title: Cold treatment of Ceratitis capitata (Diptera: Tephritidae) in oranges using a larval endpoint.
abstract: South Africa currently exports fresh citrus (Citrus spp.) fruit to Japan using an in-transit cold treatment protocol of 14 d or 12 d at temperatures <0 degrees C for treatment of Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) in 'Clementine' mandarins (Citrus reticulata Blanco) and other citrus types, respectively. To reduce the risk of chilling injury with this treatment, research was conducted with temperatures >0 degrees C. Earlier South African research had shown that young (6-d-old) larvae were slightly more tolerant of cold treatment and that there were no significant differences between cold tolerance of these larvae in different citrus types [oranges, Citrus sinensis (L.) Osbeck; grapefruits, Citrus paradisi Macfad.; lemons, Citrus limon (L.) Burm.f.; and mandarins). Due to their ready availability, 'Valencia' oranges were used in this study. When 62,492 larvae in total were treated in three replicates at a mean temperature of 1.5 degrees C for 16 d, there were three larval survivors. The trial was therefore repeated with oranges using a 16-d period at a mean temperature of 1.0 degrees C and a mean of 1.4 degrees C for the hourly maximum probe readings. Three replicates were again conducted and the resultant mean mortality in the control was 8.1% of 21,801 larvae, whereas the cold treatment mortality was 100% of 71,756 larvae. This treatment at a mean temperature of 1 degree C exceeded the Japanese confidence level requirement and also exceeded the Probit-9 mortality level, but not at a confidence level of 95%. These data support the establishment of a treatment protocol of 16 d at temperatures <1.4 degrees C, commencing once all fruit pulp probes reach a temperature of 1 degree C or lower.
authors: Citrus Research International, P.O. Box 28, Nelspruit 1200, South Africa. tg@cri.co.za
authors: Tim G
authors: TG
authors: Grout
authors: Peter R
authors: PR
authors: Stephen
authors: John Henry
authors: JH
authors: Daneel
authors: Vaughan
authors: V
authors: Hatfingh
mesh_terms: D000818:Animals; D033622:Ceratitis capitata; D032084:Citrus sinensis / Q000469:parasitology*; D003080:Cold Temperature; D016266:Food Parasitology; D005638:Fruit / Q000469:parasitology*; D007300:Insect Control / Q000379:methods*; D007814:Larva