Billbug
Scientific Name:
Spenophorus brunnipennis
Order:
Coleoptera
How to identify Billbug:
The presence of Billbug can be identified by their larvae or mature / adult form:
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The immature billbug (also known as the La Plata weevil) is a legless, creamy-white ‘C’ shaped larvae with an orange head capsule, with a body up to 10mm long.
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Young adults often have dark brown striping on the wing casings, bodies up to 10mm long.
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When mature the larvae metamorphoses Dark brown to black weevil, with a distinctive ‘bill’ like snout, and elbowed antennae.
What is the biology and lifecycle of Billbugs?
Adult billbugs deposit their eggs within the plant stem, where the larvae develop and feed on the plant. It is at this stage of development that the most severe damage is inflicted to turf grass. As the larvae continue to develop, they exit the plant and begin to feed on the stem and roots. Depending on location and weather conditions billbugs generally lay their eggs during October to December. The eggs develop into larvae after 2 weeks and immediately begin feeding as they burrow their way down through the plants to roots. These insect pupae, remain in the soil from late summer to early Autumn. Billbugs have a one or possibly two year life cycle and overwinter as young adults.
Damage Caused by Billbug
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Visible turf injury results as Billbug larvae burrow down through the stem of the turf plant towards the crown. This destroys the stems and eventually results in the death of the plant itself. The stems of dead turf plants will have hollow stems filled with sawdust like material.
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Affected plants will initially turn yellow and may eventually turf brown and die. This can often appear similar to the symptoms of fungal diseases such as Dollar Spot. In periods of high pest pressure, large areas of turf can be killed.
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Tufts of dead plants can easily be pulled out of the ground as hollows stems break off at the crown
Management Tips for Billbug
Billbugs can be hard to detect until damaging populations are present. It is important to inspect areas of turf for Billbug pest presence by pulling on leaf blades. If leaves pull out easily, or if hollow stems are present then consider applying an insecticide.
