Greyback cane beetle

The greyback cane beetle (Dermolepida albohirtum) is a destructive pest belonging to the order Coleoptera and the family Scarabaeidae. It is recognized as one of the most significant insect threats to the sugar industry, particularly in Australia, where it infests vast areas of sugarcane plantations causing severe economic losses.

While the larvae are notorious for their feeding habits, the adult beetles are known to feed on the foliage of various trees and ornamental plants. However, the true damage to agricultural output is concentrated in the soil, where the subterranean larvae target the root systems of the primary crop.

The life cycle of this beetle typically spans two years, characterized by a complex progression through the egg, larval, pupal, and adult stages. The larval development occurs entirely underground, where they grow through successive instars, consuming root material at an increasing rate before pupating in the deeper soil layers.

Symptoms of an infestation are often observed as yellowing, stunted growth, and the wilting of sugarcane stalks. Because the larvae consume the primary and secondary roots, the plants lose their anchorage, often leading to them being easily toppled by wind or drought, which complicates mechanical harvesting and reduces yield.

Managing this pest requires an integrated pest management (IPM) strategy. Key methods include: chemical protection with soil-applied insecticides, the promotion of natural enemies like beneficial fungi or entomopathogenic nematodes, and strict monitoring of beetle flight activity. Cultural practices such as selecting resistant varieties and timing cultivation cycles can further suppress population levels.