DISEASES OF ALFALFA
ROOT ROT

In addition to causing seedling stand problems, Phytophthora megasperma and Aphanomyces euteiches can also cause root rot problems in older plants. Once again, P. megasperma tends to be the more aggressive of the two pathogens. It invades the taproot, causing lesions (diseased areas) on the main root system and subsequent disintegration of root tissue (see black arrows in the photo). This pathogen can eventually kill the alfalfa plant.