VIEW ARTICLE

Cytology and Histology

Scanning EM Studies on the Colonization of Dent Corn by Aspergillus flavus. Stephen F. Marsh, Graduate research assistant, Department of Plant Pathology, North Carolina State University, Raleigh 27650; Gary A. Payne, assistant professor, Department of Plant Pathology, North Carolina State University, Raleigh 27650. Phytopathology 74:557-561. Accepted for publication 24 January 1984. Copyright 1984 The American Phytopathological Society. DOI: 10.1094/Phyto-74-557.

Colonization of silks and kernels of preharvest corn by Aspergillus flavus was examined by scanning electron microscopy (SEM). Silks of three physiological ages (green unpollinated, yellow-brown, brown) were examined 4, 8, and 24 hr after inoculation. The few conidia that germinated on unpollinated silks failed to colonize the silks. Conidia on yellow-brown silks germinated in 4- 8 hr and extensively colonized the silks, especially near pollen grains, where thick hyphal mats produced numerous conidiophores. Indirect and direct penetration of silk was observed. Conidia germinated on brown silks but hyphal growth was sparse. SEM observation of split kernels from ears inoculated with A. flavus (inoculum applied to kernels) showed early hyphal growth localized in the tip cap.