Factors affecting trap catch in pheromone-based monitoring of saddle gall midge Haplodiplosis marginata (Diptera: Cecidomyiidae)

BACKGROUND: Saddle gall midge, Haplodiplosis marginata (von Roser) (Diptera: Cecidomyiidae), is a pest of cereal crops in Europe. Outbreaks are difficult to predict and effective monitoring tools are required to ensure the effectiveness of pest management options. The female sex pheromone, (R)-2-nonyl butyrate, provides the basis of a highly effective lure for this insect. Here, we demonstrate how the success of this lure can be influenced by parameters such as trap location, lure age, and interference between traps fitted with these lures. RESULTS: A pheromone lure containing (R)-2-nonyl butyrate attracted male midges for at least 9 weeks under field conditions. Pheromone-baited traps performed best when situated away from field margins and below the height of the crop. Interference between nearby traps was evident at distances less than 20 m. CONCLUSION: The results here offer new insights into the behavioural responses of male H. marginata to the female sex pheromone and provide practical recommendations for the use of H. marginata pheromone traps in the field.