Source: NCSU COOPERATIVE EXTENSION, 1/14/21
Sweetpotato black rot, caused by the fungal pathogen Ceratocystis fimbriata,
was found in two commercial sweetpotato storage facilities in January of 2021.
Afflicted sweetpotatoes exhibited symptoms of firm, circular lesions ranging
from grey to greenish black in color consistent with the disease. Growers and packers should remain vigilant as sweetpotato black rot
can develop and spread under storage conditions. To limit disease outbreaks
during storage, prevention is the best method of control. Reusable storage bins
should be clear of debris prior to use and properly sanitized. During storage,
a storing temperature of 55˚F should be maintained. Growers and packers can also consider using effective fungicides
postharvest and in the field during the next growing season. The fungicides
Mertect (thiabendazole) and Stadium (azoxystrobin, fludioxonil, difenoconazole)
are effective against black rot and have a postharvest label to use in
sweetpotato. The fungicide Mertect can also be applied to seed to protect 2021
plantings from black rot. While both fungicides can be used for domestic
markets, they may have restrictions related to maximum residue levels allowed
in particular export markets. If you think you may have sweetpotato black rot at your storage
facility and need assistance with diagnostics or management, please contact
your local Extension agent and send physical
samples and/or photos to the Plant Disease and Insect Clinic. For
additional management options, please refer to those listed in our disease factsheet.
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