Crown and Root Rot Complexes of Alfalfa
Crown rot and root rot are persistent diseases of alfalfa worldwide. Although single pathogens can cause crown and root rot, several organisms often interact to form disease complexes such as Fusarium, Pythium, and Rhizoctonia spp., as well as nematodes and bacteria. General symptoms include brown discoloration and tissue death within the crown and root cortex. The central core of the plant may rot and become hollow. As disease progresses, vigor is reduced, and stunting, wilting, and plant death occurs. Affected plants may show asymmetrical growth.
Tissue death within the crown and root cortex characteristic of crown and root rot.
Craig Grau
The pathogens that form crown and root rot complexes may survive in soil or on plant residue. Plant stress or injury from adverse weather, insect feeding, inadequate soil nutrients, frequent harvests, foliar disease, vehicle traffic favors disease development.
Reduce crop stress and ensure vigorous plant growth through cultural practices such as maintaining proper soil nutrient levels, timely harvests, managing insects and planting appropriate pathogen- and insect-resistant alfalfa cultivars.
Prepared and reviewed by the Alfalfa Pest Management Working Group.
Tissue death within the crown and root cortex characteristic of crown and root rot.
Gallery images courtesy Craig Grau.
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