Leaf miner in leek (Phytomyza gymnostma) – a rising concern?

Abstract: Between 2009 and 2012 several experiments with different insecticides to control the onion thrips [Thrips tabaci (Lindeman, 1889)] were conducted on JKI field stations. Within these experiments a direct control of the allium leaf miner [Phytomyza gymnostoma (Loew, 1858)] did not take place between 2009 and 2011 but side effects of the thrips control against the allium leaf miner were observed. From the year 2012 the allium leaf miner was included in the control strategy. The trials were carried out on an organic and a conventional experimental field. As test crop leek was used. The insecticides were tested as spray application against adult flies in different intervals during the flight period. The active ingredients and products used in the experiments on the organic experimental site were a combination of pyrethrine and rape oil (Spruzit Neu®), potassium salts (Neudosan Neu®), spinosad (SpinTor®), rape oil (Micula), azadirachtin (NeemAzal®) and on the conventional experimental site spinosad (SpinTor®), spirotetramat (Movento®), abamectin (Vertimec®), lambda-cyhalothrin (KarateZeon®), chlorpyrifos (Dursban 20 SC®), cyantraniliprole (Cyazypyr™) and a combination of thiacloprid and deltamethrin (Proteus®). Additionally, the products Vertimec®, KarateZeon® and SpinTor® were combined in a resistance strategy.