Imported parasite of greenhouse thrips established on California avocado

The parasitic wasp, Thripobius semiluteus, introduced for biological control of greenhouse thrips, has been established and spreading for up to four growing seasons at some sites in Southern California avocado orchards. Studies show that declines in thrips numbers coincide with increasing parasitization by this wasp, which could become an important mortality factor of greenhouse thrips if its widespread establishment is achieved.