Section 37
Chapter 36,708

Evaluation of curative and protective control of Penicillium digitatum following imazalil application in wax coating

Njombolwana, N.S.; Erasmus, A.; Fourie, P.H.

Postharvest Biology and Technology 77: 102-110


ISSN/ISBN: 0925-5214
DOI: 10.1016/j.postharvbio.2012.11.009
Accession: 036707641

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Imazalil (IMZ) is widely used in citrus packhouses to manage green mould, caused by Penicillium digitatum. The aim of this study was to investigate green mould control efficacy of IMZ applied in a wax coating, and the combination of aqueous dip and coating IMZ applications. Single application of IMZ at 3000?gmL?1 in carnauba wax coating at rates of 0.6, 1.2 and 1.8Ltonne?1 of fruit gave better protective (mean 13% infection) than curative (mean 70% infection) control of the sensitive isolate. Imazalil residue levels increased (0.85 to 1.75?gg?1) with increasing coating load. However, the resistant isolate could not be controlled (>74% infection). Dip only treatment (IMZ sulphate at 500?gmL?1 for 45s and 90s) gave good curative control (?77%) of the sensitive isolate at residue loading of 0.12 0.73?gg?1. Wax coating only treatment (IMZ at 3000?gmL?1 at 1.8L wax tonne?1) gave good protective control and improved sporulation inhibition (?80%) at residue loading of 1.32 7.09?gg?1. The MRL of 5?gg?1 was exceeded at higher wax loads on navels and clementines. Double application with dip (45s in IMZ sulphate at 500?gmL?1) followed by 2000?gmL?1 IMZ in wax coating at 0.6, 1.2 and 1.8L wax tonne?1 resulted in residue loading of 1.42 to 2.83?gg?1, increased protective control (?69%) as well as curative control (?83%). In all treatments, poor curative and protective control of the resistant isolate was observed (<46% and <55%, respectively). Double application demonstrated superior green mould control by giving good curative and protective control and sporulation inhibition. Imazalil (IMZ) applied in wax coating was evaluated for citrus green mould control. IMZ in coating gave better protective than curative control of a sensitive isolate. IMZ dip application showed better curative control of the sensitive isolate. IMZ in coating gave better sporulation inhibition. Double IMZ application in dip and wax showed superior green mould control.

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