Pheromone traps for moths.
Pheromone traps (delta design DeSIRe, green plastic funnel, water and A-traps) were tested for their ability to attract the potato tuber moth (PTM) (Phthorimaea operculella) in crops of potatoes, cv. Rua, in New Zealand. The 1st experiment was carried out while the crop was in flower with DeSIRe and funnel traps at 0.3 and 1.0 m high, containing blends of the 2 PTM pheromone components PTM1 and PTM2 at 1:1, 1:1.5 or 1:4. DeSIRe sticky traps caught >8 times more moths per day than the funnel traps (17 and 2 moths per day, respectively). This was consistent regardless of height or pheromone blend. The blend 1:2 caught significantly fewer moths than the other 2 blends. Moths made similar approach flights to the 2 trap designs, and readily entered the DeSIRe traps while those landing on the funnel traps made slow progress to the top of the funnel. In a 2nd experiment carried out when the tubers were bulking out, DeSIRe traps were compared to water traps (on the ground) and A-traps (also sticky) at 0.3 m. All 3 pheromone blends were tested. Numbers of moths trapped were 124, 29 and 8 moths per day in the water, DeSIRe and A-traps, respectively. Water traps took an average of 6 min to service, compared to less than 1 min to replace the base of the sticky trap. It is concluded that the integrated pest management programme for PTM will recommend the DeSIRe pheromone traps (or equivalent delta trap design), baited with a 1:1.5 blend of pheromone, to be used for monitoring moth populations in potato crops. The traps should be hung at the top of the potato canopy.