Amorphophallus paeoniifolius tubers are rich in starch and are consumed as vegetables after boiling or baking. Cynodon dactylon (Bermudagrass) a common weed in cultivated as well as non-cultivated fields was found invading on the underground tubers during dry season. It was found that Cynodon dactylon injected needle-sharp root-like runners produced at the nodes into the tubers. In some tubers Cynodon dactylon root-like runners entered inside up to 15 em depth. Necrotic lesions were developed in the infected tubers around the Cynodon dactylon rootlike runners. The dry matter content of Cynodon-infested tubers was decreased due to decrease of starch and total sugars. The anti-nutritional factor, oxalic acid content, was increased in Cynodon-infested tubers. Cynodon dactylon rendered Amorpbopballus tubers unfit for human consumption.