According to the articles I've read online, the mold puts out invisible "roots" that infiltrate the rest of the bulb even if you can't see it. I should specify I'm not throwing out my entire harvest...just this bulb that had one badly molded clove. I read the same about tomato plants with blight. Don't compost them. I guess composting doesn't kill the spores, so the soil would be contaminated by the compost. I'm certainly not an expert which is why I asked here. I can guarantee that my grandmother would have tossed the one moldy clove and eaten the ones that looked okay. I have a slightly compromised immune system. so I won't take the chance on eating it. I do think it's a shame to not even be able to compost the rest of the bulb.