Potato tubers from France and introduced to Brazil for research purposes were subjected to phytosanitary analysis at the Quarantine Laboratory of Embrapa Genetic Resources and Biotechnology (Cenargen). Some of the tubers showed sunken, water-soaked, brownish-purple lesions, with soft skin, and black pycnidia were visible in the lesions using a stereomicroscope. Examination of the fungal structures on microscope slides using light microscopy demonstrated that the fungus had the morphology of Phoma exigua var. foveata, an A1 quarantine pest for Brazil. Pathogenicity tests were carried out inoculating healthy potato tubers with a pure culture of the fungus. Rot symptoms were observed 3 days after inoculation and progressed until 8 days. The fungus was re-isolated from the lesions on potato dextrose agar, confirming that the fungus was the etiological agent of the disease. The tubers that were symptomatic were incinerated, and the other healthy-looking tubers were treated with a systemic fungicide, cultivated under quarantine for two generations, and then reanalyzed. After confirming that they were free of the pathogen, the tubers were sent to their destination solicitor.
Phytosanitary Service; quality control; quarantine; Brazil Al list
