Multi-lure and multi-trap surveillance for invasive tree pests (Multitrap)

Invasive non-native xylophagous longhorn, bark and jewel beetles are a serious threat to the biosecurity of urban, rural and forest trees, causing long-term damage and tree mortality. This has major impacts on pest and tree management as well as ecosystem services provide by trees. These beetles arrive in various forms of timber including logs, lumber, wood packaging, pallets and live trees for planting. Hence, early detection at or close to points of entry is therefore of paramount importance for the implementation and success of eradicating an invasive species.

This project aimed to advance previous studies (Rassati et al., 2014; 2015) that demonstrated multi-funnel traps baited with multi-lures could be used to monitor for invasive beetles at points of entry of imported wood, but focusing primarily on longhorn beetles (Cerambycidae).

The traps and lures currently available for surveillance of invasive xylophagous beetles were reviewed (Down and Audsley, 2017) and were used together with work conducted by INRA (Roques et al., 2017) to select lures for testing at 21 ports of entry and 22 forest sites.

This study determined that, using black cross-vane or multi-funnel traps in a parallel set-up across the partner countries, the optimal detection strategy is to use pheromone blends in combination with the host plant volatiles, ethanol and α-pinene. This maximises the taxonomic diversity of beetles captured, particularly Cerambycidae and minimises the number of traps and lures required. Over 80 species of Cerambycidae were captured in both years (2017 and 2018) of study. Such traps and lures are not suitable for Buprestidae.

A standard protocol was produced that should be followed so that surveillance can be standardised and consistent and could contribute towards compliance with community regulations on national surveys for European quarantine pests.

Although the cost-effectiveness of individual trapping programmes will always have to be evaluated on a case by case basis, there are potential benefits from replacing single-lure trapping programmes with combined multi-lure programmes for early detection. Including multi-lures in a single trap reduces the number of traps required, effort of deployment and servicing, and increases the number of different target species captured, thereby increasing trapping efficacy and reducing costs compared to multiple traps baited with single lures. Trap density is also an important success parameter for early detection, which in turn increases the probability of successful eradication thereby reducing costly pest damages.