B.PAS.0004 - Biology of Pasture Mealybug and Identification of Natural Enemies

Summary

This project aims to describe the life history of pasture mealybug, provide an understanding of the link between mealybug and pasture dieback, and find natural enemies to the mealybug.

Objectives

A two-page summary outlining key facts and findings of mealybugs and how to identify mealybugs associated with dieback

Key findings

This work has confirmed the identity of the mealybug Heliococcus summervillei and demonstrated beyond doubt that it is the causal agent of pasture dieback. Diversity within the population is very low, both in morphology and in DNA marker sequences. The diversity of the insect and its symbionts suggest this might be an incursion of a new variant within the species and require some further investigation.

Benefits to industry

The confirmation of H. summervillei as the causal agent of pasture dieback is of critical importance to industry. Graziers and agronomists can now move forward with confidence to identify management strategies that suit their farm operations.

The identification of key points in the seasonal and reproductive biology of the mealybug during which damage occurs and management can be targeted is critically important. These findings and the quantitative methods developed, will inform current management and future development of proven and quantifiable strategies suitable for a range of farm operating models and systems.

Life history studies have also led to development of rapid screening assays for fast throughput of variety screening and testing of possible controls, including microbial controls and endophytes.

A small number of beneficial insects have been identified. Augmentation of beneficial insects is an important area for further investigation.Augmentation of beneficial insects is an important area for further investigation. Further work should determine if commercial Anagyrus species will parasitise H. summervillei, a potential option to boost control in the field, or if Parectromoidella, a close relative, will parasitise other, more easily reared mealybugs used in commercial mass production such as citrus mealybug. Further work on parasitoid host range, and biocontrol with Anagyrus species, is recommended.

MLA action

MLA will use the results of this project to inform future investment.

Future research

Augmentation of beneficial insects is an important area for further investigation. Further work should determine if commercial Anagyrus species will parasitise H. summervillei, a potential option to boost control in the field, or if Parectromoidella, a close relative, will parasitise other, more easily reared mealybugs used in commercial mass production such as citrus mealybug. Further work on parasitoid host range, and biocontrol with Anagyrus species, is recommended.