Frequency of fungi associated with Creole corn seeds under different environmental conditions in Guerrero, Mexico

In Mexico, Creole corn has presented problems related to seed rot. Therefore, the objective of this study was to determine the frequency of fungi associated with Creole corn seeds. From January to February 2019, 13 Creole corn samples were collected from several localities in Guerrero, Mexico. The samples were processed in PDA culture medium and the frequency of each fungus was estimated based on cultural characteristics and taxonomic keys. Considering symptomatic corn seed samples, Fusarium oxysporum was recorded in eight samples at 97.2%, followed by F. graminearum, isolated from race “Olotillo 1” at 94.4% and from race “Cónico pepitilla” at 58.3%. Phomopsis sp. was isolated at 100% from race “Olotillo 2”. Gibberella moniliformis was isolated from “Elotes Occidental 1” at 83.3%, while the least frequent isolate (19.4%) from “Pepitilla” was Sarocladium strictum, which was recorded in three samples at the low values of 11.1% and 2.8% for races “Arrocillo 2” and “Pepitilla”, respectively; Talaromyces variabilis was found in two samples at 11.1% and 2.8% from “Arrocillo 2” and “Cónico pepitilla”, respectively; Stenocarpella macrospora was isolated at 72.2% from “Pepitilla”. Aspergillus flavus was obtained from “Cónico Pepitilla” at 16.7%, while Setosphaeria turcica and Emericella sp. were less frequently isolated. Considering asymptomatic seeds of race “Cónico pepitilla”, F. oxysporum was isolated at 8.3%, Fusarium acuminatum at 8.3% and Gibberella moniliformis at 41.7%; from asymptomatic seeds of “Olotillo 1” and “Olotillo 2”, Phomopsis sp. was isolated at 50% and Rhizoctonia solani at 50%, respectively. In the present study, the fungi F. oxysporum, Phomopsis sp., G. moniliformis and F. graminearum were most frequently associated with Creole corn seeds.