DISEASES OF ALFALFA - ROOT ROTS

In contrast, Aphanomyces. euteiches is a lateral root nibbler, invading the alfalfa plant’s fibrous root system and leading to extensive root pruning (see plants in photo). While this pruning may cause stunting and lack of vigor in the plant, it rarely causes plant death. Keep in mind that alfalfa varieties differ in the number of lateral roots that they normally produce. Therefore you need to know what a variety’s “normal” root system looks like before you can accurately assess if that root system has been pruned.

As noted earlier Phytophthora medicaginis and A. euteiches grow and reproduce most readily under wet soil conditions. Therefore think of these pathogens if there have been heavy rains preceding symptom develop, or if alfalfa is being grown in heavy soils that tend to retain water.