Neopestalotiopsis australis Causing Scab Disease on Byrsonima crassifolia in Mexico.

Abstract Nanche (Byrsonima crassifolia) has great economic importance in the dry and humid tropics in Mexico, where is used for the elaboration of different drinks, foods, and candies; also in the traditional medicine to treat fever and stomach disorders. Since 2021, a high incidence of disease-causing scabby fruit in young nanche fruits has been detected in Las Choapas, Veracruz, Mexico. Disease symptoms were visible on the skin of fruits which progressed as fruits matured. Therefore, the objectives of this study were to identify the causal agent of this scab disease based on morphology and molecular techniques and to determine their pathogenicity. Fifteen isolates were recovered from diseased fruits. Because the isolates presented similar morphology, two of them were selected to determine their identity and pathogenicity. On the basis of colony characteristics, conidial morphology, and phylogenetic analyses of the internal transcribed spacers, partial translation elongation factor 1-α gene, and partial β-tubulin gene sequence the isolates were identified as Neopestalotiopsis australis. Koch's postulates demonstrated the pathogenicity of N. australis on nanche. This is the first report implicating N. australis as a causal agent of Scab Disease on B. crassifolia in Mexico and in the world.