What was it all about? 

This project began in 2016, in response to industry concern about the impact and management of Carpophilus beetles in almond production – after confirmation that the beetles were present in almost 70 per cent of almond plantings.

The primary aim of the work was to clarify which of the many species of Carpophilus is responsible for damaging almonds, and to investigate the use of an attract and kill system (as used in stone-fruit orchards) in reducing kernel damage by the pest.

Regarding Carpophilus species, large-scale field trials were conducted to collect and identify beetles from attract and kill traps across 12 orchards in three states. At least 12 different Carpophilus species and other related beetle species were caught in the traps – however the vast majority of kernel damage was being caused by a single unidentified species. That species was temporarily named Carpophilus near dimidiatus, due to its similarity to the known species Carpophilus dimidiatus.

Infestation and damage by the new species was found to commence at hull split, with damage levels increasing rapidly thereafter – indicating the need to harvest and disinfest crops as early as possible to minimise damage.

Repeated sampling of nuts remaining in orchards after harvest showed residual and mummy nuts to be a major source of the damaging Carpophilus species, with potential to support massive population increases of the pest. The project team report that preventing these nuts or destroying them through orchard hygiene practices is likely to be a critical factor for success in managing Carpophilus, regardless of other management options being implemented.

Results from the project’s field trials also revealed that, while the stone fruit attract and kill system does trap the damaging species of Carpophilus in almond orchards, trap catches did not reflect the high level of damage being caused to kernels. The researchers note that this suggests the current trapping system is not sufficiently effective to be of economic benefit to growers.

The evidence gathered from this study strongly suggested the need for research to improve the current attract and kill system, through tailoring the attractants specifically for Carpophilus near dimidiatus, increasing longevity of these formulations, and making the trap more cost-effective to growers. This important knowledge gap was to be addressed through subsequent project An integrated pest management program for the Australian almond industry (AL16009).

ACT NOW

In its course, the project produced the following resources for growers…

• Managing Carpophilus beetle in almonds, a fact sheet with monitoring and attract and kill guidelines, updated most recently for the 2016/17 season

• Two guides, which at the time of writing were being finalised ahead of their release to industry: Identification of adult Nitidulid beetles in almond orchards and Identification of Nitidulid larvae. The project team note that although the identification of Carpophilus (Nitidulid beetles) can be a complex taxonomic task, these brochures were produced to provide a basic guide to the identification of key Carpophilus species found in almond orchards.