Testing various trapping methods to improve trapping efficiency when collecting/monitoring Euwallacea fornicatus (Coleoptera: Curculionidae: Scolytinae)

The PSHB Baker-style trap, currently available in South Africa, has several design flaws. An improved PSHB trap would provide the industry with a more reliable method of trapping the pest which is especially relevant when considering the importance of early detection in agricultural landscapes that have not yet been invaded. Four field trials were initiated to optimise trapping efficiency and to determine the effectiveness of a potential push-pull strategy.

Firstly, a trap height trial tested the efficiency of different trap height placements in trapping PSHB. To determine whether PSHB is attracted to specific colours a colour attraction trial, using various coloured sticky traps, was initiated. Five trap designs were also compared in order to maximise PSHB trap catch. Lastly, a push-pull study tested the possibility of using a repellent in a PSHB control strategy.

No significant difference in PSHB trap catch was observed between the three tested trap heights (40 cm, 1.5 m and 2.5 m above ground). In terms of accumulated trap catches, traps stationed immediately above ground (40 cm) caught the most PSHB. A single PSHB beetle was detected on a black sticky trap but no clear observations can be deducted from the results and the trial should be repeated in the future. The caged sticky trap that caught significantly fewer PSHB than any of the other traps. The lure and repellent push-pull treatment trapped the most and fewest PSHB, respectively.

No clear trends were observed in PSHB trap catch between the different trap heights and different colour sticky traps and it is recommended to repeat these trials with an optimal trap design as the caged sticky trap is not effective in collecting PSHB. The use of piperitone as a repellent should be further explored as it did show potential in repelling PSHB.

The potential does exist to effectively monitor, collect and repel PSHB if the correct trap designs and heights are in place. Caged sticky traps is not suitable for PSHB trapping and the use of piperitone as a repellent in a PSHB control strategy has potential.