Mass‐rearing optimization of the parasitoid Psyttalia lounsburyi for biological control of the olive fruit fly

Abstract

The olive fruit fly, Bactrocera oleae (Tephritidae), is a direct pest of olives that has invaded the Mediterranean Region and California. Psyttalia lounsburyi (Braconidae), a larval parasitoid from Africa, has been approved for release in the USA as a classical biological agent. However, it has been difficult to rear the parasitoid in the laboratory because it is multivoltine, and the host develops only in fresh olives, which are not available for most of the year. A method to rear the parasitoid on the factitious host, Mediterranean fruit fly (Ceratitis capitata) was developed, but it was not very efficient for producing large numbers of parasitoids needed for release. We developed a number of ways to improve the efficiency of rearing, including the frequency and duration of exposure for oviposition, optimizing the density of adult parasitoids, host age, as well as methods to quickly standardize the number of larvae exposed and to count emerging adult parasitoids. We significantly improved the number of progeny produced per female and the sex ratio of progeny. Thanks to these improvements, we produced in 2017 over 119,000 adults and shipped over 53,900 for release in California.

Exploration for olive fruit fly parasitoids across Africa reveals regional distributions and dominance of closely associated parasitoids

“…The recent successful establishment of P. lounsburyi in California should evoke further investigation into the use of this species for classical biological control of B. oleae in other climatically similar regions 31 , 46 , 51 . The advances of modern rearing techniques for these exotic parasitoid species and their tephritid hosts should further facilitate the use of classical and augmentative biological control of B. oleae 37 .…”

“…Only P. concolor, obtained from Tunisia, has been repeatedly introduced to the Mediterranean Basin since the early 1900s, but this species has established only in some southern regions and does not provide effective control 34,35 . Still, there has been continued interest in mass-rearing and releasing P. concolor and/or P. lounsburyi to improve sustainable fly management in Europe [36][37][38][39] .…”

Exploration for olive fruit fly parasitoids across Africa - regional distributions and dominance of co-evolved parasitoids

“…The recent successful establishment of P. lounsburyi in California should evoke further investigation into the use of the species for classical biological control of B. oleae in other climatically similar regions 29,43,49 . The advances of modern rearing techniques for these exotic parasitoid species and their tephritid hosts may further facilitate the use of classical and augmentative biological control of B. oleae 35 . However, identifying the suitable climatic niche of these different parasitoid species and understanding their geographic predictability helps to determine the potential establishment in released habitats in the presence of biotic interactions is paramount for successful biological control of B. oleae.…”

“…Only P. concolor, obtained from Tunisia, was repeatedly introduced since the early 1900s and extensively released in the Mediterranean Basin, but this species has established only in some southern regions and does not provide effective control 32,33 . Still, there has been continued interest in massrearing and releasing P. concolor and/or P. lounsburyi to improve sustainable y management in Europe [34][35][36] .…”

Biological Control of Tephritid Fruit Flies in the Americas and Hawaii: A Review of the Use of Parasitoids and Predators

“…Field release and recovery efforts were conducted from 2006 to 2013; both parasitoid species were recovered post-release, but only P. lounsburyi was established in California coastal regions [ 167 , 205 ]. Given these results, the parasitoid P. lounsburyi was mass-reared for release on a larger scale in olive-producing areas of California [ 206 ].…”