Canegrubs have a lifecycle consisting of egg, larva, pupa and adult stages. The cycle begins with eggs laid between October and February. Timing of egg laying may differ slightly between species and from year to year, depending on climatic conditions.
Eggs hatch into larvae, which go through three growth stages called “instars”. After the third-instar has accumulated enough fat reserves they burrow downwards and pupate. Pupa metamorpize into adult beetles which remain in the soil until triggered to emerge by temperature and rainfall.
Adult beetles usually emerge around dusk and form dense flights from about 7.00 pm. Beetles seek out feeding trees and mate. Female beetles usually feed for about two weeks while their eggs mature. They then return to the soil to lay their eggs.
Egg-laying beetles tend to be attracted to blocks where cane is taller than adjacent blocks, or sometimes to blocks on hillsides which may appear taller than cane on other blocks.
Canegrub species differ in their geographic distribution and their lifecycle may extend over either one or two years.
Being native insects (except for plectris canegrub), there are a number of natural enemies that help to regulate canegrub populations.