Dermolepida albohirtum, commonly known as the cane beetle or greyback cane beetle, is a species of scarab beetle in the subfamily Melolonthinae, native to eastern Australia. It is a primary pest of sugarcane plantations.
Taxonomy
The species was first described by Charles Owen Waterhouse in 1875 under the name Lepidoderma albohirtum. It belongs to the family Scarabaeidae. Synonyms include Lepidoderma albohirtum Waterhouse, 1875; Lepidioderma lansbergei Brenske, 1894; Lepidioderma waterhousei Brenske, 1894; and Rhopaea aruensis Lansberge, 1879.
Description
Adult cane beetles are white with speckles of black. The larvae, known as "greyback cane grubs," are small and white.
Lifecycle
Female cane beetles lay their eggs in the soil of sugarcane fields at depths of approximately 20 to 45 cm (8 to 18 in), typically at the base of the tallest cane. A single female can lay up to three clutches, each containing 20–30 eggs. The larvae feed on sugarcane roots throughout all three instar stages. The most damaging feeding period occurs from February to May, when the grubs aggressively consume roots, causing wilting, stunting, or death of the plant. After 3–4 months of feeding, the grub burrows deeper into the soil to pupate. The adult emerges from the pupa within a month but remains underground until weather conditions are suitable.
Distribution and impact
The species is native to Australia and has also been recorded in the Philippines, where it is known locally as salagubang. Adult beetles feed on sugarcane leaves, but the larvae cause greater economic damage by feeding on the roots underground.
Pest control
Control methods include the application of the entomopathogenic fungus Metarhizium anisopliae and other biocontrol strategies. However, broad-spectrum pest control can also harm beneficial insects and invertebrates.
The greyback cane beetle was one of the primary reasons (along with the Frenchi cane beetle, Lepidiota frenchi) for the introduction of the cane toad (Rhinella marina) to Australia as a biological control agent. While cane toads did consume cane beetles, they preferred other prey, and the toad itself became a major invasive pest. The cane toad's toxins have caused severe population declines in native Australian predators such as quolls (Dasyurus spp.), with declines of up to 97% recorded for the northern quoll.
