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Published on
17.03.25
Cowpea, a vital legume crop in sub-Saharan Africa, nourishes millions and supports rural economies. Yet, its productivity is under siege by a persistent enemy: cowpea anthracnose disease (CAD). Recent research has identified the causal agents of CAD in Nigeria, challenging previous understanding of the disease in the country.
Historically, Colletotrichum lindemuthianum and C. destructivum were considered the primary pathogens responsible for CAD in Nigeria. However, researchers from IITA, Obafemi Awolowo University, and the University of Ibadan conducted an in-depth investigation using traditional and molecular diagnostic methods. Their study, spanning four Nigerian states, led to a significant discovery: two species, C. chrysophilum, and C. siamense, are the causal agents of CAD in Nigeria. This is the first global report identifying these species as CAD pathogens.
Relying on morphological classification to assign isolates to their corresponding species often leads to misclassification due to similarities among species. By sequencing six key genes (ITS, ACT, GADPH, TUB, ApMat, and CAL) from Colletotrichum isolates collected in cowpea fields in the study, the researchers were able to correctly classify the obtained isolates as C. chrysophilum and C. siamense, both belonging to the C. gloeosporioides species complex. Unlike previous reports, C. lindemuthianum and C. destructivum were undetected in the studied regions.