ARS | Publication request: Mixed fruit boxes for export and little fire ant control

Submitted to: Annual International Tropical Fruit Growers Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: October 26, 2007
Publication Date: January 24, 2008
Citation: Follett, P.A. 2008. Mixed fruit boxes for export and little fire ant control.In: Proceedings of the 17th Annual International Tropical Fruit Growers Conference, September 28-30, 2007, Hilo, Hawaii. p. 53-57.

Interpretive Summary: In the past, quarantine treatment protocols are developed for and applied to single commodities. Generic irradiation treatments approved in 2006 were developed irrespective of commodity, and therefore could be applied to mixed commodities as long as the technical objectives of the treatment are met. We conducted tests to compare dose variation between single fruit and mixed fruit boxes during commercial irradiation treatment. Results showed that dose variation between fruit mixture and single fruits is quite similar, and therefore, that irradiation treatment of loads of mixed fruit using generic doses is technically feasible. This could lead to export approvals for value-added mixed fruit gift boxes which would diversify revenue for the tropical fruit industry. Future research will focus on irradiation and dose mapping of carrier loads of mixed fruit boxes. The little fire ant, Wasmannia auropunctata, has invaded a variety of agricultural sites on the island of Hawaii and is spreading fast. Several ant controls were tested in a fruit orchard. Amdro and Esteem caused a reduction in ant numbers but did not eliminate ants in the orchard plots. Many W. auropunctata were found nesting in protected sites in the orchard trees which may have compromised the ground-based control methods. Absolute density estimates from shallow core samples taken from the orchard floor indicated the W. auropunctata supercolony exceeded 244 million ants per hectare.

Technical Abstract: Traditionally, quarantine treatment protocols are developed for and applied to single commodities. Generic irradiation treatments approved in 2006 were developed irrespective of commodity, and therefore, theoretically, could be applied to mixed commodities as long as the technical objectives of the treatment are met. We conducted tests to compare dose variation between single fruit and mixed fruit boxes during commercial irradiation treatment. Results showed that dose variation between fruit mixture and single fruits is quite similar, and therefore, that irradiation treatment of loads of mixed fruit using generic doses is technically feasible. This could lead to export approvals for value-added mixed fruit gift boxes which would diversify revenue for the tropical fruit industry. Future research will focus on irradiation and dose mapping of carrier loads of mixed fruit boxes. The little fire ant, Wasmannia auropunctata (Roger) (Hymenoptera: Formicidae) has invaded a variety of agricultural sites including nurseries, tropical fruit farms, macadamia orchards, and pastures in Hawaii. Amdro (hydramethylnon; in bait stations), Esteem (pyriproxyfen; broadcast bait), and Conserve (spinosad; ground spray) were tested for their efficacy against W. auropunctata in a rambutan and mangosteen orchard by making biweekly treatments for 16 weeks. On weeks 12 and 16, the reduction in ant numbers in the Amdro plots was 65% and 38%, respectively, compared with pre-treatment numbers, and the reduction in ant numbers in the Esteem plots was 44% and 90%. Ant numbers in the untreated control plots increased by 194% and 255% on weeks 12 and 16 compared with pre-treatment counts. No plots for any of the treatments achieved 100% reduction. Many W. auropunctata were found nesting in protected sites in the orchard trees which may have compromised the ground-based control methods. Absolute density estimates from shallow core samples taken from the orchard floor indicated the W. auropunctata supercolony exceeded 244 million ants per hectare.