Improving Grapholita molesta monitoring in peach and nectarine orchards under mating disruption by using bisexual lures


Abstract: Emilia-Romagna is an important peach and nectarine production region in Italy. In this area a primary component of pest management includes the use of sex pheromones for mating disruption (MD) of oriental fruit moth, Grapholita molesta Busck (Lepidoptera: Tortricidae). Despite the typical effectiveness of MD to manage G. molesta, there have been some sporadic infestations during the last few years. To better investigate this problem, we performed field experiments during 2018 with a new pheromone-kairomone lure, Pherocon® OFM Combo Dual (Trécé Inc., Adair, OK, USA), specifically developed to be used under MD. This binary lure includes the sex pheromone of both G. molesta and codling moth, Cydia pomonella, plus terpinyl acetate and acetic acid. The experiment was conducted in 13 commercial orchards under MD, comparing moth catches in traps baited either with a standard sex pheromone (Pherocon® OFM L2) or the new lure. Within each orchard five replicates of each lure type were included and studies were conducted over a 6-8 week period using either white or orange delta traps (Pherocon® VI Delta traps) with white sticky liners (Pherocon® VI Delta liners). Our results showed that the traps baited with the new lure caught almost 3 times more moths than traps with the sex pheromone lure, and females comprised 8% of the total catch. We also noted that much fewer non-targets including pollinators were caught in the orange versus the white delta trap. Evidence of foliar and fruit damage from G. molesta were found in all orchards, yet the sex pheromone-baited trap caught moths in only 8 of the orchards. Traps baited with the kairomonal lure caught moths in all blocks and adoption and refinement of this new monitoring tool should allow growers to better assess pest pressure. We feel that the development of this new monitoring lure can improve the management of G. molesta under MD and facilitate improved pest control for Italian growers.

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