Cylindrocladium Black Rot of Peanut and Red Crown Rot of Soybean Caused by <i>Calonectria ilicicola</i>: A Review

<i>Calonectria ilicicola</i> (anamorph: <i>Cylindrocladium parasiticum</i>) is a globally important soil-borne fungal pathogen, causing Cylindrocladium black rot (CBR) in peanuts (<i>Arachis hypogaea</i>) and red crown rot (RCR) in soybeans (<i>Glycine max</i>), two legume crops central to global food security. Under favorable conditions, these diseases can cause yield losses of 15–50%, with severe epidemics causing substantial economic damage. A defining feature of <i>C. ilicicola</i> is its production of melanized microsclerotia that persist in soil for up to seven years, complicating long-term disease management across major production regions worldwide. The recent spread of RCR into the U.S. Midwest highlights the adaptive potential of the pathogen and underscores the urgency of updated, integrated control strategies. This review synthesizes current knowledge on disease symptoms, pathogen biology, the life cycle, isolation techniques, and molecular diagnostics, with particular emphasis on recent genomic and multiomics advances. These approaches have identified key virulence-associated genes and core pathogenicity factors, providing new insights into host–pathogen interactions and enabling more targeted resistance breeding through marker-assisted selection and the use of wild germplasm. We critically evaluate integrated disease management strategies, including host resistance, chemical and biological control, cultural practices, and physical interventions, highlighting their complementarities and limitations. By integrating classical pathology with emerging molecular and ecological innovations, this review provides a comprehensive background for developing more effective and sustainable management approaches for CBR and RCR.