The specific exemption section 18 label obtained in 2016 for using Mertect (thiabendazole) for control of black rot (caused by the fungus Ceratocystis fimbriata) postharvest on sweetpotatoes in North Carolina, has been renewed for use during 2018. You can find the current label here.
Recently, the European Union lowered the maximum residue level (MRL) for thiabendazole on sweetpotato to 0.01ppm. Because of this, thiabendazole should not be used postharvest for roots intended for exports to the European Union until residue data is available for sweetpotato that allows for revision of the MRL.
Information regarding current MRLs can be found here.
If you have questions please contact your Extension Agent or the NCSU Vegetable Pathology Lab.
Thiabendazole is an important complement to cultural practices used by the sweetpotato growers and packers to control black rot. For more information on the disease please see our disease fact sheet and previous posts about black rot on sweetpotato.