Imazalil resistance in Penicillium digitatum and P. italicum causing citrus postharvest green and blue mould : impact and options

dc.contributor.authorErasmus, Arno
dc.contributor.authorLennox, Cheryl L.
dc.contributor.authorKorsten, Lise
dc.contributor.authorLesar, Keith
dc.contributor.authorFourie, Paul H.
dc.date.accessioned2015-06-24T07:54:49Z
dc.date.available2015-06-24T07:54:49Z
dc.date.issued2015-09
dc.description.abstractCitrus green and blue mould, caused by Penicillium digitatum (PD) and Penicillium italicum (PI), respectively, are mostly controlled by means of postharvest fungicide applications. Currently, IMZ is regarded as the most effective fungicide in use. Effective IMZ concentrations that inhibit 50% (EC50) growth of nine PD and five PI isolates were assessed in vitro and the various isolates categorized according to their resistance (R) factors. Effective residue levels that provided 50% curative (ER50C) and protective (ER50P) control of these isolates were determined in vivo. All the PI isolates were sensitive, having EC50 values of 0.005–0.050 mg mL 1. Three PD isolates were sensitive (0.027–0.038 mg mL 1), while one resistant isolate was categorized as low resistant (R-factor of 19), one as moderately resistant (R-factor of 33.2), three as resistant (R-factor of 50–57.6) and one as highly resistant (R-factor of 70.7). Sensitive PD isolates had mean ER50C and ER50P values on Valencia orange fruit of 0.29 and 0.20 mg g 1, and 0.33 and 0.32 mg g 1 on navel fruit, respectively. ER50 values for resistant isolates did not always correlate with EC50 values and ranged from 1.22 to 4.56 mg g 1 for ER50C and 1.00–6.62 mg g 1 for ER50P values. ER50P values for resistant isolates could not be obtained on navel orange fruit, but ER50C values (1.42– 1.65 mg g 1) were similar to those obtained on Valencia fruit. The PI isolates all behaved similar to the sensitive PD isolates with ER50C and ER50P values on navel and Valencia fruit <0.38 mg g 1. Alternative fungicides were assessed for the control of an IMZ sensitive, resistant and highly resistant PD isolate; these included sodium ortho-phenylpenate (SOPP), thiabendazole (TBZ), guazatine (GZT), imazalil (IMZ), pyrimethanil (PYR) and Philabuster1 (PLB; a combination of IMZ and PYR), fludioxonil (FLU), azoxystrobin (AZO), Graduate1A+ (GRA; a combination of FLU and AZO) and propiconazole (PPZ). Multiple fungicide resistance was shown to IMZ, GZT, TBZ and PPZ in both resistant isolates. For the sensitive isolates, IMZ, SOPP, TBZ, GZT and PLB provided best curative control, while IMZ, GZT and PLB provided best protective control. For the IMZ-resistant isolates, SOPP, PYR and PLB gave the best curative control, while none of the fungicides provided adequate protective control.en_ZA
dc.description.embargo2016-09-30en_ZA
dc.description.librarianhb2015en_ZA
dc.description.sponsorshipCitrus Research International, Citrus Academy, Postharvest Innovation Fund (PHI) and Technology and Human Resources for Industry Programme (THRIP).en_ZA
dc.description.urihttp://www.elsevier.com/locate/postharvbioen_ZA
dc.identifier.citationErasmus, A., Lennox, CL, Korsten, L, Lesar, K & Fourie, PH 2015, ' Penicillium digitatum and P. italicum causing citrus postharvest green and blue mould : impact and options', Postharvest Biology and Technology, vol. 107, pp. 66-76.en_ZA
dc.identifier.issn0925-5214 (print)
dc.identifier.issn1873-2356 (online)
dc.identifier.other10.1016/j.postharvbio.2015.05.008
dc.identifier.urihttp://hdl.handle.net/2263/45748
dc.language.isoenen_ZA
dc.publisherElsevieren_ZA
dc.rights© 2015 Elsevier B.V. All rights reserved. Notice : this is the author’s version of a work that was accepted for publication in Postharvest Biology and Technology. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Postharvest Biology and Technology, vol. 107, pp. 66-76, 2015. doi : 10.1016/j.postharvbio.2015.05.008en_ZA
dc.subjectFungicideen_ZA
dc.subjectResidueen_ZA
dc.subjectAzoxystrobinen_ZA
dc.subjectFludioxonilen_ZA
dc.subjectGuazatineen_ZA
dc.subjectPropiconazoleen_ZA
dc.subjectPyrimethanilen_ZA
dc.subjectThiabendazoleen_ZA
dc.titleImazalil resistance in Penicillium digitatum and P. italicum causing citrus postharvest green and blue mould : impact and optionsen_ZA
dc.typePostprint Articleen_ZA

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