PCR characterization of diplodiosis-causing Stenocarpella species from corn in Argentina

Abstract

Stenocarpella maydis and S. macrospora are pathogenic fungi that cause Diplodia stalk rot and ear rot in maize. In Argentina, Brazil, South Africa, and Australia, S. maydis in feed causes neuromycotoxicosis in cattle and sheep. In Argentina, we analyzed corn samples from cattle feed without visible fungus and from corn fields in which animals had clinical signs of diplodiosis. Stenocarpella spp. were identified and characterized with conventional PCR. We did not detect S. macrospora in 6 samples; results in another sample were inconclusive. We identified S. maydis in the 5 corn samples consumed by animals that developed diplodiosis, suggesting that S. maydis may cause the disease in Argentina. Direct PCR testing of corn is an efficient method for the identification of S. maydis in feed. This testing could enable rapid decision-making in the field by predicting the onset of diplodiosis, thereby helping to prevent this mycotoxicosis.