaeus sp., adult, larva, insect, pest
  • Small false wireworm, adult and larva, southern false wireworm, northern false wireworm, insect, pest
    Small false wireworm, adult and larva, southern false wireworm, northern false wireworm, insect, pest

General information

Adult false wireworms emerge from the soil during spring and early summer. Eggs are laid singly in moist soil, usually under trash or low-growing weeds. Larvae feed on decaying vegetable matter and newly germinated seeds (e.g. cereals, cotton, soybeans and sunflowers). Both the seeds and growing points are damaged, resulting in patchy stands.

Scientific name

Pterohelaeus spp., Gonocephalum spp.

Description

Larvae are up to 30 mm long, shiny and cream, yellow or tan with three pairs of legs just behind the head. They are hard-bodied, cylindrical and segmented with a rounded head. Adult beetles of Pterohelaeus spp. are 20 mm long and dark grey-black with a distinctive 'pie-dish' shape formed by flanges around the outline of the beetle.

Adult beetles of Gonocephalum spp. are 9 mm long, dark grey-black and often covered in soil. There are flanges around the outline of the thorax (behind the head).

Similar species

Several species of false wireworms may occur in any particular crop, depending on locality, soil type, organic matter and tillage practices.

Pterohelaeus spp. - eastern false wireworm, striate false wireworm.

Gonocephalum spp. - small false wireworm, southern false wireworm, northern false wireworm.

Life cycle on maize

Larvae feed on decaying vegetable matter and crop residues in the soil, as well as on newly germinated seed. They usually have a single generation per year.

Risk period

Larvae cause most damage to germinating crops during spring while adults are most troublesome in summer.

Damage

Larvae feed on germinating seed and chew on seedling roots and shoots, resulting in patchy stands. Adults chew on seedlings at or above ground level, ring-barking or completely cutting the stem.

Monitoring

Use germinating seed baits (GSB) or digging and sieving to detect larvae prior to planting.

Action level

Treatment is required if more than 25 wireworm larvae are found in 20 GSB. For adults, apply bait to the whole field if the soil insect rating (SIR) is more than six.

Control

Chemical control: for larvae, use seed dressings or in-furrow sprays. For adults, use cracked grain baits. See Pest Genie or APVMA for current chemical options.

Cultural control: the false wireworm is mainly a pest in areas having heavy, black soils. It prefers cultivated soils rather than zero til. Use press wheels at sowing, which are set at 2-4 kg per cm width after planting rain or 4-8 kg per cm in dry soil.

Pest status in maize

Minor, widespread, regular

Further information

Last updated 15 July 2010