Author
BOKONON-GANTA, AIME - UNIV OF HAWAII AT MANOA | |
McQuate, Grant | |
MESSING, RUSSELL - UNIV OF HAWAII AT MANOA | |
Jang, Eric |
Submitted to: Biocontrol Science and Technology
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 5/6/2012 Publication Date: 1/31/2013 Citation: Bokonon-Ganta, A.H., McQuate, G.T., Messing, R.H., Jang, E.B. 2013. Release and establishment of Diachasmimorpha kraussii (Hymenoptera: Braconidae) against Bactrocera latifrons (Diptera: Tephritidae) in Hawaii. Biocontrol Science and Technology. 13:7. Interpretive Summary: Bactrocera latifrons (Hendel) (Diptera: Tephritidae), first reported in the State in 1983, is the fourth and most recent exotic tephritid fruit fly species of economic importance to become established in Hawaii. A number of classical biological control programs have been conducted against the first three exotic tephritid fruit fly species established in Hawaii, but no classical biological control programs have been conducted since the introduction of B. latifrons. Field studies have indicated that parasitism rates of B. latifrons by extant parasitoids are low, with parasitism rates of Fopius arisanus (Sonan), the primary parasitoid found, only about 5.2%. In order to seek to improve biological control of B. latifrons in Hawaii, we sought to introduce a new parasitoid species. We selected Diachasmimorpha kraussii Fullaway (Hymenoptera: Braconidae) because earlier laboratory studies had shown that this parasitoid successfully parasitized all three instars of B. latifrons and also showed minimal risk to non-target species in Hawaii. Over a three month period, eight releases, totaling 6,643 females and 5,107 males, were made in a turkeyberry (Solanum torvum Sw.) patch known to have a well established B. latifrons population. Collections of ripe turkeyberry fruits spanning over three years after the last parasitoid release confirmed that D. kraussii has become an established parasitoid of B. latifrons in Hawaii. Parasitoids were recovered, not only from the release site, but also from a control site about 5.0 km distant from the release site. Parasitism rates at sites where D. kraussii was present, however, were low, only 1.0 -1.4%, compared to rates of 2.8 – 8.7% for the earlier established egg-larval parasitoid, Fopius arisanus. Although the parasitism rate is low, the pool of parasitoids attacking B. latifrons has been increased. However, with none of the established parasitoids showing high rates of parasitism, further enhancement of biological control of B. latifrons is yet needed. Technical Abstract: Laboratory tests documented that Diachasmimorpha kraussii Fullaway (Hymenoptera: Braconidae) was a potentially effective biological control agent against Ceratitis capitata (Wiedemann) and Bactrocera latifrons (Hendel) (Diptera: Tephritidae). Diachasmimorpha kraussii was approved for release in Hawaii in 1998 following quarantine evaluations. Mass rearing of the parasitoid was initiated in 2003 followed by the first field releases of the wasp in March 2004. Over a three month period, eight releases, totaling 6,643 females and 5,107 males, were made in a turkeyberry (Solanum torvum Sw.) patch known to have a well established B. latifrons population. Establishment of D. kraussii was assessed through several methods for detection of adults and through regular collection of ripe fruits to collect parasitized fly larvae for three years beyond the last release. Adult recovery techniques failed to recover any adult D. kraussii, but D. kraussii was consistently recovered through fruit collections taken two weeks, 31 months, and 39 months after the last parasitoid release. Collections over three years after the last parasitoid release confirmed that D. kraussii has become an established parasitoid of B. latifrons in Hawaii. Parasitoids were recovered, not only from the release site, but also from a control site about 5.0 km distant from the release site. Parasitism rates at sites where D. kraussii is present are low, only 1.0 -1.4%, compared to rates of 2.8 – 8.7% for the earlier established egg-larval parasitoid, Fopius arisanus. |