Developing risk management treatments for taro from the Pacific Islands
Most taro imported from the Pacific are currently fumigated with toxic methyl bromide to kill pests, predominantly mites and nematodes that are generally found on the surface of taro. Combined high-pressure washing (HPW) and hot water treatment (HWT) were examined as alternative methods for disinfesting taro. Taro mites (Rhizoglyphus sp.) and root knot nematodes (Meloidogyne sp.) were exposed to a range of HWT and HPW conditions separately or together. At 47°C, mean lethal times of 2.6–2.9 mins and 3.9–4.1 mins were estimated to control 99% and 99.99% of nymph and adult mites, respectively. Mite nymphs and adults were more tolerant to HWT than mite eggs. The mean lethal time estimate to control 99% of juvenile nematodes was 4.5 mins. Nematode eggs were the most tolerant life stage with only 10% mortality after a 4-min 47°C HWT. HPW+HWT reduced heavy infestations of mobile pests on taro (n=30–117/taro) by 100%. HPW followed by HWT 50°C for 12.5 mins reduced viable egg infestation by 95.8%. HPW followed by HWT can control surface pests on taro while maintaining taro quality.
Cho D, Park K, Kim Y, Koh K, Park Y 2017. Study on hot water immersion treatment for control of Meloidogyne spp. and Pratylenchus spp. in a ginger, Zingiber officinale. Korean Journal of Applied Entomology 56(2): 171-177. https://doi.org/10.5656/KSAE.2017.04.0.002
Cleveland WS, Grosse E, Shyu WM 1992. Local regression models. In: Chambers JM, Hastie TJ eds. Statistical Models in S. Wadsworth & Brooks/Cole, CA, USA. Pp. 309–376.
Dobson AJ, Barnett AG 2008. Texts in Statistical Science: An Introduction to Generalized Linear Models. 3 ed. Florida, USA, CRC Press, Taylor & Francis Group.
Gear I 2011. New Zealand Research Programme - Stakeholders in Methyl Bromide Reduction Update, Research programme 2011 - 2016, Annual International Conference on Methyl Bromide Alternatives and Emissions Reductions, San Diego, California, USA.
Gerson U, Capua S, Thorens D 1983. Life history and life tables of Rhizoglyphus robini Claparede (Acari: Astigmata: Acaridae). Acarologia 24(4): 439-448.
Gotoh T, Kitashima Y, Sato T 2013. Effect of hot-water treatment on the two-spotted spider mite, Tetranychus urticae, and its predator, Neoseiulus californicus (Acari: Tetranychidae, Phytoseiidae). International Journal of Acarology 39(7): 533-537. https://doi.org/10.1080/01647954.2013.857720
Griffin M, Olsson SR, Jamieson LE, Kagy V, Mille C, Connolly PG, Woolf AB 2014. Reducing the risk of importing pest-infested citrus by applying high pressure washing treatments offshore. New Zealand Plant Protection 66: 109-115.
Jamieson LE, Chhagan A, Redpath SP, Griffin M J, Rohan C, Tunupopo F, Tugaga A, Connolly PG, Woolf AB 2016. Development of a hot water disinfestation treatment for taro exported from the Pacific Islands. New Zealand Plant Protection 69: 200-206.
MPI 2018. Approved Biosecurity Treatments. Ministry for Primary Industries, Wellington. https://www.mpi.govt.nz/dmsdocument/1555-approved-biosecurity-treatments-for-risk-goods (accessed 23 April 2018).
NZERMA 2011. Application for the reassessment of a hazardous substance under section 63 of the Hazardous Substances and New Organisms Act 1996. Name of substances: Methyl bromide and formulated substances containing methyl bromide, New Zealand Environmental Risk Management Authority. 107 p.
Page-Weir NEM, Jamieson LE, Bell NL, Rohan TC, Chhagan A, Clare G, Kean AM, Davis VA, Griffin M, Connolly PG 2013. Interceptions and hot water treatment of mites and nematodes on root crops from the Pacific Islands. New Zealand Plant Protection 66: 17-28
Preisler HK, Robertson JL 1989. Analysis of time-dose-mortality data. Journal of Economic Entomology 82: 1534-1542. https://doi.org/10.1093/jee/82.6.1534
R Core Team 2015. R: A language and environment for statistical computing. Vienna, Austria., R Foundation for Statistical Computing.
UNEP 2014. Montreal protocol on substances that deplete the ozone layer United Nations Environment Programme. 2014 Report of the Methyl Bromide Technical Options Committee. 2014 Assessment Nairobi, Kenya. http://ozone.unep.org/Assessment_Panels/TEAP/Reports/MBTOC/index.shtml
Woolf AB, Lay-Yee M 1997. Pretreatments at 38°C of ‘Hass’ avocado confer thermotolerance to 50°C hot-water treatments. HortScience 4(32): 705-708.
Woolf A, McDonald R, Rogers D, Olsson S, Redpath S, O’Donoghue E, Kagy V, Mille C, Cate L, Griffin M, Page-Weir N, Chhagan A, White A, Walker J, Jamieson L 2015. Advances in application of high pressure washing to enhance market access. Acta Horticulturae: 385-390. https://doi.org/10.17660/ActaHortic.2015.1105.55