Attraction of Planococcus ficus males to racemic and chiral pheromone baits: flight activity and bait longevity

Abstract

The vine mealybug (VM), Planococcus ficus (Signoret), is a worldwide pest and affects mainly grapevine and figs. In Israel, (S)-lavandulyl senecioate [(S)-LS] and (S)-lavandulyl isovalerate [(S)-LI] were identified from VM reared for several generations on potato sprouts, when compared with the identification of only (S)-LS from feral females. Racemic lavandulyl senecioate (LS) can be used for fieldwork because the unnatural enantiomer is benign and does not affect the activity of the pheromone. Lures loaded with 200 lg of LS remained active for 24 weeks but it is recommended to replace lures after 12 weeks to preserve constant and high attractiveness. Delta sticky traps, baited with 50 or 200 lg of LS were used to determine the daily flight pattern and the seasonal flight activity including vine plant infestation. A positive correlation between peak mealybug density and male capture was observed strengthening the usefulness of the pheromone traps for monitoring the pest. Addition of racemic or the two enantiomers of lavandulyl isovalerate (LI) to LS decreased the capture of VM males. The level of inhibition varied during 2003–2004. Both enantiomers of LI displayed the same antagonistic activity. Addition of (S)-lavandulol to the pheromone resulted in shutdown of the traps. Inhibition by the antipode, (R)-lavandulol, was moderate indicating a certain degree of chiral discrimination