The response of Phytoseiulus persimilis to spider mite-induced volatiles from gerbera: Influence of starvation and experience

When leaves of the ornamental crop Gerbera jamesonii are damaged by the spi der mite Tetranychus urticae, they produce many volatile compounds in large quantities. Undamaged gerbera leaves produce only a few volatiles in very small quantities. In the headspace of spider mite-damaged gerbera leaves ma ny terpenoids are present, comprising 65% of the volatile blend. In additio n, a number of nitrogen containing compounds, such as oximes and nitriles, are produced. We studied the attraction of P. persimilis to the volatiles from spider mit e-damaged gerbera leaves and how attraction is affected by starvation and p revious experience. Phytoseiulus persimilis that were reared on spider mite s (T. urticae) on Lima bean were not attracted to spider mite-induced volat iles from gerbera. Starvation did not influence the predator's response to these volatiles. In contrast, predators that were reared on spider mites on gerbera leaves were strongly attracted to volatiles from spider mite-infes ted gerbera. This was found also for predators that originated from a cultu re on spider mite-infested bean and were offered six days of experience wit h spider mites on gerbera leaves.