An improved systems approach as a phytosanitary measure for Thaumatotibia leucotreta (Lepidoptera: Tortricidae) in export citrus fruit from South Africa
- Authors: Hattingh, Vaughan , Moore, Sean D , Kirkman, Wayne , Goddard, Mathew K , Thackeray, Sean R , Peyper, Mellissa , Sharp, Gary , Cronjé, Paul , Pringle, Ken
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423700 , vital:72086 , xlink:href="https://doi.org/10.1093/jee/toz336"
- Description: A systems approach was previously developed for mitigating phytosanitary risk of Thaumatotibia leucotreta (Meyrick) in citrus fruit exported from South Africa, as an alternative to a standalone cold disinfestation treatment. The present study first tested the original systems approach by applying it on a semicommercial scale in 10 Nova mandarin orchards. Fruit were inspected at points in the production, packing, and simulated shipping process, to assess performance of the systems approach. Additional data were obtained from 17 Valencia orange orchards and six packinghouses. In the second part of this study, the systems approach was accordingly revised and improved, consisting of three measures: 1) preharvest controls and measurements and postpicking sampling, inspection, and packinghouse procedures; 2) postpacking sampling and inspection; and 3) shipping conditions. The model quantifying the effectiveness of the systems approach was improved by correcting errors in the original version, updating parameter values and adding a component that provides for comparison with the risk mitigation provided by a standalone disinfestation treatment. Consequently, the maximum potential proportion of fruit that may be infested with live T. leucotreta after application of the improved systems approach is no greater than the proportion of fruit that may be infested after application of a Probit 9 efficacy postharvest disinfestation treatment to fruit with a 2% pretreatment infestation. The probability of a mating pair surviving is also determined. The model enables a priori determination of the required threshold levels for any of the three measures, based on quantification of the other two measures.
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- Date Issued: 2020
Partial cold treatment of citrus fruit for export risk mitigation for Thaumatotibia leucotreta (Lepidoptera: Tortricidae) as part of a systems approach
- Authors: Moore, Sean D , Kirkman, Wayne , Albertyn, Sonnica , Love, C N , Coetzee, Julie A , Hattingh, Vaughan
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423796 , vital:72094 , xlink:href="https://doi.org/10.1093/jee/tow138"
- Description: Some of South Africa’s citrus export markets require mandatory postharvest cold treatment of citrus fruit as a phytosanitary risk mitigation treatment for Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae). An alternative to this may be partial cold treatment as one of the final steps in a systems approach to mitigate phytosanitary risk. Consequently, the efficacy of such partial cold treatments was evaluated. It was first determined that a 2C cold treatment was significantly more effective against fourth and fifth instars (the most cold-tolerant instars) than treatments at 3C and 4C for a duration of 18 d. Secondly, it was determined that 2C for 18 d and 1C for 16 d were similarly effective, but both treatments were significantly more effective than 1C for 14 d. Mean mortality of fourth and fifth instars treated with 2C for 18 d in seven replicates from four trials was 99.94%. Finally, it was determined that the inability of the majority of surviving larvae to develop to adulthood would further increase the efficacy of a 2C for 18 d treatment to 99.96%. Inclusion of reproductive nonviability of survivors increased mortality to 99.99%.
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- Date Issued: 2016
The host status of lemons for the false codling moth, Thaumatotibia leucotreta (Meyrick)(Lepidoptera: Tortricidae) with particular reference to export protocols
- Authors: Moore, Sean D , Kirkman, Wayne , Hattingh, Vaughan
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/452252 , vital:75115 , https://hdl.handle.net/10520/EJC176581
- Description: The South African citrus industry is dependent on export of fresh fruit to many markets around the world, with approximately 70% of South Africa's citrus crop being exported (CGA 2013). The false codling moth, Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae), is recorded as a pest of citrus fruit in southern Africa (Newton 1998; Grout and Moore 2015). As a result of its endemism to sub-Saharan Africa (Moore 2002), certain export markets of importance for the South African citrus industry, such as Peoples Republic of China, U.S.A. and South Korea, regulate it as a quarantine pest.Control of the pest in the field can be highly effective, using a suite of integrated control options, applied with diligent management (Moore and Hattingh 2012). These can succeed in reducing T. leucotreta infestation by 97% or more (Moore et al. 2015). Such an integrated system, using the sterile insect technique as the mainstay of the programme, has succeeded in reducing moth catches by 99%, fruit infestation by 96% and export rejections by 89% in the Western Cape Province of South Africa, since the inception of the programme in 2007 (Barnes et al. 2015).
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- Date Issued: 2015