Colletotrichum graminicola from leaves or stalks are similarly aggressive in cross-tissue inoculation of five maize hybrids

Abstract

The objective of this study was to assess whether the source of Colletotrichum graminicola isolates (leaves or stalks) affects anthracnose leaf blight (ALB) and anthracnose stalk rot (ASR) development. Ten greenhouse experiments were conducted, five to evaluate ALB and five to evaluate ASR, each using a distinct commercial maize hybrid varying in reaction to the diseases. A collection of 20 isolates, 10 recovered from symptomatic leaves, and ten from symptomatic stalks, were inoculated on the five hybrids. Maize leaves were inoculated 15 days after planting and ALB was evaluated 15 days after inoculation. Stalks were inoculated at pre-tasseling and ASR evaluated 30 days later. Both ALB and ASR were assessed using a 0–5 ordinal scale. No differences in ALB and ASR severity were observed between the two groups of isolates regardless of hybrid based on the non-parametric test. The ability of C. graminicola to infect and cause anthracnose on any part of the maize plant seemed to not depend on the source of the isolate.