Research progress on bioactivities and mechanism of aphid alarm pheromone (E)-β-farnesene and its analogues

The aphid alarm pheromone, (E)-β-farnesene (EBF), is a natural product secreted from the aphid cornicle to warn other companions of danger. As a natural aphid pheromone, (E)-β-farnesene can interact with odorant binding proteins (OBPs) and olfactory receptor (ORs) in the aphid olfactory system. Because of its multiple biological activities such as repellent, aphicidal and synergistic effects, (E)-β-farnesene is regarded as an aphid behavior control agent. However, its application was a challenge due to its instability arising from the conjugated double bonds in EBF. A brief introduction of the current situation in aphid control was covered in this review. The discovery and activity of (E)-β-farnesene was also summaried. According to the recent results obtained in the studies of EBF analogues, the structure modification and optimization of (E)-β-farnesene, the activities of EBF analogues and their mode of action were reviewed. And the outlook on the trend of EBF analogues as candidates of eco-friendly aphicide is proposed.