Update from Hawaii Department of Agriculture Hilo Branch, August, 2019:
Confirmed host plants:
- Kukui (Aleurites moluccanus)
- Breadfruit (Artocarpus altillis)
- Various citrus (Citrus spp.)
- Queen Sago (Cycas cirinalis)
- Cacao (Theobroma cacao)
- Mulberry (Morus sp.)
- Trumpet tree (Cercropia obtusifolia)
- Norfolk pine cut logs (Araucaria heterophylla)
- Avocado cut logs (Persea americana)
Unverified, but possible host plants:
- Gunpowder tree (Trema orientalis)
- Kalamungay (Moringa oleifera)
- Hibiscus (Hibiscus spp.)
USDA-ARS is still collecting live beetles! If you capture a beetle please bring it to our offices or contact us to arrange pick-up. Need a specimen holder? Come pick up a jar or container at our office for free any day during the week!
March 2018: An invasive beetle is attacking cacao, citrus, breadfruit, and kukui on the east side of the Big Island. The beetle, Acalolepta aesthetica, is believed to have been accidentally introduced through imported commodities from the Queensland region of Australia. Beetles in this family, the Cerambycids, are wood-borers and are known to burrow into wooden packing materials. Acalolepta aesthetica is related to the Asian longhorn beetle, infamous for devastating forests in North America with estimated costs for control more than $600 million since the 1990s.
The USDA Agricultural Research Service lab in Hilo is currently asking for live specimens of beetles for research. Dr. Sheina Sims and her team are looking to map the beetleʻs genetics, an important tool in early detection when beetles are found in the difficult to identify larval stage. Additionally, working with BIISC and the East Hawaii Cacao Association, the ARS team will be launching a trapping study to determine if there are pheromones or other attractant traps that could be used to find and monitor beetle populations.
This longhorn beetle from the Queensland area of Australia appears to have first arrived in Hawaii about a decade ago. The first sample was turned in from the Orchidland area in 2009, but for several years after, there were no reports. However, in 2013, HDOA received 3 more submissions, with a handful of beetles appearing each subsequent year. By 2017, it appeared the beetles had begun to spread, with specimens collected in Hawaiian Acres, Kea’au, and Kurtistown. In summer of 2018, specimens were captured in Pahoa and Hilo, indicating the beetle may be expanding its territory.
Adult beetles will feed on the bark, branches, and leaves of preferred plants, but the real damage is caused by the larvae. The females lay eggs in wood, usually in stressed, dying, or weakened trees. The emerging larvae will tunnel through the tree’s vascular system, creating tunnels that weaken the wood and interrupt the plant’s ability to transport nutrients and water. In one case in Puna, an infested Sago palm became so weak it collapsed under its own weight.
In addition to cacao, citrus, kukui, and Sago palms, A. aesthetica may potentially attack other hardwoods present in Hawaii, from important crop trees to native forest species.
There is no known treatment for an infestation of A. aesthetica. Adult beetles appear to be attracted to light at night, where they can be collected. HDOA advises that routine IPM insecticidal applications may deter adult beetles from selected areas; however, research is needed to determine how to address beetle infestation. The best strategy is prevention: be very cautious in moving potential host plant species from the infected area between Kea’au and Pahoa. Trees infested with the larvae should be destroyed.
Contact BIISC with a photo via email at firstname.lastname@example.org or on Facebook to report any beetle sightings. Beetles can be also dropped off at our office at 23 E. Kawili St.
August 10, 2018 Pest Release by HDOA: