Monitoring oriental fruit moth (Lepidoptera: Tortricidae) and peach twig borer (Lepidoptera: Gelechiidae) with clear delta‐shaped traps

Field studies evaluated the relative performance of a clear versus several coloured (white, orange, and red) delta‐shaped traps baited with sex pheromone or a food bait for two key moth pests of stone fruits: oriental fruit moth (OFM), Grapholita molesta (Busck); and peach twig borer (PTB), Anarsia lineatella Zeller. Preliminary studies in 2008 found that the clear was more effective than a coloured trap for G. molesta in a sex pheromone‐treated peach orchard (OFM‐MD); and for both species in an untreated (non‐MD) peach orchard. Similarly, the clear outperformed the orange trap when both were baited with terpinyl acetate (TA) plus (Z)‐3‐hexen‐1‐yl acetate lures. Studies were expanded during 2009 to include commercial orchards in WA, OR, CA, and PA. Trap comparisons with sex pheromone lures of G. molesta were more variable with clear outperforming coloured traps in three of six trials in non‐MD orchards. The clear outperformed the coloured trap with sex pheromone lures for A. lineatella in all four non‐MD orchards. Seasonal catches of G. molesta in sex pheromone‐baited traps in OFM‐MD orchards were ≤0.3 moths per trap in all but one study with no significant difference found between traps. Seasonal catches of A. lineatella in PTB‐MD orchards were generally low with both traps and significantly higher in clear traps in only one study. Traps baited with TA outperformed sex pheromone lures for G. molesta in OFM‐MD peach orchards; and clear outperformed coloured traps. Clear traps baited with TA plus (Z)‐3‐hexen‐1‐yl acetate caught significantly more G. molesta than similarly‐baited red traps in an almond orchard and more than both trap types baited with TA alone. Catches of A. lineatella in the OFM/PTB‐MD almond orchard were low with both lures in either trap.