Diplodia ear rot

Stenocarpella maydis (previously known as Diplodia maydis) is a significant fungal plant pathogen classified within the kingdom Fungi. It is primarily known as the causative agent of Diplodia ear rot and stalk rot, which are among the most destructive diseases affecting maize crops globally, particularly in warm and humid agricultural regions.

The disease affects multiple parts of the maize plant, including roots, lower stalks, and ears. The most characteristic symptom is the development of a dense, white mycelial growth on the ear, typically starting at the base. Infected ears eventually become lightweight, shriveled, and may exhibit small, black reproductive structures called pycnidia on the husks and kernels.

The pathogen's life cycle revolves around its ability to overwinter in infested crop debris left on the soil surface. During the growing season, pycnidia produce conidia (spores) that are dispersed by rain splashing or wind onto healthy plants. Infection typically occurs through silks or wounds on stalks, allowing the fungus to colonize the host tissues.

The development of Stenocarpella maydis is heavily dependent on environmental conditions, specifically temperature and moisture levels. Warm temperatures ranging between 20°C and 30°C, combined with prolonged periods of wet weather after pollination, significantly increase the risk of disease outbreaks and the severity of infection in the field.

Effective management of Diplodia ear rot requires an integrated approach to minimize inoculum levels and host vulnerability. Key strategies include the implementation of crop rotation to break the disease cycle, the use of tillage practices to bury infected residue, selecting resistant or tolerant maize hybrids, and the application of fungicide seed treatments to protect seedlings during the early stages of development.